At July 17 C.

Base/Class/Excel.py

@@ -3,11 +3,11 @@ from openpyxl.cell import MergedCell
 from openpyxl.utils import get_column_letter, column_index_from_string
 
 
-def colIndexFromString(string):
+def col_index_from_string(string):
     return column_index_from_string(string) - 1
 
 
-def rowIndexFromString(string):
+def row_index_from_string(string):
     return int(string) - 1
 
 
@@ -31,7 +31,7 @@ class Excel:
             raise Exception('文件已经打开 | File has been opened.')
         if filename:
             self.__filename__ = os.path.abspath(filename)
-            self.__workbook__ = openpyxl.load_workbook(filename, read_only=read_only)
+            self.__workbook__ = openpyxl.load_workbook(filename, read_only=False)
             self.__autosave__ = auto_save
             self.select(sheet)
         else:
@@ -181,6 +181,8 @@ class Excel:
         :param filename: 另存为的文件路径，默认为保存文件 | The file path to save as, the default is to save the file.
         :return:
         """
+        if filename is None and self.__readonly__:
+            raise Exception('只读模式 | Read-only')
         self.__workbook__.save(filename or self.__filename__)
         return True
 

Base/Class/Json.py

@@ -1,8 +1,8 @@
 import json
 
 
-def json_encode(data, indent=None):
-    return json.dumps(data, indent=indent)
+def json_encode(data, indent=None, unicode=True):
+    return json.dumps(data, indent=indent, ensure_ascii=unicode)
 
 
 def json_decode(data):
@@ -17,4 +17,5 @@ if __name__ == '__main__':
     """
     print(json_encode(data_encode))
     print(json_encode(data_encode, indent=4))
+    print(json_encode(data_encode, indent=4, unicode=False))
     print(json_decode(data_decode))

Base/Class/Yaml.py

@@ -1,8 +1,8 @@
 import yaml
 
 
-def yaml_encode(data, indent=None):
-    return yaml.dump(data, indent=indent, allow_unicode=True, sort_keys=False)
+def yaml_encode(data, indent=None, unicode=False):
+    return yaml.dump(data, indent=indent, allow_unicode=not unicode, sort_keys=False)
 
 
 def yaml_decode(data):
@@ -23,4 +23,5 @@ if __name__ == '__main__':
       b: 5
     """
     print(yaml_encode(data_encode))
+    print(yaml_encode(data_encode, unicode=True))
     print(yaml_decode(data_decode))

Business/Class/ExcelUtils.py

@@ -0,0 +1,46 @@
+from Base.Class.Excel import *
+
+
+def read_view_dict(filename=None, sheet=None,
+                   area='', from_col=0, from_row=0, to_col=0, to_row=0, fields=None,
+                   auto_truncate=False):
+    view = Excel().open(filename=filename, read_only=True).select(sheet).cellGetView(
+        area=area, from_col=from_col, from_row=from_row, to_col=to_col, to_row=to_row
+    )
+    tabs = []
+    try:
+        for i in range(len(view[0])):
+            try:
+                if not isinstance(fields[i], str):
+                    raise TypeError()
+                tabs.append(fields[i])
+            except:
+                tabs.append('col' + str(i))
+    except:
+        pass
+    if len(tabs) != len(set(tabs)):
+        raise Exception('字段存在重复项目 | There are duplicates in the field')
+    data = []
+    for line in view:
+        if auto_truncate:
+            none_number = 0
+            for value in line:
+                if value is None:
+                    none_number += 1
+            if len(line) == none_number:
+                break
+        line_dict = {}
+        for i in range(len(line)):
+            line_dict[tabs[i]] = line[i]
+        data.append(line_dict)
+    return data
+
+
+
+
+
+
+if __name__ == '__main__':
+    from Base.Class.Json import *
+    from Base.Class.Yaml import *
+    print(json_encode(read_view_dict(filename='../../example.xlsx', sheet='表一', area='A2:F530', fields=['id','name','age','city','mark1','mark2'], auto_truncate=True), 4, False))

Business/Class/JsonOrYaml.py

@@ -0,0 +1,12 @@
+from Base.Class.Json import *
+from Base.Class.Yaml import *
+
+
+def auto_decode(data):
+    try:
+        try:
+            return json_decode(data)
+        except:
+            return yaml_decode(data)
+    except:
+        raise Exception('非Json或Yaml数据格式 | String in not a Json or Yaml format.')

Runner/API/DefaultRunner.py

@@ -0,0 +1,138 @@
+from Business.Class.ExcelUtils import *
+from Business.Class.JsonOrYaml import *
+from Base.Class.Http import *
+
+from Base.Debug.Decorator import *
+import pandas as pd
+from pandas.core.frame import DataFrame
+
+
+class RunTest:
+    # 全局变量列表
+    _g_ = {}
+    # 局部变量列表
+    _l_ = {}
+    _r_ = None
+    # 日志报告输出路径
+    fileLst = {"log": None, "report": None}
+    # 执行用例级别列表
+    caseLvl = None
+    viewLst = None
+    cellLst = None
+
+    def __init__(self, *args, **kwargs):
+        self._init(*args, **kwargs)
+
+    def _setRequestMode(self, mode):
+        self._r_ = [Request, Session][mode]()
+        return True
+
+    def _setOutput(self, **kwargs):
+        import os
+        for key in kwargs:
+            self.fileLst[key] = kwargs[key] and os.path.abspath(kwargs[key])
+        return True
+
+    def _matLevelThatRun(self, lv=None):
+        if lv is None:
+            return False
+        if self.caseLvl is None:
+            return True
+        return lv in self.caseLvl
+
+    def _init(self, workbook, data='数据配置', case='测试用例', level=None, log=None, report=None):
+        init = Excel().open(workbook, read_only=True)
+        init_data = auto_decode(init.select(data).cellGet(0, 0))
+        init_case = auto_decode(init.select(case).cellGet(0, 0))
+        self.cellLst = {
+            "ITEM":
+                auto_decode(init.select(case).cellGet(cell=init_case["fixeds"]["item"])),
+            "MODE":
+                auto_decode(init.select(case).cellGet(cell=init_case["fixeds"]["mode"]))
+        }
+        self.viewLst = {
+            "HTTP":
+                DataFrame(read_view_dict(filename=workbook, sheet=data,
+                area=init_data["tables"]["http"]["views"], fields=init_data["tables"]["http"]["field"],
+                auto_truncate=True)),
+            "BASE":
+                DataFrame(read_view_dict(filename=workbook, sheet=data,
+                area=init_data["tables"]["base"]["views"],
+                fields=init_data["tables"]["base"]["field"],
+                auto_truncate=True)),
+            "DATA":
+                DataFrame(read_view_dict(filename=workbook, sheet=data,
+                area=init_data["tables"]["data"]["views"],
+                fields=init_data["tables"]["data"]["field"],
+                auto_truncate=True)),
+            "CASE":
+                DataFrame(read_view_dict(filename=workbook, sheet=case,
+                area=init_case["tables"]["case"]["views"],
+                fields=init_case["tables"]["case"]["field"],
+                auto_truncate=True)),
+        }
+        init.exit()
+        self.levels(level)
+        self.report(log=log, report=report)
+        self._setRequestMode(self.cellLst["MODE"] in ['会话模式', 'Session'])
+        return True
+
+    def _run_mini(self, case_dict):
+        print(case_dict)
+
+
+
+
+
+
+
+
+
+
+
+
+
+    def report(self, log=None, report=None):
+        self._setOutput(log=log, report=report)
+        return self
+
+    def levels(self, level=None):
+        if isinstance(level, (list, tuple, str)):
+            self.caseLvl = level
+        return self
+
+
+
+if __name__ == '__main__':
+    r = RunTest('D:/Desktop/接口自动化测试用例.xlsx','数据配置','测试用例', level=['P0'], log='./1.txt', report='./1.html')
+    r._run_mini(r.viewLst["CASE"].loc[0].to_dict())
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+# print(tables)
+# print(json_encode(tables, indent=4, unicode=False))
+# print(json_encode(tables["HTTP"], indent=4, unicode=False))
+# data = tables["HTTP"]
+# data = data.where((data["Env"] == '测试环境') & (data["Name"] == 'HTTP0'), inplace=False).dropna(how='all')
+# print(data.loc[:,"Name"])

main7.py

@@ -9,6 +9,6 @@ if __name__ == '__main__':
     # print(excel.cellGetView('A1:C9'))
     # print(excel.cellGetView('1:9'))
 
-    print(excel.cellGetView('1:9'))
+    print(excel.cellGetView('D5:F12'))
     # excel.save()
     # print(excel.cellGetView(area='F6:F11'))

run.py

@@ -0,0 +1,24 @@
+import os, time
+from HTMLTestRunner import HTMLTestRunner
+from test_case import TestDemo
+import unittest
+
+
+base_path = os.path.dirname(__file__)
+report_path = base_path
+report_filename = os.path.join(report_path, 'report.html')
+
+case_suite = unittest.TestSuite()
+case_suite.addTest(TestDemo('test_one'))
+case_suite.addTest(TestDemo('test_two'))
+case_suite.addTest(TestDemo('test_tre'))
+
+
+def start():
+    with open(report_filename, 'wb') as f:
+        runner = HTMLTestRunner(stream=f, title='自动化测试报告', verbosity=2, description='描述', tester='Tester')
+        runner.run(case_suite)
+
+
+if __name__ == '__main__':
+    start()

test_case.py

@@ -0,0 +1,23 @@
+import unittest
+
+
+class TestDemo(unittest.TestCase):
+    def test_one(self):
+        '''
+        哈哈
+        :return:
+        '''
+        assert 1 == 1
+
+    def test_two(self):
+        '''
+        呵呵
+        :return:
+        '''
+        assert 'H' in 'Hello!'
+
+    def test_tre(self):
+        assert 5 == 10, '断言失败'
+
+
+TestDemo.test_tre.__doc__ = "测试吖"

venv/Lib/site-packages/pip-21.1.2.dist-info/INSTALLER

@@ -1 +0,0 @@
-pip

venv/Lib/site-packages/pip-21.1.2.dist-info/LICENSE.txt

@@ -1,20 +0,0 @@
-Copyright (c) 2008-2021 The pip developers (see AUTHORS.txt file)
-
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

venv/Lib/site-packages/pip-21.1.2.dist-info/METADATA

@@ -1,91 +0,0 @@
-Metadata-Version: 2.1
-Name: pip
-Version: 21.1.2
-Summary: The PyPA recommended tool for installing Python packages.
-Home-page: https://pip.pypa.io/
-Author: The pip developers
-Author-email: distutils-sig@python.org
-License: MIT
-Project-URL: Documentation, https://pip.pypa.io
-Project-URL: Source, https://github.com/pypa/pip
-Project-URL: Changelog, https://pip.pypa.io/en/stable/news/
-Platform: UNKNOWN
-Classifier: Development Status :: 5 - Production/Stable
-Classifier: Intended Audience :: Developers
-Classifier: License :: OSI Approved :: MIT License
-Classifier: Topic :: Software Development :: Build Tools
-Classifier: Programming Language :: Python
-Classifier: Programming Language :: Python :: 3
-Classifier: Programming Language :: Python :: 3 :: Only
-Classifier: Programming Language :: Python :: 3.6
-Classifier: Programming Language :: Python :: 3.7
-Classifier: Programming Language :: Python :: 3.8
-Classifier: Programming Language :: Python :: 3.9
-Classifier: Programming Language :: Python :: Implementation :: CPython
-Classifier: Programming Language :: Python :: Implementation :: PyPy
-Requires-Python: >=3.6
-
-pip - The Python Package Installer
-==================================
-
-.. image:: https://img.shields.io/pypi/v/pip.svg
-   :target: https://pypi.org/project/pip/
-
-.. image:: https://readthedocs.org/projects/pip/badge/?version=latest
-   :target: https://pip.pypa.io/en/latest
-
-pip is the `package installer`_ for Python. You can use pip to install packages from the `Python Package Index`_ and other indexes.
-
-Please take a look at our documentation for how to install and use pip:
-
-* `Installation`_
-* `Usage`_
-
-We release updates regularly, with a new version every 3 months. Find more details in our documentation:
-
-* `Release notes`_
-* `Release process`_
-
-In pip 20.3, we've `made a big improvement to the heart of pip`_; `learn more`_. We want your input, so `sign up for our user experience research studies`_ to help us do it right.
-
-**Note**: pip 21.0, in January 2021, removed Python 2 support, per pip's `Python 2 support policy`_. Please migrate to Python 3.
-
-If you find bugs, need help, or want to talk to the developers, please use our mailing lists or chat rooms:
-
-* `Issue tracking`_
-* `Discourse channel`_
-* `User IRC`_
-
-If you want to get involved head over to GitHub to get the source code, look at our development documentation and feel free to jump on the developer mailing lists and chat rooms:
-
-* `GitHub page`_
-* `Development documentation`_
-* `Development mailing list`_
-* `Development IRC`_
-
-Code of Conduct
----------------
-
-Everyone interacting in the pip project's codebases, issue trackers, chat
-rooms, and mailing lists is expected to follow the `PSF Code of Conduct`_.
-
-.. _package installer: https://packaging.python.org/guides/tool-recommendations/
-.. _Python Package Index: https://pypi.org
-.. _Installation: https://pip.pypa.io/en/stable/installing.html
-.. _Usage: https://pip.pypa.io/en/stable/
-.. _Release notes: https://pip.pypa.io/en/stable/news.html
-.. _Release process: https://pip.pypa.io/en/latest/development/release-process/
-.. _GitHub page: https://github.com/pypa/pip
-.. _Development documentation: https://pip.pypa.io/en/latest/development
-.. _made a big improvement to the heart of pip: https://pyfound.blogspot.com/2020/11/pip-20-3-new-resolver.html
-.. _learn more: https://pip.pypa.io/en/latest/user_guide/#changes-to-the-pip-dependency-resolver-in-20-3-2020
-.. _sign up for our user experience research studies: https://pyfound.blogspot.com/2020/03/new-pip-resolver-to-roll-out-this-year.html
-.. _Python 2 support policy: https://pip.pypa.io/en/latest/development/release-process/#python-2-support
-.. _Issue tracking: https://github.com/pypa/pip/issues
-.. _Discourse channel: https://discuss.python.org/c/packaging
-.. _Development mailing list: https://mail.python.org/mailman3/lists/distutils-sig.python.org/
-.. _User IRC: https://webchat.freenode.net/?channels=%23pypa
-.. _Development IRC: https://webchat.freenode.net/?channels=%23pypa-dev
-.. _PSF Code of Conduct: https://github.com/pypa/.github/blob/main/CODE_OF_CONDUCT.md
-
-

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venv/Lib/site-packages/pip-21.1.2.dist-info/WHEEL

@@ -1,5 +0,0 @@
-Wheel-Version: 1.0
-Generator: bdist_wheel (0.36.2)
-Root-Is-Purelib: true
-Tag: py3-none-any
-

venv/Lib/site-packages/pip-21.1.2.dist-info/entry_points.txt

@@ -1,5 +0,0 @@
-[console_scripts]
-pip = pip._internal.cli.main:main
-pip3 = pip._internal.cli.main:main
-pip3.8 = pip._internal.cli.main:main
-

venv/Lib/site-packages/pip-21.1.2.dist-info/top_level.txt

@@ -1 +0,0 @@
-pip

venv/Lib/site-packages/pip/__init__.py

@@ -1,10 +1,9 @@
 from typing import List, Optional
 
-__version__ = "21.1.2"
+__version__ = "22.1.2"
 
 
-def main(args=None):
-    # type: (Optional[List[str]]) -> int
+def main(args: Optional[List[str]] = None) -> int:
     """This is an internal API only meant for use by pip's own console scripts.
 
     For additional details, see https://github.com/pypa/pip/issues/7498.

venv/Lib/site-packages/pip/_internal/__init__.py

@@ -1,10 +1,14 @@
 from typing import List, Optional
 
 import pip._internal.utils.inject_securetransport  # noqa
+from pip._internal.utils import _log
+
+# init_logging() must be called before any call to logging.getLogger()
+# which happens at import of most modules.
+_log.init_logging()
 
 
-def main(args=None):
-    # type: (Optional[List[str]]) -> int
+def main(args: (Optional[List[str]]) = None) -> int:
     """This is preserved for old console scripts that may still be referencing
     it.
 

venv/Lib/site-packages/pip/_internal/build_env.py

@@ -11,14 +11,16 @@ import zipfile
 from collections import OrderedDict
 from sysconfig import get_paths
 from types import TracebackType
-from typing import TYPE_CHECKING, Iterable, Iterator, List, Optional, Set, Tuple, Type
+from typing import TYPE_CHECKING, Generator, Iterable, List, Optional, Set, Tuple, Type
 
 from pip._vendor.certifi import where
-from pip._vendor.pkg_resources import Requirement, VersionConflict, WorkingSet
+from pip._vendor.packaging.requirements import Requirement
+from pip._vendor.packaging.version import Version
 
 from pip import __file__ as pip_location
 from pip._internal.cli.spinners import open_spinner
 from pip._internal.locations import get_platlib, get_prefixed_libs, get_purelib
+from pip._internal.metadata import get_default_environment, get_environment
 from pip._internal.utils.subprocess import call_subprocess
 from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
 
@@ -29,20 +31,18 @@ logger = logging.getLogger(__name__)
 
 
 class _Prefix:
-
-    def __init__(self, path):
-        # type: (str) -> None
+    def __init__(self, path: str) -> None:
         self.path = path
         self.setup = False
         self.bin_dir = get_paths(
-            'nt' if os.name == 'nt' else 'posix_prefix',
-            vars={'base': path, 'platbase': path}
-        )['scripts']
+            "nt" if os.name == "nt" else "posix_prefix",
+            vars={"base": path, "platbase": path},
+        )["scripts"]
         self.lib_dirs = get_prefixed_libs(path)
 
 
 @contextlib.contextmanager
-def _create_standalone_pip() -> Iterator[str]:
+def _create_standalone_pip() -> Generator[str, None, None]:
     """Create a "standalone pip" zip file.
 
     The zip file's content is identical to the currently-running pip.
@@ -68,22 +68,18 @@ def _create_standalone_pip() -> Iterator[str]:
 
 
 class BuildEnvironment:
-    """Creates and manages an isolated environment to install build deps
-    """
+    """Creates and manages an isolated environment to install build deps"""
 
-    def __init__(self):
-        # type: () -> None
-        temp_dir = TempDirectory(
-            kind=tempdir_kinds.BUILD_ENV, globally_managed=True
-        )
+    def __init__(self) -> None:
+        temp_dir = TempDirectory(kind=tempdir_kinds.BUILD_ENV, globally_managed=True)
 
         self._prefixes = OrderedDict(
             (name, _Prefix(os.path.join(temp_dir.path, name)))
-            for name in ('normal', 'overlay')
+            for name in ("normal", "overlay")
         )
 
-        self._bin_dirs = []  # type: List[str]
-        self._lib_dirs = []  # type: List[str]
+        self._bin_dirs: List[str] = []
+        self._lib_dirs: List[str] = []
         for prefix in reversed(list(self._prefixes.values())):
             self._bin_dirs.append(prefix.bin_dir)
             self._lib_dirs.extend(prefix.lib_dirs)
@@ -94,12 +90,15 @@ class BuildEnvironment:
         system_sites = {
             os.path.normcase(site) for site in (get_purelib(), get_platlib())
         }
-        self._site_dir = os.path.join(temp_dir.path, 'site')
+        self._site_dir = os.path.join(temp_dir.path, "site")
         if not os.path.exists(self._site_dir):
             os.mkdir(self._site_dir)
-        with open(os.path.join(self._site_dir, 'sitecustomize.py'), 'w') as fp:
-            fp.write(textwrap.dedent(
-                '''
+        with open(
+            os.path.join(self._site_dir, "sitecustomize.py"), "w", encoding="utf-8"
+        ) as fp:
+            fp.write(
+                textwrap.dedent(
+                    """
                 import os, site, sys
 
                 # First, drop system-sites related paths.
@@ -122,89 +121,98 @@ class BuildEnvironment:
                 for path in {lib_dirs!r}:
                     assert not path in sys.path
                     site.addsitedir(path)
-                '''
-            ).format(system_sites=system_sites, lib_dirs=self._lib_dirs))
+                """
+                ).format(system_sites=system_sites, lib_dirs=self._lib_dirs)
+            )
 
-    def __enter__(self):
-        # type: () -> None
+    def __enter__(self) -> None:
         self._save_env = {
             name: os.environ.get(name, None)
-            for name in ('PATH', 'PYTHONNOUSERSITE', 'PYTHONPATH')
+            for name in ("PATH", "PYTHONNOUSERSITE", "PYTHONPATH")
         }
 
         path = self._bin_dirs[:]
-        old_path = self._save_env['PATH']
+        old_path = self._save_env["PATH"]
         if old_path:
             path.extend(old_path.split(os.pathsep))
 
         pythonpath = [self._site_dir]
 
-        os.environ.update({
-            'PATH': os.pathsep.join(path),
-            'PYTHONNOUSERSITE': '1',
-            'PYTHONPATH': os.pathsep.join(pythonpath),
-        })
+        os.environ.update(
+            {
+                "PATH": os.pathsep.join(path),
+                "PYTHONNOUSERSITE": "1",
+                "PYTHONPATH": os.pathsep.join(pythonpath),
+            }
+        )
 
     def __exit__(
         self,
-        exc_type,  # type: Optional[Type[BaseException]]
-        exc_val,  # type: Optional[BaseException]
-        exc_tb  # type: Optional[TracebackType]
-    ):
-        # type: (...) -> None
+        exc_type: Optional[Type[BaseException]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> None:
         for varname, old_value in self._save_env.items():
             if old_value is None:
                 os.environ.pop(varname, None)
             else:
                 os.environ[varname] = old_value
 
-    def check_requirements(self, reqs):
-        # type: (Iterable[str]) -> Tuple[Set[Tuple[str, str]], Set[str]]
+    def check_requirements(
+        self, reqs: Iterable[str]
+    ) -> Tuple[Set[Tuple[str, str]], Set[str]]:
         """Return 2 sets:
-            - conflicting requirements: set of (installed, wanted) reqs tuples
-            - missing requirements: set of reqs
+        - conflicting requirements: set of (installed, wanted) reqs tuples
+        - missing requirements: set of reqs
         """
         missing = set()
         conflicting = set()
         if reqs:
-            ws = WorkingSet(self._lib_dirs)
-            for req in reqs:
-                try:
-                    if ws.find(Requirement.parse(req)) is None:
-                        missing.add(req)
-                except VersionConflict as e:
-                    conflicting.add((str(e.args[0].as_requirement()),
-                                     str(e.args[1])))
+            env = (
+                get_environment(self._lib_dirs)
+                if hasattr(self, "_lib_dirs")
+                else get_default_environment()
+            )
+            for req_str in reqs:
+                req = Requirement(req_str)
+                # We're explicitly evaluating with an empty extra value, since build
+                # environments are not provided any mechanism to select specific extras.
+                if req.marker is not None and not req.marker.evaluate({"extra": ""}):
+                    continue
+                dist = env.get_distribution(req.name)
+                if not dist:
+                    missing.add(req_str)
+                    continue
+                if isinstance(dist.version, Version):
+                    installed_req_str = f"{req.name}=={dist.version}"
+                else:
+                    installed_req_str = f"{req.name}==={dist.version}"
+                if not req.specifier.contains(dist.version, prereleases=True):
+                    conflicting.add((installed_req_str, req_str))
+                # FIXME: Consider direct URL?
         return conflicting, missing
 
     def install_requirements(
         self,
-        finder,  # type: PackageFinder
-        requirements,  # type: Iterable[str]
-        prefix_as_string,  # type: str
-        message  # type: str
-    ):
-        # type: (...) -> None
+        finder: "PackageFinder",
+        requirements: Iterable[str],
+        prefix_as_string: str,
+        *,
+        kind: str,
+    ) -> None:
         prefix = self._prefixes[prefix_as_string]
         assert not prefix.setup
         prefix.setup = True
         if not requirements:
             return
         with contextlib.ExitStack() as ctx:
-            # TODO: Remove this block when dropping 3.6 support. Python 3.6
-            # lacks importlib.resources and pep517 has issues loading files in
-            # a zip, so we fallback to the "old" method by adding the current
-            # pip directory to the child process's sys.path.
-            if sys.version_info < (3, 7):
-                pip_runnable = os.path.dirname(pip_location)
-            else:
-                pip_runnable = ctx.enter_context(_create_standalone_pip())
+            pip_runnable = ctx.enter_context(_create_standalone_pip())
             self._install_requirements(
                 pip_runnable,
                 finder,
                 requirements,
                 prefix,
-                message,
+                kind=kind,
             )
 
     @staticmethod
@@ -213,74 +221,84 @@ class BuildEnvironment:
         finder: "PackageFinder",
         requirements: Iterable[str],
         prefix: _Prefix,
-        message: str,
+        *,
+        kind: str,
     ) -> None:
-        args = [
-            sys.executable, pip_runnable, 'install',
-            '--ignore-installed', '--no-user', '--prefix', prefix.path,
-            '--no-warn-script-location',
-        ]  # type: List[str]
+        args: List[str] = [
+            sys.executable,
+            pip_runnable,
+            "install",
+            "--ignore-installed",
+            "--no-user",
+            "--prefix",
+            prefix.path,
+            "--no-warn-script-location",
+        ]
         if logger.getEffectiveLevel() <= logging.DEBUG:
-            args.append('-v')
-        for format_control in ('no_binary', 'only_binary'):
+            args.append("-v")
+        for format_control in ("no_binary", "only_binary"):
             formats = getattr(finder.format_control, format_control)
-            args.extend(('--' + format_control.replace('_', '-'),
-                         ','.join(sorted(formats or {':none:'}))))
+            args.extend(
+                (
+                    "--" + format_control.replace("_", "-"),
+                    ",".join(sorted(formats or {":none:"})),
+                )
+            )
 
         index_urls = finder.index_urls
         if index_urls:
-            args.extend(['-i', index_urls[0]])
+            args.extend(["-i", index_urls[0]])
             for extra_index in index_urls[1:]:
-                args.extend(['--extra-index-url', extra_index])
+                args.extend(["--extra-index-url", extra_index])
         else:
-            args.append('--no-index')
+            args.append("--no-index")
         for link in finder.find_links:
-            args.extend(['--find-links', link])
+            args.extend(["--find-links", link])
 
         for host in finder.trusted_hosts:
-            args.extend(['--trusted-host', host])
+            args.extend(["--trusted-host", host])
         if finder.allow_all_prereleases:
-            args.append('--pre')
+            args.append("--pre")
         if finder.prefer_binary:
-            args.append('--prefer-binary')
-        args.append('--')
+            args.append("--prefer-binary")
+        args.append("--")
         args.extend(requirements)
         extra_environ = {"_PIP_STANDALONE_CERT": where()}
-        with open_spinner(message) as spinner:
-            call_subprocess(args, spinner=spinner, extra_environ=extra_environ)
+        with open_spinner(f"Installing {kind}") as spinner:
+            call_subprocess(
+                args,
+                command_desc=f"pip subprocess to install {kind}",
+                spinner=spinner,
+                extra_environ=extra_environ,
+            )
 
 
 class NoOpBuildEnvironment(BuildEnvironment):
-    """A no-op drop-in replacement for BuildEnvironment
-    """
+    """A no-op drop-in replacement for BuildEnvironment"""
 
-    def __init__(self):
-        # type: () -> None
+    def __init__(self) -> None:
         pass
 
-    def __enter__(self):
-        # type: () -> None
+    def __enter__(self) -> None:
         pass
 
     def __exit__(
         self,
-        exc_type,  # type: Optional[Type[BaseException]]
-        exc_val,  # type: Optional[BaseException]
-        exc_tb  # type: Optional[TracebackType]
-    ):
-        # type: (...) -> None
+        exc_type: Optional[Type[BaseException]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> None:
         pass
 
-    def cleanup(self):
-        # type: () -> None
+    def cleanup(self) -> None:
         pass
 
     def install_requirements(
         self,
-        finder,  # type: PackageFinder
-        requirements,  # type: Iterable[str]
-        prefix_as_string,  # type: str
-        message  # type: str
-    ):
-        # type: (...) -> None
+        finder: "PackageFinder",
+        requirements: Iterable[str],
+        prefix_as_string: str,
+        *,
+        kind: str,
+    ) -> None:
         raise NotImplementedError()

venv/Lib/site-packages/pip/_internal/cache.py

@@ -20,8 +20,7 @@ from pip._internal.utils.urls import path_to_url
 logger = logging.getLogger(__name__)
 
 
-def _hash_dict(d):
-    # type: (Dict[str, str]) -> str
+def _hash_dict(d: Dict[str, str]) -> str:
     """Return a stable sha224 of a dictionary."""
     s = json.dumps(d, sort_keys=True, separators=(",", ":"), ensure_ascii=True)
     return hashlib.sha224(s.encode("ascii")).hexdigest()
@@ -31,15 +30,16 @@ class Cache:
     """An abstract class - provides cache directories for data from links
 
 
-        :param cache_dir: The root of the cache.
-        :param format_control: An object of FormatControl class to limit
-            binaries being read from the cache.
-        :param allowed_formats: which formats of files the cache should store.
-            ('binary' and 'source' are the only allowed values)
+    :param cache_dir: The root of the cache.
+    :param format_control: An object of FormatControl class to limit
+        binaries being read from the cache.
+    :param allowed_formats: which formats of files the cache should store.
+        ('binary' and 'source' are the only allowed values)
     """
 
-    def __init__(self, cache_dir, format_control, allowed_formats):
-        # type: (str, FormatControl, Set[str]) -> None
+    def __init__(
+        self, cache_dir: str, format_control: FormatControl, allowed_formats: Set[str]
+    ) -> None:
         super().__init__()
         assert not cache_dir or os.path.isabs(cache_dir)
         self.cache_dir = cache_dir or None
@@ -49,10 +49,8 @@ class Cache:
         _valid_formats = {"source", "binary"}
         assert self.allowed_formats.union(_valid_formats) == _valid_formats
 
-    def _get_cache_path_parts(self, link):
-        # type: (Link) -> List[str]
-        """Get parts of part that must be os.path.joined with cache_dir
-        """
+    def _get_cache_path_parts(self, link: Link) -> List[str]:
+        """Get parts of part that must be os.path.joined with cache_dir"""
 
         # We want to generate an url to use as our cache key, we don't want to
         # just re-use the URL because it might have other items in the fragment
@@ -84,19 +82,12 @@ class Cache:
 
         return parts
 
-    def _get_candidates(self, link, canonical_package_name):
-        # type: (Link, str) -> List[Any]
-        can_not_cache = (
-            not self.cache_dir or
-            not canonical_package_name or
-            not link
-        )
+    def _get_candidates(self, link: Link, canonical_package_name: str) -> List[Any]:
+        can_not_cache = not self.cache_dir or not canonical_package_name or not link
         if can_not_cache:
             return []
 
-        formats = self.format_control.get_allowed_formats(
-            canonical_package_name
-        )
+        formats = self.format_control.get_allowed_formats(canonical_package_name)
         if not self.allowed_formats.intersection(formats):
             return []
 
@@ -107,19 +98,16 @@ class Cache:
                 candidates.append((candidate, path))
         return candidates
 
-    def get_path_for_link(self, link):
-        # type: (Link) -> str
-        """Return a directory to store cached items in for link.
-        """
+    def get_path_for_link(self, link: Link) -> str:
+        """Return a directory to store cached items in for link."""
         raise NotImplementedError()
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
-        supported_tags,  # type: List[Tag]
-    ):
-        # type: (...) -> Link
+        link: Link,
+        package_name: Optional[str],
+        supported_tags: List[Tag],
+    ) -> Link:
         """Returns a link to a cached item if it exists, otherwise returns the
         passed link.
         """
@@ -127,15 +115,12 @@ class Cache:
 
 
 class SimpleWheelCache(Cache):
-    """A cache of wheels for future installs.
-    """
+    """A cache of wheels for future installs."""
 
-    def __init__(self, cache_dir, format_control):
-        # type: (str, FormatControl) -> None
+    def __init__(self, cache_dir: str, format_control: FormatControl) -> None:
         super().__init__(cache_dir, format_control, {"binary"})
 
-    def get_path_for_link(self, link):
-        # type: (Link) -> str
+    def get_path_for_link(self, link: Link) -> str:
         """Return a directory to store cached wheels for link
 
         Because there are M wheels for any one sdist, we provide a directory
@@ -157,20 +142,17 @@ class SimpleWheelCache(Cache):
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
-        supported_tags,  # type: List[Tag]
-    ):
-        # type: (...) -> Link
+        link: Link,
+        package_name: Optional[str],
+        supported_tags: List[Tag],
+    ) -> Link:
         candidates = []
 
         if not package_name:
             return link
 
         canonical_package_name = canonicalize_name(package_name)
-        for wheel_name, wheel_dir in self._get_candidates(
-            link, canonical_package_name
-        ):
+        for wheel_name, wheel_dir in self._get_candidates(link, canonical_package_name):
             try:
                 wheel = Wheel(wheel_name)
             except InvalidWheelFilename:
@@ -179,7 +161,9 @@ class SimpleWheelCache(Cache):
                 logger.debug(
                     "Ignoring cached wheel %s for %s as it "
                     "does not match the expected distribution name %s.",
-                    wheel_name, link, package_name,
+                    wheel_name,
+                    link,
+                    package_name,
                 )
                 continue
             if not wheel.supported(supported_tags):
@@ -201,11 +185,9 @@ class SimpleWheelCache(Cache):
 
 
 class EphemWheelCache(SimpleWheelCache):
-    """A SimpleWheelCache that creates it's own temporary cache directory
-    """
+    """A SimpleWheelCache that creates it's own temporary cache directory"""
 
-    def __init__(self, format_control):
-        # type: (FormatControl) -> None
+    def __init__(self, format_control: FormatControl) -> None:
         self._temp_dir = TempDirectory(
             kind=tempdir_kinds.EPHEM_WHEEL_CACHE,
             globally_managed=True,
@@ -217,8 +199,8 @@ class EphemWheelCache(SimpleWheelCache):
 class CacheEntry:
     def __init__(
         self,
-        link,  # type: Link
-        persistent,  # type: bool
+        link: Link,
+        persistent: bool,
     ):
         self.link = link
         self.persistent = persistent
@@ -231,27 +213,23 @@ class WheelCache(Cache):
     when a certain link is not found in the simple wheel cache first.
     """
 
-    def __init__(self, cache_dir, format_control):
-        # type: (str, FormatControl) -> None
-        super().__init__(cache_dir, format_control, {'binary'})
+    def __init__(self, cache_dir: str, format_control: FormatControl) -> None:
+        super().__init__(cache_dir, format_control, {"binary"})
         self._wheel_cache = SimpleWheelCache(cache_dir, format_control)
         self._ephem_cache = EphemWheelCache(format_control)
 
-    def get_path_for_link(self, link):
-        # type: (Link) -> str
+    def get_path_for_link(self, link: Link) -> str:
         return self._wheel_cache.get_path_for_link(link)
 
-    def get_ephem_path_for_link(self, link):
-        # type: (Link) -> str
+    def get_ephem_path_for_link(self, link: Link) -> str:
         return self._ephem_cache.get_path_for_link(link)
 
     def get(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
-        supported_tags,  # type: List[Tag]
-    ):
-        # type: (...) -> Link
+        link: Link,
+        package_name: Optional[str],
+        supported_tags: List[Tag],
+    ) -> Link:
         cache_entry = self.get_cache_entry(link, package_name, supported_tags)
         if cache_entry is None:
             return link
@@ -259,11 +237,10 @@ class WheelCache(Cache):
 
     def get_cache_entry(
         self,
-        link,            # type: Link
-        package_name,    # type: Optional[str]
-        supported_tags,  # type: List[Tag]
-    ):
-        # type: (...) -> Optional[CacheEntry]
+        link: Link,
+        package_name: Optional[str],
+        supported_tags: List[Tag],
+    ) -> Optional[CacheEntry]:
         """Returns a CacheEntry with a link to a cached item if it exists or
         None. The cache entry indicates if the item was found in the persistent
         or ephemeral cache.

venv/Lib/site-packages/pip/_internal/cli/autocompletion.py

@@ -9,11 +9,10 @@ from typing import Any, Iterable, List, Optional
 
 from pip._internal.cli.main_parser import create_main_parser
 from pip._internal.commands import commands_dict, create_command
-from pip._internal.utils.misc import get_installed_distributions
+from pip._internal.metadata import get_default_environment
 
 
-def autocomplete():
-    # type: () -> None
+def autocomplete() -> None:
     """Entry Point for completion of main and subcommand options."""
     # Don't complete if user hasn't sourced bash_completion file.
     if "PIP_AUTO_COMPLETE" not in os.environ:
@@ -30,7 +29,7 @@ def autocomplete():
     options = []
 
     # subcommand
-    subcommand_name = None  # type: Optional[str]
+    subcommand_name: Optional[str] = None
     for word in cwords:
         if word in subcommands:
             subcommand_name = word
@@ -46,11 +45,13 @@ def autocomplete():
             "uninstall",
         ]
         if should_list_installed:
+            env = get_default_environment()
             lc = current.lower()
             installed = [
-                dist.key
-                for dist in get_installed_distributions(local_only=True)
-                if dist.key.startswith(lc) and dist.key not in cwords[1:]
+                dist.canonical_name
+                for dist in env.iter_installed_distributions(local_only=True)
+                if dist.canonical_name.startswith(lc)
+                and dist.canonical_name not in cwords[1:]
             ]
             # if there are no dists installed, fall back to option completion
             if installed:
@@ -58,6 +59,14 @@ def autocomplete():
                     print(dist)
                 sys.exit(1)
 
+        should_list_installables = (
+            not current.startswith("-") and subcommand_name == "install"
+        )
+        if should_list_installables:
+            for path in auto_complete_paths(current, "path"):
+                print(path)
+            sys.exit(1)
+
         subcommand = create_command(subcommand_name)
 
         for opt in subcommand.parser.option_list_all:
@@ -107,8 +116,9 @@ def autocomplete():
     sys.exit(1)
 
 
-def get_path_completion_type(cwords, cword, opts):
-    # type: (List[str], int, Iterable[Any]) -> Optional[str]
+def get_path_completion_type(
+    cwords: List[str], cword: int, opts: Iterable[Any]
+) -> Optional[str]:
     """Get the type of path completion (``file``, ``dir``, ``path`` or None)
 
     :param cwords: same as the environmental variable ``COMP_WORDS``
@@ -130,14 +140,13 @@ def get_path_completion_type(cwords, cword, opts):
     return None
 
 
-def auto_complete_paths(current, completion_type):
-    # type: (str, str) -> Iterable[str]
+def auto_complete_paths(current: str, completion_type: str) -> Iterable[str]:
     """If ``completion_type`` is ``file`` or ``path``, list all regular files
     and directories starting with ``current``; otherwise only list directories
     starting with ``current``.
 
     :param current: The word to be completed
-    :param completion_type: path completion type(`file`, `path` or `dir`)i
+    :param completion_type: path completion type(``file``, ``path`` or ``dir``)
     :return: A generator of regular files and/or directories
     """
     directory, filename = os.path.split(current)

venv/Lib/site-packages/pip/_internal/cli/base_command.py

@@ -1,5 +1,6 @@
 """Base Command class, and related routines"""
 
+import functools
 import logging
 import logging.config
 import optparse
@@ -7,7 +8,9 @@ import os
 import sys
 import traceback
 from optparse import Values
-from typing import Any, List, Optional, Tuple
+from typing import Any, Callable, List, Optional, Tuple
+
+from pip._vendor.rich import traceback as rich_traceback
 
 from pip._internal.cli import cmdoptions
 from pip._internal.cli.command_context import CommandContextMixIn
@@ -21,12 +24,12 @@ from pip._internal.cli.status_codes import (
 from pip._internal.exceptions import (
     BadCommand,
     CommandError,
+    DiagnosticPipError,
     InstallationError,
     NetworkConnectionError,
     PreviousBuildDirError,
     UninstallationError,
 )
-from pip._internal.utils.deprecation import deprecated
 from pip._internal.utils.filesystem import check_path_owner
 from pip._internal.utils.logging import BrokenStdoutLoggingError, setup_logging
 from pip._internal.utils.misc import get_prog, normalize_path
@@ -40,11 +43,10 @@ logger = logging.getLogger(__name__)
 
 
 class Command(CommandContextMixIn):
-    usage = None  # type: str
-    ignore_require_venv = False  # type: bool
+    usage: str = ""
+    ignore_require_venv: bool = False
 
-    def __init__(self, name, summary, isolated=False):
-        # type: (str, str, bool) -> None
+    def __init__(self, name: str, summary: str, isolated: bool = False) -> None:
         super().__init__()
 
         self.name = name
@@ -59,7 +61,7 @@ class Command(CommandContextMixIn):
             isolated=isolated,
         )
 
-        self.tempdir_registry = None  # type: Optional[TempDirRegistry]
+        self.tempdir_registry: Optional[TempDirRegistry] = None
 
         # Commands should add options to this option group
         optgroup_name = f"{self.name.capitalize()} Options"
@@ -74,12 +76,10 @@ class Command(CommandContextMixIn):
 
         self.add_options()
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         pass
 
-    def handle_pip_version_check(self, options):
-        # type: (Values) -> None
+    def handle_pip_version_check(self, options: Values) -> None:
         """
         This is a no-op so that commands by default do not do the pip version
         check.
@@ -88,25 +88,21 @@ class Command(CommandContextMixIn):
         # are present.
         assert not hasattr(options, "no_index")
 
-    def run(self, options, args):
-        # type: (Values, List[Any]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         raise NotImplementedError
 
-    def parse_args(self, args):
-        # type: (List[str]) -> Tuple[Any, Any]
+    def parse_args(self, args: List[str]) -> Tuple[Values, List[str]]:
         # factored out for testability
         return self.parser.parse_args(args)
 
-    def main(self, args):
-        # type: (List[str]) -> int
+    def main(self, args: List[str]) -> int:
         try:
             with self.main_context():
                 return self._main(args)
         finally:
             logging.shutdown()
 
-    def _main(self, args):
-        # type: (List[str]) -> int
+    def _main(self, args: List[str]) -> int:
         # We must initialize this before the tempdir manager, otherwise the
         # configuration would not be accessible by the time we clean up the
         # tempdir manager.
@@ -155,20 +151,6 @@ class Command(CommandContextMixIn):
                 )
                 options.cache_dir = None
 
-        if getattr(options, "build_dir", None):
-            deprecated(
-                reason=(
-                    "The -b/--build/--build-dir/--build-directory "
-                    "option is deprecated and has no effect anymore."
-                ),
-                replacement=(
-                    "use the TMPDIR/TEMP/TMP environment variable, "
-                    "possibly combined with --no-clean"
-                ),
-                gone_in="21.3",
-                issue=8333,
-            )
-
         if "2020-resolver" in options.features_enabled:
             logger.warning(
                 "--use-feature=2020-resolver no longer has any effect, "
@@ -176,46 +158,66 @@ class Command(CommandContextMixIn):
                 "This will become an error in pip 21.0."
             )
 
+        def intercepts_unhandled_exc(
+            run_func: Callable[..., int]
+        ) -> Callable[..., int]:
+            @functools.wraps(run_func)
+            def exc_logging_wrapper(*args: Any) -> int:
+                try:
+                    status = run_func(*args)
+                    assert isinstance(status, int)
+                    return status
+                except DiagnosticPipError as exc:
+                    logger.error("[present-rich] %s", exc)
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return ERROR
+                except PreviousBuildDirError as exc:
+                    logger.critical(str(exc))
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return PREVIOUS_BUILD_DIR_ERROR
+                except (
+                    InstallationError,
+                    UninstallationError,
+                    BadCommand,
+                    NetworkConnectionError,
+                ) as exc:
+                    logger.critical(str(exc))
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return ERROR
+                except CommandError as exc:
+                    logger.critical("%s", exc)
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return ERROR
+                except BrokenStdoutLoggingError:
+                    # Bypass our logger and write any remaining messages to
+                    # stderr because stdout no longer works.
+                    print("ERROR: Pipe to stdout was broken", file=sys.stderr)
+                    if level_number <= logging.DEBUG:
+                        traceback.print_exc(file=sys.stderr)
+
+                    return ERROR
+                except KeyboardInterrupt:
+                    logger.critical("Operation cancelled by user")
+                    logger.debug("Exception information:", exc_info=True)
+
+                    return ERROR
+                except BaseException:
+                    logger.critical("Exception:", exc_info=True)
+
+                    return UNKNOWN_ERROR
+
+            return exc_logging_wrapper
+
         try:
-            status = self.run(options, args)
-            assert isinstance(status, int)
-            return status
-        except PreviousBuildDirError as exc:
-            logger.critical(str(exc))
-            logger.debug("Exception information:", exc_info=True)
-
-            return PREVIOUS_BUILD_DIR_ERROR
-        except (
-            InstallationError,
-            UninstallationError,
-            BadCommand,
-            NetworkConnectionError,
-        ) as exc:
-            logger.critical(str(exc))
-            logger.debug("Exception information:", exc_info=True)
-
-            return ERROR
-        except CommandError as exc:
-            logger.critical("%s", exc)
-            logger.debug("Exception information:", exc_info=True)
-
-            return ERROR
-        except BrokenStdoutLoggingError:
-            # Bypass our logger and write any remaining messages to stderr
-            # because stdout no longer works.
-            print("ERROR: Pipe to stdout was broken", file=sys.stderr)
-            if level_number <= logging.DEBUG:
-                traceback.print_exc(file=sys.stderr)
-
-            return ERROR
-        except KeyboardInterrupt:
-            logger.critical("Operation cancelled by user")
-            logger.debug("Exception information:", exc_info=True)
-
-            return ERROR
-        except BaseException:
-            logger.critical("Exception:", exc_info=True)
-
-            return UNKNOWN_ERROR
+            if not options.debug_mode:
+                run = intercepts_unhandled_exc(self.run)
+            else:
+                run = self.run
+                rich_traceback.install(show_locals=True)
+            return run(options, args)
         finally:
             self.handle_pip_version_check(options)

venv/Lib/site-packages/pip/_internal/cli/cmdoptions.py

@@ -10,9 +10,10 @@ pass on state. To be consistent, all options will follow this design.
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
 
+import importlib.util
+import logging
 import os
 import textwrap
-import warnings
 from functools import partial
 from optparse import SUPPRESS_HELP, Option, OptionGroup, OptionParser, Values
 from textwrap import dedent
@@ -21,7 +22,6 @@ from typing import Any, Callable, Dict, Optional, Tuple
 from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.cli.parser import ConfigOptionParser
-from pip._internal.cli.progress_bars import BAR_TYPES
 from pip._internal.exceptions import CommandError
 from pip._internal.locations import USER_CACHE_DIR, get_src_prefix
 from pip._internal.models.format_control import FormatControl
@@ -30,9 +30,10 @@ from pip._internal.models.target_python import TargetPython
 from pip._internal.utils.hashes import STRONG_HASHES
 from pip._internal.utils.misc import strtobool
 
+logger = logging.getLogger(__name__)
 
-def raise_option_error(parser, option, msg):
-    # type: (OptionParser, Option, str) -> None
+
+def raise_option_error(parser: OptionParser, option: Option, msg: str) -> None:
     """
     Raise an option parsing error using parser.error().
 
@@ -46,8 +47,7 @@ def raise_option_error(parser, option, msg):
     parser.error(msg)
 
 
-def make_option_group(group, parser):
-    # type: (Dict[str, Any], ConfigOptionParser) -> OptionGroup
+def make_option_group(group: Dict[str, Any], parser: ConfigOptionParser) -> OptionGroup:
     """
     Return an OptionGroup object
     group  -- assumed to be dict with 'name' and 'options' keys
@@ -59,8 +59,9 @@ def make_option_group(group, parser):
     return option_group
 
 
-def check_install_build_global(options, check_options=None):
-    # type: (Values, Optional[Values]) -> None
+def check_install_build_global(
+    options: Values, check_options: Optional[Values] = None
+) -> None:
     """Disable wheels if per-setup.py call options are set.
 
     :param options: The OptionParser options to update.
@@ -70,23 +71,20 @@ def check_install_build_global(options, check_options=None):
     if check_options is None:
         check_options = options
 
-    def getname(n):
-        # type: (str) -> Optional[Any]
+    def getname(n: str) -> Optional[Any]:
         return getattr(check_options, n, None)
 
     names = ["build_options", "global_options", "install_options"]
     if any(map(getname, names)):
         control = options.format_control
         control.disallow_binaries()
-        warnings.warn(
+        logger.warning(
             "Disabling all use of wheels due to the use of --build-option "
             "/ --global-option / --install-option.",
-            stacklevel=2,
         )
 
 
-def check_dist_restriction(options, check_target=False):
-    # type: (Values, bool) -> None
+def check_dist_restriction(options: Values, check_target: bool = False) -> None:
     """Function for determining if custom platform options are allowed.
 
     :param options: The OptionParser options.
@@ -126,13 +124,11 @@ def check_dist_restriction(options, check_target=False):
             )
 
 
-def _path_option_check(option, opt, value):
-    # type: (Option, str, str) -> str
+def _path_option_check(option: Option, opt: str, value: str) -> str:
     return os.path.expanduser(value)
 
 
-def _package_name_option_check(option, opt, value):
-    # type: (Option, str, str) -> str
+def _package_name_option_check(option: Option, opt: str, value: str) -> str:
     return canonicalize_name(value)
 
 
@@ -147,16 +143,28 @@ class PipOption(Option):
 # options #
 ###########
 
-help_ = partial(
+help_: Callable[..., Option] = partial(
     Option,
     "-h",
     "--help",
     dest="help",
     action="help",
     help="Show help.",
-)  # type: Callable[..., Option]
+)
 
-isolated_mode = partial(
+debug_mode: Callable[..., Option] = partial(
+    Option,
+    "--debug",
+    dest="debug_mode",
+    action="store_true",
+    default=False,
+    help=(
+        "Let unhandled exceptions propagate outside the main subroutine, "
+        "instead of logging them to stderr."
+    ),
+)
+
+isolated_mode: Callable[..., Option] = partial(
     Option,
     "--isolated",
     dest="isolated_mode",
@@ -166,20 +174,22 @@ isolated_mode = partial(
         "Run pip in an isolated mode, ignoring environment variables and user "
         "configuration."
     ),
-)  # type: Callable[..., Option]
+)
 
-require_virtualenv = partial(
+require_virtualenv: Callable[..., Option] = partial(
     Option,
-    # Run only if inside a virtualenv, bail if not.
     "--require-virtualenv",
     "--require-venv",
     dest="require_venv",
     action="store_true",
     default=False,
-    help=SUPPRESS_HELP,
-)  # type: Callable[..., Option]
+    help=(
+        "Allow pip to only run in a virtual environment; "
+        "exit with an error otherwise."
+    ),
+)
 
-verbose = partial(
+verbose: Callable[..., Option] = partial(
     Option,
     "-v",
     "--verbose",
@@ -187,27 +197,27 @@ verbose = partial(
     action="count",
     default=0,
     help="Give more output. Option is additive, and can be used up to 3 times.",
-)  # type: Callable[..., Option]
+)
 
-no_color = partial(
+no_color: Callable[..., Option] = partial(
     Option,
     "--no-color",
     dest="no_color",
     action="store_true",
     default=False,
     help="Suppress colored output.",
-)  # type: Callable[..., Option]
+)
 
-version = partial(
+version: Callable[..., Option] = partial(
     Option,
     "-V",
     "--version",
     dest="version",
     action="store_true",
     help="Show version and exit.",
-)  # type: Callable[..., Option]
+)
 
-quiet = partial(
+quiet: Callable[..., Option] = partial(
     Option,
     "-q",
     "--quiet",
@@ -219,23 +229,19 @@ quiet = partial(
         " times (corresponding to WARNING, ERROR, and CRITICAL logging"
         " levels)."
     ),
-)  # type: Callable[..., Option]
+)
 
-progress_bar = partial(
+progress_bar: Callable[..., Option] = partial(
     Option,
     "--progress-bar",
     dest="progress_bar",
     type="choice",
-    choices=list(BAR_TYPES.keys()),
+    choices=["on", "off"],
     default="on",
-    help=(
-        "Specify type of progress to be displayed ["
-        + "|".join(BAR_TYPES.keys())
-        + "] (default: %default)"
-    ),
-)  # type: Callable[..., Option]
+    help="Specify whether the progress bar should be used [on, off] (default: on)",
+)
 
-log = partial(
+log: Callable[..., Option] = partial(
     PipOption,
     "--log",
     "--log-file",
@@ -244,9 +250,9 @@ log = partial(
     metavar="path",
     type="path",
     help="Path to a verbose appending log.",
-)  # type: Callable[..., Option]
+)
 
-no_input = partial(
+no_input: Callable[..., Option] = partial(
     Option,
     # Don't ask for input
     "--no-input",
@@ -254,18 +260,18 @@ no_input = partial(
     action="store_true",
     default=False,
     help="Disable prompting for input.",
-)  # type: Callable[..., Option]
+)
 
-proxy = partial(
+proxy: Callable[..., Option] = partial(
     Option,
     "--proxy",
     dest="proxy",
     type="str",
     default="",
-    help="Specify a proxy in the form [user:passwd@]proxy.server:port.",
-)  # type: Callable[..., Option]
+    help="Specify a proxy in the form scheme://[user:passwd@]proxy.server:port.",
+)
 
-retries = partial(
+retries: Callable[..., Option] = partial(
     Option,
     "--retries",
     dest="retries",
@@ -273,9 +279,9 @@ retries = partial(
     default=5,
     help="Maximum number of retries each connection should attempt "
     "(default %default times).",
-)  # type: Callable[..., Option]
+)
 
-timeout = partial(
+timeout: Callable[..., Option] = partial(
     Option,
     "--timeout",
     "--default-timeout",
@@ -284,11 +290,10 @@ timeout = partial(
     type="float",
     default=15,
     help="Set the socket timeout (default %default seconds).",
-)  # type: Callable[..., Option]
+)
 
 
-def exists_action():
-    # type: () -> Option
+def exists_action() -> Option:
     return Option(
         # Option when path already exist
         "--exists-action",
@@ -303,7 +308,7 @@ def exists_action():
     )
 
 
-cert = partial(
+cert: Callable[..., Option] = partial(
     PipOption,
     "--cert",
     dest="cert",
@@ -315,9 +320,9 @@ cert = partial(
         "See 'SSL Certificate Verification' in pip documentation "
         "for more information."
     ),
-)  # type: Callable[..., Option]
+)
 
-client_cert = partial(
+client_cert: Callable[..., Option] = partial(
     PipOption,
     "--client-cert",
     dest="client_cert",
@@ -326,9 +331,9 @@ client_cert = partial(
     metavar="path",
     help="Path to SSL client certificate, a single file containing the "
     "private key and the certificate in PEM format.",
-)  # type: Callable[..., Option]
+)
 
-index_url = partial(
+index_url: Callable[..., Option] = partial(
     Option,
     "-i",
     "--index-url",
@@ -340,11 +345,10 @@ index_url = partial(
     "This should point to a repository compliant with PEP 503 "
     "(the simple repository API) or a local directory laid out "
     "in the same format.",
-)  # type: Callable[..., Option]
+)
 
 
-def extra_index_url():
-    # type: () -> Option
+def extra_index_url() -> Option:
     return Option(
         "--extra-index-url",
         dest="extra_index_urls",
@@ -357,18 +361,17 @@ def extra_index_url():
     )
 
 
-no_index = partial(
+no_index: Callable[..., Option] = partial(
     Option,
     "--no-index",
     dest="no_index",
     action="store_true",
     default=False,
     help="Ignore package index (only looking at --find-links URLs instead).",
-)  # type: Callable[..., Option]
+)
 
 
-def find_links():
-    # type: () -> Option
+def find_links() -> Option:
     return Option(
         "-f",
         "--find-links",
@@ -378,14 +381,13 @@ def find_links():
         metavar="url",
         help="If a URL or path to an html file, then parse for links to "
         "archives such as sdist (.tar.gz) or wheel (.whl) files. "
-        "If a local path or file:// URL that's a directory,  "
+        "If a local path or file:// URL that's a directory, "
         "then look for archives in the directory listing. "
         "Links to VCS project URLs are not supported.",
     )
 
 
-def trusted_host():
-    # type: () -> Option
+def trusted_host() -> Option:
     return Option(
         "--trusted-host",
         dest="trusted_hosts",
@@ -397,8 +399,7 @@ def trusted_host():
     )
 
 
-def constraints():
-    # type: () -> Option
+def constraints() -> Option:
     return Option(
         "-c",
         "--constraint",
@@ -411,8 +412,7 @@ def constraints():
     )
 
 
-def requirements():
-    # type: () -> Option
+def requirements() -> Option:
     return Option(
         "-r",
         "--requirement",
@@ -425,8 +425,7 @@ def requirements():
     )
 
 
-def editable():
-    # type: () -> Option
+def editable() -> Option:
     return Option(
         "-e",
         "--editable",
@@ -441,13 +440,12 @@ def editable():
     )
 
 
-def _handle_src(option, opt_str, value, parser):
-    # type: (Option, str, str, OptionParser) -> None
+def _handle_src(option: Option, opt_str: str, value: str, parser: OptionParser) -> None:
     value = os.path.abspath(value)
     setattr(parser.values, option.dest, value)
 
 
-src = partial(
+src: Callable[..., Option] = partial(
     PipOption,
     "--src",
     "--source",
@@ -462,17 +460,17 @@ src = partial(
     help="Directory to check out editable projects into. "
     'The default in a virtualenv is "<venv path>/src". '
     'The default for global installs is "<current dir>/src".',
-)  # type: Callable[..., Option]
+)
 
 
-def _get_format_control(values, option):
-    # type: (Values, Option) -> Any
+def _get_format_control(values: Values, option: Option) -> Any:
     """Get a format_control object."""
     return getattr(values, option.dest)
 
 
-def _handle_no_binary(option, opt_str, value, parser):
-    # type: (Option, str, str, OptionParser) -> None
+def _handle_no_binary(
+    option: Option, opt_str: str, value: str, parser: OptionParser
+) -> None:
     existing = _get_format_control(parser.values, option)
     FormatControl.handle_mutual_excludes(
         value,
@@ -481,8 +479,9 @@ def _handle_no_binary(option, opt_str, value, parser):
     )
 
 
-def _handle_only_binary(option, opt_str, value, parser):
-    # type: (Option, str, str, OptionParser) -> None
+def _handle_only_binary(
+    option: Option, opt_str: str, value: str, parser: OptionParser
+) -> None:
     existing = _get_format_control(parser.values, option)
     FormatControl.handle_mutual_excludes(
         value,
@@ -491,8 +490,7 @@ def _handle_only_binary(option, opt_str, value, parser):
     )
 
 
-def no_binary():
-    # type: () -> Option
+def no_binary() -> Option:
     format_control = FormatControl(set(), set())
     return Option(
         "--no-binary",
@@ -510,8 +508,7 @@ def no_binary():
     )
 
 
-def only_binary():
-    # type: () -> Option
+def only_binary() -> Option:
     format_control = FormatControl(set(), set())
     return Option(
         "--only-binary",
@@ -529,7 +526,7 @@ def only_binary():
     )
 
 
-platforms = partial(
+platforms: Callable[..., Option] = partial(
     Option,
     "--platform",
     dest="platforms",
@@ -541,12 +538,11 @@ platforms = partial(
         "platform of the running system. Use this option multiple times to "
         "specify multiple platforms supported by the target interpreter."
     ),
-)  # type: Callable[..., Option]
+)
 
 
 # This was made a separate function for unit-testing purposes.
-def _convert_python_version(value):
-    # type: (str) -> Tuple[Tuple[int, ...], Optional[str]]
+def _convert_python_version(value: str) -> Tuple[Tuple[int, ...], Optional[str]]:
     """
     Convert a version string like "3", "37", or "3.7.3" into a tuple of ints.
 
@@ -575,8 +571,9 @@ def _convert_python_version(value):
     return (version_info, None)
 
 
-def _handle_python_version(option, opt_str, value, parser):
-    # type: (Option, str, str, OptionParser) -> None
+def _handle_python_version(
+    option: Option, opt_str: str, value: str, parser: OptionParser
+) -> None:
     """
     Handle a provided --python-version value.
     """
@@ -591,7 +588,7 @@ def _handle_python_version(option, opt_str, value, parser):
     parser.values.python_version = version_info
 
 
-python_version = partial(
+python_version: Callable[..., Option] = partial(
     Option,
     "--python-version",
     dest="python_version",
@@ -609,10 +606,10 @@ python_version = partial(
     version can also be given as a string without dots (e.g. "37" for 3.7.0).
     """
     ),
-)  # type: Callable[..., Option]
+)
 
 
-implementation = partial(
+implementation: Callable[..., Option] = partial(
     Option,
     "--implementation",
     dest="implementation",
@@ -625,10 +622,10 @@ implementation = partial(
         "interpreter implementation is used.  Use 'py' to force "
         "implementation-agnostic wheels."
     ),
-)  # type: Callable[..., Option]
+)
 
 
-abis = partial(
+abis: Callable[..., Option] = partial(
     Option,
     "--abi",
     dest="abis",
@@ -643,19 +640,17 @@ abis = partial(
         "--implementation, --platform, and --python-version when using this "
         "option."
     ),
-)  # type: Callable[..., Option]
+)
 
 
-def add_target_python_options(cmd_opts):
-    # type: (OptionGroup) -> None
+def add_target_python_options(cmd_opts: OptionGroup) -> None:
     cmd_opts.add_option(platforms())
     cmd_opts.add_option(python_version())
     cmd_opts.add_option(implementation())
     cmd_opts.add_option(abis())
 
 
-def make_target_python(options):
-    # type: (Values) -> TargetPython
+def make_target_python(options: Values) -> TargetPython:
     target_python = TargetPython(
         platforms=options.platforms,
         py_version_info=options.python_version,
@@ -666,8 +661,7 @@ def make_target_python(options):
     return target_python
 
 
-def prefer_binary():
-    # type: () -> Option
+def prefer_binary() -> Option:
     return Option(
         "--prefer-binary",
         dest="prefer_binary",
@@ -677,7 +671,7 @@ def prefer_binary():
     )
 
 
-cache_dir = partial(
+cache_dir: Callable[..., Option] = partial(
     PipOption,
     "--cache-dir",
     dest="cache_dir",
@@ -685,11 +679,12 @@ cache_dir = partial(
     metavar="dir",
     type="path",
     help="Store the cache data in <dir>.",
-)  # type: Callable[..., Option]
+)
 
 
-def _handle_no_cache_dir(option, opt, value, parser):
-    # type: (Option, str, str, OptionParser) -> None
+def _handle_no_cache_dir(
+    option: Option, opt: str, value: str, parser: OptionParser
+) -> None:
     """
     Process a value provided for the --no-cache-dir option.
 
@@ -716,16 +711,16 @@ def _handle_no_cache_dir(option, opt, value, parser):
     parser.values.cache_dir = False
 
 
-no_cache = partial(
+no_cache: Callable[..., Option] = partial(
     Option,
     "--no-cache-dir",
     dest="cache_dir",
     action="callback",
     callback=_handle_no_cache_dir,
     help="Disable the cache.",
-)  # type: Callable[..., Option]
+)
 
-no_deps = partial(
+no_deps: Callable[..., Option] = partial(
     Option,
     "--no-deps",
     "--no-dependencies",
@@ -733,29 +728,17 @@ no_deps = partial(
     action="store_true",
     default=False,
     help="Don't install package dependencies.",
-)  # type: Callable[..., Option]
+)
 
-build_dir = partial(
-    PipOption,
-    "-b",
-    "--build",
-    "--build-dir",
-    "--build-directory",
-    dest="build_dir",
-    type="path",
-    metavar="dir",
-    help=SUPPRESS_HELP,
-)  # type: Callable[..., Option]
-
-ignore_requires_python = partial(
+ignore_requires_python: Callable[..., Option] = partial(
     Option,
     "--ignore-requires-python",
     dest="ignore_requires_python",
     action="store_true",
     help="Ignore the Requires-Python information.",
-)  # type: Callable[..., Option]
+)
 
-no_build_isolation = partial(
+no_build_isolation: Callable[..., Option] = partial(
     Option,
     "--no-build-isolation",
     dest="build_isolation",
@@ -764,11 +747,21 @@ no_build_isolation = partial(
     help="Disable isolation when building a modern source distribution. "
     "Build dependencies specified by PEP 518 must be already installed "
     "if this option is used.",
-)  # type: Callable[..., Option]
+)
+
+check_build_deps: Callable[..., Option] = partial(
+    Option,
+    "--check-build-dependencies",
+    dest="check_build_deps",
+    action="store_true",
+    default=False,
+    help="Check the build dependencies when PEP517 is used.",
+)
 
 
-def _handle_no_use_pep517(option, opt, value, parser):
-    # type: (Option, str, str, OptionParser) -> None
+def _handle_no_use_pep517(
+    option: Option, opt: str, value: str, parser: OptionParser
+) -> None:
     """
     Process a value provided for the --no-use-pep517 option.
 
@@ -787,11 +780,17 @@ def _handle_no_use_pep517(option, opt, value, parser):
         """
         raise_option_error(parser, option=option, msg=msg)
 
+    # If user doesn't wish to use pep517, we check if setuptools is installed
+    # and raise error if it is not.
+    if not importlib.util.find_spec("setuptools"):
+        msg = "It is not possible to use --no-use-pep517 without setuptools installed."
+        raise_option_error(parser, option=option, msg=msg)
+
     # Otherwise, --no-use-pep517 was passed via the command-line.
     parser.values.use_pep517 = False
 
 
-use_pep517 = partial(
+use_pep517: Any = partial(
     Option,
     "--use-pep517",
     dest="use_pep517",
@@ -799,9 +798,9 @@ use_pep517 = partial(
     default=None,
     help="Use PEP 517 for building source distributions "
     "(use --no-use-pep517 to force legacy behaviour).",
-)  # type: Any
+)
 
-no_use_pep517 = partial(
+no_use_pep517: Any = partial(
     Option,
     "--no-use-pep517",
     dest="use_pep517",
@@ -809,9 +808,36 @@ no_use_pep517 = partial(
     callback=_handle_no_use_pep517,
     default=None,
     help=SUPPRESS_HELP,
-)  # type: Any
+)
 
-install_options = partial(
+
+def _handle_config_settings(
+    option: Option, opt_str: str, value: str, parser: OptionParser
+) -> None:
+    key, sep, val = value.partition("=")
+    if sep != "=":
+        parser.error(f"Arguments to {opt_str} must be of the form KEY=VAL")  # noqa
+    dest = getattr(parser.values, option.dest)
+    if dest is None:
+        dest = {}
+        setattr(parser.values, option.dest, dest)
+    dest[key] = val
+
+
+config_settings: Callable[..., Option] = partial(
+    Option,
+    "--config-settings",
+    dest="config_settings",
+    type=str,
+    action="callback",
+    callback=_handle_config_settings,
+    metavar="settings",
+    help="Configuration settings to be passed to the PEP 517 build backend. "
+    "Settings take the form KEY=VALUE. Use multiple --config-settings options "
+    "to pass multiple keys to the backend.",
+)
+
+install_options: Callable[..., Option] = partial(
     Option,
     "--install-option",
     dest="install_options",
@@ -822,18 +848,18 @@ install_options = partial(
     'bin"). Use multiple --install-option options to pass multiple '
     "options to setup.py install. If you are using an option with a "
     "directory path, be sure to use absolute path.",
-)  # type: Callable[..., Option]
+)
 
-build_options = partial(
+build_options: Callable[..., Option] = partial(
     Option,
     "--build-option",
     dest="build_options",
     metavar="options",
     action="append",
     help="Extra arguments to be supplied to 'setup.py bdist_wheel'.",
-)  # type: Callable[..., Option]
+)
 
-global_options = partial(
+global_options: Callable[..., Option] = partial(
     Option,
     "--global-option",
     dest="global_options",
@@ -841,26 +867,26 @@ global_options = partial(
     metavar="options",
     help="Extra global options to be supplied to the setup.py "
     "call before the install or bdist_wheel command.",
-)  # type: Callable[..., Option]
+)
 
-no_clean = partial(
+no_clean: Callable[..., Option] = partial(
     Option,
     "--no-clean",
     action="store_true",
     default=False,
     help="Don't clean up build directories.",
-)  # type: Callable[..., Option]
+)
 
-pre = partial(
+pre: Callable[..., Option] = partial(
     Option,
     "--pre",
     action="store_true",
     default=False,
     help="Include pre-release and development versions. By default, "
     "pip only finds stable versions.",
-)  # type: Callable[..., Option]
+)
 
-disable_pip_version_check = partial(
+disable_pip_version_check: Callable[..., Option] = partial(
     Option,
     "--disable-pip-version-check",
     dest="disable_pip_version_check",
@@ -868,11 +894,21 @@ disable_pip_version_check = partial(
     default=False,
     help="Don't periodically check PyPI to determine whether a new version "
     "of pip is available for download. Implied with --no-index.",
-)  # type: Callable[..., Option]
+)
+
+root_user_action: Callable[..., Option] = partial(
+    Option,
+    "--root-user-action",
+    dest="root_user_action",
+    default="warn",
+    choices=["warn", "ignore"],
+    help="Action if pip is run as a root user. By default, a warning message is shown.",
+)
 
 
-def _handle_merge_hash(option, opt_str, value, parser):
-    # type: (Option, str, str, OptionParser) -> None
+def _handle_merge_hash(
+    option: Option, opt_str: str, value: str, parser: OptionParser
+) -> None:
     """Given a value spelled "algo:digest", append the digest to a list
     pointed to in a dict by the algo name."""
     if not parser.values.hashes:
@@ -894,7 +930,7 @@ def _handle_merge_hash(option, opt_str, value, parser):
     parser.values.hashes.setdefault(algo, []).append(digest)
 
 
-hash = partial(
+hash: Callable[..., Option] = partial(
     Option,
     "--hash",
     # Hash values eventually end up in InstallRequirement.hashes due to
@@ -905,10 +941,10 @@ hash = partial(
     type="string",
     help="Verify that the package's archive matches this "
     "hash before installing. Example: --hash=sha256:abcdef...",
-)  # type: Callable[..., Option]
+)
 
 
-require_hashes = partial(
+require_hashes: Callable[..., Option] = partial(
     Option,
     "--require-hashes",
     dest="require_hashes",
@@ -917,10 +953,10 @@ require_hashes = partial(
     help="Require a hash to check each requirement against, for "
     "repeatable installs. This option is implied when any package in a "
     "requirements file has a --hash option.",
-)  # type: Callable[..., Option]
+)
 
 
-list_path = partial(
+list_path: Callable[..., Option] = partial(
     PipOption,
     "--path",
     dest="path",
@@ -928,16 +964,15 @@ list_path = partial(
     action="append",
     help="Restrict to the specified installation path for listing "
     "packages (can be used multiple times).",
-)  # type: Callable[..., Option]
+)
 
 
-def check_list_path_option(options):
-    # type: (Values) -> None
+def check_list_path_option(options: Values) -> None:
     if options.path and (options.user or options.local):
         raise CommandError("Cannot combine '--path' with '--user' or '--local'")
 
 
-list_exclude = partial(
+list_exclude: Callable[..., Option] = partial(
     PipOption,
     "--exclude",
     dest="excludes",
@@ -945,50 +980,55 @@ list_exclude = partial(
     metavar="package",
     type="package_name",
     help="Exclude specified package from the output",
-)  # type: Callable[..., Option]
+)
 
 
-no_python_version_warning = partial(
+no_python_version_warning: Callable[..., Option] = partial(
     Option,
     "--no-python-version-warning",
     dest="no_python_version_warning",
     action="store_true",
     default=False,
     help="Silence deprecation warnings for upcoming unsupported Pythons.",
-)  # type: Callable[..., Option]
+)
 
 
-use_new_feature = partial(
+use_new_feature: Callable[..., Option] = partial(
     Option,
     "--use-feature",
     dest="features_enabled",
     metavar="feature",
     action="append",
     default=[],
-    choices=["2020-resolver", "fast-deps", "in-tree-build"],
+    choices=["2020-resolver", "fast-deps"],
     help="Enable new functionality, that may be backward incompatible.",
-)  # type: Callable[..., Option]
+)
 
-use_deprecated_feature = partial(
+use_deprecated_feature: Callable[..., Option] = partial(
     Option,
     "--use-deprecated",
     dest="deprecated_features_enabled",
     metavar="feature",
     action="append",
     default=[],
-    choices=["legacy-resolver"],
+    choices=[
+        "legacy-resolver",
+        "backtrack-on-build-failures",
+        "html5lib",
+    ],
     help=("Enable deprecated functionality, that will be removed in the future."),
-)  # type: Callable[..., Option]
+)
 
 
 ##########
 # groups #
 ##########
 
-general_group = {
+general_group: Dict[str, Any] = {
     "name": "General Options",
     "options": [
         help_,
+        debug_mode,
         isolated_mode,
         require_virtualenv,
         verbose,
@@ -1011,9 +1051,9 @@ general_group = {
         use_new_feature,
         use_deprecated_feature,
     ],
-}  # type: Dict[str, Any]
+}
 
-index_group = {
+index_group: Dict[str, Any] = {
     "name": "Package Index Options",
     "options": [
         index_url,
@@ -1021,4 +1061,4 @@ index_group = {
         no_index,
         find_links,
     ],
-}  # type: Dict[str, Any]
+}

venv/Lib/site-packages/pip/_internal/cli/command_context.py

@@ -1,19 +1,17 @@
 from contextlib import ExitStack, contextmanager
-from typing import ContextManager, Iterator, TypeVar
+from typing import ContextManager, Generator, TypeVar
 
 _T = TypeVar("_T", covariant=True)
 
 
 class CommandContextMixIn:
-    def __init__(self):
-        # type: () -> None
+    def __init__(self) -> None:
         super().__init__()
         self._in_main_context = False
         self._main_context = ExitStack()
 
     @contextmanager
-    def main_context(self):
-        # type: () -> Iterator[None]
+    def main_context(self) -> Generator[None, None, None]:
         assert not self._in_main_context
 
         self._in_main_context = True
@@ -23,8 +21,7 @@ class CommandContextMixIn:
         finally:
             self._in_main_context = False
 
-    def enter_context(self, context_provider):
-        # type: (ContextManager[_T]) -> _T
+    def enter_context(self, context_provider: ContextManager[_T]) -> _T:
         assert self._in_main_context
 
         return self._main_context.enter_context(context_provider)

venv/Lib/site-packages/pip/_internal/cli/main.py

@@ -42,8 +42,7 @@ logger = logging.getLogger(__name__)
 # main, this should not be an issue in practice.
 
 
-def main(args=None):
-    # type: (Optional[List[str]]) -> int
+def main(args: Optional[List[str]] = None) -> int:
     if args is None:
         args = sys.argv[1:]
 

venv/Lib/site-packages/pip/_internal/cli/main_parser.py

@@ -14,8 +14,7 @@ from pip._internal.utils.misc import get_pip_version, get_prog
 __all__ = ["create_main_parser", "parse_command"]
 
 
-def create_main_parser():
-    # type: () -> ConfigOptionParser
+def create_main_parser() -> ConfigOptionParser:
     """Creates and returns the main parser for pip's CLI"""
 
     parser = ConfigOptionParser(
@@ -46,8 +45,7 @@ def create_main_parser():
     return parser
 
 
-def parse_command(args):
-    # type: (List[str]) -> Tuple[str, List[str]]
+def parse_command(args: List[str]) -> Tuple[str, List[str]]:
     parser = create_main_parser()
 
     # Note: parser calls disable_interspersed_args(), so the result of this

venv/Lib/site-packages/pip/_internal/cli/parser.py

@@ -6,7 +6,7 @@ import shutil
 import sys
 import textwrap
 from contextlib import suppress
-from typing import Any, Dict, Iterator, List, Tuple
+from typing import Any, Dict, Generator, List, Tuple
 
 from pip._internal.cli.status_codes import UNKNOWN_ERROR
 from pip._internal.configuration import Configuration, ConfigurationError
@@ -18,20 +18,19 @@ logger = logging.getLogger(__name__)
 class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
     """A prettier/less verbose help formatter for optparse."""
 
-    def __init__(self, *args, **kwargs):
-        # type: (*Any, **Any) -> None
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
         # help position must be aligned with __init__.parseopts.description
         kwargs["max_help_position"] = 30
         kwargs["indent_increment"] = 1
         kwargs["width"] = shutil.get_terminal_size()[0] - 2
         super().__init__(*args, **kwargs)
 
-    def format_option_strings(self, option):
-        # type: (optparse.Option) -> str
+    def format_option_strings(self, option: optparse.Option) -> str:
         return self._format_option_strings(option)
 
-    def _format_option_strings(self, option, mvarfmt=" <{}>", optsep=", "):
-        # type: (optparse.Option, str, str) -> str
+    def _format_option_strings(
+        self, option: optparse.Option, mvarfmt: str = " <{}>", optsep: str = ", "
+    ) -> str:
         """
         Return a comma-separated list of option strings and metavars.
 
@@ -55,14 +54,12 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
 
         return "".join(opts)
 
-    def format_heading(self, heading):
-        # type: (str) -> str
+    def format_heading(self, heading: str) -> str:
         if heading == "Options":
             return ""
         return heading + ":\n"
 
-    def format_usage(self, usage):
-        # type: (str) -> str
+    def format_usage(self, usage: str) -> str:
         """
         Ensure there is only one newline between usage and the first heading
         if there is no description.
@@ -70,8 +67,7 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
         msg = "\nUsage: {}\n".format(self.indent_lines(textwrap.dedent(usage), "  "))
         return msg
 
-    def format_description(self, description):
-        # type: (str) -> str
+    def format_description(self, description: str) -> str:
         # leave full control over description to us
         if description:
             if hasattr(self.parser, "main"):
@@ -89,16 +85,14 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
         else:
             return ""
 
-    def format_epilog(self, epilog):
-        # type: (str) -> str
+    def format_epilog(self, epilog: str) -> str:
         # leave full control over epilog to us
         if epilog:
             return epilog
         else:
             return ""
 
-    def indent_lines(self, text, indent):
-        # type: (str, str) -> str
+    def indent_lines(self, text: str, indent: str) -> str:
         new_lines = [indent + line for line in text.split("\n")]
         return "\n".join(new_lines)
 
@@ -112,8 +106,7 @@ class UpdatingDefaultsHelpFormatter(PrettyHelpFormatter):
     Also redact auth from url type options
     """
 
-    def expand_default(self, option):
-        # type: (optparse.Option) -> str
+    def expand_default(self, option: optparse.Option) -> str:
         default_values = None
         if self.parser is not None:
             assert isinstance(self.parser, ConfigOptionParser)
@@ -137,8 +130,9 @@ class UpdatingDefaultsHelpFormatter(PrettyHelpFormatter):
 
 
 class CustomOptionParser(optparse.OptionParser):
-    def insert_option_group(self, idx, *args, **kwargs):
-        # type: (int, Any, Any) -> optparse.OptionGroup
+    def insert_option_group(
+        self, idx: int, *args: Any, **kwargs: Any
+    ) -> optparse.OptionGroup:
         """Insert an OptionGroup at a given position."""
         group = self.add_option_group(*args, **kwargs)
 
@@ -148,8 +142,7 @@ class CustomOptionParser(optparse.OptionParser):
         return group
 
     @property
-    def option_list_all(self):
-        # type: () -> List[optparse.Option]
+    def option_list_all(self) -> List[optparse.Option]:
         """Get a list of all options, including those in option groups."""
         res = self.option_list[:]
         for i in self.option_groups:
@@ -164,35 +157,34 @@ class ConfigOptionParser(CustomOptionParser):
 
     def __init__(
         self,
-        *args,  # type: Any
-        name,  # type: str
-        isolated=False,  # type: bool
-        **kwargs,  # type: Any
-    ):
-        # type: (...) -> None
+        *args: Any,
+        name: str,
+        isolated: bool = False,
+        **kwargs: Any,
+    ) -> None:
         self.name = name
         self.config = Configuration(isolated)
 
         assert self.name
         super().__init__(*args, **kwargs)
 
-    def check_default(self, option, key, val):
-        # type: (optparse.Option, str, Any) -> Any
+    def check_default(self, option: optparse.Option, key: str, val: Any) -> Any:
         try:
             return option.check_value(key, val)
         except optparse.OptionValueError as exc:
             print(f"An error occurred during configuration: {exc}")
             sys.exit(3)
 
-    def _get_ordered_configuration_items(self):
-        # type: () -> Iterator[Tuple[str, Any]]
+    def _get_ordered_configuration_items(
+        self,
+    ) -> Generator[Tuple[str, Any], None, None]:
         # Configuration gives keys in an unordered manner. Order them.
         override_order = ["global", self.name, ":env:"]
 
         # Pool the options into different groups
-        section_items = {
+        section_items: Dict[str, List[Tuple[str, Any]]] = {
             name: [] for name in override_order
-        }  # type: Dict[str, List[Tuple[str, Any]]]
+        }
         for section_key, val in self.config.items():
             # ignore empty values
             if not val:
@@ -211,8 +203,7 @@ class ConfigOptionParser(CustomOptionParser):
             for key, val in section_items[section]:
                 yield key, val
 
-    def _update_defaults(self, defaults):
-        # type: (Dict[str, Any]) -> Dict[str, Any]
+    def _update_defaults(self, defaults: Dict[str, Any]) -> Dict[str, Any]:
         """Updates the given defaults with values from the config files and
         the environ. Does a little special handling for certain types of
         options (lists)."""
@@ -276,8 +267,7 @@ class ConfigOptionParser(CustomOptionParser):
         self.values = None
         return defaults
 
-    def get_default_values(self):
-        # type: () -> optparse.Values
+    def get_default_values(self) -> optparse.Values:
         """Overriding to make updating the defaults after instantiation of
         the option parser possible, _update_defaults() does the dirty work."""
         if not self.process_default_values:
@@ -299,7 +289,6 @@ class ConfigOptionParser(CustomOptionParser):
                 defaults[option.dest] = option.check_value(opt_str, default)
         return optparse.Values(defaults)
 
-    def error(self, msg):
-        # type: (str) -> None
+    def error(self, msg: str) -> None:
         self.print_usage(sys.stderr)
         self.exit(UNKNOWN_ERROR, f"{msg}\n")

venv/Lib/site-packages/pip/_internal/cli/progress_bars.py

@@ -1,261 +1,68 @@
-import itertools
-import sys
-from signal import SIGINT, default_int_handler, signal
-from typing import Any, Dict, List
+import functools
+from typing import Callable, Generator, Iterable, Iterator, Optional, Tuple
 
-from pip._vendor.progress.bar import Bar, FillingCirclesBar, IncrementalBar
-from pip._vendor.progress.spinner import Spinner
+from pip._vendor.rich.progress import (
+    BarColumn,
+    DownloadColumn,
+    FileSizeColumn,
+    Progress,
+    ProgressColumn,
+    SpinnerColumn,
+    TextColumn,
+    TimeElapsedColumn,
+    TimeRemainingColumn,
+    TransferSpeedColumn,
+)
 
-from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.logging import get_indentation
-from pip._internal.utils.misc import format_size
 
-try:
-    from pip._vendor import colorama
-# Lots of different errors can come from this, including SystemError and
-# ImportError.
-except Exception:
-    colorama = None
+DownloadProgressRenderer = Callable[[Iterable[bytes]], Iterator[bytes]]
 
 
-def _select_progress_class(preferred, fallback):
-    # type: (Bar, Bar) -> Bar
-    encoding = getattr(preferred.file, "encoding", None)
+def _rich_progress_bar(
+    iterable: Iterable[bytes],
+    *,
+    bar_type: str,
+    size: int,
+) -> Generator[bytes, None, None]:
+    assert bar_type == "on", "This should only be used in the default mode."
 
-    # If we don't know what encoding this file is in, then we'll just assume
-    # that it doesn't support unicode and use the ASCII bar.
-    if not encoding:
-        return fallback
-
-    # Collect all of the possible characters we want to use with the preferred
-    # bar.
-    characters = [
-        getattr(preferred, "empty_fill", ""),
-        getattr(preferred, "fill", ""),
-    ]
-    characters += list(getattr(preferred, "phases", []))
-
-    # Try to decode the characters we're using for the bar using the encoding
-    # of the given file, if this works then we'll assume that we can use the
-    # fancier bar and if not we'll fall back to the plaintext bar.
-    try:
-        "".join(characters).encode(encoding)
-    except UnicodeEncodeError:
-        return fallback
+    if not size:
+        total = float("inf")
+        columns: Tuple[ProgressColumn, ...] = (
+            TextColumn("[progress.description]{task.description}"),
+            SpinnerColumn("line", speed=1.5),
+            FileSizeColumn(),
+            TransferSpeedColumn(),
+            TimeElapsedColumn(),
+        )
     else:
-        return preferred
-
-
-_BaseBar = _select_progress_class(IncrementalBar, Bar)  # type: Any
-
-
-class InterruptibleMixin:
-    """
-    Helper to ensure that self.finish() gets called on keyboard interrupt.
-
-    This allows downloads to be interrupted without leaving temporary state
-    (like hidden cursors) behind.
-
-    This class is similar to the progress library's existing SigIntMixin
-    helper, but as of version 1.2, that helper has the following problems:
-
-    1. It calls sys.exit().
-    2. It discards the existing SIGINT handler completely.
-    3. It leaves its own handler in place even after an uninterrupted finish,
-       which will have unexpected delayed effects if the user triggers an
-       unrelated keyboard interrupt some time after a progress-displaying
-       download has already completed, for example.
-    """
-
-    def __init__(self, *args, **kwargs):
-        # type: (List[Any], Dict[Any, Any]) -> None
-        """
-        Save the original SIGINT handler for later.
-        """
-        # https://github.com/python/mypy/issues/5887
-        super().__init__(*args, **kwargs)  # type: ignore
-
-        self.original_handler = signal(SIGINT, self.handle_sigint)
-
-        # If signal() returns None, the previous handler was not installed from
-        # Python, and we cannot restore it. This probably should not happen,
-        # but if it does, we must restore something sensible instead, at least.
-        # The least bad option should be Python's default SIGINT handler, which
-        # just raises KeyboardInterrupt.
-        if self.original_handler is None:
-            self.original_handler = default_int_handler
-
-    def finish(self):
-        # type: () -> None
-        """
-        Restore the original SIGINT handler after finishing.
-
-        This should happen regardless of whether the progress display finishes
-        normally, or gets interrupted.
-        """
-        super().finish()  # type: ignore
-        signal(SIGINT, self.original_handler)
-
-    def handle_sigint(self, signum, frame):  # type: ignore
-        """
-        Call self.finish() before delegating to the original SIGINT handler.
-
-        This handler should only be in place while the progress display is
-        active.
-        """
-        self.finish()
-        self.original_handler(signum, frame)
-
-
-class SilentBar(Bar):
-    def update(self):
-        # type: () -> None
-        pass
-
-
-class BlueEmojiBar(IncrementalBar):
-
-    suffix = "%(percent)d%%"
-    bar_prefix = " "
-    bar_suffix = " "
-    phases = ("\U0001F539", "\U0001F537", "\U0001F535")
-
-
-class DownloadProgressMixin:
-    def __init__(self, *args, **kwargs):
-        # type: (List[Any], Dict[Any, Any]) -> None
-        # https://github.com/python/mypy/issues/5887
-        super().__init__(*args, **kwargs)  # type: ignore
-        self.message = (" " * (get_indentation() + 2)) + self.message  # type: str
-
-    @property
-    def downloaded(self):
-        # type: () -> str
-        return format_size(self.index)  # type: ignore
-
-    @property
-    def download_speed(self):
-        # type: () -> str
-        # Avoid zero division errors...
-        if self.avg == 0.0:  # type: ignore
-            return "..."
-        return format_size(1 / self.avg) + "/s"  # type: ignore
-
-    @property
-    def pretty_eta(self):
-        # type: () -> str
-        if self.eta:  # type: ignore
-            return f"eta {self.eta_td}"  # type: ignore
-        return ""
-
-    def iter(self, it):  # type: ignore
-        for x in it:
-            yield x
-            # B305 is incorrectly raised here
-            # https://github.com/PyCQA/flake8-bugbear/issues/59
-            self.next(len(x))  # noqa: B305
-        self.finish()
-
-
-class WindowsMixin:
-    def __init__(self, *args, **kwargs):
-        # type: (List[Any], Dict[Any, Any]) -> None
-        # The Windows terminal does not support the hide/show cursor ANSI codes
-        # even with colorama. So we'll ensure that hide_cursor is False on
-        # Windows.
-        # This call needs to go before the super() call, so that hide_cursor
-        # is set in time. The base progress bar class writes the "hide cursor"
-        # code to the terminal in its init, so if we don't set this soon
-        # enough, we get a "hide" with no corresponding "show"...
-        if WINDOWS and self.hide_cursor:  # type: ignore
-            self.hide_cursor = False
-
-        # https://github.com/python/mypy/issues/5887
-        super().__init__(*args, **kwargs)  # type: ignore
-
-        # Check if we are running on Windows and we have the colorama module,
-        # if we do then wrap our file with it.
-        if WINDOWS and colorama:
-            self.file = colorama.AnsiToWin32(self.file)  # type: ignore
-            # The progress code expects to be able to call self.file.isatty()
-            # but the colorama.AnsiToWin32() object doesn't have that, so we'll
-            # add it.
-            self.file.isatty = lambda: self.file.wrapped.isatty()
-            # The progress code expects to be able to call self.file.flush()
-            # but the colorama.AnsiToWin32() object doesn't have that, so we'll
-            # add it.
-            self.file.flush = lambda: self.file.wrapped.flush()
-
-
-class BaseDownloadProgressBar(WindowsMixin, InterruptibleMixin, DownloadProgressMixin):
-
-    file = sys.stdout
-    message = "%(percent)d%%"
-    suffix = "%(downloaded)s %(download_speed)s %(pretty_eta)s"
-
-
-class DefaultDownloadProgressBar(BaseDownloadProgressBar, _BaseBar):
-    pass
-
-
-class DownloadSilentBar(BaseDownloadProgressBar, SilentBar):
-    pass
-
-
-class DownloadBar(BaseDownloadProgressBar, Bar):
-    pass
-
-
-class DownloadFillingCirclesBar(BaseDownloadProgressBar, FillingCirclesBar):
-    pass
-
-
-class DownloadBlueEmojiProgressBar(BaseDownloadProgressBar, BlueEmojiBar):
-    pass
-
-
-class DownloadProgressSpinner(
-    WindowsMixin, InterruptibleMixin, DownloadProgressMixin, Spinner
-):
-
-    file = sys.stdout
-    suffix = "%(downloaded)s %(download_speed)s"
-
-    def next_phase(self):
-        # type: () -> str
-        if not hasattr(self, "_phaser"):
-            self._phaser = itertools.cycle(self.phases)
-        return next(self._phaser)
-
-    def update(self):
-        # type: () -> None
-        message = self.message % self
-        phase = self.next_phase()
-        suffix = self.suffix % self
-        line = "".join(
-            [
-                message,
-                " " if message else "",
-                phase,
-                " " if suffix else "",
-                suffix,
-            ]
+        total = size
+        columns = (
+            TextColumn("[progress.description]{task.description}"),
+            BarColumn(),
+            DownloadColumn(),
+            TransferSpeedColumn(),
+            TextColumn("eta"),
+            TimeRemainingColumn(),
         )
 
-        self.writeln(line)
+    progress = Progress(*columns, refresh_per_second=30)
+    task_id = progress.add_task(" " * (get_indentation() + 2), total=total)
+    with progress:
+        for chunk in iterable:
+            yield chunk
+            progress.update(task_id, advance=len(chunk))
 
 
-BAR_TYPES = {
-    "off": (DownloadSilentBar, DownloadSilentBar),
-    "on": (DefaultDownloadProgressBar, DownloadProgressSpinner),
-    "ascii": (DownloadBar, DownloadProgressSpinner),
-    "pretty": (DownloadFillingCirclesBar, DownloadProgressSpinner),
-    "emoji": (DownloadBlueEmojiProgressBar, DownloadProgressSpinner),
-}
+def get_download_progress_renderer(
+    *, bar_type: str, size: Optional[int] = None
+) -> DownloadProgressRenderer:
+    """Get an object that can be used to render the download progress.
 
-
-def DownloadProgressProvider(progress_bar, max=None):  # type: ignore
-    if max is None or max == 0:
-        return BAR_TYPES[progress_bar][1]().iter
+    Returns a callable, that takes an iterable to "wrap".
+    """
+    if bar_type == "on":
+        return functools.partial(_rich_progress_bar, bar_type=bar_type, size=size)
     else:
-        return BAR_TYPES[progress_bar][0](max=max).iter
+        return iter  # no-op, when passed an iterator

venv/Lib/site-packages/pip/_internal/cli/req_command.py

@@ -22,6 +22,7 @@ from pip._internal.index.package_finder import PackageFinder
 from pip._internal.models.selection_prefs import SelectionPreferences
 from pip._internal.models.target_python import TargetPython
 from pip._internal.network.session import PipSession
+from pip._internal.operations.build.build_tracker import BuildTracker
 from pip._internal.operations.prepare import RequirementPreparer
 from pip._internal.req.constructors import (
     install_req_from_editable,
@@ -31,9 +32,9 @@ from pip._internal.req.constructors import (
 )
 from pip._internal.req.req_file import parse_requirements
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_tracker import RequirementTracker
 from pip._internal.resolution.base import BaseResolver
 from pip._internal.self_outdated_check import pip_self_version_check
+from pip._internal.utils.deprecation import deprecated
 from pip._internal.utils.temp_dir import (
     TempDirectory,
     TempDirectoryTypeRegistry,
@@ -50,14 +51,12 @@ class SessionCommandMixin(CommandContextMixIn):
     A class mixin for command classes needing _build_session().
     """
 
-    def __init__(self):
-        # type: () -> None
+    def __init__(self) -> None:
         super().__init__()
-        self._session = None  # Optional[PipSession]
+        self._session: Optional[PipSession] = None
 
     @classmethod
-    def _get_index_urls(cls, options):
-        # type: (Values) -> Optional[List[str]]
+    def _get_index_urls(cls, options: Values) -> Optional[List[str]]:
         """Return a list of index urls from user-provided options."""
         index_urls = []
         if not getattr(options, "no_index", False):
@@ -70,8 +69,7 @@ class SessionCommandMixin(CommandContextMixIn):
         # Return None rather than an empty list
         return index_urls or None
 
-    def get_default_session(self, options):
-        # type: (Values) -> PipSession
+    def get_default_session(self, options: Values) -> PipSession:
         """Get a default-managed session."""
         if self._session is None:
             self._session = self.enter_context(self._build_session(options))
@@ -81,8 +79,12 @@ class SessionCommandMixin(CommandContextMixIn):
             assert self._session is not None
         return self._session
 
-    def _build_session(self, options, retries=None, timeout=None):
-        # type: (Values, Optional[int], Optional[int]) -> PipSession
+    def _build_session(
+        self,
+        options: Values,
+        retries: Optional[int] = None,
+        timeout: Optional[int] = None,
+    ) -> PipSession:
         assert not options.cache_dir or os.path.isabs(options.cache_dir)
         session = PipSession(
             cache=(
@@ -126,8 +128,7 @@ class IndexGroupCommand(Command, SessionCommandMixin):
     This also corresponds to the commands that permit the pip version check.
     """
 
-    def handle_pip_version_check(self, options):
-        # type: (Values) -> None
+    def handle_pip_version_check(self, options: Values) -> None:
         """
         Do the pip version check if not disabled.
 
@@ -154,8 +155,7 @@ KEEPABLE_TEMPDIR_TYPES = [
 ]
 
 
-def warn_if_run_as_root():
-    # type: () -> None
+def warn_if_run_as_root() -> None:
     """Output a warning for sudo users on Unix.
 
     In a virtual environment, sudo pip still writes to virtualenv.
@@ -173,29 +173,30 @@ def warn_if_run_as_root():
     # checks: https://mypy.readthedocs.io/en/stable/common_issues.html
     if sys.platform == "win32" or sys.platform == "cygwin":
         return
-    if sys.platform == "darwin" or sys.platform == "linux":
-        if os.getuid() != 0:
-            return
+
+    if os.getuid() != 0:
+        return
+
     logger.warning(
-        "Running pip as root will break packages and permissions. "
-        "You should install packages reliably by using venv: "
+        "Running pip as the 'root' user can result in broken permissions and "
+        "conflicting behaviour with the system package manager. "
+        "It is recommended to use a virtual environment instead: "
         "https://pip.pypa.io/warnings/venv"
     )
 
 
-def with_cleanup(func):
-    # type: (Any) -> Any
+def with_cleanup(func: Any) -> Any:
     """Decorator for common logic related to managing temporary
     directories.
     """
 
-    def configure_tempdir_registry(registry):
-        # type: (TempDirectoryTypeRegistry) -> None
+    def configure_tempdir_registry(registry: TempDirectoryTypeRegistry) -> None:
         for t in KEEPABLE_TEMPDIR_TYPES:
             registry.set_delete(t, False)
 
-    def wrapper(self, options, args):
-        # type: (RequirementCommand, Values, List[Any]) -> Optional[int]
+    def wrapper(
+        self: RequirementCommand, options: Values, args: List[Any]
+    ) -> Optional[int]:
         assert self.tempdir_registry is not None
         if options.no_clean:
             configure_tempdir_registry(self.tempdir_registry)
@@ -213,33 +214,56 @@ def with_cleanup(func):
 
 
 class RequirementCommand(IndexGroupCommand):
-    def __init__(self, *args, **kw):
-        # type: (Any, Any) -> None
+    def __init__(self, *args: Any, **kw: Any) -> None:
         super().__init__(*args, **kw)
 
         self.cmd_opts.add_option(cmdoptions.no_clean())
 
     @staticmethod
-    def determine_resolver_variant(options):
-        # type: (Values) -> str
+    def determine_resolver_variant(options: Values) -> str:
         """Determines which resolver should be used, based on the given options."""
         if "legacy-resolver" in options.deprecated_features_enabled:
             return "legacy"
 
         return "2020-resolver"
 
+    @staticmethod
+    def determine_build_failure_suppression(options: Values) -> bool:
+        """Determines whether build failures should be suppressed and backtracked on."""
+        if "backtrack-on-build-failures" not in options.deprecated_features_enabled:
+            return False
+
+        if "legacy-resolver" in options.deprecated_features_enabled:
+            raise CommandError("Cannot backtrack with legacy resolver.")
+
+        deprecated(
+            reason=(
+                "Backtracking on build failures can mask issues related to how "
+                "a package generates metadata or builds a wheel. This flag will "
+                "be removed in pip 22.2."
+            ),
+            gone_in=None,
+            replacement=(
+                "avoiding known-bad versions by explicitly telling pip to ignore them "
+                "(either directly as requirements, or via a constraints file)"
+            ),
+            feature_flag=None,
+            issue=10655,
+        )
+        return True
+
     @classmethod
     def make_requirement_preparer(
         cls,
-        temp_build_dir,  # type: TempDirectory
-        options,  # type: Values
-        req_tracker,  # type: RequirementTracker
-        session,  # type: PipSession
-        finder,  # type: PackageFinder
-        use_user_site,  # type: bool
-        download_dir=None,  # type: str
-    ):
-        # type: (...) -> RequirementPreparer
+        temp_build_dir: TempDirectory,
+        options: Values,
+        build_tracker: BuildTracker,
+        session: PipSession,
+        finder: PackageFinder,
+        use_user_site: bool,
+        download_dir: Optional[str] = None,
+        verbosity: int = 0,
+    ) -> RequirementPreparer:
         """
         Create a RequirementPreparer instance for the given parameters.
         """
@@ -269,32 +293,32 @@ class RequirementCommand(IndexGroupCommand):
             src_dir=options.src_dir,
             download_dir=download_dir,
             build_isolation=options.build_isolation,
-            req_tracker=req_tracker,
+            check_build_deps=options.check_build_deps,
+            build_tracker=build_tracker,
             session=session,
             progress_bar=options.progress_bar,
             finder=finder,
             require_hashes=options.require_hashes,
             use_user_site=use_user_site,
             lazy_wheel=lazy_wheel,
-            in_tree_build="in-tree-build" in options.features_enabled,
+            verbosity=verbosity,
         )
 
     @classmethod
     def make_resolver(
         cls,
-        preparer,  # type: RequirementPreparer
-        finder,  # type: PackageFinder
-        options,  # type: Values
-        wheel_cache=None,  # type: Optional[WheelCache]
-        use_user_site=False,  # type: bool
-        ignore_installed=True,  # type: bool
-        ignore_requires_python=False,  # type: bool
-        force_reinstall=False,  # type: bool
-        upgrade_strategy="to-satisfy-only",  # type: str
-        use_pep517=None,  # type: Optional[bool]
-        py_version_info=None,  # type: Optional[Tuple[int, ...]]
-    ):
-        # type: (...) -> BaseResolver
+        preparer: RequirementPreparer,
+        finder: PackageFinder,
+        options: Values,
+        wheel_cache: Optional[WheelCache] = None,
+        use_user_site: bool = False,
+        ignore_installed: bool = True,
+        ignore_requires_python: bool = False,
+        force_reinstall: bool = False,
+        upgrade_strategy: str = "to-satisfy-only",
+        use_pep517: Optional[bool] = None,
+        py_version_info: Optional[Tuple[int, ...]] = None,
+    ) -> BaseResolver:
         """
         Create a Resolver instance for the given parameters.
         """
@@ -302,7 +326,9 @@ class RequirementCommand(IndexGroupCommand):
             install_req_from_req_string,
             isolated=options.isolated_mode,
             use_pep517=use_pep517,
+            config_settings=getattr(options, "config_settings", None),
         )
+        suppress_build_failures = cls.determine_build_failure_suppression(options)
         resolver_variant = cls.determine_resolver_variant(options)
         # The long import name and duplicated invocation is needed to convince
         # Mypy into correctly typechecking. Otherwise it would complain the
@@ -322,6 +348,7 @@ class RequirementCommand(IndexGroupCommand):
                 force_reinstall=force_reinstall,
                 upgrade_strategy=upgrade_strategy,
                 py_version_info=py_version_info,
+                suppress_build_failures=suppress_build_failures,
             )
         import pip._internal.resolution.legacy.resolver
 
@@ -341,16 +368,15 @@ class RequirementCommand(IndexGroupCommand):
 
     def get_requirements(
         self,
-        args,  # type: List[str]
-        options,  # type: Values
-        finder,  # type: PackageFinder
-        session,  # type: PipSession
-    ):
-        # type: (...) -> List[InstallRequirement]
+        args: List[str],
+        options: Values,
+        finder: PackageFinder,
+        session: PipSession,
+    ) -> List[InstallRequirement]:
         """
         Parse command-line arguments into the corresponding requirements.
         """
-        requirements = []  # type: List[InstallRequirement]
+        requirements: List[InstallRequirement] = []
         for filename in options.constraints:
             for parsed_req in parse_requirements(
                 filename,
@@ -373,6 +399,7 @@ class RequirementCommand(IndexGroupCommand):
                 isolated=options.isolated_mode,
                 use_pep517=options.use_pep517,
                 user_supplied=True,
+                config_settings=getattr(options, "config_settings", None),
             )
             requirements.append(req_to_add)
 
@@ -382,6 +409,7 @@ class RequirementCommand(IndexGroupCommand):
                 user_supplied=True,
                 isolated=options.isolated_mode,
                 use_pep517=options.use_pep517,
+                config_settings=getattr(options, "config_settings", None),
             )
             requirements.append(req_to_add)
 
@@ -420,8 +448,7 @@ class RequirementCommand(IndexGroupCommand):
         return requirements
 
     @staticmethod
-    def trace_basic_info(finder):
-        # type: (PackageFinder) -> None
+    def trace_basic_info(finder: PackageFinder) -> None:
         """
         Trace basic information about the provided objects.
         """
@@ -433,12 +460,11 @@ class RequirementCommand(IndexGroupCommand):
 
     def _build_package_finder(
         self,
-        options,  # type: Values
-        session,  # type: PipSession
-        target_python=None,  # type: Optional[TargetPython]
-        ignore_requires_python=None,  # type: Optional[bool]
-    ):
-        # type: (...) -> PackageFinder
+        options: Values,
+        session: PipSession,
+        target_python: Optional[TargetPython] = None,
+        ignore_requires_python: Optional[bool] = None,
+    ) -> PackageFinder:
         """
         Create a package finder appropriate to this requirement command.
 
@@ -458,4 +484,5 @@ class RequirementCommand(IndexGroupCommand):
             link_collector=link_collector,
             selection_prefs=selection_prefs,
             target_python=target_python,
+            use_deprecated_html5lib="html5lib" in options.deprecated_features_enabled,
         )

venv/Lib/site-packages/pip/_internal/cli/spinners.py

@@ -3,9 +3,7 @@ import itertools
 import logging
 import sys
 import time
-from typing import IO, Iterator
-
-from pip._vendor.progress import HIDE_CURSOR, SHOW_CURSOR
+from typing import IO, Generator
 
 from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.logging import get_indentation
@@ -14,25 +12,22 @@ logger = logging.getLogger(__name__)
 
 
 class SpinnerInterface:
-    def spin(self):
-        # type: () -> None
+    def spin(self) -> None:
         raise NotImplementedError()
 
-    def finish(self, final_status):
-        # type: (str) -> None
+    def finish(self, final_status: str) -> None:
         raise NotImplementedError()
 
 
 class InteractiveSpinner(SpinnerInterface):
     def __init__(
         self,
-        message,
-        file=None,
-        spin_chars="-\\|/",
+        message: str,
+        file: IO[str] = None,
+        spin_chars: str = "-\\|/",
         # Empirically, 8 updates/second looks nice
-        min_update_interval_seconds=0.125,
+        min_update_interval_seconds: float = 0.125,
     ):
-        # type: (str, IO[str], str, float) -> None
         self._message = message
         if file is None:
             file = sys.stdout
@@ -45,8 +40,7 @@ class InteractiveSpinner(SpinnerInterface):
         self._file.write(" " * get_indentation() + self._message + " ... ")
         self._width = 0
 
-    def _write(self, status):
-        # type: (str) -> None
+    def _write(self, status: str) -> None:
         assert not self._finished
         # Erase what we wrote before by backspacing to the beginning, writing
         # spaces to overwrite the old text, and then backspacing again
@@ -58,16 +52,14 @@ class InteractiveSpinner(SpinnerInterface):
         self._file.flush()
         self._rate_limiter.reset()
 
-    def spin(self):
-        # type: () -> None
+    def spin(self) -> None:
         if self._finished:
             return
         if not self._rate_limiter.ready():
             return
         self._write(next(self._spin_cycle))
 
-    def finish(self, final_status):
-        # type: (str) -> None
+    def finish(self, final_status: str) -> None:
         if self._finished:
             return
         self._write(final_status)
@@ -81,29 +73,25 @@ class InteractiveSpinner(SpinnerInterface):
 # act as a keep-alive for systems like Travis-CI that take lack-of-output as
 # an indication that a task has frozen.
 class NonInteractiveSpinner(SpinnerInterface):
-    def __init__(self, message, min_update_interval_seconds=60):
-        # type: (str, float) -> None
+    def __init__(self, message: str, min_update_interval_seconds: float = 60.0) -> None:
         self._message = message
         self._finished = False
         self._rate_limiter = RateLimiter(min_update_interval_seconds)
         self._update("started")
 
-    def _update(self, status):
-        # type: (str) -> None
+    def _update(self, status: str) -> None:
         assert not self._finished
         self._rate_limiter.reset()
         logger.info("%s: %s", self._message, status)
 
-    def spin(self):
-        # type: () -> None
+    def spin(self) -> None:
         if self._finished:
             return
         if not self._rate_limiter.ready():
             return
         self._update("still running...")
 
-    def finish(self, final_status):
-        # type: (str) -> None
+    def finish(self, final_status: str) -> None:
         if self._finished:
             return
         self._update(f"finished with status '{final_status}'")
@@ -111,32 +99,28 @@ class NonInteractiveSpinner(SpinnerInterface):
 
 
 class RateLimiter:
-    def __init__(self, min_update_interval_seconds):
-        # type: (float) -> None
+    def __init__(self, min_update_interval_seconds: float) -> None:
         self._min_update_interval_seconds = min_update_interval_seconds
-        self._last_update = 0  # type: float
+        self._last_update: float = 0
 
-    def ready(self):
-        # type: () -> bool
+    def ready(self) -> bool:
         now = time.time()
         delta = now - self._last_update
         return delta >= self._min_update_interval_seconds
 
-    def reset(self):
-        # type: () -> None
+    def reset(self) -> None:
         self._last_update = time.time()
 
 
 @contextlib.contextmanager
-def open_spinner(message):
-    # type: (str) -> Iterator[SpinnerInterface]
+def open_spinner(message: str) -> Generator[SpinnerInterface, None, None]:
     # Interactive spinner goes directly to sys.stdout rather than being routed
     # through the logging system, but it acts like it has level INFO,
     # i.e. it's only displayed if we're at level INFO or better.
     # Non-interactive spinner goes through the logging system, so it is always
     # in sync with logging configuration.
     if sys.stdout.isatty() and logger.getEffectiveLevel() <= logging.INFO:
-        spinner = InteractiveSpinner(message)  # type: SpinnerInterface
+        spinner: SpinnerInterface = InteractiveSpinner(message)
     else:
         spinner = NonInteractiveSpinner(message)
     try:
@@ -152,9 +136,12 @@ def open_spinner(message):
         spinner.finish("done")
 
 
+HIDE_CURSOR = "\x1b[?25l"
+SHOW_CURSOR = "\x1b[?25h"
+
+
 @contextlib.contextmanager
-def hidden_cursor(file):
-    # type: (IO[str]) -> Iterator[None]
+def hidden_cursor(file: IO[str]) -> Generator[None, None, None]:
     # The Windows terminal does not support the hide/show cursor ANSI codes,
     # even via colorama. So don't even try.
     if WINDOWS:

venv/Lib/site-packages/pip/_internal/commands/__init__.py

@@ -3,87 +3,105 @@ Package containing all pip commands
 """
 
 import importlib
-from collections import OrderedDict, namedtuple
-from typing import Any, Optional
+from collections import namedtuple
+from typing import Any, Dict, Optional
 
 from pip._internal.cli.base_command import Command
 
-CommandInfo = namedtuple('CommandInfo', 'module_path, class_name, summary')
+CommandInfo = namedtuple("CommandInfo", "module_path, class_name, summary")
 
-# The ordering matters for help display.
-#    Also, even though the module path starts with the same
-# "pip._internal.commands" prefix in each case, we include the full path
-# because it makes testing easier (specifically when modifying commands_dict
-# in test setup / teardown by adding info for a FakeCommand class defined
-# in a test-related module).
-#    Finally, we need to pass an iterable of pairs here rather than a dict
-# so that the ordering won't be lost when using Python 2.7.
-commands_dict = OrderedDict([
-    ('install', CommandInfo(
-        'pip._internal.commands.install', 'InstallCommand',
-        'Install packages.',
-    )),
-    ('download', CommandInfo(
-        'pip._internal.commands.download', 'DownloadCommand',
-        'Download packages.',
-    )),
-    ('uninstall', CommandInfo(
-        'pip._internal.commands.uninstall', 'UninstallCommand',
-        'Uninstall packages.',
-    )),
-    ('freeze', CommandInfo(
-        'pip._internal.commands.freeze', 'FreezeCommand',
-        'Output installed packages in requirements format.',
-    )),
-    ('list', CommandInfo(
-        'pip._internal.commands.list', 'ListCommand',
-        'List installed packages.',
-    )),
-    ('show', CommandInfo(
-        'pip._internal.commands.show', 'ShowCommand',
-        'Show information about installed packages.',
-    )),
-    ('check', CommandInfo(
-        'pip._internal.commands.check', 'CheckCommand',
-        'Verify installed packages have compatible dependencies.',
-    )),
-    ('config', CommandInfo(
-        'pip._internal.commands.configuration', 'ConfigurationCommand',
-        'Manage local and global configuration.',
-    )),
-    ('search', CommandInfo(
-        'pip._internal.commands.search', 'SearchCommand',
-        'Search PyPI for packages.',
-    )),
-    ('cache', CommandInfo(
-        'pip._internal.commands.cache', 'CacheCommand',
+# This dictionary does a bunch of heavy lifting for help output:
+# - Enables avoiding additional (costly) imports for presenting `--help`.
+# - The ordering matters for help display.
+#
+# Even though the module path starts with the same "pip._internal.commands"
+# prefix, the full path makes testing easier (specifically when modifying
+# `commands_dict` in test setup / teardown).
+commands_dict: Dict[str, CommandInfo] = {
+    "install": CommandInfo(
+        "pip._internal.commands.install",
+        "InstallCommand",
+        "Install packages.",
+    ),
+    "download": CommandInfo(
+        "pip._internal.commands.download",
+        "DownloadCommand",
+        "Download packages.",
+    ),
+    "uninstall": CommandInfo(
+        "pip._internal.commands.uninstall",
+        "UninstallCommand",
+        "Uninstall packages.",
+    ),
+    "freeze": CommandInfo(
+        "pip._internal.commands.freeze",
+        "FreezeCommand",
+        "Output installed packages in requirements format.",
+    ),
+    "list": CommandInfo(
+        "pip._internal.commands.list",
+        "ListCommand",
+        "List installed packages.",
+    ),
+    "show": CommandInfo(
+        "pip._internal.commands.show",
+        "ShowCommand",
+        "Show information about installed packages.",
+    ),
+    "check": CommandInfo(
+        "pip._internal.commands.check",
+        "CheckCommand",
+        "Verify installed packages have compatible dependencies.",
+    ),
+    "config": CommandInfo(
+        "pip._internal.commands.configuration",
+        "ConfigurationCommand",
+        "Manage local and global configuration.",
+    ),
+    "search": CommandInfo(
+        "pip._internal.commands.search",
+        "SearchCommand",
+        "Search PyPI for packages.",
+    ),
+    "cache": CommandInfo(
+        "pip._internal.commands.cache",
+        "CacheCommand",
         "Inspect and manage pip's wheel cache.",
-    )),
-    ('wheel', CommandInfo(
-        'pip._internal.commands.wheel', 'WheelCommand',
-        'Build wheels from your requirements.',
-    )),
-    ('hash', CommandInfo(
-        'pip._internal.commands.hash', 'HashCommand',
-        'Compute hashes of package archives.',
-    )),
-    ('completion', CommandInfo(
-        'pip._internal.commands.completion', 'CompletionCommand',
-        'A helper command used for command completion.',
-    )),
-    ('debug', CommandInfo(
-        'pip._internal.commands.debug', 'DebugCommand',
-        'Show information useful for debugging.',
-    )),
-    ('help', CommandInfo(
-        'pip._internal.commands.help', 'HelpCommand',
-        'Show help for commands.',
-    )),
-])  # type: OrderedDict[str, CommandInfo]
+    ),
+    "index": CommandInfo(
+        "pip._internal.commands.index",
+        "IndexCommand",
+        "Inspect information available from package indexes.",
+    ),
+    "wheel": CommandInfo(
+        "pip._internal.commands.wheel",
+        "WheelCommand",
+        "Build wheels from your requirements.",
+    ),
+    "hash": CommandInfo(
+        "pip._internal.commands.hash",
+        "HashCommand",
+        "Compute hashes of package archives.",
+    ),
+    "completion": CommandInfo(
+        "pip._internal.commands.completion",
+        "CompletionCommand",
+        "A helper command used for command completion.",
+    ),
+    "debug": CommandInfo(
+        "pip._internal.commands.debug",
+        "DebugCommand",
+        "Show information useful for debugging.",
+    ),
+    "help": CommandInfo(
+        "pip._internal.commands.help",
+        "HelpCommand",
+        "Show help for commands.",
+    ),
+}
 
 
-def create_command(name, **kwargs):
-    # type: (str, **Any) -> Command
+def create_command(name: str, **kwargs: Any) -> Command:
     """
     Create an instance of the Command class with the given name.
     """
@@ -95,8 +113,7 @@ def create_command(name, **kwargs):
     return command
 
 
-def get_similar_commands(name):
-    # type: (str) -> Optional[str]
+def get_similar_commands(name: str) -> Optional[str]:
     """Command name auto-correct."""
     from difflib import get_close_matches
 

venv/Lib/site-packages/pip/_internal/commands/cache.py

@@ -1,4 +1,3 @@
-import logging
 import os
 import textwrap
 from optparse import Values
@@ -8,8 +7,9 @@ import pip._internal.utils.filesystem as filesystem
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.status_codes import ERROR, SUCCESS
 from pip._internal.exceptions import CommandError, PipError
+from pip._internal.utils.logging import getLogger
 
-logger = logging.getLogger(__name__)
+logger = getLogger(__name__)
 
 
 class CacheCommand(Command):
@@ -36,22 +36,20 @@ class CacheCommand(Command):
         %prog purge
     """
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
 
         self.cmd_opts.add_option(
-            '--format',
-            action='store',
-            dest='list_format',
+            "--format",
+            action="store",
+            dest="list_format",
             default="human",
-            choices=('human', 'abspath'),
-            help="Select the output format among: human (default) or abspath"
+            choices=("human", "abspath"),
+            help="Select the output format among: human (default) or abspath",
         )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options, args):
-        # type: (Values, List[Any]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         handlers = {
             "dir": self.get_cache_dir,
             "info": self.get_cache_info,
@@ -61,8 +59,7 @@ class CacheCommand(Command):
         }
 
         if not options.cache_dir:
-            logger.error("pip cache commands can not "
-                         "function since cache is disabled.")
+            logger.error("pip cache commands can not function since cache is disabled.")
             return ERROR
 
         # Determine action
@@ -84,78 +81,77 @@ class CacheCommand(Command):
 
         return SUCCESS
 
-    def get_cache_dir(self, options, args):
-        # type: (Values, List[Any]) -> None
+    def get_cache_dir(self, options: Values, args: List[Any]) -> None:
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         logger.info(options.cache_dir)
 
-    def get_cache_info(self, options, args):
-        # type: (Values, List[Any]) -> None
+    def get_cache_info(self, options: Values, args: List[Any]) -> None:
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         num_http_files = len(self._find_http_files(options))
-        num_packages = len(self._find_wheels(options, '*'))
+        num_packages = len(self._find_wheels(options, "*"))
 
-        http_cache_location = self._cache_dir(options, 'http')
-        wheels_cache_location = self._cache_dir(options, 'wheels')
+        http_cache_location = self._cache_dir(options, "http")
+        wheels_cache_location = self._cache_dir(options, "wheels")
         http_cache_size = filesystem.format_directory_size(http_cache_location)
-        wheels_cache_size = filesystem.format_directory_size(
-            wheels_cache_location
-        )
+        wheels_cache_size = filesystem.format_directory_size(wheels_cache_location)
 
-        message = textwrap.dedent("""
-            Package index page cache location: {http_cache_location}
-            Package index page cache size: {http_cache_size}
-            Number of HTTP files: {num_http_files}
-            Wheels location: {wheels_cache_location}
-            Wheels size: {wheels_cache_size}
-            Number of wheels: {package_count}
-        """).format(
-            http_cache_location=http_cache_location,
-            http_cache_size=http_cache_size,
-            num_http_files=num_http_files,
-            wheels_cache_location=wheels_cache_location,
-            package_count=num_packages,
-            wheels_cache_size=wheels_cache_size,
-        ).strip()
+        message = (
+            textwrap.dedent(
+                """
+                    Package index page cache location: {http_cache_location}
+                    Package index page cache size: {http_cache_size}
+                    Number of HTTP files: {num_http_files}
+                    Wheels location: {wheels_cache_location}
+                    Wheels size: {wheels_cache_size}
+                    Number of wheels: {package_count}
+                """
+            )
+            .format(
+                http_cache_location=http_cache_location,
+                http_cache_size=http_cache_size,
+                num_http_files=num_http_files,
+                wheels_cache_location=wheels_cache_location,
+                package_count=num_packages,
+                wheels_cache_size=wheels_cache_size,
+            )
+            .strip()
+        )
 
         logger.info(message)
 
-    def list_cache_items(self, options, args):
-        # type: (Values, List[Any]) -> None
+    def list_cache_items(self, options: Values, args: List[Any]) -> None:
         if len(args) > 1:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         if args:
             pattern = args[0]
         else:
-            pattern = '*'
+            pattern = "*"
 
         files = self._find_wheels(options, pattern)
-        if options.list_format == 'human':
+        if options.list_format == "human":
             self.format_for_human(files)
         else:
             self.format_for_abspath(files)
 
-    def format_for_human(self, files):
-        # type: (List[str]) -> None
+    def format_for_human(self, files: List[str]) -> None:
         if not files:
-            logger.info('Nothing cached.')
+            logger.info("Nothing cached.")
             return
 
         results = []
         for filename in files:
             wheel = os.path.basename(filename)
             size = filesystem.format_file_size(filename)
-            results.append(f' - {wheel} ({size})')
-        logger.info('Cache contents:\n')
-        logger.info('\n'.join(sorted(results)))
+            results.append(f" - {wheel} ({size})")
+        logger.info("Cache contents:\n")
+        logger.info("\n".join(sorted(results)))
 
-    def format_for_abspath(self, files):
-        # type: (List[str]) -> None
+    def format_for_abspath(self, files: List[str]) -> None:
         if not files:
             return
 
@@ -163,49 +159,48 @@ class CacheCommand(Command):
         for filename in files:
             results.append(filename)
 
-        logger.info('\n'.join(sorted(results)))
+        logger.info("\n".join(sorted(results)))
 
-    def remove_cache_items(self, options, args):
-        # type: (Values, List[Any]) -> None
+    def remove_cache_items(self, options: Values, args: List[Any]) -> None:
         if len(args) > 1:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
         if not args:
-            raise CommandError('Please provide a pattern')
+            raise CommandError("Please provide a pattern")
 
         files = self._find_wheels(options, args[0])
 
-        # Only fetch http files if no specific pattern given
-        if args[0] == '*':
+        no_matching_msg = "No matching packages"
+        if args[0] == "*":
+            # Only fetch http files if no specific pattern given
             files += self._find_http_files(options)
+        else:
+            # Add the pattern to the log message
+            no_matching_msg += ' for pattern "{}"'.format(args[0])
 
         if not files:
-            raise CommandError('No matching packages')
+            logger.warning(no_matching_msg)
 
         for filename in files:
             os.unlink(filename)
-            logger.debug('Removed %s', filename)
-        logger.info('Files removed: %s', len(files))
+            logger.verbose("Removed %s", filename)
+        logger.info("Files removed: %s", len(files))
 
-    def purge_cache(self, options, args):
-        # type: (Values, List[Any]) -> None
+    def purge_cache(self, options: Values, args: List[Any]) -> None:
         if args:
-            raise CommandError('Too many arguments')
+            raise CommandError("Too many arguments")
 
-        return self.remove_cache_items(options, ['*'])
+        return self.remove_cache_items(options, ["*"])
 
-    def _cache_dir(self, options, subdir):
-        # type: (Values, str) -> str
+    def _cache_dir(self, options: Values, subdir: str) -> str:
         return os.path.join(options.cache_dir, subdir)
 
-    def _find_http_files(self, options):
-        # type: (Values) -> List[str]
-        http_dir = self._cache_dir(options, 'http')
-        return filesystem.find_files(http_dir, '*')
+    def _find_http_files(self, options: Values) -> List[str]:
+        http_dir = self._cache_dir(options, "http")
+        return filesystem.find_files(http_dir, "*")
 
-    def _find_wheels(self, options, pattern):
-        # type: (Values, str) -> List[str]
-        wheel_dir = self._cache_dir(options, 'wheels')
+    def _find_wheels(self, options: Values, pattern: str) -> List[str]:
+        wheel_dir = self._cache_dir(options, "wheels")
 
         # The wheel filename format, as specified in PEP 427, is:
         #     {distribution}-{version}(-{build})?-{python}-{abi}-{platform}.whl

venv/Lib/site-packages/pip/_internal/commands/check.py

@@ -1,6 +1,6 @@
 import logging
 from optparse import Values
-from typing import Any, List
+from typing import List
 
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.status_codes import ERROR, SUCCESS
@@ -19,8 +19,7 @@ class CheckCommand(Command):
     usage = """
       %prog [options]"""
 
-    def run(self, options, args):
-        # type: (Values, List[Any]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
 
         package_set, parsing_probs = create_package_set_from_installed()
         missing, conflicting = check_package_set(package_set)
@@ -30,7 +29,9 @@ class CheckCommand(Command):
             for dependency in missing[project_name]:
                 write_output(
                     "%s %s requires %s, which is not installed.",
-                    project_name, version, dependency[0],
+                    project_name,
+                    version,
+                    dependency[0],
                 )
 
         for project_name in conflicting:
@@ -38,7 +39,11 @@ class CheckCommand(Command):
             for dep_name, dep_version, req in conflicting[project_name]:
                 write_output(
                     "%s %s has requirement %s, but you have %s %s.",
-                    project_name, version, req, dep_name, dep_version,
+                    project_name,
+                    version,
+                    req,
+                    dep_name,
+                    dep_version,
                 )
 
         if missing or conflicting or parsing_probs:

venv/Lib/site-packages/pip/_internal/commands/completion.py

@@ -12,7 +12,7 @@ BASE_COMPLETION = """
 """
 
 COMPLETION_SCRIPTS = {
-    'bash': """
+    "bash": """
         _pip_completion()
         {{
             COMPREPLY=( $( COMP_WORDS="${{COMP_WORDS[*]}}" \\
@@ -21,7 +21,7 @@ COMPLETION_SCRIPTS = {
         }}
         complete -o default -F _pip_completion {prog}
     """,
-    'zsh': """
+    "zsh": """
         function _pip_completion {{
           local words cword
           read -Ac words
@@ -32,7 +32,7 @@ COMPLETION_SCRIPTS = {
         }}
         compctl -K _pip_completion {prog}
     """,
-    'fish': """
+    "fish": """
         function __fish_complete_pip
             set -lx COMP_WORDS (commandline -o) ""
             set -lx COMP_CWORD ( \\
@@ -43,6 +43,28 @@ COMPLETION_SCRIPTS = {
         end
         complete -fa "(__fish_complete_pip)" -c {prog}
     """,
+    "powershell": """
+        if ((Test-Path Function:\\TabExpansion) -and -not `
+            (Test-Path Function:\\_pip_completeBackup)) {{
+            Rename-Item Function:\\TabExpansion _pip_completeBackup
+        }}
+        function TabExpansion($line, $lastWord) {{
+            $lastBlock = [regex]::Split($line, '[|;]')[-1].TrimStart()
+            if ($lastBlock.StartsWith("{prog} ")) {{
+                $Env:COMP_WORDS=$lastBlock
+                $Env:COMP_CWORD=$lastBlock.Split().Length - 1
+                $Env:PIP_AUTO_COMPLETE=1
+                (& {prog}).Split()
+                Remove-Item Env:COMP_WORDS
+                Remove-Item Env:COMP_CWORD
+                Remove-Item Env:PIP_AUTO_COMPLETE
+            }}
+            elseif (Test-Path Function:\\_pip_completeBackup) {{
+                # Fall back on existing tab expansion
+                _pip_completeBackup $line $lastWord
+            }}
+        }}
+    """,
 }
 
 
@@ -51,43 +73,54 @@ class CompletionCommand(Command):
 
     ignore_require_venv = True
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '--bash', '-b',
-            action='store_const',
-            const='bash',
-            dest='shell',
-            help='Emit completion code for bash')
+            "--bash",
+            "-b",
+            action="store_const",
+            const="bash",
+            dest="shell",
+            help="Emit completion code for bash",
+        )
         self.cmd_opts.add_option(
-            '--zsh', '-z',
-            action='store_const',
-            const='zsh',
-            dest='shell',
-            help='Emit completion code for zsh')
+            "--zsh",
+            "-z",
+            action="store_const",
+            const="zsh",
+            dest="shell",
+            help="Emit completion code for zsh",
+        )
         self.cmd_opts.add_option(
-            '--fish', '-f',
-            action='store_const',
-            const='fish',
-            dest='shell',
-            help='Emit completion code for fish')
+            "--fish",
+            "-f",
+            action="store_const",
+            const="fish",
+            dest="shell",
+            help="Emit completion code for fish",
+        )
+        self.cmd_opts.add_option(
+            "--powershell",
+            "-p",
+            action="store_const",
+            const="powershell",
+            dest="shell",
+            help="Emit completion code for powershell",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options, args):
-        #  type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         """Prints the completion code of the given shell"""
         shells = COMPLETION_SCRIPTS.keys()
-        shell_options = ['--' + shell for shell in sorted(shells)]
+        shell_options = ["--" + shell for shell in sorted(shells)]
         if options.shell in shells:
             script = textwrap.dedent(
-                COMPLETION_SCRIPTS.get(options.shell, '').format(
-                    prog=get_prog())
+                COMPLETION_SCRIPTS.get(options.shell, "").format(prog=get_prog())
             )
             print(BASE_COMPLETION.format(script=script, shell=options.shell))
             return SUCCESS
         else:
             sys.stderr.write(
-                'ERROR: You must pass {}\n' .format(' or '.join(shell_options))
+                "ERROR: You must pass {}\n".format(" or ".join(shell_options))
             )
             return SUCCESS

venv/Lib/site-packages/pip/_internal/commands/configuration.py

@@ -27,14 +27,20 @@ class ConfigurationCommand(Command):
 
     - list: List the active configuration (or from the file specified)
     - edit: Edit the configuration file in an editor
-    - get: Get the value associated with name
-    - set: Set the name=value
-    - unset: Unset the value associated with name
+    - get: Get the value associated with command.option
+    - set: Set the command.option=value
+    - unset: Unset the value associated with command.option
     - debug: List the configuration files and values defined under them
 
+    Configuration keys should be dot separated command and option name,
+    with the special prefix "global" affecting any command. For example,
+    "pip config set global.index-url https://example.org/" would configure
+    the index url for all commands, but "pip config set download.timeout 10"
+    would configure a 10 second timeout only for "pip download" commands.
+
     If none of --user, --global and --site are passed, a virtual
     environment configuration file is used if one is active and the file
-    exists. Otherwise, all modifications happen on the to the user file by
+    exists. Otherwise, all modifications happen to the user file by
     default.
     """
 
@@ -43,53 +49,51 @@ class ConfigurationCommand(Command):
         %prog [<file-option>] list
         %prog [<file-option>] [--editor <editor-path>] edit
 
-        %prog [<file-option>] get name
-        %prog [<file-option>] set name value
-        %prog [<file-option>] unset name
+        %prog [<file-option>] get command.option
+        %prog [<file-option>] set command.option value
+        %prog [<file-option>] unset command.option
         %prog [<file-option>] debug
     """
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '--editor',
-            dest='editor',
-            action='store',
+            "--editor",
+            dest="editor",
+            action="store",
             default=None,
             help=(
-                'Editor to use to edit the file. Uses VISUAL or EDITOR '
-                'environment variables if not provided.'
-            )
+                "Editor to use to edit the file. Uses VISUAL or EDITOR "
+                "environment variables if not provided."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--global',
-            dest='global_file',
-            action='store_true',
+            "--global",
+            dest="global_file",
+            action="store_true",
             default=False,
-            help='Use the system-wide configuration file only'
+            help="Use the system-wide configuration file only",
         )
 
         self.cmd_opts.add_option(
-            '--user',
-            dest='user_file',
-            action='store_true',
+            "--user",
+            dest="user_file",
+            action="store_true",
             default=False,
-            help='Use the user configuration file only'
+            help="Use the user configuration file only",
         )
 
         self.cmd_opts.add_option(
-            '--site',
-            dest='site_file',
-            action='store_true',
+            "--site",
+            dest="site_file",
+            action="store_true",
             default=False,
-            help='Use the current environment configuration file only'
+            help="Use the current environment configuration file only",
         )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         handlers = {
             "list": self.list_values,
             "edit": self.open_in_editor,
@@ -134,13 +138,16 @@ class ConfigurationCommand(Command):
 
         return SUCCESS
 
-    def _determine_file(self, options, need_value):
-        # type: (Values, bool) -> Optional[Kind]
-        file_options = [key for key, value in (
-            (kinds.USER, options.user_file),
-            (kinds.GLOBAL, options.global_file),
-            (kinds.SITE, options.site_file),
-        ) if value]
+    def _determine_file(self, options: Values, need_value: bool) -> Optional[Kind]:
+        file_options = [
+            key
+            for key, value in (
+                (kinds.USER, options.user_file),
+                (kinds.GLOBAL, options.global_file),
+                (kinds.SITE, options.site_file),
+            )
+            if value
+        ]
 
         if not file_options:
             if not need_value:
@@ -161,36 +168,31 @@ class ConfigurationCommand(Command):
             "(--user, --site, --global) to perform."
         )
 
-    def list_values(self, options, args):
-        # type: (Values, List[str]) -> None
+    def list_values(self, options: Values, args: List[str]) -> None:
         self._get_n_args(args, "list", n=0)
 
         for key, value in sorted(self.configuration.items()):
             write_output("%s=%r", key, value)
 
-    def get_name(self, options, args):
-        # type: (Values, List[str]) -> None
+    def get_name(self, options: Values, args: List[str]) -> None:
         key = self._get_n_args(args, "get [name]", n=1)
         value = self.configuration.get_value(key)
 
         write_output("%s", value)
 
-    def set_name_value(self, options, args):
-        # type: (Values, List[str]) -> None
+    def set_name_value(self, options: Values, args: List[str]) -> None:
         key, value = self._get_n_args(args, "set [name] [value]", n=2)
         self.configuration.set_value(key, value)
 
         self._save_configuration()
 
-    def unset_name(self, options, args):
-        # type: (Values, List[str]) -> None
+    def unset_name(self, options: Values, args: List[str]) -> None:
         key = self._get_n_args(args, "unset [name]", n=1)
         self.configuration.unset_value(key)
 
         self._save_configuration()
 
-    def list_config_values(self, options, args):
-        # type: (Values, List[str]) -> None
+    def list_config_values(self, options: Values, args: List[str]) -> None:
         """List config key-value pairs across different config files"""
         self._get_n_args(args, "debug", n=0)
 
@@ -202,30 +204,25 @@ class ConfigurationCommand(Command):
             for fname in files:
                 with indent_log():
                     file_exists = os.path.exists(fname)
-                    write_output("%s, exists: %r",
-                                 fname, file_exists)
+                    write_output("%s, exists: %r", fname, file_exists)
                     if file_exists:
                         self.print_config_file_values(variant)
 
-    def print_config_file_values(self, variant):
-        # type: (Kind) -> None
+    def print_config_file_values(self, variant: Kind) -> None:
         """Get key-value pairs from the file of a variant"""
-        for name, value in self.configuration.\
-                get_values_in_config(variant).items():
+        for name, value in self.configuration.get_values_in_config(variant).items():
             with indent_log():
                 write_output("%s: %s", name, value)
 
-    def print_env_var_values(self):
-        # type: () -> None
+    def print_env_var_values(self) -> None:
         """Get key-values pairs present as environment variables"""
-        write_output("%s:", 'env_var')
+        write_output("%s:", "env_var")
         with indent_log():
             for key, value in sorted(self.configuration.get_environ_vars()):
-                env_var = f'PIP_{key.upper()}'
+                env_var = f"PIP_{key.upper()}"
                 write_output("%s=%r", env_var, value)
 
-    def open_in_editor(self, options, args):
-        # type: (Values, List[str]) -> None
+    def open_in_editor(self, options: Values, args: List[str]) -> None:
         editor = self._determine_editor(options)
 
         fname = self.configuration.get_file_to_edit()
@@ -234,19 +231,20 @@ class ConfigurationCommand(Command):
 
         try:
             subprocess.check_call([editor, fname])
+        except FileNotFoundError as e:
+            if not e.filename:
+                e.filename = editor
+            raise
         except subprocess.CalledProcessError as e:
             raise PipError(
-                "Editor Subprocess exited with exit code {}"
-                .format(e.returncode)
+                "Editor Subprocess exited with exit code {}".format(e.returncode)
             )
 
-    def _get_n_args(self, args, example, n):
-        # type: (List[str], str, int) -> Any
-        """Helper to make sure the command got the right number of arguments
-        """
+    def _get_n_args(self, args: List[str], example: str, n: int) -> Any:
+        """Helper to make sure the command got the right number of arguments"""
         if len(args) != n:
             msg = (
-                'Got unexpected number of arguments, expected {}. '
+                "Got unexpected number of arguments, expected {}. "
                 '(example: "{} config {}")'
             ).format(n, get_prog(), example)
             raise PipError(msg)
@@ -256,8 +254,7 @@ class ConfigurationCommand(Command):
         else:
             return args
 
-    def _save_configuration(self):
-        # type: () -> None
+    def _save_configuration(self) -> None:
         # We successfully ran a modifying command. Need to save the
         # configuration.
         try:
@@ -268,8 +265,7 @@ class ConfigurationCommand(Command):
             )
             raise PipError("Internal Error.")
 
-    def _determine_editor(self, options):
-        # type: (Values) -> str
+    def _determine_editor(self, options: Values) -> str:
         if options.editor is not None:
             return options.editor
         elif "VISUAL" in os.environ:

venv/Lib/site-packages/pip/_internal/commands/debug.py

@@ -23,61 +23,51 @@ from pip._internal.utils.misc import get_pip_version
 logger = logging.getLogger(__name__)
 
 
-def show_value(name, value):
-    # type: (str, Any) -> None
-    logger.info('%s: %s', name, value)
+def show_value(name: str, value: Any) -> None:
+    logger.info("%s: %s", name, value)
 
 
-def show_sys_implementation():
-    # type: () -> None
-    logger.info('sys.implementation:')
+def show_sys_implementation() -> None:
+    logger.info("sys.implementation:")
     implementation_name = sys.implementation.name
     with indent_log():
-        show_value('name', implementation_name)
+        show_value("name", implementation_name)
 
 
-def create_vendor_txt_map():
-    # type: () -> Dict[str, str]
+def create_vendor_txt_map() -> Dict[str, str]:
     vendor_txt_path = os.path.join(
-        os.path.dirname(pip_location),
-        '_vendor',
-        'vendor.txt'
+        os.path.dirname(pip_location), "_vendor", "vendor.txt"
     )
 
     with open(vendor_txt_path) as f:
         # Purge non version specifying lines.
         # Also, remove any space prefix or suffixes (including comments).
-        lines = [line.strip().split(' ', 1)[0]
-                 for line in f.readlines() if '==' in line]
+        lines = [
+            line.strip().split(" ", 1)[0] for line in f.readlines() if "==" in line
+        ]
 
     # Transform into "module" -> version dict.
-    return dict(line.split('==', 1) for line in lines)  # type: ignore
+    return dict(line.split("==", 1) for line in lines)
 
 
-def get_module_from_module_name(module_name):
-    # type: (str) -> ModuleType
+def get_module_from_module_name(module_name: str) -> ModuleType:
     # Module name can be uppercase in vendor.txt for some reason...
     module_name = module_name.lower()
     # PATCH: setuptools is actually only pkg_resources.
-    if module_name == 'setuptools':
-        module_name = 'pkg_resources'
+    if module_name == "setuptools":
+        module_name = "pkg_resources"
 
-    __import__(
-        f'pip._vendor.{module_name}',
-        globals(),
-        locals(),
-        level=0
-    )
+    __import__(f"pip._vendor.{module_name}", globals(), locals(), level=0)
     return getattr(pip._vendor, module_name)
 
 
-def get_vendor_version_from_module(module_name):
-    # type: (str) -> Optional[str]
+def get_vendor_version_from_module(module_name: str) -> Optional[str]:
     module = get_module_from_module_name(module_name)
-    version = getattr(module, '__version__', None)
+    version = getattr(module, "__version__", None)
 
     if not version:
         # Try to find version in debundled module info.
+        assert module.__file__ is not None
         env = get_environment([os.path.dirname(module.__file__)])
         dist = env.get_distribution(module_name)
         if dist:
@@ -86,35 +76,36 @@ def get_vendor_version_from_module(module_name):
     return version
 
 
-def show_actual_vendor_versions(vendor_txt_versions):
-    # type: (Dict[str, str]) -> None
+def show_actual_vendor_versions(vendor_txt_versions: Dict[str, str]) -> None:
     """Log the actual version and print extra info if there is
     a conflict or if the actual version could not be imported.
     """
     for module_name, expected_version in vendor_txt_versions.items():
-        extra_message = ''
+        extra_message = ""
         actual_version = get_vendor_version_from_module(module_name)
         if not actual_version:
-            extra_message = ' (Unable to locate actual module version, using'\
-                            ' vendor.txt specified version)'
+            extra_message = (
+                " (Unable to locate actual module version, using"
+                " vendor.txt specified version)"
+            )
             actual_version = expected_version
         elif parse_version(actual_version) != parse_version(expected_version):
-            extra_message = ' (CONFLICT: vendor.txt suggests version should'\
-                            ' be {})'.format(expected_version)
-        logger.info('%s==%s%s', module_name, actual_version, extra_message)
+            extra_message = (
+                " (CONFLICT: vendor.txt suggests version should"
+                " be {})".format(expected_version)
+            )
+        logger.info("%s==%s%s", module_name, actual_version, extra_message)
 
 
-def show_vendor_versions():
-    # type: () -> None
-    logger.info('vendored library versions:')
+def show_vendor_versions() -> None:
+    logger.info("vendored library versions:")
 
     vendor_txt_versions = create_vendor_txt_map()
     with indent_log():
         show_actual_vendor_versions(vendor_txt_versions)
 
 
-def show_tags(options):
-    # type: (Values) -> None
+def show_tags(options: Values) -> None:
     tag_limit = 10
 
     target_python = make_target_python(options)
@@ -122,11 +113,11 @@ def show_tags(options):
 
     # Display the target options that were explicitly provided.
     formatted_target = target_python.format_given()
-    suffix = ''
+    suffix = ""
     if formatted_target:
-        suffix = f' (target: {formatted_target})'
+        suffix = f" (target: {formatted_target})"
 
-    msg = 'Compatible tags: {}{}'.format(len(tags), suffix)
+    msg = "Compatible tags: {}{}".format(len(tags), suffix)
     logger.info(msg)
 
     if options.verbose < 1 and len(tags) > tag_limit:
@@ -141,30 +132,28 @@ def show_tags(options):
 
         if tags_limited:
             msg = (
-                '...\n'
-                '[First {tag_limit} tags shown. Pass --verbose to show all.]'
+                "...\n[First {tag_limit} tags shown. Pass --verbose to show all.]"
             ).format(tag_limit=tag_limit)
             logger.info(msg)
 
 
-def ca_bundle_info(config):
-    # type: (Configuration) -> str
+def ca_bundle_info(config: Configuration) -> str:
     levels = set()
     for key, _ in config.items():
-        levels.add(key.split('.')[0])
+        levels.add(key.split(".")[0])
 
     if not levels:
         return "Not specified"
 
-    levels_that_override_global = ['install', 'wheel', 'download']
+    levels_that_override_global = ["install", "wheel", "download"]
     global_overriding_level = [
         level for level in levels if level in levels_that_override_global
     ]
     if not global_overriding_level:
-        return 'global'
+        return "global"
 
-    if 'global' in levels:
-        levels.remove('global')
+    if "global" in levels:
+        levels.remove("global")
     return ", ".join(levels)
 
 
@@ -177,34 +166,33 @@ class DebugCommand(Command):
       %prog <options>"""
     ignore_require_venv = True
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         cmdoptions.add_target_python_options(self.cmd_opts)
         self.parser.insert_option_group(0, self.cmd_opts)
         self.parser.config.load()
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         logger.warning(
             "This command is only meant for debugging. "
             "Do not use this with automation for parsing and getting these "
             "details, since the output and options of this command may "
             "change without notice."
         )
-        show_value('pip version', get_pip_version())
-        show_value('sys.version', sys.version)
-        show_value('sys.executable', sys.executable)
-        show_value('sys.getdefaultencoding', sys.getdefaultencoding())
-        show_value('sys.getfilesystemencoding', sys.getfilesystemencoding())
+        show_value("pip version", get_pip_version())
+        show_value("sys.version", sys.version)
+        show_value("sys.executable", sys.executable)
+        show_value("sys.getdefaultencoding", sys.getdefaultencoding())
+        show_value("sys.getfilesystemencoding", sys.getfilesystemencoding())
         show_value(
-            'locale.getpreferredencoding', locale.getpreferredencoding(),
+            "locale.getpreferredencoding",
+            locale.getpreferredencoding(),
         )
-        show_value('sys.platform', sys.platform)
+        show_value("sys.platform", sys.platform)
         show_sys_implementation()
 
         show_value("'cert' config value", ca_bundle_info(self.parser.config))
-        show_value("REQUESTS_CA_BUNDLE", os.environ.get('REQUESTS_CA_BUNDLE'))
-        show_value("CURL_CA_BUNDLE", os.environ.get('CURL_CA_BUNDLE'))
+        show_value("REQUESTS_CA_BUNDLE", os.environ.get("REQUESTS_CA_BUNDLE"))
+        show_value("CURL_CA_BUNDLE", os.environ.get("CURL_CA_BUNDLE"))
         show_value("pip._vendor.certifi.where()", where())
         show_value("pip._vendor.DEBUNDLED", pip._vendor.DEBUNDLED)
 

venv/Lib/site-packages/pip/_internal/commands/download.py

@@ -7,7 +7,7 @@ from pip._internal.cli import cmdoptions
 from pip._internal.cli.cmdoptions import make_target_python
 from pip._internal.cli.req_command import RequirementCommand, with_cleanup
 from pip._internal.cli.status_codes import SUCCESS
-from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.operations.build.build_tracker import get_build_tracker
 from pip._internal.utils.misc import ensure_dir, normalize_path, write_output
 from pip._internal.utils.temp_dir import TempDirectory
 
@@ -34,11 +34,9 @@ class DownloadCommand(RequirementCommand):
       %prog [options] <local project path> ...
       %prog [options] <archive url/path> ..."""
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(cmdoptions.constraints())
         self.cmd_opts.add_option(cmdoptions.requirements())
-        self.cmd_opts.add_option(cmdoptions.build_dir())
         self.cmd_opts.add_option(cmdoptions.no_deps())
         self.cmd_opts.add_option(cmdoptions.global_options())
         self.cmd_opts.add_option(cmdoptions.no_binary())
@@ -51,14 +49,18 @@ class DownloadCommand(RequirementCommand):
         self.cmd_opts.add_option(cmdoptions.no_build_isolation())
         self.cmd_opts.add_option(cmdoptions.use_pep517())
         self.cmd_opts.add_option(cmdoptions.no_use_pep517())
+        self.cmd_opts.add_option(cmdoptions.check_build_deps())
         self.cmd_opts.add_option(cmdoptions.ignore_requires_python())
 
         self.cmd_opts.add_option(
-            '-d', '--dest', '--destination-dir', '--destination-directory',
-            dest='download_dir',
-            metavar='dir',
+            "-d",
+            "--dest",
+            "--destination-dir",
+            "--destination-directory",
+            dest="download_dir",
+            metavar="dir",
             default=os.curdir,
-            help=("Download packages into <dir>."),
+            help="Download packages into <dir>.",
         )
 
         cmdoptions.add_target_python_options(self.cmd_opts)
@@ -72,8 +74,7 @@ class DownloadCommand(RequirementCommand):
         self.parser.insert_option_group(0, self.cmd_opts)
 
     @with_cleanup
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
 
         options.ignore_installed = True
         # editable doesn't really make sense for `pip download`, but the bowels
@@ -95,7 +96,7 @@ class DownloadCommand(RequirementCommand):
             ignore_requires_python=options.ignore_requires_python,
         )
 
-        req_tracker = self.enter_context(get_requirement_tracker())
+        build_tracker = self.enter_context(get_build_tracker())
 
         directory = TempDirectory(
             delete=not options.no_clean,
@@ -108,11 +109,12 @@ class DownloadCommand(RequirementCommand):
         preparer = self.make_requirement_preparer(
             temp_build_dir=directory,
             options=options,
-            req_tracker=req_tracker,
+            build_tracker=build_tracker,
             session=session,
             finder=finder,
             download_dir=options.download_dir,
             use_user_site=False,
+            verbosity=self.verbosity,
         )
 
         resolver = self.make_resolver(
@@ -125,17 +127,15 @@ class DownloadCommand(RequirementCommand):
 
         self.trace_basic_info(finder)
 
-        requirement_set = resolver.resolve(
-            reqs, check_supported_wheels=True
-        )
+        requirement_set = resolver.resolve(reqs, check_supported_wheels=True)
 
-        downloaded = []  # type: List[str]
+        downloaded: List[str] = []
         for req in requirement_set.requirements.values():
             if req.satisfied_by is None:
                 assert req.name is not None
                 preparer.save_linked_requirement(req)
                 downloaded.append(req.name)
         if downloaded:
-            write_output('Successfully downloaded %s', ' '.join(downloaded))
+            write_output("Successfully downloaded %s", " ".join(downloaded))
 
         return SUCCESS

venv/Lib/site-packages/pip/_internal/commands/freeze.py

@@ -7,9 +7,8 @@ from pip._internal.cli.base_command import Command
 from pip._internal.cli.status_codes import SUCCESS
 from pip._internal.operations.freeze import freeze
 from pip._internal.utils.compat import stdlib_pkgs
-from pip._internal.utils.deprecation import deprecated
 
-DEV_PKGS = {'pip', 'setuptools', 'distribute', 'wheel'}
+DEV_PKGS = {"pip", "setuptools", "distribute", "wheel"}
 
 
 class FreezeCommand(Command):
@@ -23,56 +22,59 @@ class FreezeCommand(Command):
       %prog [options]"""
     log_streams = ("ext://sys.stderr", "ext://sys.stderr")
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-r', '--requirement',
-            dest='requirements',
-            action='append',
+            "-r",
+            "--requirement",
+            dest="requirements",
+            action="append",
             default=[],
-            metavar='file',
-            help="Use the order in the given requirements file and its "
-                 "comments when generating output. This option can be "
-                 "used multiple times.")
+            metavar="file",
+            help=(
+                "Use the order in the given requirements file and its "
+                "comments when generating output. This option can be "
+                "used multiple times."
+            ),
+        )
         self.cmd_opts.add_option(
-            '-f', '--find-links',
-            dest='find_links',
-            action='append',
-            default=[],
-            metavar='URL',
-            help='URL for finding packages, which will be added to the '
-                 'output.')
-        self.cmd_opts.add_option(
-            '-l', '--local',
-            dest='local',
-            action='store_true',
+            "-l",
+            "--local",
+            dest="local",
+            action="store_true",
             default=False,
-            help='If in a virtualenv that has global access, do not output '
-                 'globally-installed packages.')
+            help=(
+                "If in a virtualenv that has global access, do not output "
+                "globally-installed packages."
+            ),
+        )
         self.cmd_opts.add_option(
-            '--user',
-            dest='user',
-            action='store_true',
+            "--user",
+            dest="user",
+            action="store_true",
             default=False,
-            help='Only output packages installed in user-site.')
+            help="Only output packages installed in user-site.",
+        )
         self.cmd_opts.add_option(cmdoptions.list_path())
         self.cmd_opts.add_option(
-            '--all',
-            dest='freeze_all',
-            action='store_true',
-            help='Do not skip these packages in the output:'
-                 ' {}'.format(', '.join(DEV_PKGS)))
+            "--all",
+            dest="freeze_all",
+            action="store_true",
+            help=(
+                "Do not skip these packages in the output:"
+                " {}".format(", ".join(DEV_PKGS))
+            ),
+        )
         self.cmd_opts.add_option(
-            '--exclude-editable',
-            dest='exclude_editable',
-            action='store_true',
-            help='Exclude editable package from output.')
+            "--exclude-editable",
+            dest="exclude_editable",
+            action="store_true",
+            help="Exclude editable package from output.",
+        )
         self.cmd_opts.add_option(cmdoptions.list_exclude())
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         skip = set(stdlib_pkgs)
         if not options.freeze_all:
             skip.update(DEV_PKGS)
@@ -82,17 +84,8 @@ class FreezeCommand(Command):
 
         cmdoptions.check_list_path_option(options)
 
-        if options.find_links:
-            deprecated(
-                "--find-links option in pip freeze is deprecated.",
-                replacement=None,
-                gone_in="21.2",
-                issue=9069,
-            )
-
         for line in freeze(
             requirement=options.requirements,
-            find_links=options.find_links,
             local_only=options.local,
             user_only=options.user,
             paths=options.path,
@@ -100,5 +93,5 @@ class FreezeCommand(Command):
             skip=skip,
             exclude_editable=options.exclude_editable,
         ):
-            sys.stdout.write(line + '\n')
+            sys.stdout.write(line + "\n")
         return SUCCESS

venv/Lib/site-packages/pip/_internal/commands/hash.py

@@ -20,38 +20,39 @@ class HashCommand(Command):
     installs.
     """
 
-    usage = '%prog [options] <file> ...'
+    usage = "%prog [options] <file> ..."
     ignore_require_venv = True
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-a', '--algorithm',
-            dest='algorithm',
+            "-a",
+            "--algorithm",
+            dest="algorithm",
             choices=STRONG_HASHES,
-            action='store',
+            action="store",
             default=FAVORITE_HASH,
-            help='The hash algorithm to use: one of {}'.format(
-                 ', '.join(STRONG_HASHES)))
+            help="The hash algorithm to use: one of {}".format(
+                ", ".join(STRONG_HASHES)
+            ),
+        )
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         if not args:
             self.parser.print_usage(sys.stderr)
             return ERROR
 
         algorithm = options.algorithm
         for path in args:
-            write_output('%s:\n--hash=%s:%s',
-                         path, algorithm, _hash_of_file(path, algorithm))
+            write_output(
+                "%s:\n--hash=%s:%s", path, algorithm, _hash_of_file(path, algorithm)
+            )
         return SUCCESS
 
 
-def _hash_of_file(path, algorithm):
-    # type: (str, str) -> str
+def _hash_of_file(path: str, algorithm: str) -> str:
     """Return the hash digest of a file."""
-    with open(path, 'rb') as archive:
+    with open(path, "rb") as archive:
         hash = hashlib.new(algorithm)
         for chunk in read_chunks(archive):
             hash.update(chunk)

venv/Lib/site-packages/pip/_internal/commands/help.py

@@ -13,8 +13,7 @@ class HelpCommand(Command):
       %prog <command>"""
     ignore_require_venv = True
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         from pip._internal.commands import (
             commands_dict,
             create_command,
@@ -34,7 +33,7 @@ class HelpCommand(Command):
             if guess:
                 msg.append(f'maybe you meant "{guess}"')
 
-            raise CommandError(' - '.join(msg))
+            raise CommandError(" - ".join(msg))
 
         command = create_command(cmd_name)
         command.parser.print_help()

venv/Lib/site-packages/pip/_internal/commands/install.py

@@ -1,5 +1,4 @@
 import errno
-import logging
 import operator
 import os
 import shutil
@@ -22,12 +21,14 @@ from pip._internal.exceptions import CommandError, InstallationError
 from pip._internal.locations import get_scheme
 from pip._internal.metadata import get_environment
 from pip._internal.models.format_control import FormatControl
+from pip._internal.operations.build.build_tracker import get_build_tracker
 from pip._internal.operations.check import ConflictDetails, check_install_conflicts
 from pip._internal.req import install_given_reqs
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.distutils_args import parse_distutils_args
 from pip._internal.utils.filesystem import test_writable_dir
+from pip._internal.utils.logging import getLogger
 from pip._internal.utils.misc import (
     ensure_dir,
     get_pip_version,
@@ -45,13 +46,11 @@ from pip._internal.wheel_builder import (
     should_build_for_install_command,
 )
 
-logger = logging.getLogger(__name__)
+logger = getLogger(__name__)
 
 
-def get_check_binary_allowed(format_control):
-    # type: (FormatControl) -> BinaryAllowedPredicate
-    def check_binary_allowed(req):
-        # type: (InstallRequirement) -> bool
+def get_check_binary_allowed(format_control: FormatControl) -> BinaryAllowedPredicate:
+    def check_binary_allowed(req: InstallRequirement) -> bool:
         canonical_name = canonicalize_name(req.name or "")
         allowed_formats = format_control.get_allowed_formats(canonical_name)
         return "binary" in allowed_formats
@@ -79,8 +78,7 @@ class InstallCommand(RequirementCommand):
       %prog [options] [-e] <local project path> ...
       %prog [options] <archive url/path> ..."""
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(cmdoptions.requirements())
         self.cmd_opts.add_option(cmdoptions.constraints())
         self.cmd_opts.add_option(cmdoptions.no_deps())
@@ -88,94 +86,112 @@ class InstallCommand(RequirementCommand):
 
         self.cmd_opts.add_option(cmdoptions.editable())
         self.cmd_opts.add_option(
-            '-t', '--target',
-            dest='target_dir',
-            metavar='dir',
+            "-t",
+            "--target",
+            dest="target_dir",
+            metavar="dir",
             default=None,
-            help='Install packages into <dir>. '
-                 'By default this will not replace existing files/folders in '
-                 '<dir>. Use --upgrade to replace existing packages in <dir> '
-                 'with new versions.'
+            help=(
+                "Install packages into <dir>. "
+                "By default this will not replace existing files/folders in "
+                "<dir>. Use --upgrade to replace existing packages in <dir> "
+                "with new versions."
+            ),
         )
         cmdoptions.add_target_python_options(self.cmd_opts)
 
         self.cmd_opts.add_option(
-            '--user',
-            dest='use_user_site',
-            action='store_true',
-            help="Install to the Python user install directory for your "
-                 "platform. Typically ~/.local/, or %APPDATA%\\Python on "
-                 "Windows. (See the Python documentation for site.USER_BASE "
-                 "for full details.)")
+            "--user",
+            dest="use_user_site",
+            action="store_true",
+            help=(
+                "Install to the Python user install directory for your "
+                "platform. Typically ~/.local/, or %APPDATA%\\Python on "
+                "Windows. (See the Python documentation for site.USER_BASE "
+                "for full details.)"
+            ),
+        )
         self.cmd_opts.add_option(
-            '--no-user',
-            dest='use_user_site',
-            action='store_false',
-            help=SUPPRESS_HELP)
+            "--no-user",
+            dest="use_user_site",
+            action="store_false",
+            help=SUPPRESS_HELP,
+        )
         self.cmd_opts.add_option(
-            '--root',
-            dest='root_path',
-            metavar='dir',
+            "--root",
+            dest="root_path",
+            metavar="dir",
             default=None,
-            help="Install everything relative to this alternate root "
-                 "directory.")
+            help="Install everything relative to this alternate root directory.",
+        )
         self.cmd_opts.add_option(
-            '--prefix',
-            dest='prefix_path',
-            metavar='dir',
+            "--prefix",
+            dest="prefix_path",
+            metavar="dir",
             default=None,
-            help="Installation prefix where lib, bin and other top-level "
-                 "folders are placed")
-
-        self.cmd_opts.add_option(cmdoptions.build_dir())
+            help=(
+                "Installation prefix where lib, bin and other top-level "
+                "folders are placed"
+            ),
+        )
 
         self.cmd_opts.add_option(cmdoptions.src())
 
         self.cmd_opts.add_option(
-            '-U', '--upgrade',
-            dest='upgrade',
-            action='store_true',
-            help='Upgrade all specified packages to the newest available '
-                 'version. The handling of dependencies depends on the '
-                 'upgrade-strategy used.'
+            "-U",
+            "--upgrade",
+            dest="upgrade",
+            action="store_true",
+            help=(
+                "Upgrade all specified packages to the newest available "
+                "version. The handling of dependencies depends on the "
+                "upgrade-strategy used."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--upgrade-strategy',
-            dest='upgrade_strategy',
-            default='only-if-needed',
-            choices=['only-if-needed', 'eager'],
-            help='Determines how dependency upgrading should be handled '
-                 '[default: %default]. '
-                 '"eager" - dependencies are upgraded regardless of '
-                 'whether the currently installed version satisfies the '
-                 'requirements of the upgraded package(s). '
-                 '"only-if-needed" -  are upgraded only when they do not '
-                 'satisfy the requirements of the upgraded package(s).'
+            "--upgrade-strategy",
+            dest="upgrade_strategy",
+            default="only-if-needed",
+            choices=["only-if-needed", "eager"],
+            help=(
+                "Determines how dependency upgrading should be handled "
+                "[default: %default]. "
+                '"eager" - dependencies are upgraded regardless of '
+                "whether the currently installed version satisfies the "
+                "requirements of the upgraded package(s). "
+                '"only-if-needed" -  are upgraded only when they do not '
+                "satisfy the requirements of the upgraded package(s)."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--force-reinstall',
-            dest='force_reinstall',
-            action='store_true',
-            help='Reinstall all packages even if they are already '
-                 'up-to-date.')
+            "--force-reinstall",
+            dest="force_reinstall",
+            action="store_true",
+            help="Reinstall all packages even if they are already up-to-date.",
+        )
 
         self.cmd_opts.add_option(
-            '-I', '--ignore-installed',
-            dest='ignore_installed',
-            action='store_true',
-            help='Ignore the installed packages, overwriting them. '
-                 'This can break your system if the existing package '
-                 'is of a different version or was installed '
-                 'with a different package manager!'
+            "-I",
+            "--ignore-installed",
+            dest="ignore_installed",
+            action="store_true",
+            help=(
+                "Ignore the installed packages, overwriting them. "
+                "This can break your system if the existing package "
+                "is of a different version or was installed "
+                "with a different package manager!"
+            ),
         )
 
         self.cmd_opts.add_option(cmdoptions.ignore_requires_python())
         self.cmd_opts.add_option(cmdoptions.no_build_isolation())
         self.cmd_opts.add_option(cmdoptions.use_pep517())
         self.cmd_opts.add_option(cmdoptions.no_use_pep517())
+        self.cmd_opts.add_option(cmdoptions.check_build_deps())
 
+        self.cmd_opts.add_option(cmdoptions.config_settings())
         self.cmd_opts.add_option(cmdoptions.install_options())
         self.cmd_opts.add_option(cmdoptions.global_options())
 
@@ -208,12 +224,12 @@ class InstallCommand(RequirementCommand):
             default=True,
             help="Do not warn about broken dependencies",
         )
-
         self.cmd_opts.add_option(cmdoptions.no_binary())
         self.cmd_opts.add_option(cmdoptions.only_binary())
         self.cmd_opts.add_option(cmdoptions.prefer_binary())
         self.cmd_opts.add_option(cmdoptions.require_hashes())
         self.cmd_opts.add_option(cmdoptions.progress_bar())
+        self.cmd_opts.add_option(cmdoptions.root_user_action())
 
         index_opts = cmdoptions.make_option_group(
             cmdoptions.index_group,
@@ -224,8 +240,7 @@ class InstallCommand(RequirementCommand):
         self.parser.insert_option_group(0, self.cmd_opts)
 
     @with_cleanup
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         if options.use_user_site and options.target_dir is not None:
             raise CommandError("Can not combine '--user' and '--target'")
 
@@ -238,7 +253,7 @@ class InstallCommand(RequirementCommand):
 
         install_options = options.install_options or []
 
-        logger.debug("Using %s", get_pip_version())
+        logger.verbose("Using %s", get_pip_version())
         options.use_user_site = decide_user_install(
             options.use_user_site,
             prefix_path=options.prefix_path,
@@ -247,16 +262,19 @@ class InstallCommand(RequirementCommand):
             isolated_mode=options.isolated_mode,
         )
 
-        target_temp_dir = None  # type: Optional[TempDirectory]
-        target_temp_dir_path = None  # type: Optional[str]
+        target_temp_dir: Optional[TempDirectory] = None
+        target_temp_dir_path: Optional[str] = None
         if options.target_dir:
             options.ignore_installed = True
             options.target_dir = os.path.abspath(options.target_dir)
-            if (os.path.exists(options.target_dir) and not
-                    os.path.isdir(options.target_dir)):
+            if (
+                # fmt: off
+                os.path.exists(options.target_dir) and
+                not os.path.isdir(options.target_dir)
+                # fmt: on
+            ):
                 raise CommandError(
-                    "Target path exists but is not a directory, will not "
-                    "continue."
+                    "Target path exists but is not a directory, will not continue."
                 )
 
             # Create a target directory for using with the target option
@@ -277,7 +295,7 @@ class InstallCommand(RequirementCommand):
         )
         wheel_cache = WheelCache(options.cache_dir, options.format_control)
 
-        req_tracker = self.enter_context(get_requirement_tracker())
+        build_tracker = self.enter_context(get_build_tracker())
 
         directory = TempDirectory(
             delete=not options.no_clean,
@@ -288,17 +306,22 @@ class InstallCommand(RequirementCommand):
         try:
             reqs = self.get_requirements(args, options, finder, session)
 
-            reject_location_related_install_options(
-                reqs, options.install_options
-            )
+            # Only when installing is it permitted to use PEP 660.
+            # In other circumstances (pip wheel, pip download) we generate
+            # regular (i.e. non editable) metadata and wheels.
+            for req in reqs:
+                req.permit_editable_wheels = True
+
+            reject_location_related_install_options(reqs, options.install_options)
 
             preparer = self.make_requirement_preparer(
                 temp_build_dir=directory,
                 options=options,
-                req_tracker=req_tracker,
+                build_tracker=build_tracker,
                 session=session,
                 finder=finder,
                 use_user_site=options.use_user_site,
+                verbosity=self.verbosity,
             )
             resolver = self.make_resolver(
                 preparer=preparer,
@@ -327,19 +350,14 @@ class InstallCommand(RequirementCommand):
                 # If we're not replacing an already installed pip,
                 # we're not modifying it.
                 modifying_pip = pip_req.satisfied_by is None
-            protect_pip_from_modification_on_windows(
-                modifying_pip=modifying_pip
-            )
+            protect_pip_from_modification_on_windows(modifying_pip=modifying_pip)
 
-            check_binary_allowed = get_check_binary_allowed(
-                finder.format_control
-            )
+            check_binary_allowed = get_check_binary_allowed(finder.format_control)
 
             reqs_to_build = [
-                r for r in requirement_set.requirements.values()
-                if should_build_for_install_command(
-                    r, check_binary_allowed
-                )
+                r
+                for r in requirement_set.requirements.values()
+                if should_build_for_install_command(r, check_binary_allowed)
             ]
 
             _, build_failures = build(
@@ -350,44 +368,40 @@ class InstallCommand(RequirementCommand):
                 global_options=[],
             )
 
-            # If we're using PEP 517, we cannot do a direct install
+            # If we're using PEP 517, we cannot do a legacy setup.py install
             # so we fail here.
-            pep517_build_failure_names = [
-                r.name   # type: ignore
-                for r in build_failures if r.use_pep517
-            ]  # type: List[str]
+            pep517_build_failure_names: List[str] = [
+                r.name for r in build_failures if r.use_pep517  # type: ignore
+            ]
             if pep517_build_failure_names:
                 raise InstallationError(
-                    "Could not build wheels for {} which use"
-                    " PEP 517 and cannot be installed directly".format(
+                    "Could not build wheels for {}, which is required to "
+                    "install pyproject.toml-based projects".format(
                         ", ".join(pep517_build_failure_names)
                     )
                 )
 
             # For now, we just warn about failures building legacy
-            # requirements, as we'll fall through to a direct
-            # install for those.
+            # requirements, as we'll fall through to a setup.py install for
+            # those.
             for r in build_failures:
                 if not r.use_pep517:
                     r.legacy_install_reason = 8368
 
-            to_install = resolver.get_installation_order(
-                requirement_set
-            )
+            to_install = resolver.get_installation_order(requirement_set)
 
             # Check for conflicts in the package set we're installing.
-            conflicts = None  # type: Optional[ConflictDetails]
+            conflicts: Optional[ConflictDetails] = None
             should_warn_about_conflicts = (
-                not options.ignore_dependencies and
-                options.warn_about_conflicts
+                not options.ignore_dependencies and options.warn_about_conflicts
             )
             if should_warn_about_conflicts:
                 conflicts = self._determine_conflicts(to_install)
 
             # Don't warn about script install locations if
-            # --target has been specified
+            # --target or --prefix has been specified
             warn_script_location = options.warn_script_location
-            if options.target_dir:
+            if options.target_dir or options.prefix_path:
                 warn_script_location = False
 
             installed = install_given_reqs(
@@ -411,7 +425,7 @@ class InstallCommand(RequirementCommand):
             )
             env = get_environment(lib_locations)
 
-            installed.sort(key=operator.attrgetter('name'))
+            installed.sort(key=operator.attrgetter("name"))
             items = []
             for result in installed:
                 item = result.name
@@ -429,16 +443,19 @@ class InstallCommand(RequirementCommand):
                     resolver_variant=self.determine_resolver_variant(options),
                 )
 
-            installed_desc = ' '.join(items)
+            installed_desc = " ".join(items)
             if installed_desc:
                 write_output(
-                    'Successfully installed %s', installed_desc,
+                    "Successfully installed %s",
+                    installed_desc,
                 )
         except OSError as error:
-            show_traceback = (self.verbosity >= 1)
+            show_traceback = self.verbosity >= 1
 
             message = create_os_error_message(
-                error, show_traceback, options.use_user_site,
+                error,
+                show_traceback,
+                options.use_user_site,
             )
             logger.error(message, exc_info=show_traceback)  # noqa
 
@@ -449,12 +466,13 @@ class InstallCommand(RequirementCommand):
             self._handle_target_dir(
                 options.target_dir, target_temp_dir, options.upgrade
             )
-
-        warn_if_run_as_root()
+        if options.root_user_action == "warn":
+            warn_if_run_as_root()
         return SUCCESS
 
-    def _handle_target_dir(self, target_dir, target_temp_dir, upgrade):
-        # type: (str, TempDirectory, bool) -> None
+    def _handle_target_dir(
+        self, target_dir: str, target_temp_dir: TempDirectory, upgrade: bool
+    ) -> None:
         ensure_dir(target_dir)
 
         # Checking both purelib and platlib directories for installed
@@ -463,7 +481,7 @@ class InstallCommand(RequirementCommand):
 
         # Checking both purelib and platlib directories for installed
         # packages to be moved to target directory
-        scheme = get_scheme('', home=target_temp_dir.path)
+        scheme = get_scheme("", home=target_temp_dir.path)
         purelib_dir = scheme.purelib
         platlib_dir = scheme.platlib
         data_dir = scheme.data
@@ -485,18 +503,18 @@ class InstallCommand(RequirementCommand):
                 if os.path.exists(target_item_dir):
                     if not upgrade:
                         logger.warning(
-                            'Target directory %s already exists. Specify '
-                            '--upgrade to force replacement.',
-                            target_item_dir
+                            "Target directory %s already exists. Specify "
+                            "--upgrade to force replacement.",
+                            target_item_dir,
                         )
                         continue
                     if os.path.islink(target_item_dir):
                         logger.warning(
-                            'Target directory %s already exists and is '
-                            'a link. pip will not automatically replace '
-                            'links, please remove if replacement is '
-                            'desired.',
-                            target_item_dir
+                            "Target directory %s already exists and is "
+                            "a link. pip will not automatically replace "
+                            "links, please remove if replacement is "
+                            "desired.",
+                            target_item_dir,
                         )
                         continue
                     if os.path.isdir(target_item_dir):
@@ -504,13 +522,11 @@ class InstallCommand(RequirementCommand):
                     else:
                         os.remove(target_item_dir)
 
-                shutil.move(
-                    os.path.join(lib_dir, item),
-                    target_item_dir
-                )
+                shutil.move(os.path.join(lib_dir, item), target_item_dir)
 
-    def _determine_conflicts(self, to_install):
-        # type: (List[InstallRequirement]) -> Optional[ConflictDetails]
+    def _determine_conflicts(
+        self, to_install: List[InstallRequirement]
+    ) -> Optional[ConflictDetails]:
         try:
             return check_install_conflicts(to_install)
         except Exception:
@@ -520,13 +536,14 @@ class InstallCommand(RequirementCommand):
             )
             return None
 
-    def _warn_about_conflicts(self, conflict_details, resolver_variant):
-        # type: (ConflictDetails, str) -> None
+    def _warn_about_conflicts(
+        self, conflict_details: ConflictDetails, resolver_variant: str
+    ) -> None:
         package_set, (missing, conflicting) = conflict_details
         if not missing and not conflicting:
             return
 
-        parts = []  # type: List[str]
+        parts: List[str] = []
         if resolver_variant == "legacy":
             parts.append(
                 "pip's legacy dependency resolver does not consider dependency "
@@ -567,7 +584,7 @@ class InstallCommand(RequirementCommand):
                     requirement=req,
                     dep_name=dep_name,
                     dep_version=dep_version,
-                    you=("you" if resolver_variant == "2020-resolver" else "you'll")
+                    you=("you" if resolver_variant == "2020-resolver" else "you'll"),
                 )
                 parts.append(message)
 
@@ -575,15 +592,14 @@ class InstallCommand(RequirementCommand):
 
 
 def get_lib_location_guesses(
-        user=False,  # type: bool
-        home=None,  # type: Optional[str]
-        root=None,  # type: Optional[str]
-        isolated=False,  # type: bool
-        prefix=None  # type: Optional[str]
-):
-    # type:(...) -> List[str]
+    user: bool = False,
+    home: Optional[str] = None,
+    root: Optional[str] = None,
+    isolated: bool = False,
+    prefix: Optional[str] = None,
+) -> List[str]:
     scheme = get_scheme(
-        '',
+        "",
         user=user,
         home=home,
         root=root,
@@ -593,22 +609,20 @@ def get_lib_location_guesses(
     return [scheme.purelib, scheme.platlib]
 
 
-def site_packages_writable(root, isolated):
-    # type: (Optional[str], bool) -> bool
+def site_packages_writable(root: Optional[str], isolated: bool) -> bool:
     return all(
-        test_writable_dir(d) for d in set(
-            get_lib_location_guesses(root=root, isolated=isolated))
+        test_writable_dir(d)
+        for d in set(get_lib_location_guesses(root=root, isolated=isolated))
     )
 
 
 def decide_user_install(
-    use_user_site,  # type: Optional[bool]
-    prefix_path=None,  # type: Optional[str]
-    target_dir=None,  # type: Optional[str]
-    root_path=None,  # type: Optional[str]
-    isolated_mode=False,  # type: bool
-):
-    # type: (...) -> bool
+    use_user_site: Optional[bool],
+    prefix_path: Optional[str] = None,
+    target_dir: Optional[str] = None,
+    root_path: Optional[str] = None,
+    isolated_mode: bool = False,
+) -> bool:
     """Determine whether to do a user install based on the input options.
 
     If use_user_site is False, no additional checks are done.
@@ -656,18 +670,21 @@ def decide_user_install(
         logger.debug("Non-user install because site-packages writeable")
         return False
 
-    logger.info("Defaulting to user installation because normal site-packages "
-                "is not writeable")
+    logger.info(
+        "Defaulting to user installation because normal site-packages "
+        "is not writeable"
+    )
     return True
 
 
-def reject_location_related_install_options(requirements, options):
-    # type: (List[InstallRequirement], Optional[List[str]]) -> None
+def reject_location_related_install_options(
+    requirements: List[InstallRequirement], options: Optional[List[str]]
+) -> None:
     """If any location-changing --install-option arguments were passed for
     requirements or on the command-line, then show a deprecation warning.
     """
-    def format_options(option_names):
-        # type: (Iterable[str]) -> List[str]
+
+    def format_options(option_names: Iterable[str]) -> List[str]:
         return ["--{}".format(name.replace("_", "-")) for name in option_names]
 
     offenders = []
@@ -686,9 +703,7 @@ def reject_location_related_install_options(requirements, options):
         location_options = parse_distutils_args(options)
         if location_options:
             offenders.append(
-                "{!r} from command line".format(
-                    format_options(location_options.keys())
-                )
+                "{!r} from command line".format(format_options(location_options.keys()))
             )
 
     if not offenders:
@@ -697,14 +712,13 @@ def reject_location_related_install_options(requirements, options):
     raise CommandError(
         "Location-changing options found in --install-option: {}."
         " This is unsupported, use pip-level options like --user,"
-        " --prefix, --root, and --target instead.".format(
-            "; ".join(offenders)
-        )
+        " --prefix, --root, and --target instead.".format("; ".join(offenders))
     )
 
 
-def create_os_error_message(error, show_traceback, using_user_site):
-    # type: (OSError, bool, bool) -> str
+def create_os_error_message(
+    error: OSError, show_traceback: bool, using_user_site: bool
+) -> str:
     """Format an error message for an OSError
 
     It may occur anytime during the execution of the install command.
@@ -729,12 +743,31 @@ def create_os_error_message(error, show_traceback, using_user_site):
         permissions_part = "Check the permissions"
 
         if not running_under_virtualenv() and not using_user_site:
-            parts.extend([
-                user_option_part, " or ",
-                permissions_part.lower(),
-            ])
+            parts.extend(
+                [
+                    user_option_part,
+                    " or ",
+                    permissions_part.lower(),
+                ]
+            )
         else:
             parts.append(permissions_part)
         parts.append(".\n")
 
+    # Suggest the user to enable Long Paths if path length is
+    # more than 260
+    if (
+        WINDOWS
+        and error.errno == errno.ENOENT
+        and error.filename
+        and len(error.filename) > 260
+    ):
+        parts.append(
+            "HINT: This error might have occurred since "
+            "this system does not have Windows Long Path "
+            "support enabled. You can find information on "
+            "how to enable this at "
+            "https://pip.pypa.io/warnings/enable-long-paths\n"
+        )
+
     return "".join(parts).strip() + "\n"

venv/Lib/site-packages/pip/_internal/commands/list.py

@@ -1,9 +1,9 @@
 import json
 import logging
 from optparse import Values
-from typing import Iterator, List, Set, Tuple
+from typing import TYPE_CHECKING, Generator, List, Optional, Sequence, Tuple, cast
 
-from pip._vendor.pkg_resources import Distribution
+from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.cli import cmdoptions
 from pip._internal.cli.req_command import IndexGroupCommand
@@ -11,17 +11,27 @@ from pip._internal.cli.status_codes import SUCCESS
 from pip._internal.exceptions import CommandError
 from pip._internal.index.collector import LinkCollector
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata import BaseDistribution, get_environment
 from pip._internal.models.selection_prefs import SelectionPreferences
 from pip._internal.network.session import PipSession
 from pip._internal.utils.compat import stdlib_pkgs
-from pip._internal.utils.misc import (
-    dist_is_editable,
-    get_installed_distributions,
-    tabulate,
-    write_output,
-)
-from pip._internal.utils.packaging import get_installer
-from pip._internal.utils.parallel import map_multithread
+from pip._internal.utils.misc import tabulate, write_output
+
+if TYPE_CHECKING:
+    from pip._internal.metadata.base import DistributionVersion
+
+    class _DistWithLatestInfo(BaseDistribution):
+        """Give the distribution object a couple of extra fields.
+
+        These will be populated during ``get_outdated()``. This is dirty but
+        makes the rest of the code much cleaner.
+        """
+
+        latest_version: DistributionVersion
+        latest_filetype: str
+
+    _ProcessedDists = Sequence[_DistWithLatestInfo]
+
 
 logger = logging.getLogger(__name__)
 
@@ -37,86 +47,94 @@ class ListCommand(IndexGroupCommand):
     usage = """
       %prog [options]"""
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-o', '--outdated',
-            action='store_true',
+            "-o",
+            "--outdated",
+            action="store_true",
             default=False,
-            help='List outdated packages')
-        self.cmd_opts.add_option(
-            '-u', '--uptodate',
-            action='store_true',
-            default=False,
-            help='List uptodate packages')
-        self.cmd_opts.add_option(
-            '-e', '--editable',
-            action='store_true',
-            default=False,
-            help='List editable projects.')
-        self.cmd_opts.add_option(
-            '-l', '--local',
-            action='store_true',
-            default=False,
-            help=('If in a virtualenv that has global access, do not list '
-                  'globally-installed packages.'),
+            help="List outdated packages",
         )
         self.cmd_opts.add_option(
-            '--user',
-            dest='user',
-            action='store_true',
+            "-u",
+            "--uptodate",
+            action="store_true",
             default=False,
-            help='Only output packages installed in user-site.')
+            help="List uptodate packages",
+        )
+        self.cmd_opts.add_option(
+            "-e",
+            "--editable",
+            action="store_true",
+            default=False,
+            help="List editable projects.",
+        )
+        self.cmd_opts.add_option(
+            "-l",
+            "--local",
+            action="store_true",
+            default=False,
+            help=(
+                "If in a virtualenv that has global access, do not list "
+                "globally-installed packages."
+            ),
+        )
+        self.cmd_opts.add_option(
+            "--user",
+            dest="user",
+            action="store_true",
+            default=False,
+            help="Only output packages installed in user-site.",
+        )
         self.cmd_opts.add_option(cmdoptions.list_path())
         self.cmd_opts.add_option(
-            '--pre',
-            action='store_true',
+            "--pre",
+            action="store_true",
             default=False,
-            help=("Include pre-release and development versions. By default, "
-                  "pip only finds stable versions."),
+            help=(
+                "Include pre-release and development versions. By default, "
+                "pip only finds stable versions."
+            ),
         )
 
         self.cmd_opts.add_option(
-            '--format',
-            action='store',
-            dest='list_format',
+            "--format",
+            action="store",
+            dest="list_format",
             default="columns",
-            choices=('columns', 'freeze', 'json'),
-            help="Select the output format among: columns (default), freeze, "
-                 "or json",
+            choices=("columns", "freeze", "json"),
+            help="Select the output format among: columns (default), freeze, or json",
         )
 
         self.cmd_opts.add_option(
-            '--not-required',
-            action='store_true',
-            dest='not_required',
-            help="List packages that are not dependencies of "
-                 "installed packages.",
+            "--not-required",
+            action="store_true",
+            dest="not_required",
+            help="List packages that are not dependencies of installed packages.",
         )
 
         self.cmd_opts.add_option(
-            '--exclude-editable',
-            action='store_false',
-            dest='include_editable',
-            help='Exclude editable package from output.',
+            "--exclude-editable",
+            action="store_false",
+            dest="include_editable",
+            help="Exclude editable package from output.",
         )
         self.cmd_opts.add_option(
-            '--include-editable',
-            action='store_true',
-            dest='include_editable',
-            help='Include editable package from output.',
+            "--include-editable",
+            action="store_true",
+            dest="include_editable",
+            help="Include editable package from output.",
             default=True,
         )
         self.cmd_opts.add_option(cmdoptions.list_exclude())
-        index_opts = cmdoptions.make_option_group(
-            cmdoptions.index_group, self.parser
-        )
+        index_opts = cmdoptions.make_option_group(cmdoptions.index_group, self.parser)
 
         self.parser.insert_option_group(0, index_opts)
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def _build_package_finder(self, options, session):
-        # type: (Values, PipSession) -> PackageFinder
+    def _build_package_finder(
+        self, options: Values, session: PipSession
+    ) -> PackageFinder:
         """
         Create a package finder appropriate to this list command.
         """
@@ -131,28 +149,29 @@ class ListCommand(IndexGroupCommand):
         return PackageFinder.create(
             link_collector=link_collector,
             selection_prefs=selection_prefs,
+            use_deprecated_html5lib="html5lib" in options.deprecated_features_enabled,
         )
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         if options.outdated and options.uptodate:
-            raise CommandError(
-                "Options --outdated and --uptodate cannot be combined.")
+            raise CommandError("Options --outdated and --uptodate cannot be combined.")
 
         cmdoptions.check_list_path_option(options)
 
         skip = set(stdlib_pkgs)
         if options.excludes:
-            skip.update(options.excludes)
+            skip.update(canonicalize_name(n) for n in options.excludes)
 
-        packages = get_installed_distributions(
-            local_only=options.local,
-            user_only=options.user,
-            editables_only=options.editable,
-            include_editables=options.include_editable,
-            paths=options.path,
-            skip=skip,
-        )
+        packages: "_ProcessedDists" = [
+            cast("_DistWithLatestInfo", d)
+            for d in get_environment(options.path).iter_installed_distributions(
+                local_only=options.local,
+                user_only=options.user,
+                editables_only=options.editable,
+                include_editables=options.include_editable,
+                skip=skip,
+            )
+        ]
 
         # get_not_required must be called firstly in order to find and
         # filter out all dependencies correctly. Otherwise a package
@@ -169,46 +188,58 @@ class ListCommand(IndexGroupCommand):
         self.output_package_listing(packages, options)
         return SUCCESS
 
-    def get_outdated(self, packages, options):
-        # type: (List[Distribution], Values) -> List[Distribution]
+    def get_outdated(
+        self, packages: "_ProcessedDists", options: Values
+    ) -> "_ProcessedDists":
         return [
-            dist for dist in self.iter_packages_latest_infos(packages, options)
-            if dist.latest_version > dist.parsed_version
+            dist
+            for dist in self.iter_packages_latest_infos(packages, options)
+            if dist.latest_version > dist.version
         ]
 
-    def get_uptodate(self, packages, options):
-        # type: (List[Distribution], Values) -> List[Distribution]
+    def get_uptodate(
+        self, packages: "_ProcessedDists", options: Values
+    ) -> "_ProcessedDists":
         return [
-            dist for dist in self.iter_packages_latest_infos(packages, options)
-            if dist.latest_version == dist.parsed_version
+            dist
+            for dist in self.iter_packages_latest_infos(packages, options)
+            if dist.latest_version == dist.version
         ]
 
-    def get_not_required(self, packages, options):
-        # type: (List[Distribution], Values) -> List[Distribution]
-        dep_keys = set()  # type: Set[Distribution]
-        for dist in packages:
-            dep_keys.update(requirement.key for requirement in dist.requires())
+    def get_not_required(
+        self, packages: "_ProcessedDists", options: Values
+    ) -> "_ProcessedDists":
+        dep_keys = {
+            canonicalize_name(dep.name)
+            for dist in packages
+            for dep in (dist.iter_dependencies() or ())
+        }
 
         # Create a set to remove duplicate packages, and cast it to a list
         # to keep the return type consistent with get_outdated and
         # get_uptodate
-        return list({pkg for pkg in packages if pkg.key not in dep_keys})
+        return list({pkg for pkg in packages if pkg.canonical_name not in dep_keys})
 
-    def iter_packages_latest_infos(self, packages, options):
-        # type: (List[Distribution], Values) -> Iterator[Distribution]
+    def iter_packages_latest_infos(
+        self, packages: "_ProcessedDists", options: Values
+    ) -> Generator["_DistWithLatestInfo", None, None]:
         with self._build_session(options) as session:
             finder = self._build_package_finder(options, session)
 
-            def latest_info(dist):
-                # type: (Distribution) -> Distribution
-                all_candidates = finder.find_all_candidates(dist.key)
+            def latest_info(
+                dist: "_DistWithLatestInfo",
+            ) -> Optional["_DistWithLatestInfo"]:
+                all_candidates = finder.find_all_candidates(dist.canonical_name)
                 if not options.pre:
                     # Remove prereleases
-                    all_candidates = [candidate for candidate in all_candidates
-                                      if not candidate.version.is_prerelease]
+                    all_candidates = [
+                        candidate
+                        for candidate in all_candidates
+                        if not candidate.version.is_prerelease
+                    ]
 
                 evaluator = finder.make_candidate_evaluator(
-                    project_name=dist.project_name,
+                    project_name=dist.canonical_name,
                 )
                 best_candidate = evaluator.sort_best_candidate(all_candidates)
                 if best_candidate is None:
@@ -216,39 +247,41 @@ class ListCommand(IndexGroupCommand):
 
                 remote_version = best_candidate.version
                 if best_candidate.link.is_wheel:
-                    typ = 'wheel'
+                    typ = "wheel"
                 else:
-                    typ = 'sdist'
-                # This is dirty but makes the rest of the code much cleaner
+                    typ = "sdist"
                 dist.latest_version = remote_version
                 dist.latest_filetype = typ
                 return dist
 
-            for dist in map_multithread(latest_info, packages):
+            for dist in map(latest_info, packages):
                 if dist is not None:
                     yield dist
 
-    def output_package_listing(self, packages, options):
-        # type: (List[Distribution], Values) -> None
+    def output_package_listing(
+        self, packages: "_ProcessedDists", options: Values
+    ) -> None:
         packages = sorted(
             packages,
-            key=lambda dist: dist.project_name.lower(),
+            key=lambda dist: dist.canonical_name,
         )
-        if options.list_format == 'columns' and packages:
+        if options.list_format == "columns" and packages:
             data, header = format_for_columns(packages, options)
             self.output_package_listing_columns(data, header)
-        elif options.list_format == 'freeze':
+        elif options.list_format == "freeze":
             for dist in packages:
                 if options.verbose >= 1:
-                    write_output("%s==%s (%s)", dist.project_name,
-                                 dist.version, dist.location)
+                    write_output(
+                        "%s==%s (%s)", dist.raw_name, dist.version, dist.location
+                    )
                 else:
-                    write_output("%s==%s", dist.project_name, dist.version)
-        elif options.list_format == 'json':
+                    write_output("%s==%s", dist.raw_name, dist.version)
+        elif options.list_format == "json":
             write_output(format_for_json(packages, options))
 
-    def output_package_listing_columns(self, data, header):
-        # type: (List[List[str]], List[str]) -> None
+    def output_package_listing_columns(
+        self, data: List[List[str]], header: List[str]
+    ) -> None:
         # insert the header first: we need to know the size of column names
         if len(data) > 0:
             data.insert(0, header)
@@ -257,63 +290,72 @@ class ListCommand(IndexGroupCommand):
 
         # Create and add a separator.
         if len(data) > 0:
-            pkg_strings.insert(1, " ".join(map(lambda x: '-' * x, sizes)))
+            pkg_strings.insert(1, " ".join(map(lambda x: "-" * x, sizes)))
 
         for val in pkg_strings:
             write_output(val)
 
 
-def format_for_columns(pkgs, options):
-    # type: (List[Distribution], Values) -> Tuple[List[List[str]], List[str]]
+def format_for_columns(
+    pkgs: "_ProcessedDists", options: Values
+) -> Tuple[List[List[str]], List[str]]:
     """
     Convert the package data into something usable
     by output_package_listing_columns.
     """
-    running_outdated = options.outdated
-    # Adjust the header for the `pip list --outdated` case.
-    if running_outdated:
-        header = ["Package", "Version", "Latest", "Type"]
-    else:
-        header = ["Package", "Version"]
+    header = ["Package", "Version"]
 
-    data = []
-    if options.verbose >= 1 or any(dist_is_editable(x) for x in pkgs):
+    running_outdated = options.outdated
+    if running_outdated:
+        header.extend(["Latest", "Type"])
+
+    has_editables = any(x.editable for x in pkgs)
+    if has_editables:
+        header.append("Editable project location")
+
+    if options.verbose >= 1:
         header.append("Location")
     if options.verbose >= 1:
         header.append("Installer")
 
+    data = []
     for proj in pkgs:
         # if we're working on the 'outdated' list, separate out the
         # latest_version and type
-        row = [proj.project_name, proj.version]
+        row = [proj.raw_name, str(proj.version)]
 
         if running_outdated:
-            row.append(proj.latest_version)
+            row.append(str(proj.latest_version))
             row.append(proj.latest_filetype)
 
-        if options.verbose >= 1 or dist_is_editable(proj):
-            row.append(proj.location)
+        if has_editables:
+            row.append(proj.editable_project_location or "")
+
         if options.verbose >= 1:
-            row.append(get_installer(proj))
+            row.append(proj.location or "")
+        if options.verbose >= 1:
+            row.append(proj.installer)
 
         data.append(row)
 
     return data, header
 
 
-def format_for_json(packages, options):
-    # type: (List[Distribution], Values) -> str
+def format_for_json(packages: "_ProcessedDists", options: Values) -> str:
     data = []
     for dist in packages:
         info = {
-            'name': dist.project_name,
-            'version': str(dist.version),
+            "name": dist.raw_name,
+            "version": str(dist.version),
         }
         if options.verbose >= 1:
-            info['location'] = dist.location
-            info['installer'] = get_installer(dist)
+            info["location"] = dist.location or ""
+            info["installer"] = dist.installer
         if options.outdated:
-            info['latest_version'] = str(dist.latest_version)
-            info['latest_filetype'] = dist.latest_filetype
+            info["latest_version"] = str(dist.latest_version)
+            info["latest_filetype"] = dist.latest_filetype
+        editable_project_location = dist.editable_project_location
+        if editable_project_location:
+            info["editable_project_location"] = editable_project_location
         data.append(info)
     return json.dumps(data)

venv/Lib/site-packages/pip/_internal/commands/search.py

@@ -27,6 +27,7 @@ if TYPE_CHECKING:
         summary: str
         versions: List[str]
 
+
 logger = logging.getLogger(__name__)
 
 
@@ -37,21 +38,21 @@ class SearchCommand(Command, SessionCommandMixin):
       %prog [options] <query>"""
     ignore_require_venv = True
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-i', '--index',
-            dest='index',
-            metavar='URL',
+            "-i",
+            "--index",
+            dest="index",
+            metavar="URL",
             default=PyPI.pypi_url,
-            help='Base URL of Python Package Index (default %default)')
+            help="Base URL of Python Package Index (default %default)",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         if not args:
-            raise CommandError('Missing required argument (search query).')
+            raise CommandError("Missing required argument (search query).")
         query = args
         pypi_hits = self.search(query, options)
         hits = transform_hits(pypi_hits)
@@ -65,8 +66,7 @@ class SearchCommand(Command, SessionCommandMixin):
             return SUCCESS
         return NO_MATCHES_FOUND
 
-    def search(self, query, options):
-        # type: (List[str], Values) -> List[Dict[str, str]]
+    def search(self, query: List[str], options: Values) -> List[Dict[str, str]]:
         index_url = options.index
 
         session = self.get_default_session(options)
@@ -74,7 +74,7 @@ class SearchCommand(Command, SessionCommandMixin):
         transport = PipXmlrpcTransport(index_url, session)
         pypi = xmlrpc.client.ServerProxy(index_url, transport)
         try:
-            hits = pypi.search({'name': query, 'summary': query}, 'or')
+            hits = pypi.search({"name": query, "summary": query}, "or")
         except xmlrpc.client.Fault as fault:
             message = "XMLRPC request failed [code: {code}]\n{string}".format(
                 code=fault.faultCode,
@@ -85,78 +85,90 @@ class SearchCommand(Command, SessionCommandMixin):
         return hits
 
 
-def transform_hits(hits):
-    # type: (List[Dict[str, str]]) -> List[TransformedHit]
+def transform_hits(hits: List[Dict[str, str]]) -> List["TransformedHit"]:
     """
     The list from pypi is really a list of versions. We want a list of
     packages with the list of versions stored inline. This converts the
     list from pypi into one we can use.
     """
-    packages = OrderedDict()  # type: OrderedDict[str, TransformedHit]
+    packages: Dict[str, "TransformedHit"] = OrderedDict()
     for hit in hits:
-        name = hit['name']
-        summary = hit['summary']
-        version = hit['version']
+        name = hit["name"]
+        summary = hit["summary"]
+        version = hit["version"]
 
         if name not in packages.keys():
             packages[name] = {
-                'name': name,
-                'summary': summary,
-                'versions': [version],
+                "name": name,
+                "summary": summary,
+                "versions": [version],
             }
         else:
-            packages[name]['versions'].append(version)
+            packages[name]["versions"].append(version)
 
             # if this is the highest version, replace summary and score
-            if version == highest_version(packages[name]['versions']):
-                packages[name]['summary'] = summary
+            if version == highest_version(packages[name]["versions"]):
+                packages[name]["summary"] = summary
 
     return list(packages.values())
 
 
-def print_results(hits, name_column_width=None, terminal_width=None):
-    # type: (List[TransformedHit], Optional[int], Optional[int]) -> None
+def print_dist_installation_info(name: str, latest: str) -> None:
+    env = get_default_environment()
+    dist = env.get_distribution(name)
+    if dist is not None:
+        with indent_log():
+            if dist.version == latest:
+                write_output("INSTALLED: %s (latest)", dist.version)
+            else:
+                write_output("INSTALLED: %s", dist.version)
+                if parse_version(latest).pre:
+                    write_output(
+                        "LATEST:    %s (pre-release; install"
+                        " with `pip install --pre`)",
+                        latest,
+                    )
+                else:
+                    write_output("LATEST:    %s", latest)
+
+
+def print_results(
+    hits: List["TransformedHit"],
+    name_column_width: Optional[int] = None,
+    terminal_width: Optional[int] = None,
+) -> None:
     if not hits:
         return
     if name_column_width is None:
-        name_column_width = max([
-            len(hit['name']) + len(highest_version(hit.get('versions', ['-'])))
-            for hit in hits
-        ]) + 4
+        name_column_width = (
+            max(
+                [
+                    len(hit["name"]) + len(highest_version(hit.get("versions", ["-"])))
+                    for hit in hits
+                ]
+            )
+            + 4
+        )
 
-    env = get_default_environment()
     for hit in hits:
-        name = hit['name']
-        summary = hit['summary'] or ''
-        latest = highest_version(hit.get('versions', ['-']))
+        name = hit["name"]
+        summary = hit["summary"] or ""
+        latest = highest_version(hit.get("versions", ["-"]))
         if terminal_width is not None:
             target_width = terminal_width - name_column_width - 5
             if target_width > 10:
                 # wrap and indent summary to fit terminal
                 summary_lines = textwrap.wrap(summary, target_width)
-                summary = ('\n' + ' ' * (name_column_width + 3)).join(
-                    summary_lines)
+                summary = ("\n" + " " * (name_column_width + 3)).join(summary_lines)
 
-        name_latest = f'{name} ({latest})'
-        line = f'{name_latest:{name_column_width}} - {summary}'
+        name_latest = f"{name} ({latest})"
+        line = f"{name_latest:{name_column_width}} - {summary}"
         try:
             write_output(line)
-            dist = env.get_distribution(name)
-            if dist is not None:
-                with indent_log():
-                    if dist.version == latest:
-                        write_output('INSTALLED: %s (latest)', dist.version)
-                    else:
-                        write_output('INSTALLED: %s', dist.version)
-                        if parse_version(latest).pre:
-                            write_output('LATEST:    %s (pre-release; install'
-                                         ' with "pip install --pre")', latest)
-                        else:
-                            write_output('LATEST:    %s', latest)
+            print_dist_installation_info(name, latest)
         except UnicodeEncodeError:
             pass
 
 
-def highest_version(versions):
-    # type: (List[str]) -> str
+def highest_version(versions: List[str]) -> str:
     return max(versions, key=parse_version)

venv/Lib/site-packages/pip/_internal/commands/show.py

@@ -1,14 +1,12 @@
 import logging
-import os
-from email.parser import FeedParser
 from optparse import Values
-from typing import Dict, Iterator, List
+from typing import Generator, Iterable, Iterator, List, NamedTuple, Optional
 
-from pip._vendor import pkg_resources
 from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.status_codes import ERROR, SUCCESS
+from pip._internal.metadata import BaseDistribution, get_default_environment
 from pip._internal.utils.misc import write_output
 
 logger = logging.getLogger(__name__)
@@ -25,123 +23,124 @@ class ShowCommand(Command):
       %prog [options] <package> ..."""
     ignore_require_venv = True
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-f', '--files',
-            dest='files',
-            action='store_true',
+            "-f",
+            "--files",
+            dest="files",
+            action="store_true",
             default=False,
-            help='Show the full list of installed files for each package.')
+            help="Show the full list of installed files for each package.",
+        )
 
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         if not args:
-            logger.warning('ERROR: Please provide a package name or names.')
+            logger.warning("ERROR: Please provide a package name or names.")
             return ERROR
         query = args
 
         results = search_packages_info(query)
         if not print_results(
-                results, list_files=options.files, verbose=options.verbose):
+            results, list_files=options.files, verbose=options.verbose
+        ):
             return ERROR
         return SUCCESS
 
 
-def search_packages_info(query):
-    # type: (List[str]) -> Iterator[Dict[str, str]]
+class _PackageInfo(NamedTuple):
+    name: str
+    version: str
+    location: str
+    requires: List[str]
+    required_by: List[str]
+    installer: str
+    metadata_version: str
+    classifiers: List[str]
+    summary: str
+    homepage: str
+    project_urls: List[str]
+    author: str
+    author_email: str
+    license: str
+    entry_points: List[str]
+    files: Optional[List[str]]
+
+
+def search_packages_info(query: List[str]) -> Generator[_PackageInfo, None, None]:
     """
     Gather details from installed distributions. Print distribution name,
     version, location, and installed files. Installed files requires a
     pip generated 'installed-files.txt' in the distributions '.egg-info'
     directory.
     """
-    installed = {}
-    for p in pkg_resources.working_set:
-        installed[canonicalize_name(p.project_name)] = p
+    env = get_default_environment()
 
+    installed = {dist.canonical_name: dist for dist in env.iter_all_distributions()}
     query_names = [canonicalize_name(name) for name in query]
     missing = sorted(
         [name for name, pkg in zip(query, query_names) if pkg not in installed]
     )
     if missing:
-        logger.warning('Package(s) not found: %s', ', '.join(missing))
+        logger.warning("Package(s) not found: %s", ", ".join(missing))
 
-    def get_requiring_packages(package_name):
-        # type: (str) -> List[str]
-        canonical_name = canonicalize_name(package_name)
-        return [
-            pkg.project_name for pkg in pkg_resources.working_set
-            if canonical_name in
-               [canonicalize_name(required.name) for required in
-                pkg.requires()]
-        ]
+    def _get_requiring_packages(current_dist: BaseDistribution) -> Iterator[str]:
+        return (
+            dist.metadata["Name"] or "UNKNOWN"
+            for dist in installed.values()
+            if current_dist.canonical_name
+            in {canonicalize_name(d.name) for d in dist.iter_dependencies()}
+        )
 
-    for dist in [installed[pkg] for pkg in query_names if pkg in installed]:
-        package = {
-            'name': dist.project_name,
-            'version': dist.version,
-            'location': dist.location,
-            'requires': [dep.project_name for dep in dist.requires()],
-            'required_by': get_requiring_packages(dist.project_name)
-        }
-        file_list = None
-        metadata = ''
-        if isinstance(dist, pkg_resources.DistInfoDistribution):
-            # RECORDs should be part of .dist-info metadatas
-            if dist.has_metadata('RECORD'):
-                lines = dist.get_metadata_lines('RECORD')
-                paths = [line.split(',')[0] for line in lines]
-                paths = [os.path.join(dist.location, p) for p in paths]
-                file_list = [os.path.relpath(p, dist.location) for p in paths]
+    for query_name in query_names:
+        try:
+            dist = installed[query_name]
+        except KeyError:
+            continue
 
-            if dist.has_metadata('METADATA'):
-                metadata = dist.get_metadata('METADATA')
+        requires = sorted((req.name for req in dist.iter_dependencies()), key=str.lower)
+        required_by = sorted(_get_requiring_packages(dist), key=str.lower)
+
+        try:
+            entry_points_text = dist.read_text("entry_points.txt")
+            entry_points = entry_points_text.splitlines(keepends=False)
+        except FileNotFoundError:
+            entry_points = []
+
+        files_iter = dist.iter_declared_entries()
+        if files_iter is None:
+            files: Optional[List[str]] = None
         else:
-            # Otherwise use pip's log for .egg-info's
-            if dist.has_metadata('installed-files.txt'):
-                paths = dist.get_metadata_lines('installed-files.txt')
-                paths = [os.path.join(dist.egg_info, p) for p in paths]
-                file_list = [os.path.relpath(p, dist.location) for p in paths]
+            files = sorted(files_iter)
 
-            if dist.has_metadata('PKG-INFO'):
-                metadata = dist.get_metadata('PKG-INFO')
+        metadata = dist.metadata
 
-        if dist.has_metadata('entry_points.txt'):
-            entry_points = dist.get_metadata_lines('entry_points.txt')
-            package['entry_points'] = entry_points
-
-        if dist.has_metadata('INSTALLER'):
-            for line in dist.get_metadata_lines('INSTALLER'):
-                if line.strip():
-                    package['installer'] = line.strip()
-                    break
-
-        # @todo: Should pkg_resources.Distribution have a
-        # `get_pkg_info` method?
-        feed_parser = FeedParser()
-        feed_parser.feed(metadata)
-        pkg_info_dict = feed_parser.close()
-        for key in ('metadata-version', 'summary',
-                    'home-page', 'author', 'author-email', 'license'):
-            package[key] = pkg_info_dict.get(key)
-
-        # It looks like FeedParser cannot deal with repeated headers
-        classifiers = []
-        for line in metadata.splitlines():
-            if line.startswith('Classifier: '):
-                classifiers.append(line[len('Classifier: '):])
-        package['classifiers'] = classifiers
-
-        if file_list:
-            package['files'] = sorted(file_list)
-        yield package
+        yield _PackageInfo(
+            name=dist.raw_name,
+            version=str(dist.version),
+            location=dist.location or "",
+            requires=requires,
+            required_by=required_by,
+            installer=dist.installer,
+            metadata_version=dist.metadata_version or "",
+            classifiers=metadata.get_all("Classifier", []),
+            summary=metadata.get("Summary", ""),
+            homepage=metadata.get("Home-page", ""),
+            project_urls=metadata.get_all("Project-URL", []),
+            author=metadata.get("Author", ""),
+            author_email=metadata.get("Author-email", ""),
+            license=metadata.get("License", ""),
+            entry_points=entry_points,
+            files=files,
+        )
 
 
-def print_results(distributions, list_files=False, verbose=False):
-    # type: (Iterator[Dict[str, str]], bool, bool) -> bool
+def print_results(
+    distributions: Iterable[_PackageInfo],
+    list_files: bool,
+    verbose: bool,
+) -> bool:
     """
     Print the information from installed distributions found.
     """
@@ -151,31 +150,34 @@ def print_results(distributions, list_files=False, verbose=False):
         if i > 0:
             write_output("---")
 
-        write_output("Name: %s", dist.get('name', ''))
-        write_output("Version: %s", dist.get('version', ''))
-        write_output("Summary: %s", dist.get('summary', ''))
-        write_output("Home-page: %s", dist.get('home-page', ''))
-        write_output("Author: %s", dist.get('author', ''))
-        write_output("Author-email: %s", dist.get('author-email', ''))
-        write_output("License: %s", dist.get('license', ''))
-        write_output("Location: %s", dist.get('location', ''))
-        write_output("Requires: %s", ', '.join(dist.get('requires', [])))
-        write_output("Required-by: %s", ', '.join(dist.get('required_by', [])))
+        write_output("Name: %s", dist.name)
+        write_output("Version: %s", dist.version)
+        write_output("Summary: %s", dist.summary)
+        write_output("Home-page: %s", dist.homepage)
+        write_output("Author: %s", dist.author)
+        write_output("Author-email: %s", dist.author_email)
+        write_output("License: %s", dist.license)
+        write_output("Location: %s", dist.location)
+        write_output("Requires: %s", ", ".join(dist.requires))
+        write_output("Required-by: %s", ", ".join(dist.required_by))
 
         if verbose:
-            write_output("Metadata-Version: %s",
-                         dist.get('metadata-version', ''))
-            write_output("Installer: %s", dist.get('installer', ''))
+            write_output("Metadata-Version: %s", dist.metadata_version)
+            write_output("Installer: %s", dist.installer)
             write_output("Classifiers:")
-            for classifier in dist.get('classifiers', []):
+            for classifier in dist.classifiers:
                 write_output("  %s", classifier)
             write_output("Entry-points:")
-            for entry in dist.get('entry_points', []):
+            for entry in dist.entry_points:
                 write_output("  %s", entry.strip())
+            write_output("Project-URLs:")
+            for project_url in dist.project_urls:
+                write_output("  %s", project_url)
         if list_files:
             write_output("Files:")
-            for line in dist.get('files', []):
-                write_output("  %s", line.strip())
-            if "files" not in dist:
-                write_output("Cannot locate installed-files.txt")
+            if dist.files is None:
+                write_output("Cannot locate RECORD or installed-files.txt")
+            else:
+                for line in dist.files:
+                    write_output("  %s", line.strip())
     return results_printed

venv/Lib/site-packages/pip/_internal/commands/uninstall.py

@@ -1,8 +1,10 @@
+import logging
 from optparse import Values
 from typing import List
 
 from pip._vendor.packaging.utils import canonicalize_name
 
+from pip._internal.cli import cmdoptions
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.req_command import SessionCommandMixin, warn_if_run_as_root
 from pip._internal.cli.status_codes import SUCCESS
@@ -14,6 +16,8 @@ from pip._internal.req.constructors import (
 )
 from pip._internal.utils.misc import protect_pip_from_modification_on_windows
 
+logger = logging.getLogger(__name__)
+
 
 class UninstallCommand(Command, SessionCommandMixin):
     """
@@ -30,50 +34,59 @@ class UninstallCommand(Command, SessionCommandMixin):
       %prog [options] <package> ...
       %prog [options] -r <requirements file> ..."""
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
         self.cmd_opts.add_option(
-            '-r', '--requirement',
-            dest='requirements',
-            action='append',
+            "-r",
+            "--requirement",
+            dest="requirements",
+            action="append",
             default=[],
-            metavar='file',
-            help='Uninstall all the packages listed in the given requirements '
-                 'file.  This option can be used multiple times.',
+            metavar="file",
+            help=(
+                "Uninstall all the packages listed in the given requirements "
+                "file.  This option can be used multiple times."
+            ),
         )
         self.cmd_opts.add_option(
-            '-y', '--yes',
-            dest='yes',
-            action='store_true',
-            help="Don't ask for confirmation of uninstall deletions.")
-
+            "-y",
+            "--yes",
+            dest="yes",
+            action="store_true",
+            help="Don't ask for confirmation of uninstall deletions.",
+        )
+        self.cmd_opts.add_option(cmdoptions.root_user_action())
         self.parser.insert_option_group(0, self.cmd_opts)
 
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         session = self.get_default_session(options)
 
         reqs_to_uninstall = {}
         for name in args:
             req = install_req_from_line(
-                name, isolated=options.isolated_mode,
+                name,
+                isolated=options.isolated_mode,
             )
             if req.name:
                 reqs_to_uninstall[canonicalize_name(req.name)] = req
+            else:
+                logger.warning(
+                    "Invalid requirement: %r ignored -"
+                    " the uninstall command expects named"
+                    " requirements.",
+                    name,
+                )
         for filename in options.requirements:
             for parsed_req in parse_requirements(
-                    filename,
-                    options=options,
-                    session=session):
+                filename, options=options, session=session
+            ):
                 req = install_req_from_parsed_requirement(
-                    parsed_req,
-                    isolated=options.isolated_mode
+                    parsed_req, isolated=options.isolated_mode
                 )
                 if req.name:
                     reqs_to_uninstall[canonicalize_name(req.name)] = req
         if not reqs_to_uninstall:
             raise InstallationError(
-                f'You must give at least one requirement to {self.name} (see '
+                f"You must give at least one requirement to {self.name} (see "
                 f'"pip help {self.name}")'
             )
 
@@ -83,10 +96,11 @@ class UninstallCommand(Command, SessionCommandMixin):
 
         for req in reqs_to_uninstall.values():
             uninstall_pathset = req.uninstall(
-                auto_confirm=options.yes, verbose=self.verbosity > 0,
+                auto_confirm=options.yes,
+                verbose=self.verbosity > 0,
             )
             if uninstall_pathset:
                 uninstall_pathset.commit()
-
-        warn_if_run_as_root()
+        if options.root_user_action == "warn":
+            warn_if_run_as_root()
         return SUCCESS

venv/Lib/site-packages/pip/_internal/commands/wheel.py

@@ -9,8 +9,8 @@ from pip._internal.cli import cmdoptions
 from pip._internal.cli.req_command import RequirementCommand, with_cleanup
 from pip._internal.cli.status_codes import SUCCESS
 from pip._internal.exceptions import CommandError
+from pip._internal.operations.build.build_tracker import get_build_tracker
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_tracker import get_requirement_tracker
 from pip._internal.utils.misc import ensure_dir, normalize_path
 from pip._internal.utils.temp_dir import TempDirectory
 from pip._internal.wheel_builder import build, should_build_for_wheel_command
@@ -26,10 +26,8 @@ class WheelCommand(RequirementCommand):
     recompiling your software during every install. For more details, see the
     wheel docs: https://wheel.readthedocs.io/en/latest/
 
-    Requirements: setuptools>=0.8, and wheel.
-
-    'pip wheel' uses the bdist_wheel setuptools extension from the wheel
-    package to build individual wheels.
+    'pip wheel' uses the build system interface as described here:
+    https://pip.pypa.io/en/stable/reference/build-system/
 
     """
 
@@ -40,16 +38,18 @@ class WheelCommand(RequirementCommand):
       %prog [options] [-e] <local project path> ...
       %prog [options] <archive url/path> ..."""
 
-    def add_options(self):
-        # type: () -> None
+    def add_options(self) -> None:
 
         self.cmd_opts.add_option(
-            '-w', '--wheel-dir',
-            dest='wheel_dir',
-            metavar='dir',
+            "-w",
+            "--wheel-dir",
+            dest="wheel_dir",
+            metavar="dir",
             default=os.curdir,
-            help=("Build wheels into <dir>, where the default is the "
-                  "current working directory."),
+            help=(
+                "Build wheels into <dir>, where the default is the "
+                "current working directory."
+            ),
         )
         self.cmd_opts.add_option(cmdoptions.no_binary())
         self.cmd_opts.add_option(cmdoptions.only_binary())
@@ -57,32 +57,35 @@ class WheelCommand(RequirementCommand):
         self.cmd_opts.add_option(cmdoptions.no_build_isolation())
         self.cmd_opts.add_option(cmdoptions.use_pep517())
         self.cmd_opts.add_option(cmdoptions.no_use_pep517())
+        self.cmd_opts.add_option(cmdoptions.check_build_deps())
         self.cmd_opts.add_option(cmdoptions.constraints())
         self.cmd_opts.add_option(cmdoptions.editable())
         self.cmd_opts.add_option(cmdoptions.requirements())
         self.cmd_opts.add_option(cmdoptions.src())
         self.cmd_opts.add_option(cmdoptions.ignore_requires_python())
         self.cmd_opts.add_option(cmdoptions.no_deps())
-        self.cmd_opts.add_option(cmdoptions.build_dir())
         self.cmd_opts.add_option(cmdoptions.progress_bar())
 
         self.cmd_opts.add_option(
-            '--no-verify',
-            dest='no_verify',
-            action='store_true',
+            "--no-verify",
+            dest="no_verify",
+            action="store_true",
             default=False,
             help="Don't verify if built wheel is valid.",
         )
 
+        self.cmd_opts.add_option(cmdoptions.config_settings())
         self.cmd_opts.add_option(cmdoptions.build_options())
         self.cmd_opts.add_option(cmdoptions.global_options())
 
         self.cmd_opts.add_option(
-            '--pre',
-            action='store_true',
+            "--pre",
+            action="store_true",
             default=False,
-            help=("Include pre-release and development versions. By default, "
-                  "pip only finds stable versions."),
+            help=(
+                "Include pre-release and development versions. By default, "
+                "pip only finds stable versions."
+            ),
         )
 
         self.cmd_opts.add_option(cmdoptions.require_hashes())
@@ -96,8 +99,7 @@ class WheelCommand(RequirementCommand):
         self.parser.insert_option_group(0, self.cmd_opts)
 
     @with_cleanup
-    def run(self, options, args):
-        # type: (Values, List[str]) -> int
+    def run(self, options: Values, args: List[str]) -> int:
         cmdoptions.check_install_build_global(options)
 
         session = self.get_default_session(options)
@@ -108,7 +110,7 @@ class WheelCommand(RequirementCommand):
         options.wheel_dir = normalize_path(options.wheel_dir)
         ensure_dir(options.wheel_dir)
 
-        req_tracker = self.enter_context(get_requirement_tracker())
+        build_tracker = self.enter_context(get_build_tracker())
 
         directory = TempDirectory(
             delete=not options.no_clean,
@@ -121,11 +123,12 @@ class WheelCommand(RequirementCommand):
         preparer = self.make_requirement_preparer(
             temp_build_dir=directory,
             options=options,
-            req_tracker=req_tracker,
+            build_tracker=build_tracker,
             session=session,
             finder=finder,
             download_dir=options.wheel_dir,
             use_user_site=False,
+            verbosity=self.verbosity,
         )
 
         resolver = self.make_resolver(
@@ -139,11 +142,9 @@ class WheelCommand(RequirementCommand):
 
         self.trace_basic_info(finder)
 
-        requirement_set = resolver.resolve(
-            reqs, check_supported_wheels=True
-        )
+        requirement_set = resolver.resolve(reqs, check_supported_wheels=True)
 
-        reqs_to_build = []  # type: List[InstallRequirement]
+        reqs_to_build: List[InstallRequirement] = []
         for req in requirement_set.requirements.values():
             if req.is_wheel:
                 preparer.save_linked_requirement(req)
@@ -167,12 +168,11 @@ class WheelCommand(RequirementCommand):
             except OSError as e:
                 logger.warning(
                     "Building wheel for %s failed: %s",
-                    req.name, e,
+                    req.name,
+                    e,
                 )
                 build_failures.append(req)
         if len(build_failures) != 0:
-            raise CommandError(
-                "Failed to build one or more wheels"
-            )
+            raise CommandError("Failed to build one or more wheels")
 
         return SUCCESS

venv/Lib/site-packages/pip/_internal/configuration.py

@@ -13,7 +13,6 @@ Some terminology:
 
 import configparser
 import locale
-import logging
 import os
 import sys
 from typing import Any, Dict, Iterable, List, NewType, Optional, Tuple
@@ -24,41 +23,39 @@ from pip._internal.exceptions import (
 )
 from pip._internal.utils import appdirs
 from pip._internal.utils.compat import WINDOWS
+from pip._internal.utils.logging import getLogger
 from pip._internal.utils.misc import ensure_dir, enum
 
 RawConfigParser = configparser.RawConfigParser  # Shorthand
 Kind = NewType("Kind", str)
 
-CONFIG_BASENAME = 'pip.ini' if WINDOWS else 'pip.conf'
+CONFIG_BASENAME = "pip.ini" if WINDOWS else "pip.conf"
 ENV_NAMES_IGNORED = "version", "help"
 
 # The kinds of configurations there are.
 kinds = enum(
-    USER="user",        # User Specific
-    GLOBAL="global",    # System Wide
-    SITE="site",        # [Virtual] Environment Specific
-    ENV="env",          # from PIP_CONFIG_FILE
+    USER="user",  # User Specific
+    GLOBAL="global",  # System Wide
+    SITE="site",  # [Virtual] Environment Specific
+    ENV="env",  # from PIP_CONFIG_FILE
     ENV_VAR="env-var",  # from Environment Variables
 )
 OVERRIDE_ORDER = kinds.GLOBAL, kinds.USER, kinds.SITE, kinds.ENV, kinds.ENV_VAR
 VALID_LOAD_ONLY = kinds.USER, kinds.GLOBAL, kinds.SITE
 
-logger = logging.getLogger(__name__)
+logger = getLogger(__name__)
 
 
 # NOTE: Maybe use the optionx attribute to normalize keynames.
-def _normalize_name(name):
-    # type: (str) -> str
-    """Make a name consistent regardless of source (environment or file)
-    """
-    name = name.lower().replace('_', '-')
-    if name.startswith('--'):
+def _normalize_name(name: str) -> str:
+    """Make a name consistent regardless of source (environment or file)"""
+    name = name.lower().replace("_", "-")
+    if name.startswith("--"):
         name = name[2:]  # only prefer long opts
     return name
 
 
-def _disassemble_key(name):
-    # type: (str) -> List[str]
+def _disassemble_key(name: str) -> List[str]:
     if "." not in name:
         error_message = (
             "Key does not contain dot separated section and key. "
@@ -68,22 +65,18 @@ def _disassemble_key(name):
     return name.split(".", 1)
 
 
-def get_configuration_files():
-    # type: () -> Dict[Kind, List[str]]
+def get_configuration_files() -> Dict[Kind, List[str]]:
     global_config_files = [
-        os.path.join(path, CONFIG_BASENAME)
-        for path in appdirs.site_config_dirs('pip')
+        os.path.join(path, CONFIG_BASENAME) for path in appdirs.site_config_dirs("pip")
     ]
 
     site_config_file = os.path.join(sys.prefix, CONFIG_BASENAME)
     legacy_config_file = os.path.join(
-        os.path.expanduser('~'),
-        'pip' if WINDOWS else '.pip',
+        os.path.expanduser("~"),
+        "pip" if WINDOWS else ".pip",
         CONFIG_BASENAME,
     )
-    new_config_file = os.path.join(
-        appdirs.user_config_dir("pip"), CONFIG_BASENAME
-    )
+    new_config_file = os.path.join(appdirs.user_config_dir("pip"), CONFIG_BASENAME)
     return {
         kinds.GLOBAL: global_config_files,
         kinds.SITE: [site_config_file],
@@ -105,8 +98,7 @@ class Configuration:
     and the data stored is also nice.
     """
 
-    def __init__(self, isolated, load_only=None):
-        # type: (bool, Optional[Kind]) -> None
+    def __init__(self, isolated: bool, load_only: Optional[Kind] = None) -> None:
         super().__init__()
 
         if load_only is not None and load_only not in VALID_LOAD_ONLY:
@@ -119,54 +111,50 @@ class Configuration:
         self.load_only = load_only
 
         # Because we keep track of where we got the data from
-        self._parsers = {
+        self._parsers: Dict[Kind, List[Tuple[str, RawConfigParser]]] = {
             variant: [] for variant in OVERRIDE_ORDER
-        }  # type: Dict[Kind, List[Tuple[str, RawConfigParser]]]
-        self._config = {
+        }
+        self._config: Dict[Kind, Dict[str, Any]] = {
             variant: {} for variant in OVERRIDE_ORDER
-        }  # type: Dict[Kind, Dict[str, Any]]
-        self._modified_parsers = []  # type: List[Tuple[str, RawConfigParser]]
+        }
+        self._modified_parsers: List[Tuple[str, RawConfigParser]] = []
 
-    def load(self):
-        # type: () -> None
-        """Loads configuration from configuration files and environment
-        """
+    def load(self) -> None:
+        """Loads configuration from configuration files and environment"""
         self._load_config_files()
         if not self.isolated:
             self._load_environment_vars()
 
-    def get_file_to_edit(self):
-        # type: () -> Optional[str]
-        """Returns the file with highest priority in configuration
-        """
-        assert self.load_only is not None, \
-            "Need to be specified a file to be editing"
+    def get_file_to_edit(self) -> Optional[str]:
+        """Returns the file with highest priority in configuration"""
+        assert self.load_only is not None, "Need to be specified a file to be editing"
 
         try:
             return self._get_parser_to_modify()[0]
         except IndexError:
             return None
 
-    def items(self):
-        # type: () -> Iterable[Tuple[str, Any]]
+    def items(self) -> Iterable[Tuple[str, Any]]:
         """Returns key-value pairs like dict.items() representing the loaded
         configuration
         """
         return self._dictionary.items()
 
-    def get_value(self, key):
-        # type: (str) -> Any
-        """Get a value from the configuration.
-        """
+    def get_value(self, key: str) -> Any:
+        """Get a value from the configuration."""
+        orig_key = key
+        key = _normalize_name(key)
         try:
             return self._dictionary[key]
         except KeyError:
-            raise ConfigurationError(f"No such key - {key}")
+            # disassembling triggers a more useful error message than simply
+            # "No such key" in the case that the key isn't in the form command.option
+            _disassemble_key(key)
+            raise ConfigurationError(f"No such key - {orig_key}")
 
-    def set_value(self, key, value):
-        # type: (str, Any) -> None
-        """Modify a value in the configuration.
-        """
+    def set_value(self, key: str, value: Any) -> None:
+        """Modify a value in the configuration."""
+        key = _normalize_name(key)
         self._ensure_have_load_only()
 
         assert self.load_only
@@ -183,21 +171,23 @@ class Configuration:
         self._config[self.load_only][key] = value
         self._mark_as_modified(fname, parser)
 
-    def unset_value(self, key):
-        # type: (str) -> None
+    def unset_value(self, key: str) -> None:
         """Unset a value in the configuration."""
+        orig_key = key
+        key = _normalize_name(key)
         self._ensure_have_load_only()
 
         assert self.load_only
         if key not in self._config[self.load_only]:
-            raise ConfigurationError(f"No such key - {key}")
+            raise ConfigurationError(f"No such key - {orig_key}")
 
         fname, parser = self._get_parser_to_modify()
 
         if parser is not None:
             section, name = _disassemble_key(key)
-            if not (parser.has_section(section)
-                    and parser.remove_option(section, name)):
+            if not (
+                parser.has_section(section) and parser.remove_option(section, name)
+            ):
                 # The option was not removed.
                 raise ConfigurationError(
                     "Fatal Internal error [id=1]. Please report as a bug."
@@ -210,10 +200,8 @@ class Configuration:
 
         del self._config[self.load_only][key]
 
-    def save(self):
-        # type: () -> None
-        """Save the current in-memory state.
-        """
+    def save(self) -> None:
+        """Save the current in-memory state."""
         self._ensure_have_load_only()
 
         for fname, parser in self._modified_parsers:
@@ -229,17 +217,14 @@ class Configuration:
     # Private routines
     #
 
-    def _ensure_have_load_only(self):
-        # type: () -> None
+    def _ensure_have_load_only(self) -> None:
         if self.load_only is None:
             raise ConfigurationError("Needed a specific file to be modifying.")
         logger.debug("Will be working with %s variant only", self.load_only)
 
     @property
-    def _dictionary(self):
-        # type: () -> Dict[str, Any]
-        """A dictionary representing the loaded configuration.
-        """
+    def _dictionary(self) -> Dict[str, Any]:
+        """A dictionary representing the loaded configuration."""
         # NOTE: Dictionaries are not populated if not loaded. So, conditionals
         #       are not needed here.
         retval = {}
@@ -249,10 +234,8 @@ class Configuration:
 
         return retval
 
-    def _load_config_files(self):
-        # type: () -> None
-        """Loads configuration from configuration files
-        """
+    def _load_config_files(self) -> None:
+        """Loads configuration from configuration files"""
         config_files = dict(self.iter_config_files())
         if config_files[kinds.ENV][0:1] == [os.devnull]:
             logger.debug(
@@ -266,9 +249,7 @@ class Configuration:
                 # If there's specific variant set in `load_only`, load only
                 # that variant, not the others.
                 if self.load_only is not None and variant != self.load_only:
-                    logger.debug(
-                        "Skipping file '%s' (variant: %s)", fname, variant
-                    )
+                    logger.debug("Skipping file '%s' (variant: %s)", fname, variant)
                     continue
 
                 parser = self._load_file(variant, fname)
@@ -276,9 +257,8 @@ class Configuration:
                 # Keeping track of the parsers used
                 self._parsers[variant].append((fname, parser))
 
-    def _load_file(self, variant, fname):
-        # type: (Kind, str) -> RawConfigParser
-        logger.debug("For variant '%s', will try loading '%s'", variant, fname)
+    def _load_file(self, variant: Kind, fname: str) -> RawConfigParser:
+        logger.verbose("For variant '%s', will try loading '%s'", variant, fname)
         parser = self._construct_parser(fname)
 
         for section in parser.sections():
@@ -287,22 +267,20 @@ class Configuration:
 
         return parser
 
-    def _construct_parser(self, fname):
-        # type: (str) -> RawConfigParser
+    def _construct_parser(self, fname: str) -> RawConfigParser:
         parser = configparser.RawConfigParser()
         # If there is no such file, don't bother reading it but create the
         # parser anyway, to hold the data.
         # Doing this is useful when modifying and saving files, where we don't
         # need to construct a parser.
         if os.path.exists(fname):
+            locale_encoding = locale.getpreferredencoding(False)
             try:
-                parser.read(fname)
+                parser.read(fname, encoding=locale_encoding)
             except UnicodeDecodeError:
                 # See https://github.com/pypa/pip/issues/4963
                 raise ConfigurationFileCouldNotBeLoaded(
-                    reason="contains invalid {} characters".format(
-                        locale.getpreferredencoding(False)
-                    ),
+                    reason=f"contains invalid {locale_encoding} characters",
                     fname=fname,
                 )
             except configparser.Error as error:
@@ -310,16 +288,15 @@ class Configuration:
                 raise ConfigurationFileCouldNotBeLoaded(error=error)
         return parser
 
-    def _load_environment_vars(self):
-        # type: () -> None
-        """Loads configuration from environment variables
-        """
+    def _load_environment_vars(self) -> None:
+        """Loads configuration from environment variables"""
         self._config[kinds.ENV_VAR].update(
             self._normalized_keys(":env:", self.get_environ_vars())
         )
 
-    def _normalized_keys(self, section, items):
-        # type: (str, Iterable[Tuple[str, Any]]) -> Dict[str, Any]
+    def _normalized_keys(
+        self, section: str, items: Iterable[Tuple[str, Any]]
+    ) -> Dict[str, Any]:
         """Normalizes items to construct a dictionary with normalized keys.
 
         This routine is where the names become keys and are made the same
@@ -331,8 +308,7 @@ class Configuration:
             normalized[key] = val
         return normalized
 
-    def get_environ_vars(self):
-        # type: () -> Iterable[Tuple[str, str]]
+    def get_environ_vars(self) -> Iterable[Tuple[str, str]]:
         """Returns a generator with all environmental vars with prefix PIP_"""
         for key, val in os.environ.items():
             if key.startswith("PIP_"):
@@ -341,8 +317,7 @@ class Configuration:
                     yield name, val
 
     # XXX: This is patched in the tests.
-    def iter_config_files(self):
-        # type: () -> Iterable[Tuple[Kind, List[str]]]
+    def iter_config_files(self) -> Iterable[Tuple[Kind, List[str]]]:
         """Yields variant and configuration files associated with it.
 
         This should be treated like items of a dictionary.
@@ -350,7 +325,7 @@ class Configuration:
         # SMELL: Move the conditions out of this function
 
         # environment variables have the lowest priority
-        config_file = os.environ.get('PIP_CONFIG_FILE', None)
+        config_file = os.environ.get("PIP_CONFIG_FILE", None)
         if config_file is not None:
             yield kinds.ENV, [config_file]
         else:
@@ -372,13 +347,11 @@ class Configuration:
         # finally virtualenv configuration first trumping others
         yield kinds.SITE, config_files[kinds.SITE]
 
-    def get_values_in_config(self, variant):
-        # type: (Kind) -> Dict[str, Any]
+    def get_values_in_config(self, variant: Kind) -> Dict[str, Any]:
         """Get values present in a config file"""
         return self._config[variant]
 
-    def _get_parser_to_modify(self):
-        # type: () -> Tuple[str, RawConfigParser]
+    def _get_parser_to_modify(self) -> Tuple[str, RawConfigParser]:
         # Determine which parser to modify
         assert self.load_only
         parsers = self._parsers[self.load_only]
@@ -392,12 +365,10 @@ class Configuration:
         return parsers[-1]
 
     # XXX: This is patched in the tests.
-    def _mark_as_modified(self, fname, parser):
-        # type: (str, RawConfigParser) -> None
+    def _mark_as_modified(self, fname: str, parser: RawConfigParser) -> None:
         file_parser_tuple = (fname, parser)
         if file_parser_tuple not in self._modified_parsers:
             self._modified_parsers.append(file_parser_tuple)
 
-    def __repr__(self):
-        # type: () -> str
+    def __repr__(self) -> str:
         return f"{self.__class__.__name__}({self._dictionary!r})"

venv/Lib/site-packages/pip/_internal/distributions/__init__.py

@@ -4,8 +4,9 @@ from pip._internal.distributions.wheel import WheelDistribution
 from pip._internal.req.req_install import InstallRequirement
 
 
-def make_distribution_for_install_requirement(install_req):
-    # type: (InstallRequirement) -> AbstractDistribution
+def make_distribution_for_install_requirement(
+    install_req: InstallRequirement,
+) -> AbstractDistribution:
     """Returns a Distribution for the given InstallRequirement"""
     # Editable requirements will always be source distributions. They use the
     # legacy logic until we create a modern standard for them.

venv/Lib/site-packages/pip/_internal/distributions/base.py

@@ -1,9 +1,7 @@
 import abc
-from typing import Optional
-
-from pip._vendor.pkg_resources import Distribution
 
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata.base import BaseDistribution
 from pip._internal.req import InstallRequirement
 
 
@@ -23,17 +21,19 @@ class AbstractDistribution(metaclass=abc.ABCMeta):
        above metadata.
     """
 
-    def __init__(self, req):
-        # type: (InstallRequirement) -> None
+    def __init__(self, req: InstallRequirement) -> None:
         super().__init__()
         self.req = req
 
     @abc.abstractmethod
-    def get_pkg_resources_distribution(self):
-        # type: () -> Optional[Distribution]
+    def get_metadata_distribution(self) -> BaseDistribution:
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def prepare_distribution_metadata(self, finder, build_isolation):
-        # type: (PackageFinder, bool) -> None
+    def prepare_distribution_metadata(
+        self,
+        finder: PackageFinder,
+        build_isolation: bool,
+        check_build_deps: bool,
+    ) -> None:
         raise NotImplementedError()

venv/Lib/site-packages/pip/_internal/distributions/installed.py

@@ -1,9 +1,6 @@
-from typing import Optional
-
-from pip._vendor.pkg_resources import Distribution
-
 from pip._internal.distributions.base import AbstractDistribution
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata import BaseDistribution
 
 
 class InstalledDistribution(AbstractDistribution):
@@ -13,10 +10,14 @@ class InstalledDistribution(AbstractDistribution):
     been computed.
     """
 
-    def get_pkg_resources_distribution(self):
-        # type: () -> Optional[Distribution]
+    def get_metadata_distribution(self) -> BaseDistribution:
+        assert self.req.satisfied_by is not None, "not actually installed"
         return self.req.satisfied_by
 
-    def prepare_distribution_metadata(self, finder, build_isolation):
-        # type: (PackageFinder, bool) -> None
+    def prepare_distribution_metadata(
+        self,
+        finder: PackageFinder,
+        build_isolation: bool,
+        check_build_deps: bool,
+    ) -> None:
         pass

venv/Lib/site-packages/pip/_internal/distributions/sdist.py

@@ -1,12 +1,11 @@
 import logging
-from typing import Set, Tuple
-
-from pip._vendor.pkg_resources import Distribution
+from typing import Iterable, Set, Tuple
 
 from pip._internal.build_env import BuildEnvironment
 from pip._internal.distributions.base import AbstractDistribution
 from pip._internal.exceptions import InstallationError
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata import BaseDistribution
 from pip._internal.utils.subprocess import runner_with_spinner_message
 
 logger = logging.getLogger(__name__)
@@ -19,40 +18,49 @@ class SourceDistribution(AbstractDistribution):
     generated, either using PEP 517 or using the legacy `setup.py egg_info`.
     """
 
-    def get_pkg_resources_distribution(self):
-        # type: () -> Distribution
+    def get_metadata_distribution(self) -> BaseDistribution:
         return self.req.get_dist()
 
-    def prepare_distribution_metadata(self, finder, build_isolation):
-        # type: (PackageFinder, bool) -> None
+    def prepare_distribution_metadata(
+        self,
+        finder: PackageFinder,
+        build_isolation: bool,
+        check_build_deps: bool,
+    ) -> None:
         # Load pyproject.toml, to determine whether PEP 517 is to be used
         self.req.load_pyproject_toml()
 
         # Set up the build isolation, if this requirement should be isolated
         should_isolate = self.req.use_pep517 and build_isolation
         if should_isolate:
-            self._setup_isolation(finder)
-
+            # Setup an isolated environment and install the build backend static
+            # requirements in it.
+            self._prepare_build_backend(finder)
+            # Check that if the requirement is editable, it either supports PEP 660 or
+            # has a setup.py or a setup.cfg. This cannot be done earlier because we need
+            # to setup the build backend to verify it supports build_editable, nor can
+            # it be done later, because we want to avoid installing build requirements
+            # needlessly. Doing it here also works around setuptools generating
+            # UNKNOWN.egg-info when running get_requires_for_build_wheel on a directory
+            # without setup.py nor setup.cfg.
+            self.req.isolated_editable_sanity_check()
+            # Install the dynamic build requirements.
+            self._install_build_reqs(finder)
+        # Check if the current environment provides build dependencies
+        should_check_deps = self.req.use_pep517 and check_build_deps
+        if should_check_deps:
+            pyproject_requires = self.req.pyproject_requires
+            assert pyproject_requires is not None
+            conflicting, missing = self.req.build_env.check_requirements(
+                pyproject_requires
+            )
+            if conflicting:
+                self._raise_conflicts("the backend dependencies", conflicting)
+            if missing:
+                self._raise_missing_reqs(missing)
         self.req.prepare_metadata()
 
-    def _setup_isolation(self, finder):
-        # type: (PackageFinder) -> None
-        def _raise_conflicts(conflicting_with, conflicting_reqs):
-            # type: (str, Set[Tuple[str, str]]) -> None
-            format_string = (
-                "Some build dependencies for {requirement} "
-                "conflict with {conflicting_with}: {description}."
-            )
-            error_message = format_string.format(
-                requirement=self.req,
-                conflicting_with=conflicting_with,
-                description=", ".join(
-                    f"{installed} is incompatible with {wanted}"
-                    for installed, wanted in sorted(conflicting)
-                ),
-            )
-            raise InstallationError(error_message)
-
+    def _prepare_build_backend(self, finder: PackageFinder) -> None:
         # Isolate in a BuildEnvironment and install the build-time
         # requirements.
         pyproject_requires = self.req.pyproject_requires
@@ -60,13 +68,13 @@ class SourceDistribution(AbstractDistribution):
 
         self.req.build_env = BuildEnvironment()
         self.req.build_env.install_requirements(
-            finder, pyproject_requires, "overlay", "Installing build dependencies"
+            finder, pyproject_requires, "overlay", kind="build dependencies"
         )
         conflicting, missing = self.req.build_env.check_requirements(
             self.req.requirements_to_check
         )
         if conflicting:
-            _raise_conflicts("PEP 517/518 supported requirements", conflicting)
+            self._raise_conflicts("PEP 517/518 supported requirements", conflicting)
         if missing:
             logger.warning(
                 "Missing build requirements in pyproject.toml for %s.",
@@ -77,19 +85,66 @@ class SourceDistribution(AbstractDistribution):
                 "pip cannot fall back to setuptools without %s.",
                 " and ".join(map(repr, sorted(missing))),
             )
-        # Install any extra build dependencies that the backend requests.
-        # This must be done in a second pass, as the pyproject.toml
-        # dependencies must be installed before we can call the backend.
+
+    def _get_build_requires_wheel(self) -> Iterable[str]:
         with self.req.build_env:
             runner = runner_with_spinner_message("Getting requirements to build wheel")
             backend = self.req.pep517_backend
             assert backend is not None
             with backend.subprocess_runner(runner):
-                reqs = backend.get_requires_for_build_wheel()
+                return backend.get_requires_for_build_wheel()
 
-        conflicting, missing = self.req.build_env.check_requirements(reqs)
+    def _get_build_requires_editable(self) -> Iterable[str]:
+        with self.req.build_env:
+            runner = runner_with_spinner_message(
+                "Getting requirements to build editable"
+            )
+            backend = self.req.pep517_backend
+            assert backend is not None
+            with backend.subprocess_runner(runner):
+                return backend.get_requires_for_build_editable()
+
+    def _install_build_reqs(self, finder: PackageFinder) -> None:
+        # Install any extra build dependencies that the backend requests.
+        # This must be done in a second pass, as the pyproject.toml
+        # dependencies must be installed before we can call the backend.
+        if (
+            self.req.editable
+            and self.req.permit_editable_wheels
+            and self.req.supports_pyproject_editable()
+        ):
+            build_reqs = self._get_build_requires_editable()
+        else:
+            build_reqs = self._get_build_requires_wheel()
+        conflicting, missing = self.req.build_env.check_requirements(build_reqs)
         if conflicting:
-            _raise_conflicts("the backend dependencies", conflicting)
+            self._raise_conflicts("the backend dependencies", conflicting)
         self.req.build_env.install_requirements(
-            finder, missing, "normal", "Installing backend dependencies"
+            finder, missing, "normal", kind="backend dependencies"
         )
+
+    def _raise_conflicts(
+        self, conflicting_with: str, conflicting_reqs: Set[Tuple[str, str]]
+    ) -> None:
+        format_string = (
+            "Some build dependencies for {requirement} "
+            "conflict with {conflicting_with}: {description}."
+        )
+        error_message = format_string.format(
+            requirement=self.req,
+            conflicting_with=conflicting_with,
+            description=", ".join(
+                f"{installed} is incompatible with {wanted}"
+                for installed, wanted in sorted(conflicting_reqs)
+            ),
+        )
+        raise InstallationError(error_message)
+
+    def _raise_missing_reqs(self, missing: Set[str]) -> None:
+        format_string = (
+            "Some build dependencies for {requirement} are missing: {missing}."
+        )
+        error_message = format_string.format(
+            requirement=self.req, missing=", ".join(map(repr, sorted(missing)))
+        )
+        raise InstallationError(error_message)

venv/Lib/site-packages/pip/_internal/distributions/wheel.py

@@ -1,10 +1,12 @@
-from zipfile import ZipFile
-
-from pip._vendor.pkg_resources import Distribution
+from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.distributions.base import AbstractDistribution
 from pip._internal.index.package_finder import PackageFinder
-from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
+from pip._internal.metadata import (
+    BaseDistribution,
+    FilesystemWheel,
+    get_wheel_distribution,
+)
 
 
 class WheelDistribution(AbstractDistribution):
@@ -13,22 +15,20 @@ class WheelDistribution(AbstractDistribution):
     This does not need any preparation as wheels can be directly unpacked.
     """
 
-    def get_pkg_resources_distribution(self):
-        # type: () -> Distribution
+    def get_metadata_distribution(self) -> BaseDistribution:
         """Loads the metadata from the wheel file into memory and returns a
         Distribution that uses it, not relying on the wheel file or
         requirement.
         """
-        # Set as part of preparation during download.
-        assert self.req.local_file_path
-        # Wheels are never unnamed.
-        assert self.req.name
+        assert self.req.local_file_path, "Set as part of preparation during download"
+        assert self.req.name, "Wheels are never unnamed"
+        wheel = FilesystemWheel(self.req.local_file_path)
+        return get_wheel_distribution(wheel, canonicalize_name(self.req.name))
 
-        with ZipFile(self.req.local_file_path, allowZip64=True) as z:
-            return pkg_resources_distribution_for_wheel(
-                z, self.req.name, self.req.local_file_path
-            )
-
-    def prepare_distribution_metadata(self, finder, build_isolation):
-        # type: (PackageFinder, bool) -> None
+    def prepare_distribution_metadata(
+        self,
+        finder: PackageFinder,
+        build_isolation: bool,
+        check_build_deps: bool,
+    ) -> None:
         pass

venv/Lib/site-packages/pip/_internal/exceptions.py

@@ -1,22 +1,174 @@
-"""Exceptions used throughout package"""
+"""Exceptions used throughout package.
+
+This module MUST NOT try to import from anything within `pip._internal` to
+operate. This is expected to be importable from any/all files within the
+subpackage and, thus, should not depend on them.
+"""
 
 import configparser
+import re
 from itertools import chain, groupby, repeat
-from typing import TYPE_CHECKING, Dict, List, Optional
+from typing import TYPE_CHECKING, Dict, List, Optional, Union
 
-from pip._vendor.pkg_resources import Distribution
 from pip._vendor.requests.models import Request, Response
+from pip._vendor.rich.console import Console, ConsoleOptions, RenderResult
+from pip._vendor.rich.markup import escape
+from pip._vendor.rich.text import Text
 
 if TYPE_CHECKING:
     from hashlib import _Hash
+    from typing import Literal
 
+    from pip._internal.metadata import BaseDistribution
     from pip._internal.req.req_install import InstallRequirement
 
 
+#
+# Scaffolding
+#
+def _is_kebab_case(s: str) -> bool:
+    return re.match(r"^[a-z]+(-[a-z]+)*$", s) is not None
+
+
+def _prefix_with_indent(
+    s: Union[Text, str],
+    console: Console,
+    *,
+    prefix: str,
+    indent: str,
+) -> Text:
+    if isinstance(s, Text):
+        text = s
+    else:
+        text = console.render_str(s)
+
+    return console.render_str(prefix, overflow="ignore") + console.render_str(
+        f"\n{indent}", overflow="ignore"
+    ).join(text.split(allow_blank=True))
+
+
 class PipError(Exception):
-    """Base pip exception"""
+    """The base pip error."""
 
 
+class DiagnosticPipError(PipError):
+    """An error, that presents diagnostic information to the user.
+
+    This contains a bunch of logic, to enable pretty presentation of our error
+    messages. Each error gets a unique reference. Each error can also include
+    additional context, a hint and/or a note -- which are presented with the
+    main error message in a consistent style.
+
+    This is adapted from the error output styling in `sphinx-theme-builder`.
+    """
+
+    reference: str
+
+    def __init__(
+        self,
+        *,
+        kind: 'Literal["error", "warning"]' = "error",
+        reference: Optional[str] = None,
+        message: Union[str, Text],
+        context: Optional[Union[str, Text]],
+        hint_stmt: Optional[Union[str, Text]],
+        note_stmt: Optional[Union[str, Text]] = None,
+        link: Optional[str] = None,
+    ) -> None:
+        # Ensure a proper reference is provided.
+        if reference is None:
+            assert hasattr(self, "reference"), "error reference not provided!"
+            reference = self.reference
+        assert _is_kebab_case(reference), "error reference must be kebab-case!"
+
+        self.kind = kind
+        self.reference = reference
+
+        self.message = message
+        self.context = context
+
+        self.note_stmt = note_stmt
+        self.hint_stmt = hint_stmt
+
+        self.link = link
+
+        super().__init__(f"<{self.__class__.__name__}: {self.reference}>")
+
+    def __repr__(self) -> str:
+        return (
+            f"<{self.__class__.__name__}("
+            f"reference={self.reference!r}, "
+            f"message={self.message!r}, "
+            f"context={self.context!r}, "
+            f"note_stmt={self.note_stmt!r}, "
+            f"hint_stmt={self.hint_stmt!r}"
+            ")>"
+        )
+
+    def __rich_console__(
+        self,
+        console: Console,
+        options: ConsoleOptions,
+    ) -> RenderResult:
+        colour = "red" if self.kind == "error" else "yellow"
+
+        yield f"[{colour} bold]{self.kind}[/]: [bold]{self.reference}[/]"
+        yield ""
+
+        if not options.ascii_only:
+            # Present the main message, with relevant context indented.
+            if self.context is not None:
+                yield _prefix_with_indent(
+                    self.message,
+                    console,
+                    prefix=f"[{colour}]×[/] ",
+                    indent=f"[{colour}]│[/] ",
+                )
+                yield _prefix_with_indent(
+                    self.context,
+                    console,
+                    prefix=f"[{colour}]╰─>[/] ",
+                    indent=f"[{colour}]   [/] ",
+                )
+            else:
+                yield _prefix_with_indent(
+                    self.message,
+                    console,
+                    prefix="[red]×[/] ",
+                    indent="  ",
+                )
+        else:
+            yield self.message
+            if self.context is not None:
+                yield ""
+                yield self.context
+
+        if self.note_stmt is not None or self.hint_stmt is not None:
+            yield ""
+
+        if self.note_stmt is not None:
+            yield _prefix_with_indent(
+                self.note_stmt,
+                console,
+                prefix="[magenta bold]note[/]: ",
+                indent="      ",
+            )
+        if self.hint_stmt is not None:
+            yield _prefix_with_indent(
+                self.hint_stmt,
+                console,
+                prefix="[cyan bold]hint[/]: ",
+                indent="      ",
+            )
+
+        if self.link is not None:
+            yield ""
+            yield f"Link: {self.link}"
+
+
+#
+# Actual Errors
+#
 class ConfigurationError(PipError):
     """General exception in configuration"""
 
@@ -29,17 +181,54 @@ class UninstallationError(PipError):
     """General exception during uninstallation"""
 
 
+class MissingPyProjectBuildRequires(DiagnosticPipError):
+    """Raised when pyproject.toml has `build-system`, but no `build-system.requires`."""
+
+    reference = "missing-pyproject-build-system-requires"
+
+    def __init__(self, *, package: str) -> None:
+        super().__init__(
+            message=f"Can not process {escape(package)}",
+            context=Text(
+                "This package has an invalid pyproject.toml file.\n"
+                "The [build-system] table is missing the mandatory `requires` key."
+            ),
+            note_stmt="This is an issue with the package mentioned above, not pip.",
+            hint_stmt=Text("See PEP 518 for the detailed specification."),
+        )
+
+
+class InvalidPyProjectBuildRequires(DiagnosticPipError):
+    """Raised when pyproject.toml an invalid `build-system.requires`."""
+
+    reference = "invalid-pyproject-build-system-requires"
+
+    def __init__(self, *, package: str, reason: str) -> None:
+        super().__init__(
+            message=f"Can not process {escape(package)}",
+            context=Text(
+                "This package has an invalid `build-system.requires` key in "
+                f"pyproject.toml.\n{reason}"
+            ),
+            note_stmt="This is an issue with the package mentioned above, not pip.",
+            hint_stmt=Text("See PEP 518 for the detailed specification."),
+        )
+
+
 class NoneMetadataError(PipError):
-    """
-    Raised when accessing "METADATA" or "PKG-INFO" metadata for a
-    pip._vendor.pkg_resources.Distribution object and
-    `dist.has_metadata('METADATA')` returns True but
-    `dist.get_metadata('METADATA')` returns None (and similarly for
-    "PKG-INFO").
+    """Raised when accessing a Distribution's "METADATA" or "PKG-INFO".
+
+    This signifies an inconsistency, when the Distribution claims to have
+    the metadata file (if not, raise ``FileNotFoundError`` instead), but is
+    not actually able to produce its content. This may be due to permission
+    errors.
     """
 
-    def __init__(self, dist, metadata_name):
-        # type: (Distribution, str) -> None
+    def __init__(
+        self,
+        dist: "BaseDistribution",
+        metadata_name: str,
+    ) -> None:
         """
         :param dist: A Distribution object.
         :param metadata_name: The name of the metadata being accessed
@@ -48,28 +237,24 @@ class NoneMetadataError(PipError):
         self.dist = dist
         self.metadata_name = metadata_name
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         # Use `dist` in the error message because its stringification
         # includes more information, like the version and location.
-        return (
-            'None {} metadata found for distribution: {}'.format(
-                self.metadata_name, self.dist,
-            )
+        return "None {} metadata found for distribution: {}".format(
+            self.metadata_name,
+            self.dist,
         )
 
 
 class UserInstallationInvalid(InstallationError):
     """A --user install is requested on an environment without user site."""
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         return "User base directory is not specified"
 
 
 class InvalidSchemeCombination(InstallationError):
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         before = ", ".join(str(a) for a in self.args[:-1])
         return f"Cannot set {before} and {self.args[-1]} together"
 
@@ -102,8 +287,9 @@ class PreviousBuildDirError(PipError):
 class NetworkConnectionError(PipError):
     """HTTP connection error"""
 
-    def __init__(self, error_msg, response=None, request=None):
-        # type: (str, Response, Request) -> None
+    def __init__(
+        self, error_msg: str, response: Response = None, request: Request = None
+    ) -> None:
         """
         Initialize NetworkConnectionError with  `request` and `response`
         objects.
@@ -111,13 +297,15 @@ class NetworkConnectionError(PipError):
         self.response = response
         self.request = request
         self.error_msg = error_msg
-        if (self.response is not None and not self.request and
-                hasattr(response, 'request')):
+        if (
+            self.response is not None
+            and not self.request
+            and hasattr(response, "request")
+        ):
             self.request = self.response.request
         super().__init__(error_msg, response, request)
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         return str(self.error_msg)
 
 
@@ -129,6 +317,17 @@ class UnsupportedWheel(InstallationError):
     """Unsupported wheel."""
 
 
+class InvalidWheel(InstallationError):
+    """Invalid (e.g. corrupt) wheel."""
+
+    def __init__(self, location: str, name: str):
+        self.location = location
+        self.name = name
+
+    def __str__(self) -> str:
+        return f"Wheel '{self.name}' located at {self.location} is invalid."
+
+
 class MetadataInconsistent(InstallationError):
     """Built metadata contains inconsistent information.
 
@@ -136,15 +335,16 @@ class MetadataInconsistent(InstallationError):
     that do not match the information previously obtained from sdist filename
     or user-supplied ``#egg=`` value.
     """
-    def __init__(self, ireq, field, f_val, m_val):
-        # type: (InstallRequirement, str, str, str) -> None
+
+    def __init__(
+        self, ireq: "InstallRequirement", field: str, f_val: str, m_val: str
+    ) -> None:
         self.ireq = ireq
         self.field = field
         self.f_val = f_val
         self.m_val = m_val
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         template = (
             "Requested {} has inconsistent {}: "
             "filename has {!r}, but metadata has {!r}"
@@ -152,51 +352,102 @@ class MetadataInconsistent(InstallationError):
         return template.format(self.ireq, self.field, self.f_val, self.m_val)
 
 
-class InstallationSubprocessError(InstallationError):
-    """A subprocess call failed during installation."""
-    def __init__(self, returncode, description):
-        # type: (int, str) -> None
-        self.returncode = returncode
-        self.description = description
+class LegacyInstallFailure(DiagnosticPipError):
+    """Error occurred while executing `setup.py install`"""
 
-    def __str__(self):
-        # type: () -> str
-        return (
-            "Command errored out with exit status {}: {} "
-            "Check the logs for full command output."
-        ).format(self.returncode, self.description)
+    reference = "legacy-install-failure"
+
+    def __init__(self, package_details: str) -> None:
+        super().__init__(
+            message="Encountered error while trying to install package.",
+            context=package_details,
+            hint_stmt="See above for output from the failure.",
+            note_stmt="This is an issue with the package mentioned above, not pip.",
+        )
+
+
+class InstallationSubprocessError(DiagnosticPipError, InstallationError):
+    """A subprocess call failed."""
+
+    reference = "subprocess-exited-with-error"
+
+    def __init__(
+        self,
+        *,
+        command_description: str,
+        exit_code: int,
+        output_lines: Optional[List[str]],
+    ) -> None:
+        if output_lines is None:
+            output_prompt = Text("See above for output.")
+        else:
+            output_prompt = (
+                Text.from_markup(f"[red][{len(output_lines)} lines of output][/]\n")
+                + Text("".join(output_lines))
+                + Text.from_markup(R"[red]\[end of output][/]")
+            )
+
+        super().__init__(
+            message=(
+                f"[green]{escape(command_description)}[/] did not run successfully.\n"
+                f"exit code: {exit_code}"
+            ),
+            context=output_prompt,
+            hint_stmt=None,
+            note_stmt=(
+                "This error originates from a subprocess, and is likely not a "
+                "problem with pip."
+            ),
+        )
+
+        self.command_description = command_description
+        self.exit_code = exit_code
+
+    def __str__(self) -> str:
+        return f"{self.command_description} exited with {self.exit_code}"
+
+
+class MetadataGenerationFailed(InstallationSubprocessError, InstallationError):
+    reference = "metadata-generation-failed"
+
+    def __init__(
+        self,
+        *,
+        package_details: str,
+    ) -> None:
+        super(InstallationSubprocessError, self).__init__(
+            message="Encountered error while generating package metadata.",
+            context=escape(package_details),
+            hint_stmt="See above for details.",
+            note_stmt="This is an issue with the package mentioned above, not pip.",
+        )
+
+    def __str__(self) -> str:
+        return "metadata generation failed"
 
 
 class HashErrors(InstallationError):
     """Multiple HashError instances rolled into one for reporting"""
 
-    def __init__(self):
-        # type: () -> None
-        self.errors = []  # type: List[HashError]
+    def __init__(self) -> None:
+        self.errors: List["HashError"] = []
 
-    def append(self, error):
-        # type: (HashError) -> None
+    def append(self, error: "HashError") -> None:
         self.errors.append(error)
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         lines = []
         self.errors.sort(key=lambda e: e.order)
         for cls, errors_of_cls in groupby(self.errors, lambda e: e.__class__):
             lines.append(cls.head)
             lines.extend(e.body() for e in errors_of_cls)
         if lines:
-            return '\n'.join(lines)
-        return ''
+            return "\n".join(lines)
+        return ""
 
-    def __nonzero__(self):
-        # type: () -> bool
+    def __bool__(self) -> bool:
         return bool(self.errors)
 
-    def __bool__(self):
-        # type: () -> bool
-        return self.__nonzero__()
-
 
 class HashError(InstallationError):
     """
@@ -214,12 +465,12 @@ class HashError(InstallationError):
         typically available earlier.
 
     """
-    req = None  # type: Optional[InstallRequirement]
-    head = ''
-    order = -1  # type: int
 
-    def body(self):
-        # type: () -> str
+    req: Optional["InstallRequirement"] = None
+    head = ""
+    order: int = -1
+
+    def body(self) -> str:
         """Return a summary of me for display under the heading.
 
         This default implementation simply prints a description of the
@@ -229,21 +480,19 @@ class HashError(InstallationError):
             its link already populated by the resolver's _populate_link().
 
         """
-        return f'    {self._requirement_name()}'
+        return f"    {self._requirement_name()}"
 
-    def __str__(self):
-        # type: () -> str
-        return f'{self.head}\n{self.body()}'
+    def __str__(self) -> str:
+        return f"{self.head}\n{self.body()}"
 
-    def _requirement_name(self):
-        # type: () -> str
+    def _requirement_name(self) -> str:
         """Return a description of the requirement that triggered me.
 
         This default implementation returns long description of the req, with
         line numbers
 
         """
-        return str(self.req) if self.req else 'unknown package'
+        return str(self.req) if self.req else "unknown package"
 
 
 class VcsHashUnsupported(HashError):
@@ -251,8 +500,10 @@ class VcsHashUnsupported(HashError):
     we don't have a method for hashing those."""
 
     order = 0
-    head = ("Can't verify hashes for these requirements because we don't "
-            "have a way to hash version control repositories:")
+    head = (
+        "Can't verify hashes for these requirements because we don't "
+        "have a way to hash version control repositories:"
+    )
 
 
 class DirectoryUrlHashUnsupported(HashError):
@@ -260,32 +511,34 @@ class DirectoryUrlHashUnsupported(HashError):
     we don't have a method for hashing those."""
 
     order = 1
-    head = ("Can't verify hashes for these file:// requirements because they "
-            "point to directories:")
+    head = (
+        "Can't verify hashes for these file:// requirements because they "
+        "point to directories:"
+    )
 
 
 class HashMissing(HashError):
     """A hash was needed for a requirement but is absent."""
 
     order = 2
-    head = ('Hashes are required in --require-hashes mode, but they are '
-            'missing from some requirements. Here is a list of those '
-            'requirements along with the hashes their downloaded archives '
-            'actually had. Add lines like these to your requirements files to '
-            'prevent tampering. (If you did not enable --require-hashes '
-            'manually, note that it turns on automatically when any package '
-            'has a hash.)')
+    head = (
+        "Hashes are required in --require-hashes mode, but they are "
+        "missing from some requirements. Here is a list of those "
+        "requirements along with the hashes their downloaded archives "
+        "actually had. Add lines like these to your requirements files to "
+        "prevent tampering. (If you did not enable --require-hashes "
+        "manually, note that it turns on automatically when any package "
+        "has a hash.)"
+    )
 
-    def __init__(self, gotten_hash):
-        # type: (str) -> None
+    def __init__(self, gotten_hash: str) -> None:
         """
         :param gotten_hash: The hash of the (possibly malicious) archive we
             just downloaded
         """
         self.gotten_hash = gotten_hash
 
-    def body(self):
-        # type: () -> str
+    def body(self) -> str:
         # Dodge circular import.
         from pip._internal.utils.hashes import FAVORITE_HASH
 
@@ -294,13 +547,16 @@ class HashMissing(HashError):
             # In the case of URL-based requirements, display the original URL
             # seen in the requirements file rather than the package name,
             # so the output can be directly copied into the requirements file.
-            package = (self.req.original_link if self.req.original_link
-                       # In case someone feeds something downright stupid
-                       # to InstallRequirement's constructor.
-                       else getattr(self.req, 'req', None))
-        return '    {} --hash={}:{}'.format(package or 'unknown package',
-                                            FAVORITE_HASH,
-                                            self.gotten_hash)
+            package = (
+                self.req.original_link
+                if self.req.original_link
+                # In case someone feeds something downright stupid
+                # to InstallRequirement's constructor.
+                else getattr(self.req, "req", None)
+            )
+        return "    {} --hash={}:{}".format(
+            package or "unknown package", FAVORITE_HASH, self.gotten_hash
+        )
 
 
 class HashUnpinned(HashError):
@@ -308,8 +564,10 @@ class HashUnpinned(HashError):
     version."""
 
     order = 3
-    head = ('In --require-hashes mode, all requirements must have their '
-            'versions pinned with ==. These do not:')
+    head = (
+        "In --require-hashes mode, all requirements must have their "
+        "versions pinned with ==. These do not:"
+    )
 
 
 class HashMismatch(HashError):
@@ -321,14 +579,16 @@ class HashMismatch(HashError):
         improve its error message.
 
     """
-    order = 4
-    head = ('THESE PACKAGES DO NOT MATCH THE HASHES FROM THE REQUIREMENTS '
-            'FILE. If you have updated the package versions, please update '
-            'the hashes. Otherwise, examine the package contents carefully; '
-            'someone may have tampered with them.')
 
-    def __init__(self, allowed, gots):
-        # type: (Dict[str, List[str]], Dict[str, _Hash]) -> None
+    order = 4
+    head = (
+        "THESE PACKAGES DO NOT MATCH THE HASHES FROM THE REQUIREMENTS "
+        "FILE. If you have updated the package versions, please update "
+        "the hashes. Otherwise, examine the package contents carefully; "
+        "someone may have tampered with them."
+    )
+
+    def __init__(self, allowed: Dict[str, List[str]], gots: Dict[str, "_Hash"]) -> None:
         """
         :param allowed: A dict of algorithm names pointing to lists of allowed
             hex digests
@@ -338,13 +598,10 @@ class HashMismatch(HashError):
         self.allowed = allowed
         self.gots = gots
 
-    def body(self):
-        # type: () -> str
-        return '    {}:\n{}'.format(self._requirement_name(),
-                                    self._hash_comparison())
+    def body(self) -> str:
+        return "    {}:\n{}".format(self._requirement_name(), self._hash_comparison())
 
-    def _hash_comparison(self):
-        # type: () -> str
+    def _hash_comparison(self) -> str:
         """
         Return a comparison of actual and expected hash values.
 
@@ -355,20 +612,22 @@ class HashMismatch(HashError):
                     Got        bcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdef
 
         """
-        def hash_then_or(hash_name):
-            # type: (str) -> chain[str]
+
+        def hash_then_or(hash_name: str) -> "chain[str]":
             # For now, all the decent hashes have 6-char names, so we can get
             # away with hard-coding space literals.
-            return chain([hash_name], repeat('    or'))
+            return chain([hash_name], repeat("    or"))
 
-        lines = []  # type: List[str]
+        lines: List[str] = []
         for hash_name, expecteds in self.allowed.items():
             prefix = hash_then_or(hash_name)
-            lines.extend(('        Expected {} {}'.format(next(prefix), e))
-                         for e in expecteds)
-            lines.append('             Got        {}\n'.format(
-                         self.gots[hash_name].hexdigest()))
-        return '\n'.join(lines)
+            lines.extend(
+                ("        Expected {} {}".format(next(prefix), e)) for e in expecteds
+            )
+            lines.append(
+                "             Got        {}\n".format(self.gots[hash_name].hexdigest())
+            )
+        return "\n".join(lines)
 
 
 class UnsupportedPythonVersion(InstallationError):
@@ -377,18 +636,20 @@ class UnsupportedPythonVersion(InstallationError):
 
 
 class ConfigurationFileCouldNotBeLoaded(ConfigurationError):
-    """When there are errors while loading a configuration file
-    """
+    """When there are errors while loading a configuration file"""
 
-    def __init__(self, reason="could not be loaded", fname=None, error=None):
-        # type: (str, Optional[str], Optional[configparser.Error]) -> None
+    def __init__(
+        self,
+        reason: str = "could not be loaded",
+        fname: Optional[str] = None,
+        error: Optional[configparser.Error] = None,
+    ) -> None:
         super().__init__(error)
         self.reason = reason
         self.fname = fname
         self.error = error
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         if self.fname is not None:
             message_part = f" in {self.fname}."
         else:

venv/Lib/site-packages/pip/_internal/index/collector.py

@@ -5,7 +5,6 @@ The main purpose of this module is to expose LinkCollector.collect_sources().
 import cgi
 import collections
 import functools
-import html
 import itertools
 import logging
 import os
@@ -13,15 +12,19 @@ import re
 import urllib.parse
 import urllib.request
 import xml.etree.ElementTree
+from html.parser import HTMLParser
 from optparse import Values
 from typing import (
+    TYPE_CHECKING,
     Callable,
+    Dict,
     Iterable,
     List,
     MutableMapping,
     NamedTuple,
     Optional,
     Sequence,
+    Tuple,
     Union,
 )
 
@@ -40,34 +43,36 @@ from pip._internal.vcs import vcs
 
 from .sources import CandidatesFromPage, LinkSource, build_source
 
+if TYPE_CHECKING:
+    from typing import Protocol
+else:
+    Protocol = object
+
 logger = logging.getLogger(__name__)
 
 HTMLElement = xml.etree.ElementTree.Element
 ResponseHeaders = MutableMapping[str, str]
 
 
-def _match_vcs_scheme(url):
-    # type: (str) -> Optional[str]
+def _match_vcs_scheme(url: str) -> Optional[str]:
     """Look for VCS schemes in the URL.
 
     Returns the matched VCS scheme, or None if there's no match.
     """
     for scheme in vcs.schemes:
-        if url.lower().startswith(scheme) and url[len(scheme)] in '+:':
+        if url.lower().startswith(scheme) and url[len(scheme)] in "+:":
             return scheme
     return None
 
 
 class _NotHTML(Exception):
-    def __init__(self, content_type, request_desc):
-        # type: (str, str) -> None
+    def __init__(self, content_type: str, request_desc: str) -> None:
         super().__init__(content_type, request_desc)
         self.content_type = content_type
         self.request_desc = request_desc
 
 
-def _ensure_html_header(response):
-    # type: (Response) -> None
+def _ensure_html_header(response: Response) -> None:
     """Check the Content-Type header to ensure the response contains HTML.
 
     Raises `_NotHTML` if the content type is not text/html.
@@ -81,15 +86,14 @@ class _NotHTTP(Exception):
     pass
 
 
-def _ensure_html_response(url, session):
-    # type: (str, PipSession) -> None
+def _ensure_html_response(url: str, session: PipSession) -> None:
     """Send a HEAD request to the URL, and ensure the response contains HTML.
 
     Raises `_NotHTTP` if the URL is not available for a HEAD request, or
     `_NotHTML` if the content type is not text/html.
     """
     scheme, netloc, path, query, fragment = urllib.parse.urlsplit(url)
-    if scheme not in {'http', 'https'}:
+    if scheme not in {"http", "https"}:
         raise _NotHTTP()
 
     resp = session.head(url, allow_redirects=True)
@@ -98,8 +102,7 @@ def _ensure_html_response(url, session):
     _ensure_html_header(resp)
 
 
-def _get_html_response(url, session):
-    # type: (str, PipSession) -> Response
+def _get_html_response(url: str, session: PipSession) -> Response:
     """Access an HTML page with GET, and return the response.
 
     This consists of three parts:
@@ -115,7 +118,7 @@ def _get_html_response(url, session):
     if is_archive_file(Link(url).filename):
         _ensure_html_response(url, session=session)
 
-    logger.debug('Getting page %s', redact_auth_from_url(url))
+    logger.debug("Getting page %s", redact_auth_from_url(url))
 
     resp = session.get(
         url,
@@ -149,19 +152,16 @@ def _get_html_response(url, session):
     return resp
 
 
-def _get_encoding_from_headers(headers):
-    # type: (ResponseHeaders) -> Optional[str]
-    """Determine if we have any encoding information in our headers.
-    """
+def _get_encoding_from_headers(headers: ResponseHeaders) -> Optional[str]:
+    """Determine if we have any encoding information in our headers."""
     if headers and "Content-Type" in headers:
         content_type, params = cgi.parse_header(headers["Content-Type"])
         if "charset" in params:
-            return params['charset']
+            return params["charset"]
     return None
 
 
-def _determine_base_url(document, page_url):
-    # type: (HTMLElement, str) -> str
+def _determine_base_url(document: HTMLElement, page_url: str) -> str:
     """Determine the HTML document's base URL.
 
     This looks for a ``<base>`` tag in the HTML document. If present, its href
@@ -172,6 +172,8 @@ def _determine_base_url(document, page_url):
     :param document: An HTML document representation. The current
         implementation expects the result of ``html5lib.parse()``.
     :param page_url: The URL of the HTML document.
+
+    TODO: Remove when `html5lib` is dropped.
     """
     for base in document.findall(".//base"):
         href = base.get("href")
@@ -180,8 +182,7 @@ def _determine_base_url(document, page_url):
     return page_url
 
 
-def _clean_url_path_part(part):
-    # type: (str) -> str
+def _clean_url_path_part(part: str) -> str:
     """
     Clean a "part" of a URL path (i.e. after splitting on "@" characters).
     """
@@ -189,8 +190,7 @@ def _clean_url_path_part(part):
     return urllib.parse.quote(urllib.parse.unquote(part))
 
 
-def _clean_file_url_path(part):
-    # type: (str) -> str
+def _clean_file_url_path(part: str) -> str:
     """
     Clean the first part of a URL path that corresponds to a local
     filesystem path (i.e. the first part after splitting on "@" characters).
@@ -204,11 +204,10 @@ def _clean_file_url_path(part):
 
 
 # percent-encoded:                   /
-_reserved_chars_re = re.compile('(@|%2F)', re.IGNORECASE)
+_reserved_chars_re = re.compile("(@|%2F)", re.IGNORECASE)
 
 
-def _clean_url_path(path, is_local_path):
-    # type: (str, bool) -> str
+def _clean_url_path(path: str, is_local_path: bool) -> str:
     """
     Clean the path portion of a URL.
     """
@@ -222,16 +221,15 @@ def _clean_url_path(path, is_local_path):
     parts = _reserved_chars_re.split(path)
 
     cleaned_parts = []
-    for to_clean, reserved in pairwise(itertools.chain(parts, [''])):
+    for to_clean, reserved in pairwise(itertools.chain(parts, [""])):
         cleaned_parts.append(clean_func(to_clean))
         # Normalize %xx escapes (e.g. %2f -> %2F)
         cleaned_parts.append(reserved.upper())
 
-    return ''.join(cleaned_parts)
+    return "".join(cleaned_parts)
 
 
-def _clean_link(url):
-    # type: (str) -> str
+def _clean_link(url: str) -> str:
     """
     Make sure a link is fully quoted.
     For example, if ' ' occurs in the URL, it will be replaced with "%20",
@@ -247,25 +245,20 @@ def _clean_link(url):
 
 
 def _create_link_from_element(
-    anchor,    # type: HTMLElement
-    page_url,  # type: str
-    base_url,  # type: str
-):
-    # type: (...) -> Optional[Link]
+    element_attribs: Dict[str, Optional[str]],
+    page_url: str,
+    base_url: str,
+) -> Optional[Link]:
     """
-    Convert an anchor element in a simple repository page to a Link.
+    Convert an anchor element's attributes in a simple repository page to a Link.
     """
-    href = anchor.get("href")
+    href = element_attribs.get("href")
     if not href:
         return None
 
     url = _clean_link(urllib.parse.urljoin(base_url, href))
-    pyrequire = anchor.get('data-requires-python')
-    pyrequire = html.unescape(pyrequire) if pyrequire else None
-
-    yanked_reason = anchor.get('data-yanked')
-    if yanked_reason:
-        yanked_reason = html.unescape(yanked_reason)
+    pyrequire = element_attribs.get("data-requires-python")
+    yanked_reason = element_attribs.get("data-yanked")
 
     link = Link(
         url,
@@ -278,25 +271,25 @@ def _create_link_from_element(
 
 
 class CacheablePageContent:
-    def __init__(self, page):
-        # type: (HTMLPage) -> None
+    def __init__(self, page: "HTMLPage") -> None:
         assert page.cache_link_parsing
         self.page = page
 
-    def __eq__(self, other):
-        # type: (object) -> bool
-        return (isinstance(other, type(self)) and
-                self.page.url == other.page.url)
+    def __eq__(self, other: object) -> bool:
+        return isinstance(other, type(self)) and self.page.url == other.page.url
 
-    def __hash__(self):
-        # type: () -> int
+    def __hash__(self) -> int:
         return hash(self.page.url)
 
 
-def with_cached_html_pages(
-    fn,    # type: Callable[[HTMLPage], Iterable[Link]]
-):
-    # type: (...) -> Callable[[HTMLPage], List[Link]]
+class ParseLinks(Protocol):
+    def __call__(
+        self, page: "HTMLPage", use_deprecated_html5lib: bool
+    ) -> Iterable[Link]:
+        ...
+
+
+def with_cached_html_pages(fn: ParseLinks) -> ParseLinks:
     """
     Given a function that parses an Iterable[Link] from an HTMLPage, cache the
     function's result (keyed by CacheablePageContent), unless the HTMLPage
@@ -304,25 +297,25 @@ def with_cached_html_pages(
     """
 
     @functools.lru_cache(maxsize=None)
-    def wrapper(cacheable_page):
-        # type: (CacheablePageContent) -> List[Link]
-        return list(fn(cacheable_page.page))
+    def wrapper(
+        cacheable_page: CacheablePageContent, use_deprecated_html5lib: bool
+    ) -> List[Link]:
+        return list(fn(cacheable_page.page, use_deprecated_html5lib))
 
     @functools.wraps(fn)
-    def wrapper_wrapper(page):
-        # type: (HTMLPage) -> List[Link]
+    def wrapper_wrapper(page: "HTMLPage", use_deprecated_html5lib: bool) -> List[Link]:
         if page.cache_link_parsing:
-            return wrapper(CacheablePageContent(page))
-        return list(fn(page))
+            return wrapper(CacheablePageContent(page), use_deprecated_html5lib)
+        return list(fn(page, use_deprecated_html5lib))
 
     return wrapper_wrapper
 
 
-@with_cached_html_pages
-def parse_links(page):
-    # type: (HTMLPage) -> Iterable[Link]
+def _parse_links_html5lib(page: "HTMLPage") -> Iterable[Link]:
     """
     Parse an HTML document, and yield its anchor elements as Link objects.
+
+    TODO: Remove when `html5lib` is dropped.
     """
     document = html5lib.parse(
         page.content,
@@ -333,6 +326,33 @@ def parse_links(page):
     url = page.url
     base_url = _determine_base_url(document, url)
     for anchor in document.findall(".//a"):
+        link = _create_link_from_element(
+            anchor.attrib,
+            page_url=url,
+            base_url=base_url,
+        )
+        if link is None:
+            continue
+        yield link
+
+
+@with_cached_html_pages
+def parse_links(page: "HTMLPage", use_deprecated_html5lib: bool) -> Iterable[Link]:
+    """
+    Parse an HTML document, and yield its anchor elements as Link objects.
+    """
+
+    if use_deprecated_html5lib:
+        yield from _parse_links_html5lib(page)
+        return
+
+    parser = HTMLLinkParser(page.url)
+    encoding = page.encoding or "utf-8"
+    parser.feed(page.content.decode(encoding))
+
+    url = page.url
+    base_url = parser.base_url or url
+    for anchor in parser.anchors:
         link = _create_link_from_element(
             anchor,
             page_url=url,
@@ -348,12 +368,11 @@ class HTMLPage:
 
     def __init__(
         self,
-        content,                  # type: bytes
-        encoding,                 # type: Optional[str]
-        url,                      # type: str
-        cache_link_parsing=True,  # type: bool
-    ):
-        # type: (...) -> None
+        content: bytes,
+        encoding: Optional[str],
+        url: str,
+        cache_link_parsing: bool = True,
+    ) -> None:
         """
         :param encoding: the encoding to decode the given content.
         :param url: the URL from which the HTML was downloaded.
@@ -366,70 +385,103 @@ class HTMLPage:
         self.url = url
         self.cache_link_parsing = cache_link_parsing
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         return redact_auth_from_url(self.url)
 
 
+class HTMLLinkParser(HTMLParser):
+    """
+    HTMLParser that keeps the first base HREF and a list of all anchor
+    elements' attributes.
+    """
+
+    def __init__(self, url: str) -> None:
+        super().__init__(convert_charrefs=True)
+
+        self.url: str = url
+        self.base_url: Optional[str] = None
+        self.anchors: List[Dict[str, Optional[str]]] = []
+
+    def handle_starttag(self, tag: str, attrs: List[Tuple[str, Optional[str]]]) -> None:
+        if tag == "base" and self.base_url is None:
+            href = self.get_href(attrs)
+            if href is not None:
+                self.base_url = href
+        elif tag == "a":
+            self.anchors.append(dict(attrs))
+
+    def get_href(self, attrs: List[Tuple[str, Optional[str]]]) -> Optional[str]:
+        for name, value in attrs:
+            if name == "href":
+                return value
+        return None
+
+
 def _handle_get_page_fail(
-    link,  # type: Link
-    reason,  # type: Union[str, Exception]
-    meth=None  # type: Optional[Callable[..., None]]
-):
-    # type: (...) -> None
+    link: Link,
+    reason: Union[str, Exception],
+    meth: Optional[Callable[..., None]] = None,
+) -> None:
     if meth is None:
         meth = logger.debug
     meth("Could not fetch URL %s: %s - skipping", link, reason)
 
 
-def _make_html_page(response, cache_link_parsing=True):
-    # type: (Response, bool) -> HTMLPage
+def _make_html_page(response: Response, cache_link_parsing: bool = True) -> HTMLPage:
     encoding = _get_encoding_from_headers(response.headers)
     return HTMLPage(
         response.content,
         encoding=encoding,
         url=response.url,
-        cache_link_parsing=cache_link_parsing)
+        cache_link_parsing=cache_link_parsing,
+    )
 
 
-def _get_html_page(link, session=None):
-    # type: (Link, Optional[PipSession]) -> Optional[HTMLPage]
+def _get_html_page(
+    link: Link, session: Optional[PipSession] = None
+) -> Optional["HTMLPage"]:
     if session is None:
         raise TypeError(
             "_get_html_page() missing 1 required keyword argument: 'session'"
         )
 
-    url = link.url.split('#', 1)[0]
+    url = link.url.split("#", 1)[0]
 
     # Check for VCS schemes that do not support lookup as web pages.
     vcs_scheme = _match_vcs_scheme(url)
     if vcs_scheme:
-        logger.warning('Cannot look at %s URL %s because it does not support '
-                       'lookup as web pages.', vcs_scheme, link)
+        logger.warning(
+            "Cannot look at %s URL %s because it does not support lookup as web pages.",
+            vcs_scheme,
+            link,
+        )
         return None
 
     # Tack index.html onto file:// URLs that point to directories
     scheme, _, path, _, _, _ = urllib.parse.urlparse(url)
-    if (scheme == 'file' and os.path.isdir(urllib.request.url2pathname(path))):
+    if scheme == "file" and os.path.isdir(urllib.request.url2pathname(path)):
         # add trailing slash if not present so urljoin doesn't trim
         # final segment
-        if not url.endswith('/'):
-            url += '/'
-        url = urllib.parse.urljoin(url, 'index.html')
-        logger.debug(' file: URL is directory, getting %s', url)
+        if not url.endswith("/"):
+            url += "/"
+        url = urllib.parse.urljoin(url, "index.html")
+        logger.debug(" file: URL is directory, getting %s", url)
 
     try:
         resp = _get_html_response(url, session=session)
     except _NotHTTP:
         logger.warning(
-            'Skipping page %s because it looks like an archive, and cannot '
-            'be checked by a HTTP HEAD request.', link,
+            "Skipping page %s because it looks like an archive, and cannot "
+            "be checked by a HTTP HEAD request.",
+            link,
         )
     except _NotHTML as exc:
         logger.warning(
-            'Skipping page %s because the %s request got Content-Type: %s.'
-            'The only supported Content-Type is text/html',
-            link, exc.request_desc, exc.content_type,
+            "Skipping page %s because the %s request got Content-Type: %s."
+            "The only supported Content-Type is text/html",
+            link,
+            exc.request_desc,
+            exc.content_type,
         )
     except NetworkConnectionError as exc:
         _handle_get_page_fail(link, exc)
@@ -444,8 +496,7 @@ def _get_html_page(link, session=None):
     except requests.Timeout:
         _handle_get_page_fail(link, "timed out")
     else:
-        return _make_html_page(resp,
-                               cache_link_parsing=link.cache_link_parsing)
+        return _make_html_page(resp, cache_link_parsing=link.cache_link_parsing)
     return None
 
 
@@ -465,16 +516,19 @@ class LinkCollector:
 
     def __init__(
         self,
-        session,       # type: PipSession
-        search_scope,  # type: SearchScope
-    ):
-        # type: (...) -> None
+        session: PipSession,
+        search_scope: SearchScope,
+    ) -> None:
         self.search_scope = search_scope
         self.session = session
 
     @classmethod
-    def create(cls, session, options, suppress_no_index=False):
-        # type: (PipSession, Values, bool) -> LinkCollector
+    def create(
+        cls,
+        session: PipSession,
+        options: Values,
+        suppress_no_index: bool = False,
+    ) -> "LinkCollector":
         """
         :param session: The Session to use to make requests.
         :param suppress_no_index: Whether to ignore the --no-index option
@@ -483,8 +537,8 @@ class LinkCollector:
         index_urls = [options.index_url] + options.extra_index_urls
         if options.no_index and not suppress_no_index:
             logger.debug(
-                'Ignoring indexes: %s',
-                ','.join(redact_auth_from_url(url) for url in index_urls),
+                "Ignoring indexes: %s",
+                ",".join(redact_auth_from_url(url) for url in index_urls),
             )
             index_urls = []
 
@@ -492,20 +546,20 @@ class LinkCollector:
         find_links = options.find_links or []
 
         search_scope = SearchScope.create(
-            find_links=find_links, index_urls=index_urls,
+            find_links=find_links,
+            index_urls=index_urls,
         )
         link_collector = LinkCollector(
-            session=session, search_scope=search_scope,
+            session=session,
+            search_scope=search_scope,
         )
         return link_collector
 
     @property
-    def find_links(self):
-        # type: () -> List[str]
+    def find_links(self) -> List[str]:
         return self.search_scope.find_links
 
-    def fetch_page(self, location):
-        # type: (Link) -> Optional[HTMLPage]
+    def fetch_page(self, location: Link) -> Optional[HTMLPage]:
         """
         Fetch an HTML page containing package links.
         """

venv/Lib/site-packages/pip/_internal/index/package_finder.py

@@ -3,6 +3,7 @@
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
 
+import enum
 import functools
 import itertools
 import logging
@@ -30,31 +31,28 @@ from pip._internal.models.selection_prefs import SelectionPreferences
 from pip._internal.models.target_python import TargetPython
 from pip._internal.models.wheel import Wheel
 from pip._internal.req import InstallRequirement
+from pip._internal.utils._log import getLogger
 from pip._internal.utils.filetypes import WHEEL_EXTENSION
 from pip._internal.utils.hashes import Hashes
 from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import build_netloc
 from pip._internal.utils.packaging import check_requires_python
 from pip._internal.utils.unpacking import SUPPORTED_EXTENSIONS
-from pip._internal.utils.urls import url_to_path
 
-__all__ = ['FormatControl', 'BestCandidateResult', 'PackageFinder']
+__all__ = ["FormatControl", "BestCandidateResult", "PackageFinder"]
 
 
-logger = logging.getLogger(__name__)
+logger = getLogger(__name__)
 
 BuildTag = Union[Tuple[()], Tuple[int, str]]
-CandidateSortingKey = (
-    Tuple[int, int, int, _BaseVersion, Optional[int], BuildTag]
-)
+CandidateSortingKey = Tuple[int, int, int, _BaseVersion, Optional[int], BuildTag]
 
 
 def _check_link_requires_python(
-    link,  # type: Link
-    version_info,  # type: Tuple[int, int, int]
-    ignore_requires_python=False,  # type: bool
-):
-    # type: (...) -> bool
+    link: Link,
+    version_info: Tuple[int, int, int],
+    ignore_requires_python: bool = False,
+) -> bool:
     """
     Return whether the given Python version is compatible with a link's
     "Requires-Python" value.
@@ -66,39 +64,54 @@ def _check_link_requires_python(
     """
     try:
         is_compatible = check_requires_python(
-            link.requires_python, version_info=version_info,
+            link.requires_python,
+            version_info=version_info,
         )
     except specifiers.InvalidSpecifier:
         logger.debug(
             "Ignoring invalid Requires-Python (%r) for link: %s",
-            link.requires_python, link,
+            link.requires_python,
+            link,
         )
     else:
         if not is_compatible:
-            version = '.'.join(map(str, version_info))
+            version = ".".join(map(str, version_info))
             if not ignore_requires_python:
-                logger.debug(
-                    'Link requires a different Python (%s not in: %r): %s',
-                    version, link.requires_python, link,
+                logger.verbose(
+                    "Link requires a different Python (%s not in: %r): %s",
+                    version,
+                    link.requires_python,
+                    link,
                 )
                 return False
 
             logger.debug(
-                'Ignoring failed Requires-Python check (%s not in: %r) '
-                'for link: %s',
-                version, link.requires_python, link,
+                "Ignoring failed Requires-Python check (%s not in: %r) for link: %s",
+                version,
+                link.requires_python,
+                link,
             )
 
     return True
 
 
+class LinkType(enum.Enum):
+    candidate = enum.auto()
+    different_project = enum.auto()
+    yanked = enum.auto()
+    format_unsupported = enum.auto()
+    format_invalid = enum.auto()
+    platform_mismatch = enum.auto()
+    requires_python_mismatch = enum.auto()
+
+
 class LinkEvaluator:
 
     """
     Responsible for evaluating links for a particular project.
     """
 
-    _py_version_re = re.compile(r'-py([123]\.?[0-9]?)$')
+    _py_version_re = re.compile(r"-py([123]\.?[0-9]?)$")
 
     # Don't include an allow_yanked default value to make sure each call
     # site considers whether yanked releases are allowed. This also causes
@@ -106,14 +119,13 @@ class LinkEvaluator:
     # people when reading the code.
     def __init__(
         self,
-        project_name,    # type: str
-        canonical_name,  # type: str
-        formats,         # type: FrozenSet[str]
-        target_python,   # type: TargetPython
-        allow_yanked,    # type: bool
-        ignore_requires_python=None,  # type: Optional[bool]
-    ):
-        # type: (...) -> None
+        project_name: str,
+        canonical_name: str,
+        formats: FrozenSet[str],
+        target_python: TargetPython,
+        allow_yanked: bool,
+        ignore_requires_python: Optional[bool] = None,
+    ) -> None:
         """
         :param project_name: The user supplied package name.
         :param canonical_name: The canonical package name.
@@ -142,20 +154,20 @@ class LinkEvaluator:
 
         self.project_name = project_name
 
-    def evaluate_link(self, link):
-        # type: (Link) -> Tuple[bool, Optional[str]]
+    def evaluate_link(self, link: Link) -> Tuple[LinkType, str]:
         """
         Determine whether a link is a candidate for installation.
 
-        :return: A tuple (is_candidate, result), where `result` is (1) a
-            version string if `is_candidate` is True, and (2) if
-            `is_candidate` is False, an optional string to log the reason
-            the link fails to qualify.
+        :return: A tuple (result, detail), where *result* is an enum
+            representing whether the evaluation found a candidate, or the reason
+            why one is not found. If a candidate is found, *detail* will be the
+            candidate's version string; if one is not found, it contains the
+            reason the link fails to qualify.
         """
         version = None
         if link.is_yanked and not self._allow_yanked:
-            reason = link.yanked_reason or '<none given>'
-            return (False, f'yanked for reason: {reason}')
+            reason = link.yanked_reason or "<none given>"
+            return (LinkType.yanked, f"yanked for reason: {reason}")
 
         if link.egg_fragment:
             egg_info = link.egg_fragment
@@ -163,80 +175,85 @@ class LinkEvaluator:
         else:
             egg_info, ext = link.splitext()
             if not ext:
-                return (False, 'not a file')
+                return (LinkType.format_unsupported, "not a file")
             if ext not in SUPPORTED_EXTENSIONS:
-                return (False, f'unsupported archive format: {ext}')
+                return (
+                    LinkType.format_unsupported,
+                    f"unsupported archive format: {ext}",
+                )
             if "binary" not in self._formats and ext == WHEEL_EXTENSION:
-                reason = 'No binaries permitted for {}'.format(
-                    self.project_name)
-                return (False, reason)
-            if "macosx10" in link.path and ext == '.zip':
-                return (False, 'macosx10 one')
+                reason = f"No binaries permitted for {self.project_name}"
+                return (LinkType.format_unsupported, reason)
+            if "macosx10" in link.path and ext == ".zip":
+                return (LinkType.format_unsupported, "macosx10 one")
             if ext == WHEEL_EXTENSION:
                 try:
                     wheel = Wheel(link.filename)
                 except InvalidWheelFilename:
-                    return (False, 'invalid wheel filename')
+                    return (
+                        LinkType.format_invalid,
+                        "invalid wheel filename",
+                    )
                 if canonicalize_name(wheel.name) != self._canonical_name:
-                    reason = 'wrong project name (not {})'.format(
-                        self.project_name)
-                    return (False, reason)
+                    reason = f"wrong project name (not {self.project_name})"
+                    return (LinkType.different_project, reason)
 
                 supported_tags = self._target_python.get_tags()
                 if not wheel.supported(supported_tags):
                     # Include the wheel's tags in the reason string to
                     # simplify troubleshooting compatibility issues.
-                    file_tags = wheel.get_formatted_file_tags()
+                    file_tags = ", ".join(wheel.get_formatted_file_tags())
                     reason = (
-                        "none of the wheel's tags ({}) are compatible "
-                        "(run pip debug --verbose to show compatible tags)".format(
-                            ', '.join(file_tags)
-                        )
+                        f"none of the wheel's tags ({file_tags}) are compatible "
+                        f"(run pip debug --verbose to show compatible tags)"
                     )
-                    return (False, reason)
+                    return (LinkType.platform_mismatch, reason)
 
                 version = wheel.version
 
         # This should be up by the self.ok_binary check, but see issue 2700.
         if "source" not in self._formats and ext != WHEEL_EXTENSION:
-            reason = f'No sources permitted for {self.project_name}'
-            return (False, reason)
+            reason = f"No sources permitted for {self.project_name}"
+            return (LinkType.format_unsupported, reason)
 
         if not version:
             version = _extract_version_from_fragment(
-                egg_info, self._canonical_name,
+                egg_info,
+                self._canonical_name,
             )
         if not version:
-            reason = f'Missing project version for {self.project_name}'
-            return (False, reason)
+            reason = f"Missing project version for {self.project_name}"
+            return (LinkType.format_invalid, reason)
 
         match = self._py_version_re.search(version)
         if match:
-            version = version[:match.start()]
+            version = version[: match.start()]
             py_version = match.group(1)
             if py_version != self._target_python.py_version:
-                return (False, 'Python version is incorrect')
+                return (
+                    LinkType.platform_mismatch,
+                    "Python version is incorrect",
+                )
 
         supports_python = _check_link_requires_python(
-            link, version_info=self._target_python.py_version_info,
+            link,
+            version_info=self._target_python.py_version_info,
             ignore_requires_python=self._ignore_requires_python,
         )
         if not supports_python:
-            # Return None for the reason text to suppress calling
-            # _log_skipped_link().
-            return (False, None)
+            reason = f"{version} Requires-Python {link.requires_python}"
+            return (LinkType.requires_python_mismatch, reason)
 
-        logger.debug('Found link %s, version: %s', link, version)
+        logger.debug("Found link %s, version: %s", link, version)
 
-        return (True, version)
+        return (LinkType.candidate, version)
 
 
 def filter_unallowed_hashes(
-    candidates,    # type: List[InstallationCandidate]
-    hashes,        # type: Hashes
-    project_name,  # type: str
-):
-    # type: (...) -> List[InstallationCandidate]
+    candidates: List[InstallationCandidate],
+    hashes: Hashes,
+    project_name: str,
+) -> List[InstallationCandidate]:
     """
     Filter out candidates whose hashes aren't allowed, and return a new
     list of candidates.
@@ -254,8 +271,8 @@ def filter_unallowed_hashes(
     """
     if not hashes:
         logger.debug(
-            'Given no hashes to check %s links for project %r: '
-            'discarding no candidates',
+            "Given no hashes to check %s links for project %r: "
+            "discarding no candidates",
             len(candidates),
             project_name,
         )
@@ -285,22 +302,22 @@ def filter_unallowed_hashes(
         filtered = list(candidates)
 
     if len(filtered) == len(candidates):
-        discard_message = 'discarding no candidates'
+        discard_message = "discarding no candidates"
     else:
-        discard_message = 'discarding {} non-matches:\n  {}'.format(
+        discard_message = "discarding {} non-matches:\n  {}".format(
             len(non_matches),
-            '\n  '.join(str(candidate.link) for candidate in non_matches)
+            "\n  ".join(str(candidate.link) for candidate in non_matches),
         )
 
     logger.debug(
-        'Checked %s links for project %r against %s hashes '
-        '(%s matches, %s no digest): %s',
+        "Checked %s links for project %r against %s hashes "
+        "(%s matches, %s no digest): %s",
         len(candidates),
         project_name,
         hashes.digest_count,
         match_count,
         len(matches_or_no_digest) - match_count,
-        discard_message
+        discard_message,
     )
 
     return filtered
@@ -315,10 +332,9 @@ class CandidatePreferences:
 
     def __init__(
         self,
-        prefer_binary=False,  # type: bool
-        allow_all_prereleases=False,  # type: bool
-    ):
-        # type: (...) -> None
+        prefer_binary: bool = False,
+        allow_all_prereleases: bool = False,
+    ) -> None:
         """
         :param allow_all_prereleases: Whether to allow all pre-releases.
         """
@@ -335,11 +351,10 @@ class BestCandidateResult:
 
     def __init__(
         self,
-        candidates,             # type: List[InstallationCandidate]
-        applicable_candidates,  # type: List[InstallationCandidate]
-        best_candidate,         # type: Optional[InstallationCandidate]
-    ):
-        # type: (...) -> None
+        candidates: List[InstallationCandidate],
+        applicable_candidates: List[InstallationCandidate],
+        best_candidate: Optional[InstallationCandidate],
+    ) -> None:
         """
         :param candidates: A sequence of all available candidates found.
         :param applicable_candidates: The applicable candidates.
@@ -358,16 +373,12 @@ class BestCandidateResult:
 
         self.best_candidate = best_candidate
 
-    def iter_all(self):
-        # type: () -> Iterable[InstallationCandidate]
-        """Iterate through all candidates.
-        """
+    def iter_all(self) -> Iterable[InstallationCandidate]:
+        """Iterate through all candidates."""
         return iter(self._candidates)
 
-    def iter_applicable(self):
-        # type: () -> Iterable[InstallationCandidate]
-        """Iterate through the applicable candidates.
-        """
+    def iter_applicable(self) -> Iterable[InstallationCandidate]:
+        """Iterate through the applicable candidates."""
         return iter(self._applicable_candidates)
 
 
@@ -381,14 +392,13 @@ class CandidateEvaluator:
     @classmethod
     def create(
         cls,
-        project_name,         # type: str
-        target_python=None,   # type: Optional[TargetPython]
-        prefer_binary=False,  # type: bool
-        allow_all_prereleases=False,  # type: bool
-        specifier=None,       # type: Optional[specifiers.BaseSpecifier]
-        hashes=None,          # type: Optional[Hashes]
-    ):
-        # type: (...) -> CandidateEvaluator
+        project_name: str,
+        target_python: Optional[TargetPython] = None,
+        prefer_binary: bool = False,
+        allow_all_prereleases: bool = False,
+        specifier: Optional[specifiers.BaseSpecifier] = None,
+        hashes: Optional[Hashes] = None,
+    ) -> "CandidateEvaluator":
         """Create a CandidateEvaluator object.
 
         :param target_python: The target Python interpreter to use when
@@ -417,14 +427,13 @@ class CandidateEvaluator:
 
     def __init__(
         self,
-        project_name,         # type: str
-        supported_tags,       # type: List[Tag]
-        specifier,            # type: specifiers.BaseSpecifier
-        prefer_binary=False,  # type: bool
-        allow_all_prereleases=False,  # type: bool
-        hashes=None,                  # type: Optional[Hashes]
-    ):
-        # type: (...) -> None
+        project_name: str,
+        supported_tags: List[Tag],
+        specifier: specifiers.BaseSpecifier,
+        prefer_binary: bool = False,
+        allow_all_prereleases: bool = False,
+        hashes: Optional[Hashes] = None,
+    ) -> None:
         """
         :param supported_tags: The PEP 425 tags supported by the target
             Python in order of preference (most preferred first).
@@ -444,9 +453,8 @@ class CandidateEvaluator:
 
     def get_applicable_candidates(
         self,
-        candidates,  # type: List[InstallationCandidate]
-    ):
-        # type: (...) -> List[InstallationCandidate]
+        candidates: List[InstallationCandidate],
+    ) -> List[InstallationCandidate]:
         """
         Return the applicable candidates from a list of candidates.
         """
@@ -454,7 +462,8 @@ class CandidateEvaluator:
         allow_prereleases = self._allow_all_prereleases or None
         specifier = self._specifier
         versions = {
-            str(v) for v in specifier.filter(
+            str(v)
+            for v in specifier.filter(
                 # We turn the version object into a str here because otherwise
                 # when we're debundled but setuptools isn't, Python will see
                 # packaging.version.Version and
@@ -468,9 +477,7 @@ class CandidateEvaluator:
         }
 
         # Again, converting version to str to deal with debundling.
-        applicable_candidates = [
-            c for c in candidates if str(c.version) in versions
-        ]
+        applicable_candidates = [c for c in candidates if str(c.version) in versions]
 
         filtered_applicable_candidates = filter_unallowed_hashes(
             candidates=applicable_candidates,
@@ -480,8 +487,7 @@ class CandidateEvaluator:
 
         return sorted(filtered_applicable_candidates, key=self._sort_key)
 
-    def _sort_key(self, candidate):
-        # type: (InstallationCandidate) -> CandidateSortingKey
+    def _sort_key(self, candidate: InstallationCandidate) -> CandidateSortingKey:
         """
         Function to pass as the `key` argument to a call to sorted() to sort
         InstallationCandidates by preference.
@@ -513,16 +519,18 @@ class CandidateEvaluator:
         """
         valid_tags = self._supported_tags
         support_num = len(valid_tags)
-        build_tag = ()  # type: BuildTag
+        build_tag: BuildTag = ()
         binary_preference = 0
         link = candidate.link
         if link.is_wheel:
             # can raise InvalidWheelFilename
             wheel = Wheel(link.filename)
             try:
-                pri = -(wheel.find_most_preferred_tag(
-                    valid_tags, self._wheel_tag_preferences
-                ))
+                pri = -(
+                    wheel.find_most_preferred_tag(
+                        valid_tags, self._wheel_tag_preferences
+                    )
+                )
             except ValueError:
                 raise UnsupportedWheel(
                     "{} is not a supported wheel for this platform. It "
@@ -531,7 +539,7 @@ class CandidateEvaluator:
             if self._prefer_binary:
                 binary_preference = 1
             if wheel.build_tag is not None:
-                match = re.match(r'^(\d+)(.*)$', wheel.build_tag)
+                match = re.match(r"^(\d+)(.*)$", wheel.build_tag)
                 build_tag_groups = match.groups()
                 build_tag = (int(build_tag_groups[0]), build_tag_groups[1])
         else:  # sdist
@@ -539,15 +547,18 @@ class CandidateEvaluator:
         has_allowed_hash = int(link.is_hash_allowed(self._hashes))
         yank_value = -1 * int(link.is_yanked)  # -1 for yanked.
         return (
-            has_allowed_hash, yank_value, binary_preference, candidate.version,
-            pri, build_tag,
+            has_allowed_hash,
+            yank_value,
+            binary_preference,
+            candidate.version,
+            pri,
+            build_tag,
         )
 
     def sort_best_candidate(
         self,
-        candidates,    # type: List[InstallationCandidate]
-    ):
-        # type: (...) -> Optional[InstallationCandidate]
+        candidates: List[InstallationCandidate],
+    ) -> Optional[InstallationCandidate]:
         """
         Return the best candidate per the instance's sort order, or None if
         no candidate is acceptable.
@@ -559,9 +570,8 @@ class CandidateEvaluator:
 
     def compute_best_candidate(
         self,
-        candidates,      # type: List[InstallationCandidate]
-    ):
-        # type: (...) -> BestCandidateResult
+        candidates: List[InstallationCandidate],
+    ) -> BestCandidateResult:
         """
         Compute and return a `BestCandidateResult` instance.
         """
@@ -585,14 +595,14 @@ class PackageFinder:
 
     def __init__(
         self,
-        link_collector,       # type: LinkCollector
-        target_python,        # type: TargetPython
-        allow_yanked,         # type: bool
-        format_control=None,  # type: Optional[FormatControl]
-        candidate_prefs=None,         # type: CandidatePreferences
-        ignore_requires_python=None,  # type: Optional[bool]
-    ):
-        # type: (...) -> None
+        link_collector: LinkCollector,
+        target_python: TargetPython,
+        allow_yanked: bool,
+        use_deprecated_html5lib: bool,
+        format_control: Optional[FormatControl] = None,
+        candidate_prefs: Optional[CandidatePreferences] = None,
+        ignore_requires_python: Optional[bool] = None,
+    ) -> None:
         """
         This constructor is primarily meant to be used by the create() class
         method and from tests.
@@ -613,11 +623,12 @@ class PackageFinder:
         self._ignore_requires_python = ignore_requires_python
         self._link_collector = link_collector
         self._target_python = target_python
+        self._use_deprecated_html5lib = use_deprecated_html5lib
 
         self.format_control = format_control
 
         # These are boring links that have already been logged somehow.
-        self._logged_links = set()  # type: Set[Link]
+        self._logged_links: Set[Tuple[Link, LinkType, str]] = set()
 
     # Don't include an allow_yanked default value to make sure each call
     # site considers whether yanked releases are allowed. This also causes
@@ -626,11 +637,12 @@ class PackageFinder:
     @classmethod
     def create(
         cls,
-        link_collector,      # type: LinkCollector
-        selection_prefs,     # type: SelectionPreferences
-        target_python=None,  # type: Optional[TargetPython]
-    ):
-        # type: (...) -> PackageFinder
+        link_collector: LinkCollector,
+        selection_prefs: SelectionPreferences,
+        target_python: Optional[TargetPython] = None,
+        *,
+        use_deprecated_html5lib: bool,
+    ) -> "PackageFinder":
         """Create a PackageFinder.
 
         :param selection_prefs: The candidate selection preferences, as a
@@ -654,59 +666,57 @@ class PackageFinder:
             allow_yanked=selection_prefs.allow_yanked,
             format_control=selection_prefs.format_control,
             ignore_requires_python=selection_prefs.ignore_requires_python,
+            use_deprecated_html5lib=use_deprecated_html5lib,
         )
 
     @property
-    def target_python(self):
-        # type: () -> TargetPython
+    def target_python(self) -> TargetPython:
         return self._target_python
 
     @property
-    def search_scope(self):
-        # type: () -> SearchScope
+    def search_scope(self) -> SearchScope:
         return self._link_collector.search_scope
 
     @search_scope.setter
-    def search_scope(self, search_scope):
-        # type: (SearchScope) -> None
+    def search_scope(self, search_scope: SearchScope) -> None:
         self._link_collector.search_scope = search_scope
 
     @property
-    def find_links(self):
-        # type: () -> List[str]
+    def find_links(self) -> List[str]:
         return self._link_collector.find_links
 
     @property
-    def index_urls(self):
-        # type: () -> List[str]
+    def index_urls(self) -> List[str]:
         return self.search_scope.index_urls
 
     @property
-    def trusted_hosts(self):
-        # type: () -> Iterable[str]
+    def trusted_hosts(self) -> Iterable[str]:
         for host_port in self._link_collector.session.pip_trusted_origins:
             yield build_netloc(*host_port)
 
     @property
-    def allow_all_prereleases(self):
-        # type: () -> bool
+    def allow_all_prereleases(self) -> bool:
         return self._candidate_prefs.allow_all_prereleases
 
-    def set_allow_all_prereleases(self):
-        # type: () -> None
+    def set_allow_all_prereleases(self) -> None:
         self._candidate_prefs.allow_all_prereleases = True
 
     @property
-    def prefer_binary(self):
-        # type: () -> bool
+    def prefer_binary(self) -> bool:
         return self._candidate_prefs.prefer_binary
 
-    def set_prefer_binary(self):
-        # type: () -> None
+    def set_prefer_binary(self) -> None:
         self._candidate_prefs.prefer_binary = True
 
-    def make_link_evaluator(self, project_name):
-        # type: (str) -> LinkEvaluator
+    def requires_python_skipped_reasons(self) -> List[str]:
+        reasons = {
+            detail
+            for _, result, detail in self._logged_links
+            if result == LinkType.requires_python_mismatch
+        }
+        return sorted(reasons)
+
+    def make_link_evaluator(self, project_name: str) -> LinkEvaluator:
         canonical_name = canonicalize_name(project_name)
         formats = self.format_control.get_allowed_formats(canonical_name)
 
@@ -719,14 +729,13 @@ class PackageFinder:
             ignore_requires_python=self._ignore_requires_python,
         )
 
-    def _sort_links(self, links):
-        # type: (Iterable[Link]) -> List[Link]
+    def _sort_links(self, links: Iterable[Link]) -> List[Link]:
         """
         Returns elements of links in order, non-egg links first, egg links
         second, while eliminating duplicates
         """
         eggs, no_eggs = [], []
-        seen = set()  # type: Set[Link]
+        seen: Set[Link] = set()
         for link in links:
             if link not in seen:
                 seen.add(link)
@@ -736,34 +745,35 @@ class PackageFinder:
                     no_eggs.append(link)
         return no_eggs + eggs
 
-    def _log_skipped_link(self, link, reason):
-        # type: (Link, str) -> None
-        if link not in self._logged_links:
+    def _log_skipped_link(self, link: Link, result: LinkType, detail: str) -> None:
+        entry = (link, result, detail)
+        if entry not in self._logged_links:
             # Put the link at the end so the reason is more visible and because
             # the link string is usually very long.
-            logger.debug('Skipping link: %s: %s', reason, link)
-            self._logged_links.add(link)
+            logger.debug("Skipping link: %s: %s", detail, link)
+            self._logged_links.add(entry)
 
-    def get_install_candidate(self, link_evaluator, link):
-        # type: (LinkEvaluator, Link) -> Optional[InstallationCandidate]
+    def get_install_candidate(
+        self, link_evaluator: LinkEvaluator, link: Link
+    ) -> Optional[InstallationCandidate]:
         """
         If the link is a candidate for install, convert it to an
         InstallationCandidate and return it. Otherwise, return None.
         """
-        is_candidate, result = link_evaluator.evaluate_link(link)
-        if not is_candidate:
-            if result:
-                self._log_skipped_link(link, reason=result)
+        result, detail = link_evaluator.evaluate_link(link)
+        if result != LinkType.candidate:
+            self._log_skipped_link(link, result, detail)
             return None
 
         return InstallationCandidate(
             name=link_evaluator.project_name,
             link=link,
-            version=result,
+            version=detail,
         )
 
-    def evaluate_links(self, link_evaluator, links):
-        # type: (LinkEvaluator, Iterable[Link]) -> List[InstallationCandidate]
+    def evaluate_links(
+        self, link_evaluator: LinkEvaluator, links: Iterable[Link]
+    ) -> List[InstallationCandidate]:
         """
         Convert links that are candidates to InstallationCandidate objects.
         """
@@ -775,16 +785,18 @@ class PackageFinder:
 
         return candidates
 
-    def process_project_url(self, project_url, link_evaluator):
-        # type: (Link, LinkEvaluator) -> List[InstallationCandidate]
+    def process_project_url(
+        self, project_url: Link, link_evaluator: LinkEvaluator
+    ) -> List[InstallationCandidate]:
         logger.debug(
-            'Fetching project page and analyzing links: %s', project_url,
+            "Fetching project page and analyzing links: %s",
+            project_url,
         )
         html_page = self._link_collector.fetch_page(project_url)
         if html_page is None:
             return []
 
-        page_links = list(parse_links(html_page))
+        page_links = list(parse_links(html_page, self._use_deprecated_html5lib))
 
         with indent_log():
             package_links = self.evaluate_links(
@@ -795,8 +807,7 @@ class PackageFinder:
         return package_links
 
     @functools.lru_cache(maxsize=None)
-    def find_all_candidates(self, project_name):
-        # type: (str) -> List[InstallationCandidate]
+    def find_all_candidates(self, project_name: str) -> List[InstallationCandidate]:
         """Find all available InstallationCandidate for project_name
 
         This checks index_urls and find_links.
@@ -835,7 +846,14 @@ class PackageFinder:
         )
 
         if logger.isEnabledFor(logging.DEBUG) and file_candidates:
-            paths = [url_to_path(c.link.url) for c in file_candidates]
+            paths = []
+            for candidate in file_candidates:
+                assert candidate.link.url  # we need to have a URL
+                try:
+                    paths.append(candidate.link.file_path)
+                except Exception:
+                    paths.append(candidate.link.url)  # it's not a local file
+
             logger.debug("Local files found: %s", ", ".join(paths))
 
         # This is an intentional priority ordering
@@ -843,13 +861,11 @@ class PackageFinder:
 
     def make_candidate_evaluator(
         self,
-        project_name,    # type: str
-        specifier=None,  # type: Optional[specifiers.BaseSpecifier]
-        hashes=None,     # type: Optional[Hashes]
-    ):
-        # type: (...) -> CandidateEvaluator
-        """Create a CandidateEvaluator object to use.
-        """
+        project_name: str,
+        specifier: Optional[specifiers.BaseSpecifier] = None,
+        hashes: Optional[Hashes] = None,
+    ) -> CandidateEvaluator:
+        """Create a CandidateEvaluator object to use."""
         candidate_prefs = self._candidate_prefs
         return CandidateEvaluator.create(
             project_name=project_name,
@@ -863,11 +879,10 @@ class PackageFinder:
     @functools.lru_cache(maxsize=None)
     def find_best_candidate(
         self,
-        project_name,       # type: str
-        specifier=None,     # type: Optional[specifiers.BaseSpecifier]
-        hashes=None,        # type: Optional[Hashes]
-    ):
-        # type: (...) -> BestCandidateResult
+        project_name: str,
+        specifier: Optional[specifiers.BaseSpecifier] = None,
+        hashes: Optional[Hashes] = None,
+    ) -> BestCandidateResult:
         """Find matches for the given project and specifier.
 
         :param specifier: An optional object implementing `filter`
@@ -884,8 +899,9 @@ class PackageFinder:
         )
         return candidate_evaluator.compute_best_candidate(candidates)
 
-    def find_requirement(self, req, upgrade):
-        # type: (InstallRequirement, bool) -> Optional[InstallationCandidate]
+    def find_requirement(
+        self, req: InstallRequirement, upgrade: bool
+    ) -> Optional[InstallationCandidate]:
         """Try to find a Link matching req
 
         Expects req, an InstallRequirement and upgrade, a boolean
@@ -894,55 +910,60 @@ class PackageFinder:
         """
         hashes = req.hashes(trust_internet=False)
         best_candidate_result = self.find_best_candidate(
-            req.name, specifier=req.specifier, hashes=hashes,
+            req.name,
+            specifier=req.specifier,
+            hashes=hashes,
         )
         best_candidate = best_candidate_result.best_candidate
 
-        installed_version = None    # type: Optional[_BaseVersion]
+        installed_version: Optional[_BaseVersion] = None
         if req.satisfied_by is not None:
-            installed_version = parse_version(req.satisfied_by.version)
+            installed_version = req.satisfied_by.version
 
-        def _format_versions(cand_iter):
-            # type: (Iterable[InstallationCandidate]) -> str
+        def _format_versions(cand_iter: Iterable[InstallationCandidate]) -> str:
             # This repeated parse_version and str() conversion is needed to
             # handle different vendoring sources from pip and pkg_resources.
             # If we stop using the pkg_resources provided specifier and start
             # using our own, we can drop the cast to str().
-            return ", ".join(sorted(
-                {str(c.version) for c in cand_iter},
-                key=parse_version,
-            )) or "none"
+            return (
+                ", ".join(
+                    sorted(
+                        {str(c.version) for c in cand_iter},
+                        key=parse_version,
+                    )
+                )
+                or "none"
+            )
 
         if installed_version is None and best_candidate is None:
             logger.critical(
-                'Could not find a version that satisfies the requirement %s '
-                '(from versions: %s)',
+                "Could not find a version that satisfies the requirement %s "
+                "(from versions: %s)",
                 req,
                 _format_versions(best_candidate_result.iter_all()),
             )
 
             raise DistributionNotFound(
-                'No matching distribution found for {}'.format(
-                    req)
+                "No matching distribution found for {}".format(req)
             )
 
         best_installed = False
         if installed_version and (
-                best_candidate is None or
-                best_candidate.version <= installed_version):
+            best_candidate is None or best_candidate.version <= installed_version
+        ):
             best_installed = True
 
         if not upgrade and installed_version is not None:
             if best_installed:
                 logger.debug(
-                    'Existing installed version (%s) is most up-to-date and '
-                    'satisfies requirement',
+                    "Existing installed version (%s) is most up-to-date and "
+                    "satisfies requirement",
                     installed_version,
                 )
             else:
                 logger.debug(
-                    'Existing installed version (%s) satisfies requirement '
-                    '(most up-to-date version is %s)',
+                    "Existing installed version (%s) satisfies requirement "
+                    "(most up-to-date version is %s)",
                     installed_version,
                     best_candidate.version,
                 )
@@ -951,23 +972,21 @@ class PackageFinder:
         if best_installed:
             # We have an existing version, and its the best version
             logger.debug(
-                'Installed version (%s) is most up-to-date (past versions: '
-                '%s)',
+                "Installed version (%s) is most up-to-date (past versions: %s)",
                 installed_version,
                 _format_versions(best_candidate_result.iter_applicable()),
             )
             raise BestVersionAlreadyInstalled
 
         logger.debug(
-            'Using version %s (newest of versions: %s)',
+            "Using version %s (newest of versions: %s)",
             best_candidate.version,
             _format_versions(best_candidate_result.iter_applicable()),
         )
         return best_candidate
 
 
-def _find_name_version_sep(fragment, canonical_name):
-    # type: (str, str) -> int
+def _find_name_version_sep(fragment: str, canonical_name: str) -> int:
     """Find the separator's index based on the package's canonical name.
 
     :param fragment: A <package>+<version> filename "fragment" (stem) or
@@ -993,8 +1012,7 @@ def _find_name_version_sep(fragment, canonical_name):
     raise ValueError(f"{fragment} does not match {canonical_name}")
 
 
-def _extract_version_from_fragment(fragment, canonical_name):
-    # type: (str, str) -> Optional[str]
+def _extract_version_from_fragment(fragment: str, canonical_name: str) -> Optional[str]:
     """Parse the version string from a <package>+<version> filename
     "fragment" (stem) or egg fragment.
 

venv/Lib/site-packages/pip/_internal/locations/__init__.py

@@ -1,16 +1,22 @@
+import functools
 import logging
+import os
 import pathlib
 import sys
 import sysconfig
-from typing import List, Optional
+from typing import Any, Dict, Generator, List, Optional, Tuple
 
 from pip._internal.models.scheme import SCHEME_KEYS, Scheme
+from pip._internal.utils.compat import WINDOWS
+from pip._internal.utils.deprecation import deprecated
+from pip._internal.utils.virtualenv import running_under_virtualenv
 
 from . import _distutils, _sysconfig
 from .base import (
     USER_CACHE_DIR,
     get_major_minor_version,
     get_src_prefix,
+    is_osx_framework,
     site_packages,
     user_site,
 )
@@ -33,28 +39,171 @@ __all__ = [
 logger = logging.getLogger(__name__)
 
 
-def _default_base(*, user: bool) -> str:
-    if user:
-        base = sysconfig.get_config_var("userbase")
-    else:
-        base = sysconfig.get_config_var("base")
-    assert base is not None
-    return base
+_PLATLIBDIR: str = getattr(sys, "platlibdir", "lib")
+
+_USE_SYSCONFIG_DEFAULT = sys.version_info >= (3, 10)
 
 
-def _warn_if_mismatch(old: pathlib.Path, new: pathlib.Path, *, key: str) -> bool:
-    if old == new:
+def _should_use_sysconfig() -> bool:
+    """This function determines the value of _USE_SYSCONFIG.
+
+    By default, pip uses sysconfig on Python 3.10+.
+    But Python distributors can override this decision by setting:
+        sysconfig._PIP_USE_SYSCONFIG = True / False
+    Rationale in https://github.com/pypa/pip/issues/10647
+
+    This is a function for testability, but should be constant during any one
+    run.
+    """
+    return bool(getattr(sysconfig, "_PIP_USE_SYSCONFIG", _USE_SYSCONFIG_DEFAULT))
+
+
+_USE_SYSCONFIG = _should_use_sysconfig()
+
+# Be noisy about incompatibilities if this platforms "should" be using
+# sysconfig, but is explicitly opting out and using distutils instead.
+if _USE_SYSCONFIG_DEFAULT and not _USE_SYSCONFIG:
+    _MISMATCH_LEVEL = logging.WARNING
+else:
+    _MISMATCH_LEVEL = logging.DEBUG
+
+
+def _looks_like_bpo_44860() -> bool:
+    """The resolution to bpo-44860 will change this incorrect platlib.
+
+    See <https://bugs.python.org/issue44860>.
+    """
+    from distutils.command.install import INSTALL_SCHEMES
+
+    try:
+        unix_user_platlib = INSTALL_SCHEMES["unix_user"]["platlib"]
+    except KeyError:
         return False
-    issue_url = "https://github.com/pypa/pip/issues/9617"
+    return unix_user_platlib == "$usersite"
+
+
+def _looks_like_red_hat_patched_platlib_purelib(scheme: Dict[str, str]) -> bool:
+    platlib = scheme["platlib"]
+    if "/$platlibdir/" in platlib:
+        platlib = platlib.replace("/$platlibdir/", f"/{_PLATLIBDIR}/")
+    if "/lib64/" not in platlib:
+        return False
+    unpatched = platlib.replace("/lib64/", "/lib/")
+    return unpatched.replace("$platbase/", "$base/") == scheme["purelib"]
+
+
+@functools.lru_cache(maxsize=None)
+def _looks_like_red_hat_lib() -> bool:
+    """Red Hat patches platlib in unix_prefix and unix_home, but not purelib.
+
+    This is the only way I can see to tell a Red Hat-patched Python.
+    """
+    from distutils.command.install import INSTALL_SCHEMES
+
+    return all(
+        k in INSTALL_SCHEMES
+        and _looks_like_red_hat_patched_platlib_purelib(INSTALL_SCHEMES[k])
+        for k in ("unix_prefix", "unix_home")
+    )
+
+
+@functools.lru_cache(maxsize=None)
+def _looks_like_debian_scheme() -> bool:
+    """Debian adds two additional schemes."""
+    from distutils.command.install import INSTALL_SCHEMES
+
+    return "deb_system" in INSTALL_SCHEMES and "unix_local" in INSTALL_SCHEMES
+
+
+@functools.lru_cache(maxsize=None)
+def _looks_like_red_hat_scheme() -> bool:
+    """Red Hat patches ``sys.prefix`` and ``sys.exec_prefix``.
+
+    Red Hat's ``00251-change-user-install-location.patch`` changes the install
+    command's ``prefix`` and ``exec_prefix`` to append ``"/local"``. This is
+    (fortunately?) done quite unconditionally, so we create a default command
+    object without any configuration to detect this.
+    """
+    from distutils.command.install import install
+    from distutils.dist import Distribution
+
+    cmd: Any = install(Distribution())
+    cmd.finalize_options()
+    return (
+        cmd.exec_prefix == f"{os.path.normpath(sys.exec_prefix)}/local"
+        and cmd.prefix == f"{os.path.normpath(sys.prefix)}/local"
+    )
+
+
+@functools.lru_cache(maxsize=None)
+def _looks_like_slackware_scheme() -> bool:
+    """Slackware patches sysconfig but fails to patch distutils and site.
+
+    Slackware changes sysconfig's user scheme to use ``"lib64"`` for the lib
+    path, but does not do the same to the site module.
+    """
+    if user_site is None:  # User-site not available.
+        return False
+    try:
+        paths = sysconfig.get_paths(scheme="posix_user", expand=False)
+    except KeyError:  # User-site not available.
+        return False
+    return "/lib64/" in paths["purelib"] and "/lib64/" not in user_site
+
+
+@functools.lru_cache(maxsize=None)
+def _looks_like_msys2_mingw_scheme() -> bool:
+    """MSYS2 patches distutils and sysconfig to use a UNIX-like scheme.
+
+    However, MSYS2 incorrectly patches sysconfig ``nt`` scheme. The fix is
+    likely going to be included in their 3.10 release, so we ignore the warning.
+    See msys2/MINGW-packages#9319.
+
+    MSYS2 MINGW's patch uses lowercase ``"lib"`` instead of the usual uppercase,
+    and is missing the final ``"site-packages"``.
+    """
+    paths = sysconfig.get_paths("nt", expand=False)
+    return all(
+        "Lib" not in p and "lib" in p and not p.endswith("site-packages")
+        for p in (paths[key] for key in ("platlib", "purelib"))
+    )
+
+
+def _fix_abiflags(parts: Tuple[str]) -> Generator[str, None, None]:
+    ldversion = sysconfig.get_config_var("LDVERSION")
+    abiflags = getattr(sys, "abiflags", None)
+
+    # LDVERSION does not end with sys.abiflags. Just return the path unchanged.
+    if not ldversion or not abiflags or not ldversion.endswith(abiflags):
+        yield from parts
+        return
+
+    # Strip sys.abiflags from LDVERSION-based path components.
+    for part in parts:
+        if part.endswith(ldversion):
+            part = part[: (0 - len(abiflags))]
+        yield part
+
+
+@functools.lru_cache(maxsize=None)
+def _warn_mismatched(old: pathlib.Path, new: pathlib.Path, *, key: str) -> None:
+    issue_url = "https://github.com/pypa/pip/issues/10151"
     message = (
         "Value for %s does not match. Please report this to <%s>"
         "\ndistutils: %s"
         "\nsysconfig: %s"
     )
-    logger.debug(message, key, issue_url, old, new)
+    logger.log(_MISMATCH_LEVEL, message, key, issue_url, old, new)
+
+
+def _warn_if_mismatch(old: pathlib.Path, new: pathlib.Path, *, key: str) -> bool:
+    if old == new:
+        return False
+    _warn_mismatched(old, new, key=key)
     return True
 
 
+@functools.lru_cache(maxsize=None)
 def _log_context(
     *,
     user: bool = False,
@@ -62,29 +211,25 @@ def _log_context(
     root: Optional[str] = None,
     prefix: Optional[str] = None,
 ) -> None:
-    message = (
-        "Additional context:" "\nuser = %r" "\nhome = %r" "\nroot = %r" "\nprefix = %r"
-    )
-    logger.debug(message, user, home, root, prefix)
+    parts = [
+        "Additional context:",
+        "user = %r",
+        "home = %r",
+        "root = %r",
+        "prefix = %r",
+    ]
+
+    logger.log(_MISMATCH_LEVEL, "\n".join(parts), user, home, root, prefix)
 
 
 def get_scheme(
-    dist_name,  # type: str
-    user=False,  # type: bool
-    home=None,  # type: Optional[str]
-    root=None,  # type: Optional[str]
-    isolated=False,  # type: bool
-    prefix=None,  # type: Optional[str]
-):
-    # type: (...) -> Scheme
-    old = _distutils.get_scheme(
-        dist_name,
-        user=user,
-        home=home,
-        root=root,
-        isolated=isolated,
-        prefix=prefix,
-    )
+    dist_name: str,
+    user: bool = False,
+    home: Optional[str] = None,
+    root: Optional[str] = None,
+    isolated: bool = False,
+    prefix: Optional[str] = None,
+) -> Scheme:
     new = _sysconfig.get_scheme(
         dist_name,
         user=user,
@@ -93,14 +238,26 @@ def get_scheme(
         isolated=isolated,
         prefix=prefix,
     )
+    if _USE_SYSCONFIG:
+        return new
 
-    base = prefix or home or _default_base(user=user)
-    warned = []
+    old = _distutils.get_scheme(
+        dist_name,
+        user=user,
+        home=home,
+        root=root,
+        isolated=isolated,
+        prefix=prefix,
+    )
+
+    warning_contexts = []
     for k in SCHEME_KEYS:
-        # Extra join because distutils can return relative paths.
-        old_v = pathlib.Path(base, getattr(old, k))
+        old_v = pathlib.Path(getattr(old, k))
         new_v = pathlib.Path(getattr(new, k))
 
+        if old_v == new_v:
+            continue
+
         # distutils incorrectly put PyPy packages under ``site-packages/python``
         # in the ``posix_home`` scheme, but PyPy devs said they expect the
         # directory name to be ``pypy`` instead. So we treat this as a bug fix
@@ -110,59 +267,240 @@ def get_scheme(
             and home is not None
             and k in ("platlib", "purelib")
             and old_v.parent == new_v.parent
-            and old_v.name == "python"
-            and new_v.name == "pypy"
+            and old_v.name.startswith("python")
+            and new_v.name.startswith("pypy")
         )
         if skip_pypy_special_case:
             continue
 
-        warned.append(_warn_if_mismatch(old_v, new_v, key=f"scheme.{k}"))
+        # sysconfig's ``osx_framework_user`` does not include ``pythonX.Y`` in
+        # the ``include`` value, but distutils's ``headers`` does. We'll let
+        # CPython decide whether this is a bug or feature. See bpo-43948.
+        skip_osx_framework_user_special_case = (
+            user
+            and is_osx_framework()
+            and k == "headers"
+            and old_v.parent.parent == new_v.parent
+            and old_v.parent.name.startswith("python")
+        )
+        if skip_osx_framework_user_special_case:
+            continue
 
-    if any(warned):
-        _log_context(user=user, home=home, root=root, prefix=prefix)
+        # On Red Hat and derived Linux distributions, distutils is patched to
+        # use "lib64" instead of "lib" for platlib.
+        if k == "platlib" and _looks_like_red_hat_lib():
+            continue
+
+        # On Python 3.9+, sysconfig's posix_user scheme sets platlib against
+        # sys.platlibdir, but distutils's unix_user incorrectly coninutes
+        # using the same $usersite for both platlib and purelib. This creates a
+        # mismatch when sys.platlibdir is not "lib".
+        skip_bpo_44860 = (
+            user
+            and k == "platlib"
+            and not WINDOWS
+            and sys.version_info >= (3, 9)
+            and _PLATLIBDIR != "lib"
+            and _looks_like_bpo_44860()
+        )
+        if skip_bpo_44860:
+            continue
+
+        # Slackware incorrectly patches posix_user to use lib64 instead of lib,
+        # but not usersite to match the location.
+        skip_slackware_user_scheme = (
+            user
+            and k in ("platlib", "purelib")
+            and not WINDOWS
+            and _looks_like_slackware_scheme()
+        )
+        if skip_slackware_user_scheme:
+            continue
+
+        # Both Debian and Red Hat patch Python to place the system site under
+        # /usr/local instead of /usr. Debian also places lib in dist-packages
+        # instead of site-packages, but the /usr/local check should cover it.
+        skip_linux_system_special_case = (
+            not (user or home or prefix or running_under_virtualenv())
+            and old_v.parts[1:3] == ("usr", "local")
+            and len(new_v.parts) > 1
+            and new_v.parts[1] == "usr"
+            and (len(new_v.parts) < 3 or new_v.parts[2] != "local")
+            and (_looks_like_red_hat_scheme() or _looks_like_debian_scheme())
+        )
+        if skip_linux_system_special_case:
+            continue
+
+        # On Python 3.7 and earlier, sysconfig does not include sys.abiflags in
+        # the "pythonX.Y" part of the path, but distutils does.
+        skip_sysconfig_abiflag_bug = (
+            sys.version_info < (3, 8)
+            and not WINDOWS
+            and k in ("headers", "platlib", "purelib")
+            and tuple(_fix_abiflags(old_v.parts)) == new_v.parts
+        )
+        if skip_sysconfig_abiflag_bug:
+            continue
+
+        # MSYS2 MINGW's sysconfig patch does not include the "site-packages"
+        # part of the path. This is incorrect and will be fixed in MSYS.
+        skip_msys2_mingw_bug = (
+            WINDOWS and k in ("platlib", "purelib") and _looks_like_msys2_mingw_scheme()
+        )
+        if skip_msys2_mingw_bug:
+            continue
+
+        # CPython's POSIX install script invokes pip (via ensurepip) against the
+        # interpreter located in the source tree, not the install site. This
+        # triggers special logic in sysconfig that's not present in distutils.
+        # https://github.com/python/cpython/blob/8c21941ddaf/Lib/sysconfig.py#L178-L194
+        skip_cpython_build = (
+            sysconfig.is_python_build(check_home=True)
+            and not WINDOWS
+            and k in ("headers", "include", "platinclude")
+        )
+        if skip_cpython_build:
+            continue
+
+        warning_contexts.append((old_v, new_v, f"scheme.{k}"))
+
+    if not warning_contexts:
+        return old
+
+    # Check if this path mismatch is caused by distutils config files. Those
+    # files will no longer work once we switch to sysconfig, so this raises a
+    # deprecation message for them.
+    default_old = _distutils.distutils_scheme(
+        dist_name,
+        user,
+        home,
+        root,
+        isolated,
+        prefix,
+        ignore_config_files=True,
+    )
+    if any(default_old[k] != getattr(old, k) for k in SCHEME_KEYS):
+        deprecated(
+            reason=(
+                "Configuring installation scheme with distutils config files "
+                "is deprecated and will no longer work in the near future. If you "
+                "are using a Homebrew or Linuxbrew Python, please see discussion "
+                "at https://github.com/Homebrew/homebrew-core/issues/76621"
+            ),
+            replacement=None,
+            gone_in=None,
+        )
+        return old
+
+    # Post warnings about this mismatch so user can report them back.
+    for old_v, new_v, key in warning_contexts:
+        _warn_mismatched(old_v, new_v, key=key)
+    _log_context(user=user, home=home, root=root, prefix=prefix)
 
     return old
 
 
-def get_bin_prefix():
-    # type: () -> str
-    old = _distutils.get_bin_prefix()
+def get_bin_prefix() -> str:
     new = _sysconfig.get_bin_prefix()
+    if _USE_SYSCONFIG:
+        return new
+
+    old = _distutils.get_bin_prefix()
     if _warn_if_mismatch(pathlib.Path(old), pathlib.Path(new), key="bin_prefix"):
         _log_context()
     return old
 
 
-def get_bin_user():
-    # type: () -> str
+def get_bin_user() -> str:
     return _sysconfig.get_scheme("", user=True).scripts
 
 
-def get_purelib():
-    # type: () -> str
+def _looks_like_deb_system_dist_packages(value: str) -> bool:
+    """Check if the value is Debian's APT-controlled dist-packages.
+
+    Debian's ``distutils.sysconfig.get_python_lib()`` implementation returns the
+    default package path controlled by APT, but does not patch ``sysconfig`` to
+    do the same. This is similar to the bug worked around in ``get_scheme()``,
+    but here the default is ``deb_system`` instead of ``unix_local``. Ultimately
+    we can't do anything about this Debian bug, and this detection allows us to
+    skip the warning when needed.
+    """
+    if not _looks_like_debian_scheme():
+        return False
+    if value == "/usr/lib/python3/dist-packages":
+        return True
+    return False
+
+
+def get_purelib() -> str:
     """Return the default pure-Python lib location."""
-    old = _distutils.get_purelib()
     new = _sysconfig.get_purelib()
+    if _USE_SYSCONFIG:
+        return new
+
+    old = _distutils.get_purelib()
+    if _looks_like_deb_system_dist_packages(old):
+        return old
     if _warn_if_mismatch(pathlib.Path(old), pathlib.Path(new), key="purelib"):
         _log_context()
     return old
 
 
-def get_platlib():
-    # type: () -> str
+def get_platlib() -> str:
     """Return the default platform-shared lib location."""
-    old = _distutils.get_platlib()
     new = _sysconfig.get_platlib()
+    if _USE_SYSCONFIG:
+        return new
+
+    old = _distutils.get_platlib()
+    if _looks_like_deb_system_dist_packages(old):
+        return old
     if _warn_if_mismatch(pathlib.Path(old), pathlib.Path(new), key="platlib"):
         _log_context()
     return old
 
 
-def get_prefixed_libs(prefix):
-    # type: (str) -> List[str]
+def _deduplicated(v1: str, v2: str) -> List[str]:
+    """Deduplicate values from a list."""
+    if v1 == v2:
+        return [v1]
+    return [v1, v2]
+
+
+def _looks_like_apple_library(path: str) -> bool:
+    """Apple patches sysconfig to *always* look under */Library/Python*."""
+    if sys.platform[:6] != "darwin":
+        return False
+    return path == f"/Library/Python/{get_major_minor_version()}/site-packages"
+
+
+def get_prefixed_libs(prefix: str) -> List[str]:
     """Return the lib locations under ``prefix``."""
-    old_pure, old_plat = _distutils.get_prefixed_libs(prefix)
     new_pure, new_plat = _sysconfig.get_prefixed_libs(prefix)
+    if _USE_SYSCONFIG:
+        return _deduplicated(new_pure, new_plat)
+
+    old_pure, old_plat = _distutils.get_prefixed_libs(prefix)
+    old_lib_paths = _deduplicated(old_pure, old_plat)
+
+    # Apple's Python (shipped with Xcode and Command Line Tools) hard-code
+    # platlib and purelib to '/Library/Python/X.Y/site-packages'. This will
+    # cause serious build isolation bugs when Apple starts shipping 3.10 because
+    # pip will install build backends to the wrong location. This tells users
+    # who is at fault so Apple may notice it and fix the issue in time.
+    if all(_looks_like_apple_library(p) for p in old_lib_paths):
+        deprecated(
+            reason=(
+                "Python distributed by Apple's Command Line Tools incorrectly "
+                "patches sysconfig to always point to '/Library/Python'. This "
+                "will cause build isolation to operate incorrectly on Python "
+                "3.10 or later. Please help report this to Apple so they can "
+                "fix this. https://developer.apple.com/bug-reporting/"
+            ),
+            replacement=None,
+            gone_in=None,
+        )
+        return old_lib_paths
 
     warned = [
         _warn_if_mismatch(
@@ -179,6 +517,4 @@ def get_prefixed_libs(prefix):
     if any(warned):
         _log_context(prefix=prefix)
 
-    if old_pure == old_plat:
-        return [old_pure]
-    return [old_pure, old_plat]
+    return old_lib_paths

venv/Lib/site-packages/pip/_internal/locations/_distutils.py

@@ -3,6 +3,7 @@
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
 
+import logging
 import os
 import sys
 from distutils.cmd import Command as DistutilsCommand
@@ -17,23 +18,40 @@ from pip._internal.utils.virtualenv import running_under_virtualenv
 
 from .base import get_major_minor_version
 
+logger = logging.getLogger(__name__)
 
-def _distutils_scheme(
-    dist_name, user=False, home=None, root=None, isolated=False, prefix=None
-):
-    # type:(str, bool, str, str, bool, str) -> Dict[str, str]
+
+def distutils_scheme(
+    dist_name: str,
+    user: bool = False,
+    home: str = None,
+    root: str = None,
+    isolated: bool = False,
+    prefix: str = None,
+    *,
+    ignore_config_files: bool = False,
+) -> Dict[str, str]:
     """
     Return a distutils install scheme
     """
     from distutils.dist import Distribution
 
-    dist_args = {"name": dist_name}  # type: Dict[str, Union[str, List[str]]]
+    dist_args: Dict[str, Union[str, List[str]]] = {"name": dist_name}
     if isolated:
         dist_args["script_args"] = ["--no-user-cfg"]
 
     d = Distribution(dist_args)
-    d.parse_config_files()
-    obj = None  # type: Optional[DistutilsCommand]
+    if not ignore_config_files:
+        try:
+            d.parse_config_files()
+        except UnicodeDecodeError:
+            # Typeshed does not include find_config_files() for some reason.
+            paths = d.find_config_files()  # type: ignore
+            logger.warning(
+                "Ignore distutils configs in %s due to encoding errors.",
+                ", ".join(os.path.basename(p) for p in paths),
+            )
+    obj: Optional[DistutilsCommand] = None
     obj = d.get_command_obj("install", create=True)
     assert obj is not None
     i = cast(distutils_install_command, obj)
@@ -63,8 +81,14 @@ def _distutils_scheme(
         scheme.update(dict(purelib=i.install_lib, platlib=i.install_lib))
 
     if running_under_virtualenv():
+        if home:
+            prefix = home
+        elif user:
+            prefix = i.install_userbase
+        else:
+            prefix = i.prefix
         scheme["headers"] = os.path.join(
-            i.prefix,
+            prefix,
             "include",
             "site",
             f"python{get_major_minor_version()}",
@@ -73,23 +97,19 @@ def _distutils_scheme(
 
         if root is not None:
             path_no_drive = os.path.splitdrive(os.path.abspath(scheme["headers"]))[1]
-            scheme["headers"] = os.path.join(
-                root,
-                path_no_drive[1:],
-            )
+            scheme["headers"] = os.path.join(root, path_no_drive[1:])
 
     return scheme
 
 
 def get_scheme(
-    dist_name,  # type: str
-    user=False,  # type: bool
-    home=None,  # type: Optional[str]
-    root=None,  # type: Optional[str]
-    isolated=False,  # type: bool
-    prefix=None,  # type: Optional[str]
-):
-    # type: (...) -> Scheme
+    dist_name: str,
+    user: bool = False,
+    home: Optional[str] = None,
+    root: Optional[str] = None,
+    isolated: bool = False,
+    prefix: Optional[str] = None,
+) -> Scheme:
     """
     Get the "scheme" corresponding to the input parameters. The distutils
     documentation provides the context for the available schemes:
@@ -107,7 +127,7 @@ def get_scheme(
     :param prefix: indicates to use the "prefix" scheme and provides the
         base directory for the same
     """
-    scheme = _distutils_scheme(dist_name, user, home, root, isolated, prefix)
+    scheme = distutils_scheme(dist_name, user, home, root, isolated, prefix)
     return Scheme(
         platlib=scheme["platlib"],
         purelib=scheme["purelib"],
@@ -117,33 +137,32 @@ def get_scheme(
     )
 
 
-def get_bin_prefix():
-    # type: () -> str
+def get_bin_prefix() -> str:
+    # XXX: In old virtualenv versions, sys.prefix can contain '..' components,
+    # so we need to call normpath to eliminate them.
+    prefix = os.path.normpath(sys.prefix)
     if WINDOWS:
-        bin_py = os.path.join(sys.prefix, "Scripts")
+        bin_py = os.path.join(prefix, "Scripts")
         # buildout uses 'bin' on Windows too?
         if not os.path.exists(bin_py):
-            bin_py = os.path.join(sys.prefix, "bin")
+            bin_py = os.path.join(prefix, "bin")
         return bin_py
     # Forcing to use /usr/local/bin for standard macOS framework installs
     # Also log to ~/Library/Logs/ for use with the Console.app log viewer
-    if sys.platform[:6] == "darwin" and sys.prefix[:16] == "/System/Library/":
+    if sys.platform[:6] == "darwin" and prefix[:16] == "/System/Library/":
         return "/usr/local/bin"
-    return os.path.join(sys.prefix, "bin")
+    return os.path.join(prefix, "bin")
 
 
-def get_purelib():
-    # type: () -> str
+def get_purelib() -> str:
     return get_python_lib(plat_specific=False)
 
 
-def get_platlib():
-    # type: () -> str
+def get_platlib() -> str:
     return get_python_lib(plat_specific=True)
 
 
-def get_prefixed_libs(prefix):
-    # type: (str) -> Tuple[str, str]
+def get_prefixed_libs(prefix: str) -> Tuple[str, str]:
     return (
         get_python_lib(plat_specific=False, prefix=prefix),
         get_python_lib(plat_specific=True, prefix=prefix),

venv/Lib/site-packages/pip/_internal/locations/_sysconfig.py

@@ -9,14 +9,14 @@ from pip._internal.exceptions import InvalidSchemeCombination, UserInstallationI
 from pip._internal.models.scheme import SCHEME_KEYS, Scheme
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
-from .base import get_major_minor_version
+from .base import get_major_minor_version, is_osx_framework
 
 logger = logging.getLogger(__name__)
 
 
 # Notes on _infer_* functions.
-# Unfortunately ``_get_default_scheme()`` is private, so there's no way to
-# ask things like "what is the '_prefix' scheme on this platform". These
+# Unfortunately ``get_default_scheme()`` didn't exist before 3.10, so there's no
+# way to ask things like "what is the '_prefix' scheme on this platform". These
 # functions try to answer that with some heuristics while accounting for ad-hoc
 # platforms not covered by CPython's default sysconfig implementation. If the
 # ad-hoc implementation does not fully implement sysconfig, we'll fall back to
@@ -24,13 +24,42 @@ logger = logging.getLogger(__name__)
 
 _AVAILABLE_SCHEMES = set(sysconfig.get_scheme_names())
 
+_PREFERRED_SCHEME_API = getattr(sysconfig, "get_preferred_scheme", None)
 
-def _infer_prefix():
-    # type: () -> str
+
+def _should_use_osx_framework_prefix() -> bool:
+    """Check for Apple's ``osx_framework_library`` scheme.
+
+    Python distributed by Apple's Command Line Tools has this special scheme
+    that's used when:
+
+    * This is a framework build.
+    * We are installing into the system prefix.
+
+    This does not account for ``pip install --prefix`` (also means we're not
+    installing to the system prefix), which should use ``posix_prefix``, but
+    logic here means ``_infer_prefix()`` outputs ``osx_framework_library``. But
+    since ``prefix`` is not available for ``sysconfig.get_default_scheme()``,
+    which is the stdlib replacement for ``_infer_prefix()``, presumably Apple
+    wouldn't be able to magically switch between ``osx_framework_library`` and
+    ``posix_prefix``. ``_infer_prefix()`` returning ``osx_framework_library``
+    means its behavior is consistent whether we use the stdlib implementation
+    or our own, and we deal with this special case in ``get_scheme()`` instead.
+    """
+    return (
+        "osx_framework_library" in _AVAILABLE_SCHEMES
+        and not running_under_virtualenv()
+        and is_osx_framework()
+    )
+
+
+def _infer_prefix() -> str:
     """Try to find a prefix scheme for the current platform.
 
     This tries:
 
+    * A special ``osx_framework_library`` for Python distributed by Apple's
+      Command Line Tools, when not running in a virtual environment.
     * Implementation + OS, used by PyPy on Windows (``pypy_nt``).
     * Implementation without OS, used by PyPy on POSIX (``pypy``).
     * OS + "prefix", used by CPython on POSIX (``posix_prefix``).
@@ -38,6 +67,10 @@ def _infer_prefix():
 
     If none of the above works, fall back to ``posix_prefix``.
     """
+    if _PREFERRED_SCHEME_API:
+        return _PREFERRED_SCHEME_API("prefix")
+    if _should_use_osx_framework_prefix():
+        return "osx_framework_library"
     implementation_suffixed = f"{sys.implementation.name}_{os.name}"
     if implementation_suffixed in _AVAILABLE_SCHEMES:
         return implementation_suffixed
@@ -51,10 +84,14 @@ def _infer_prefix():
     return "posix_prefix"
 
 
-def _infer_user():
-    # type: () -> str
+def _infer_user() -> str:
     """Try to find a user scheme for the current platform."""
-    suffixed = f"{os.name}_user"
+    if _PREFERRED_SCHEME_API:
+        return _PREFERRED_SCHEME_API("user")
+    if is_osx_framework() and not running_under_virtualenv():
+        suffixed = "osx_framework_user"
+    else:
+        suffixed = f"{os.name}_user"
     if suffixed in _AVAILABLE_SCHEMES:
         return suffixed
     if "posix_user" not in _AVAILABLE_SCHEMES:  # User scheme unavailable.
@@ -62,9 +99,10 @@ def _infer_user():
     return "posix_user"
 
 
-def _infer_home():
-    # type: () -> str
+def _infer_home() -> str:
     """Try to find a home for the current platform."""
+    if _PREFERRED_SCHEME_API:
+        return _PREFERRED_SCHEME_API("home")
     suffixed = f"{os.name}_home"
     if suffixed in _AVAILABLE_SCHEMES:
         return suffixed
@@ -85,14 +123,13 @@ if sysconfig.get_config_var("userbase") is not None:
 
 
 def get_scheme(
-    dist_name,  # type: str
-    user=False,  # type: bool
-    home=None,  # type: typing.Optional[str]
-    root=None,  # type: typing.Optional[str]
-    isolated=False,  # type: bool
-    prefix=None,  # type: typing.Optional[str]
-):
-    # type: (...) -> Scheme
+    dist_name: str,
+    user: bool = False,
+    home: typing.Optional[str] = None,
+    root: typing.Optional[str] = None,
+    isolated: bool = False,
+    prefix: typing.Optional[str] = None,
+) -> Scheme:
     """
     Get the "scheme" corresponding to the input parameters.
 
@@ -118,6 +155,12 @@ def get_scheme(
     else:
         scheme_name = _infer_prefix()
 
+    # Special case: When installing into a custom prefix, use posix_prefix
+    # instead of osx_framework_library. See _should_use_osx_framework_prefix()
+    # docstring for details.
+    if prefix is not None and scheme_name == "osx_framework_library":
+        scheme_name = "posix_prefix"
+
     if home is not None:
         variables = {k: home for k in _HOME_KEYS}
     elif prefix is not None:
@@ -156,25 +199,21 @@ def get_scheme(
     return scheme
 
 
-def get_bin_prefix():
-    # type: () -> str
+def get_bin_prefix() -> str:
     # Forcing to use /usr/local/bin for standard macOS framework installs.
     if sys.platform[:6] == "darwin" and sys.prefix[:16] == "/System/Library/":
         return "/usr/local/bin"
     return sysconfig.get_paths()["scripts"]
 
 
-def get_purelib():
-    # type: () -> str
+def get_purelib() -> str:
     return sysconfig.get_paths()["purelib"]
 
 
-def get_platlib():
-    # type: () -> str
+def get_platlib() -> str:
     return sysconfig.get_paths()["platlib"]
 
 
-def get_prefixed_libs(prefix):
-    # type: (str) -> typing.Tuple[str, str]
+def get_prefixed_libs(prefix: str) -> typing.Tuple[str, str]:
     paths = sysconfig.get_paths(vars={"base": prefix, "platbase": prefix})
     return (paths["purelib"], paths["platlib"])

venv/Lib/site-packages/pip/_internal/locations/base.py

@@ -1,3 +1,4 @@
+import functools
 import os
 import site
 import sys
@@ -11,11 +12,10 @@ from pip._internal.utils.virtualenv import running_under_virtualenv
 USER_CACHE_DIR = appdirs.user_cache_dir("pip")
 
 # FIXME doesn't account for venv linked to global site-packages
-site_packages = sysconfig.get_path("purelib")  # type: typing.Optional[str]
+site_packages: typing.Optional[str] = sysconfig.get_path("purelib")
 
 
-def get_major_minor_version():
-    # type: () -> str
+def get_major_minor_version() -> str:
     """
     Return the major-minor version of the current Python as a string, e.g.
     "3.7" or "3.10".
@@ -23,8 +23,7 @@ def get_major_minor_version():
     return "{}.{}".format(*sys.version_info)
 
 
-def get_src_prefix():
-    # type: () -> str
+def get_src_prefix() -> str:
     if running_under_virtualenv():
         src_prefix = os.path.join(sys.prefix, "src")
     else:
@@ -43,6 +42,11 @@ def get_src_prefix():
 try:
     # Use getusersitepackages if this is present, as it ensures that the
     # value is initialised properly.
-    user_site = site.getusersitepackages()  # type: typing.Optional[str]
+    user_site: typing.Optional[str] = site.getusersitepackages()
 except AttributeError:
     user_site = site.USER_SITE
+
+
+@functools.lru_cache(maxsize=None)
+def is_osx_framework() -> bool:
+    return bool(sysconfig.get_config_var("PYTHONFRAMEWORK"))

venv/Lib/site-packages/pip/_internal/main.py

@@ -1,8 +1,7 @@
 from typing import List, Optional
 
 
-def main(args=None):
-    # type: (Optional[List[str]]) -> int
+def main(args: Optional[List[str]] = None) -> int:
     """This is preserved for old console scripts that may still be referencing
     it.
 

venv/Lib/site-packages/pip/_internal/metadata/__init__.py

@@ -1,36 +1,100 @@
-from typing import List, Optional
+import contextlib
+import functools
+import os
+import sys
+from typing import TYPE_CHECKING, List, Optional, Type, cast
 
-from .base import BaseDistribution, BaseEnvironment
+from pip._internal.utils.misc import strtobool
+
+from .base import BaseDistribution, BaseEnvironment, FilesystemWheel, MemoryWheel, Wheel
+
+if TYPE_CHECKING:
+    from typing import Protocol
+else:
+    Protocol = object
+
+__all__ = [
+    "BaseDistribution",
+    "BaseEnvironment",
+    "FilesystemWheel",
+    "MemoryWheel",
+    "Wheel",
+    "get_default_environment",
+    "get_environment",
+    "get_wheel_distribution",
+    "select_backend",
+]
 
 
-def get_default_environment():
-    # type: () -> BaseEnvironment
+def _should_use_importlib_metadata() -> bool:
+    """Whether to use the ``importlib.metadata`` or ``pkg_resources`` backend.
+
+    By default, pip uses ``importlib.metadata`` on Python 3.11+, and
+    ``pkg_resourcess`` otherwise. This can be overriden by a couple of ways:
+
+    * If environment variable ``_PIP_USE_IMPORTLIB_METADATA`` is set, it
+      dictates whether ``importlib.metadata`` is used, regardless of Python
+      version.
+    * On Python 3.11+, Python distributors can patch ``importlib.metadata``
+      to add a global constant ``_PIP_USE_IMPORTLIB_METADATA = False``. This
+      makes pip use ``pkg_resources`` (unless the user set the aforementioned
+      environment variable to *True*).
+    """
+    with contextlib.suppress(KeyError, ValueError):
+        return bool(strtobool(os.environ["_PIP_USE_IMPORTLIB_METADATA"]))
+    if sys.version_info < (3, 11):
+        return False
+    import importlib.metadata
+
+    return bool(getattr(importlib.metadata, "_PIP_USE_IMPORTLIB_METADATA", True))
+
+
+class Backend(Protocol):
+    Distribution: Type[BaseDistribution]
+    Environment: Type[BaseEnvironment]
+
+
+@functools.lru_cache(maxsize=None)
+def select_backend() -> Backend:
+    if _should_use_importlib_metadata():
+        from . import importlib
+
+        return cast(Backend, importlib)
+    from . import pkg_resources
+
+    return cast(Backend, pkg_resources)
+
+
+def get_default_environment() -> BaseEnvironment:
     """Get the default representation for the current environment.
 
     This returns an Environment instance from the chosen backend. The default
     Environment instance should be built from ``sys.path`` and may use caching
     to share instance state accorss calls.
     """
-    from .pkg_resources import Environment
-
-    return Environment.default()
+    return select_backend().Environment.default()
 
 
-def get_environment(paths):
-    # type: (Optional[List[str]]) -> BaseEnvironment
+def get_environment(paths: Optional[List[str]]) -> BaseEnvironment:
     """Get a representation of the environment specified by ``paths``.
 
     This returns an Environment instance from the chosen backend based on the
     given import paths. The backend must build a fresh instance representing
     the state of installed distributions when this function is called.
     """
-    from .pkg_resources import Environment
-
-    return Environment.from_paths(paths)
+    return select_backend().Environment.from_paths(paths)
 
 
-def get_wheel_distribution(wheel_path, canonical_name):
-    # type: (str, str) -> BaseDistribution
+def get_directory_distribution(directory: str) -> BaseDistribution:
+    """Get the distribution metadata representation in the specified directory.
+
+    This returns a Distribution instance from the chosen backend based on
+    the given on-disk ``.dist-info`` directory.
+    """
+    return select_backend().Distribution.from_directory(directory)
+
+
+def get_wheel_distribution(wheel: Wheel, canonical_name: str) -> BaseDistribution:
     """Get the representation of the specified wheel's distribution metadata.
 
     This returns a Distribution instance from the chosen backend based on
@@ -38,6 +102,4 @@ def get_wheel_distribution(wheel_path, canonical_name):
 
     :param canonical_name: Normalized project name of the given wheel.
     """
-    from .pkg_resources import Distribution
-
-    return Distribution.from_wheel(wheel_path, canonical_name)
+    return select_backend().Distribution.from_wheel(wheel, canonical_name)

venv/Lib/site-packages/pip/_internal/metadata/base.py

@@ -1,85 +1,477 @@
+import csv
+import email.message
+import json
 import logging
+import pathlib
 import re
-from typing import Container, Iterator, List, Optional, Union
+import zipfile
+from typing import (
+    IO,
+    TYPE_CHECKING,
+    Collection,
+    Container,
+    Iterable,
+    Iterator,
+    List,
+    Optional,
+    Tuple,
+    Union,
+)
 
+from pip._vendor.packaging.requirements import Requirement
+from pip._vendor.packaging.specifiers import InvalidSpecifier, SpecifierSet
+from pip._vendor.packaging.utils import NormalizedName
 from pip._vendor.packaging.version import LegacyVersion, Version
 
-from pip._internal.utils.misc import stdlib_pkgs  # TODO: Move definition here.
+from pip._internal.exceptions import NoneMetadataError
+from pip._internal.locations import site_packages, user_site
+from pip._internal.models.direct_url import (
+    DIRECT_URL_METADATA_NAME,
+    DirectUrl,
+    DirectUrlValidationError,
+)
+from pip._internal.utils.compat import stdlib_pkgs  # TODO: Move definition here.
+from pip._internal.utils.egg_link import egg_link_path_from_sys_path
+from pip._internal.utils.misc import is_local, normalize_path
+from pip._internal.utils.urls import url_to_path
+
+if TYPE_CHECKING:
+    from typing import Protocol
+else:
+    Protocol = object
 
 DistributionVersion = Union[LegacyVersion, Version]
 
+InfoPath = Union[str, pathlib.PurePath]
+
 logger = logging.getLogger(__name__)
 
 
-class BaseDistribution:
+class BaseEntryPoint(Protocol):
     @property
-    def location(self):
-        # type: () -> Optional[str]
+    def name(self) -> str:
+        raise NotImplementedError()
+
+    @property
+    def value(self) -> str:
+        raise NotImplementedError()
+
+    @property
+    def group(self) -> str:
+        raise NotImplementedError()
+
+
+def _convert_installed_files_path(
+    entry: Tuple[str, ...],
+    info: Tuple[str, ...],
+) -> str:
+    """Convert a legacy installed-files.txt path into modern RECORD path.
+
+    The legacy format stores paths relative to the info directory, while the
+    modern format stores paths relative to the package root, e.g. the
+    site-packages directory.
+
+    :param entry: Path parts of the installed-files.txt entry.
+    :param info: Path parts of the egg-info directory relative to package root.
+    :returns: The converted entry.
+
+    For best compatibility with symlinks, this does not use ``abspath()`` or
+    ``Path.resolve()``, but tries to work with path parts:
+
+    1. While ``entry`` starts with ``..``, remove the equal amounts of parts
+       from ``info``; if ``info`` is empty, start appending ``..`` instead.
+    2. Join the two directly.
+    """
+    while entry and entry[0] == "..":
+        if not info or info[-1] == "..":
+            info += ("..",)
+        else:
+            info = info[:-1]
+        entry = entry[1:]
+    return str(pathlib.Path(*info, *entry))
+
+
+class BaseDistribution(Protocol):
+    @classmethod
+    def from_directory(cls, directory: str) -> "BaseDistribution":
+        """Load the distribution from a metadata directory.
+
+        :param directory: Path to a metadata directory, e.g. ``.dist-info``.
+        """
+        raise NotImplementedError()
+
+    @classmethod
+    def from_wheel(cls, wheel: "Wheel", name: str) -> "BaseDistribution":
+        """Load the distribution from a given wheel.
+
+        :param wheel: A concrete wheel definition.
+        :param name: File name of the wheel.
+
+        :raises InvalidWheel: Whenever loading of the wheel causes a
+            :py:exc:`zipfile.BadZipFile` exception to be thrown.
+        :raises UnsupportedWheel: If the wheel is a valid zip, but malformed
+            internally.
+        """
+        raise NotImplementedError()
+
+    def __repr__(self) -> str:
+        return f"{self.raw_name} {self.version} ({self.location})"
+
+    def __str__(self) -> str:
+        return f"{self.raw_name} {self.version}"
+
+    @property
+    def location(self) -> Optional[str]:
         """Where the distribution is loaded from.
 
         A string value is not necessarily a filesystem path, since distributions
         can be loaded from other sources, e.g. arbitrary zip archives. ``None``
         means the distribution is created in-memory.
+
+        Do not canonicalize this value with e.g. ``pathlib.Path.resolve()``. If
+        this is a symbolic link, we want to preserve the relative path between
+        it and files in the distribution.
         """
         raise NotImplementedError()
 
     @property
-    def metadata_version(self):
-        # type: () -> Optional[str]
-        """Value of "Metadata-Version:" in the distribution, if available."""
+    def editable_project_location(self) -> Optional[str]:
+        """The project location for editable distributions.
+
+        This is the directory where pyproject.toml or setup.py is located.
+        None if the distribution is not installed in editable mode.
+        """
+        # TODO: this property is relatively costly to compute, memoize it ?
+        direct_url = self.direct_url
+        if direct_url:
+            if direct_url.is_local_editable():
+                return url_to_path(direct_url.url)
+        else:
+            # Search for an .egg-link file by walking sys.path, as it was
+            # done before by dist_is_editable().
+            egg_link_path = egg_link_path_from_sys_path(self.raw_name)
+            if egg_link_path:
+                # TODO: get project location from second line of egg_link file
+                #       (https://github.com/pypa/pip/issues/10243)
+                return self.location
+        return None
+
+    @property
+    def installed_location(self) -> Optional[str]:
+        """The distribution's "installed" location.
+
+        This should generally be a ``site-packages`` directory. This is
+        usually ``dist.location``, except for legacy develop-installed packages,
+        where ``dist.location`` is the source code location, and this is where
+        the ``.egg-link`` file is.
+
+        The returned location is normalized (in particular, with symlinks removed).
+        """
         raise NotImplementedError()
 
     @property
-    def canonical_name(self):
-        # type: () -> str
+    def info_location(self) -> Optional[str]:
+        """Location of the .[egg|dist]-info directory or file.
+
+        Similarly to ``location``, a string value is not necessarily a
+        filesystem path. ``None`` means the distribution is created in-memory.
+
+        For a modern .dist-info installation on disk, this should be something
+        like ``{location}/{raw_name}-{version}.dist-info``.
+
+        Do not canonicalize this value with e.g. ``pathlib.Path.resolve()``. If
+        this is a symbolic link, we want to preserve the relative path between
+        it and other files in the distribution.
+        """
         raise NotImplementedError()
 
     @property
-    def version(self):
-        # type: () -> DistributionVersion
+    def installed_by_distutils(self) -> bool:
+        """Whether this distribution is installed with legacy distutils format.
+
+        A distribution installed with "raw" distutils not patched by setuptools
+        uses one single file at ``info_location`` to store metadata. We need to
+        treat this specially on uninstallation.
+        """
+        info_location = self.info_location
+        if not info_location:
+            return False
+        return pathlib.Path(info_location).is_file()
+
+    @property
+    def installed_as_egg(self) -> bool:
+        """Whether this distribution is installed as an egg.
+
+        This usually indicates the distribution was installed by (older versions
+        of) easy_install.
+        """
+        location = self.location
+        if not location:
+            return False
+        return location.endswith(".egg")
+
+    @property
+    def installed_with_setuptools_egg_info(self) -> bool:
+        """Whether this distribution is installed with the ``.egg-info`` format.
+
+        This usually indicates the distribution was installed with setuptools
+        with an old pip version or with ``single-version-externally-managed``.
+
+        Note that this ensure the metadata store is a directory. distutils can
+        also installs an ``.egg-info``, but as a file, not a directory. This
+        property is *False* for that case. Also see ``installed_by_distutils``.
+        """
+        info_location = self.info_location
+        if not info_location:
+            return False
+        if not info_location.endswith(".egg-info"):
+            return False
+        return pathlib.Path(info_location).is_dir()
+
+    @property
+    def installed_with_dist_info(self) -> bool:
+        """Whether this distribution is installed with the "modern format".
+
+        This indicates a "modern" installation, e.g. storing metadata in the
+        ``.dist-info`` directory. This applies to installations made by
+        setuptools (but through pip, not directly), or anything using the
+        standardized build backend interface (PEP 517).
+        """
+        info_location = self.info_location
+        if not info_location:
+            return False
+        if not info_location.endswith(".dist-info"):
+            return False
+        return pathlib.Path(info_location).is_dir()
+
+    @property
+    def canonical_name(self) -> NormalizedName:
         raise NotImplementedError()
 
     @property
-    def installer(self):
-        # type: () -> str
+    def version(self) -> DistributionVersion:
         raise NotImplementedError()
 
     @property
-    def editable(self):
-        # type: () -> bool
+    def setuptools_filename(self) -> str:
+        """Convert a project name to its setuptools-compatible filename.
+
+        This is a copy of ``pkg_resources.to_filename()`` for compatibility.
+        """
+        return self.raw_name.replace("-", "_")
+
+    @property
+    def direct_url(self) -> Optional[DirectUrl]:
+        """Obtain a DirectUrl from this distribution.
+
+        Returns None if the distribution has no `direct_url.json` metadata,
+        or if `direct_url.json` is invalid.
+        """
+        try:
+            content = self.read_text(DIRECT_URL_METADATA_NAME)
+        except FileNotFoundError:
+            return None
+        try:
+            return DirectUrl.from_json(content)
+        except (
+            UnicodeDecodeError,
+            json.JSONDecodeError,
+            DirectUrlValidationError,
+        ) as e:
+            logger.warning(
+                "Error parsing %s for %s: %s",
+                DIRECT_URL_METADATA_NAME,
+                self.canonical_name,
+                e,
+            )
+            return None
+
+    @property
+    def installer(self) -> str:
+        try:
+            installer_text = self.read_text("INSTALLER")
+        except (OSError, ValueError, NoneMetadataError):
+            return ""  # Fail silently if the installer file cannot be read.
+        for line in installer_text.splitlines():
+            cleaned_line = line.strip()
+            if cleaned_line:
+                return cleaned_line
+        return ""
+
+    @property
+    def editable(self) -> bool:
+        return bool(self.editable_project_location)
+
+    @property
+    def local(self) -> bool:
+        """If distribution is installed in the current virtual environment.
+
+        Always True if we're not in a virtualenv.
+        """
+        if self.installed_location is None:
+            return False
+        return is_local(self.installed_location)
+
+    @property
+    def in_usersite(self) -> bool:
+        if self.installed_location is None or user_site is None:
+            return False
+        return self.installed_location.startswith(normalize_path(user_site))
+
+    @property
+    def in_site_packages(self) -> bool:
+        if self.installed_location is None or site_packages is None:
+            return False
+        return self.installed_location.startswith(normalize_path(site_packages))
+
+    def is_file(self, path: InfoPath) -> bool:
+        """Check whether an entry in the info directory is a file."""
+        raise NotImplementedError()
+
+    def iter_distutils_script_names(self) -> Iterator[str]:
+        """Find distutils 'scripts' entries metadata.
+
+        If 'scripts' is supplied in ``setup.py``, distutils records those in the
+        installed distribution's ``scripts`` directory, a file for each script.
+        """
+        raise NotImplementedError()
+
+    def read_text(self, path: InfoPath) -> str:
+        """Read a file in the info directory.
+
+        :raise FileNotFoundError: If ``path`` does not exist in the directory.
+        :raise NoneMetadataError: If ``path`` exists in the info directory, but
+            cannot be read.
+        """
+        raise NotImplementedError()
+
+    def iter_entry_points(self) -> Iterable[BaseEntryPoint]:
         raise NotImplementedError()
 
     @property
-    def local(self):
-        # type: () -> bool
+    def metadata(self) -> email.message.Message:
+        """Metadata of distribution parsed from e.g. METADATA or PKG-INFO.
+
+        This should return an empty message if the metadata file is unavailable.
+
+        :raises NoneMetadataError: If the metadata file is available, but does
+            not contain valid metadata.
+        """
         raise NotImplementedError()
 
     @property
-    def in_usersite(self):
-        # type: () -> bool
+    def metadata_version(self) -> Optional[str]:
+        """Value of "Metadata-Version:" in distribution metadata, if available."""
+        return self.metadata.get("Metadata-Version")
+
+    @property
+    def raw_name(self) -> str:
+        """Value of "Name:" in distribution metadata."""
+        # The metadata should NEVER be missing the Name: key, but if it somehow
+        # does, fall back to the known canonical name.
+        return self.metadata.get("Name", self.canonical_name)
+
+    @property
+    def requires_python(self) -> SpecifierSet:
+        """Value of "Requires-Python:" in distribution metadata.
+
+        If the key does not exist or contains an invalid value, an empty
+        SpecifierSet should be returned.
+        """
+        value = self.metadata.get("Requires-Python")
+        if value is None:
+            return SpecifierSet()
+        try:
+            # Convert to str to satisfy the type checker; this can be a Header object.
+            spec = SpecifierSet(str(value))
+        except InvalidSpecifier as e:
+            message = "Package %r has an invalid Requires-Python: %s"
+            logger.warning(message, self.raw_name, e)
+            return SpecifierSet()
+        return spec
+
+    def iter_dependencies(self, extras: Collection[str] = ()) -> Iterable[Requirement]:
+        """Dependencies of this distribution.
+
+        For modern .dist-info distributions, this is the collection of
+        "Requires-Dist:" entries in distribution metadata.
+        """
         raise NotImplementedError()
 
+    def iter_provided_extras(self) -> Iterable[str]:
+        """Extras provided by this distribution.
+
+        For modern .dist-info distributions, this is the collection of
+        "Provides-Extra:" entries in distribution metadata.
+        """
+        raise NotImplementedError()
+
+    def _iter_declared_entries_from_record(self) -> Optional[Iterator[str]]:
+        try:
+            text = self.read_text("RECORD")
+        except FileNotFoundError:
+            return None
+        # This extra Path-str cast normalizes entries.
+        return (str(pathlib.Path(row[0])) for row in csv.reader(text.splitlines()))
+
+    def _iter_declared_entries_from_legacy(self) -> Optional[Iterator[str]]:
+        try:
+            text = self.read_text("installed-files.txt")
+        except FileNotFoundError:
+            return None
+        paths = (p for p in text.splitlines(keepends=False) if p)
+        root = self.location
+        info = self.info_location
+        if root is None or info is None:
+            return paths
+        try:
+            info_rel = pathlib.Path(info).relative_to(root)
+        except ValueError:  # info is not relative to root.
+            return paths
+        if not info_rel.parts:  # info *is* root.
+            return paths
+        return (
+            _convert_installed_files_path(pathlib.Path(p).parts, info_rel.parts)
+            for p in paths
+        )
+
+    def iter_declared_entries(self) -> Optional[Iterator[str]]:
+        """Iterate through file entires declared in this distribution.
+
+        For modern .dist-info distributions, this is the files listed in the
+        ``RECORD`` metadata file. For legacy setuptools distributions, this
+        comes from ``installed-files.txt``, with entries normalized to be
+        compatible with the format used by ``RECORD``.
+
+        :return: An iterator for listed entries, or None if the distribution
+            contains neither ``RECORD`` nor ``installed-files.txt``.
+        """
+        return (
+            self._iter_declared_entries_from_record()
+            or self._iter_declared_entries_from_legacy()
+        )
+
 
 class BaseEnvironment:
     """An environment containing distributions to introspect."""
 
     @classmethod
-    def default(cls):
-        # type: () -> BaseEnvironment
+    def default(cls) -> "BaseEnvironment":
         raise NotImplementedError()
 
     @classmethod
-    def from_paths(cls, paths):
-        # type: (Optional[List[str]]) -> BaseEnvironment
+    def from_paths(cls, paths: Optional[List[str]]) -> "BaseEnvironment":
         raise NotImplementedError()
 
-    def get_distribution(self, name):
-        # type: (str) -> Optional[BaseDistribution]
-        """Given a requirement name, return the installed distributions."""
+    def get_distribution(self, name: str) -> Optional["BaseDistribution"]:
+        """Given a requirement name, return the installed distributions.
+
+        The name may not be normalized. The implementation must canonicalize
+        it for lookup.
+        """
         raise NotImplementedError()
 
-    def _iter_distributions(self):
-        # type: () -> Iterator[BaseDistribution]
+    def _iter_distributions(self) -> Iterator["BaseDistribution"]:
         """Iterate through installed distributions.
 
         This function should be implemented by subclass, but never called
@@ -88,9 +480,8 @@ class BaseEnvironment:
         """
         raise NotImplementedError()
 
-    def iter_distributions(self):
-        # type: () -> Iterator[BaseDistribution]
-        """Iterate through installed distributions."""
+    def iter_all_distributions(self) -> Iterator[BaseDistribution]:
+        """Iterate through all installed distributions without any filtering."""
         for dist in self._iter_distributions():
             # Make sure the distribution actually comes from a valid Python
             # packaging distribution. Pip's AdjacentTempDirectory leaves folders
@@ -112,15 +503,19 @@ class BaseEnvironment:
 
     def iter_installed_distributions(
         self,
-        local_only=True,  # type: bool
-        skip=stdlib_pkgs,  # type: Container[str]
-        include_editables=True,  # type: bool
-        editables_only=False,  # type: bool
-        user_only=False,  # type: bool
-    ):
-        # type: (...) -> Iterator[BaseDistribution]
+        local_only: bool = True,
+        skip: Container[str] = stdlib_pkgs,
+        include_editables: bool = True,
+        editables_only: bool = False,
+        user_only: bool = False,
+    ) -> Iterator[BaseDistribution]:
         """Return a list of installed distributions.
 
+        This is based on ``iter_all_distributions()`` with additional filtering
+        options. Note that ``iter_installed_distributions()`` without arguments
+        is *not* equal to ``iter_all_distributions()``, since some of the
+        configurations exclude packages by default.
+
         :param local_only: If True (default), only return installations
         local to the current virtualenv, if in a virtualenv.
         :param skip: An iterable of canonicalized project names to ignore;
@@ -130,7 +525,7 @@ class BaseEnvironment:
         :param user_only: If True, only report installations in the user
         site directory.
         """
-        it = self.iter_distributions()
+        it = self.iter_all_distributions()
         if local_only:
             it = (d for d in it if d.local)
         if not include_editables:
@@ -140,3 +535,27 @@ class BaseEnvironment:
         if user_only:
             it = (d for d in it if d.in_usersite)
         return (d for d in it if d.canonical_name not in skip)
+
+
+class Wheel(Protocol):
+    location: str
+
+    def as_zipfile(self) -> zipfile.ZipFile:
+        raise NotImplementedError()
+
+
+class FilesystemWheel(Wheel):
+    def __init__(self, location: str) -> None:
+        self.location = location
+
+    def as_zipfile(self) -> zipfile.ZipFile:
+        return zipfile.ZipFile(self.location, allowZip64=True)
+
+
+class MemoryWheel(Wheel):
+    def __init__(self, location: str, stream: IO[bytes]) -> None:
+        self.location = location
+        self.stream = stream
+
+    def as_zipfile(self) -> zipfile.ZipFile:
+        return zipfile.ZipFile(self.stream, allowZip64=True)

venv/Lib/site-packages/pip/_internal/metadata/pkg_resources.py

@@ -1,104 +1,237 @@
+import email.message
+import email.parser
+import logging
+import os
 import zipfile
-from typing import Iterator, List, Optional
+from typing import Collection, Iterable, Iterator, List, Mapping, NamedTuple, Optional
 
 from pip._vendor import pkg_resources
-from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.packaging.requirements import Requirement
+from pip._vendor.packaging.utils import NormalizedName, canonicalize_name
 from pip._vendor.packaging.version import parse as parse_version
 
-from pip._internal.utils import misc  # TODO: Move definition here.
-from pip._internal.utils.packaging import get_installer
-from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
+from pip._internal.exceptions import InvalidWheel, NoneMetadataError, UnsupportedWheel
+from pip._internal.utils.egg_link import egg_link_path_from_location
+from pip._internal.utils.misc import display_path, normalize_path
+from pip._internal.utils.wheel import parse_wheel, read_wheel_metadata_file
 
-from .base import BaseDistribution, BaseEnvironment, DistributionVersion
+from .base import (
+    BaseDistribution,
+    BaseEntryPoint,
+    BaseEnvironment,
+    DistributionVersion,
+    InfoPath,
+    Wheel,
+)
+
+logger = logging.getLogger(__name__)
+
+
+class EntryPoint(NamedTuple):
+    name: str
+    value: str
+    group: str
+
+
+class WheelMetadata:
+    """IMetadataProvider that reads metadata files from a dictionary.
+
+    This also maps metadata decoding exceptions to our internal exception type.
+    """
+
+    def __init__(self, metadata: Mapping[str, bytes], wheel_name: str) -> None:
+        self._metadata = metadata
+        self._wheel_name = wheel_name
+
+    def has_metadata(self, name: str) -> bool:
+        return name in self._metadata
+
+    def get_metadata(self, name: str) -> str:
+        try:
+            return self._metadata[name].decode()
+        except UnicodeDecodeError as e:
+            # Augment the default error with the origin of the file.
+            raise UnsupportedWheel(
+                f"Error decoding metadata for {self._wheel_name}: {e} in {name} file"
+            )
+
+    def get_metadata_lines(self, name: str) -> Iterable[str]:
+        return pkg_resources.yield_lines(self.get_metadata(name))
+
+    def metadata_isdir(self, name: str) -> bool:
+        return False
+
+    def metadata_listdir(self, name: str) -> List[str]:
+        return []
+
+    def run_script(self, script_name: str, namespace: str) -> None:
+        pass
 
 
 class Distribution(BaseDistribution):
-    def __init__(self, dist):
-        # type: (pkg_resources.Distribution) -> None
+    def __init__(self, dist: pkg_resources.Distribution) -> None:
         self._dist = dist
 
     @classmethod
-    def from_wheel(cls, path, name):
-        # type: (str, str) -> Distribution
-        with zipfile.ZipFile(path, allowZip64=True) as zf:
-            dist = pkg_resources_distribution_for_wheel(zf, name, path)
+    def from_directory(cls, directory: str) -> BaseDistribution:
+        dist_dir = directory.rstrip(os.sep)
+
+        # Build a PathMetadata object, from path to metadata. :wink:
+        base_dir, dist_dir_name = os.path.split(dist_dir)
+        metadata = pkg_resources.PathMetadata(base_dir, dist_dir)
+
+        # Determine the correct Distribution object type.
+        if dist_dir.endswith(".egg-info"):
+            dist_cls = pkg_resources.Distribution
+            dist_name = os.path.splitext(dist_dir_name)[0]
+        else:
+            assert dist_dir.endswith(".dist-info")
+            dist_cls = pkg_resources.DistInfoDistribution
+            dist_name = os.path.splitext(dist_dir_name)[0].split("-")[0]
+
+        dist = dist_cls(base_dir, project_name=dist_name, metadata=metadata)
+        return cls(dist)
+
+    @classmethod
+    def from_wheel(cls, wheel: Wheel, name: str) -> BaseDistribution:
+        try:
+            with wheel.as_zipfile() as zf:
+                info_dir, _ = parse_wheel(zf, name)
+                metadata_text = {
+                    path.split("/", 1)[-1]: read_wheel_metadata_file(zf, path)
+                    for path in zf.namelist()
+                    if path.startswith(f"{info_dir}/")
+                }
+        except zipfile.BadZipFile as e:
+            raise InvalidWheel(wheel.location, name) from e
+        except UnsupportedWheel as e:
+            raise UnsupportedWheel(f"{name} has an invalid wheel, {e}")
+        dist = pkg_resources.DistInfoDistribution(
+            location=wheel.location,
+            metadata=WheelMetadata(metadata_text, wheel.location),
+            project_name=name,
+        )
         return cls(dist)
 
     @property
-    def location(self):
-        # type: () -> Optional[str]
+    def location(self) -> Optional[str]:
         return self._dist.location
 
     @property
-    def metadata_version(self):
-        # type: () -> Optional[str]
-        for line in self._dist.get_metadata_lines(self._dist.PKG_INFO):
-            if line.lower().startswith("metadata-version:"):
-                return line.split(":", 1)[-1].strip()
-        return None
+    def installed_location(self) -> Optional[str]:
+        egg_link = egg_link_path_from_location(self.raw_name)
+        if egg_link:
+            location = egg_link
+        elif self.location:
+            location = self.location
+        else:
+            return None
+        return normalize_path(location)
 
     @property
-    def canonical_name(self):
-        # type: () -> str
+    def info_location(self) -> Optional[str]:
+        return self._dist.egg_info
+
+    @property
+    def installed_by_distutils(self) -> bool:
+        # A distutils-installed distribution is provided by FileMetadata. This
+        # provider has a "path" attribute not present anywhere else. Not the
+        # best introspection logic, but pip has been doing this for a long time.
+        try:
+            return bool(self._dist._provider.path)
+        except AttributeError:
+            return False
+
+    @property
+    def canonical_name(self) -> NormalizedName:
         return canonicalize_name(self._dist.project_name)
 
     @property
-    def version(self):
-        # type: () -> DistributionVersion
+    def version(self) -> DistributionVersion:
         return parse_version(self._dist.version)
 
-    @property
-    def installer(self):
-        # type: () -> str
-        return get_installer(self._dist)
+    def is_file(self, path: InfoPath) -> bool:
+        return self._dist.has_metadata(str(path))
+
+    def iter_distutils_script_names(self) -> Iterator[str]:
+        yield from self._dist.metadata_listdir("scripts")
+
+    def read_text(self, path: InfoPath) -> str:
+        name = str(path)
+        if not self._dist.has_metadata(name):
+            raise FileNotFoundError(name)
+        content = self._dist.get_metadata(name)
+        if content is None:
+            raise NoneMetadataError(self, name)
+        return content
+
+    def iter_entry_points(self) -> Iterable[BaseEntryPoint]:
+        for group, entries in self._dist.get_entry_map().items():
+            for name, entry_point in entries.items():
+                name, _, value = str(entry_point).partition("=")
+                yield EntryPoint(name=name.strip(), value=value.strip(), group=group)
 
     @property
-    def editable(self):
-        # type: () -> bool
-        return misc.dist_is_editable(self._dist)
+    def metadata(self) -> email.message.Message:
+        """
+        :raises NoneMetadataError: if the distribution reports `has_metadata()`
+            True but `get_metadata()` returns None.
+        """
+        if isinstance(self._dist, pkg_resources.DistInfoDistribution):
+            metadata_name = "METADATA"
+        else:
+            metadata_name = "PKG-INFO"
+        try:
+            metadata = self.read_text(metadata_name)
+        except FileNotFoundError:
+            if self.location:
+                displaying_path = display_path(self.location)
+            else:
+                displaying_path = repr(self.location)
+            logger.warning("No metadata found in %s", displaying_path)
+            metadata = ""
+        feed_parser = email.parser.FeedParser()
+        feed_parser.feed(metadata)
+        return feed_parser.close()
 
-    @property
-    def local(self):
-        # type: () -> bool
-        return misc.dist_is_local(self._dist)
+    def iter_dependencies(self, extras: Collection[str] = ()) -> Iterable[Requirement]:
+        if extras:  # pkg_resources raises on invalid extras, so we sanitize.
+            extras = frozenset(extras).intersection(self._dist.extras)
+        return self._dist.requires(extras)
 
-    @property
-    def in_usersite(self):
-        # type: () -> bool
-        return misc.dist_in_usersite(self._dist)
+    def iter_provided_extras(self) -> Iterable[str]:
+        return self._dist.extras
 
 
 class Environment(BaseEnvironment):
-    def __init__(self, ws):
-        # type: (pkg_resources.WorkingSet) -> None
+    def __init__(self, ws: pkg_resources.WorkingSet) -> None:
         self._ws = ws
 
     @classmethod
-    def default(cls):
-        # type: () -> BaseEnvironment
+    def default(cls) -> BaseEnvironment:
         return cls(pkg_resources.working_set)
 
     @classmethod
-    def from_paths(cls, paths):
-        # type: (Optional[List[str]]) -> BaseEnvironment
+    def from_paths(cls, paths: Optional[List[str]]) -> BaseEnvironment:
         return cls(pkg_resources.WorkingSet(paths))
 
-    def _search_distribution(self, name):
-        # type: (str) -> Optional[BaseDistribution]
+    def _iter_distributions(self) -> Iterator[BaseDistribution]:
+        for dist in self._ws:
+            yield Distribution(dist)
+
+    def _search_distribution(self, name: str) -> Optional[BaseDistribution]:
         """Find a distribution matching the ``name`` in the environment.
 
         This searches from *all* distributions available in the environment, to
         match the behavior of ``pkg_resources.get_distribution()``.
         """
         canonical_name = canonicalize_name(name)
-        for dist in self.iter_distributions():
+        for dist in self.iter_all_distributions():
             if dist.canonical_name == canonical_name:
                 return dist
         return None
 
-    def get_distribution(self, name):
-        # type: (str) -> Optional[BaseDistribution]
-
+    def get_distribution(self, name: str) -> Optional[BaseDistribution]:
         # Search the distribution by looking through the working set.
         dist = self._search_distribution(name)
         if dist:
@@ -119,8 +252,3 @@ class Environment(BaseEnvironment):
         except pkg_resources.DistributionNotFound:
             return None
         return self._search_distribution(name)
-
-    def _iter_distributions(self):
-        # type: () -> Iterator[BaseDistribution]
-        for dist in self._ws:
-            yield Distribution(dist)

venv/Lib/site-packages/pip/_internal/models/candidate.py

@@ -5,30 +5,30 @@ from pip._internal.utils.models import KeyBasedCompareMixin
 
 
 class InstallationCandidate(KeyBasedCompareMixin):
-    """Represents a potential "candidate" for installation.
-    """
+    """Represents a potential "candidate" for installation."""
 
     __slots__ = ["name", "version", "link"]
 
-    def __init__(self, name, version, link):
-        # type: (str, str, Link) -> None
+    def __init__(self, name: str, version: str, link: Link) -> None:
         self.name = name
         self.version = parse_version(version)
         self.link = link
 
         super().__init__(
             key=(self.name, self.version, self.link),
-            defining_class=InstallationCandidate
+            defining_class=InstallationCandidate,
         )
 
-    def __repr__(self):
-        # type: () -> str
+    def __repr__(self) -> str:
         return "<InstallationCandidate({!r}, {!r}, {!r})>".format(
-            self.name, self.version, self.link,
+            self.name,
+            self.version,
+            self.link,
         )
 
-    def __str__(self):
-        # type: () -> str
-        return '{!r} candidate (version {} at {})'.format(
-            self.name, self.version, self.link,
+    def __str__(self) -> str:
+        return "{!r} candidate (version {} at {})".format(
+            self.name,
+            self.version,
+            self.link,
         )

venv/Lib/site-packages/pip/_internal/models/direct_url.py

@@ -22,8 +22,9 @@ class DirectUrlValidationError(Exception):
     pass
 
 
-def _get(d, expected_type, key, default=None):
-    # type: (Dict[str, Any], Type[T], str, Optional[T]) -> Optional[T]
+def _get(
+    d: Dict[str, Any], expected_type: Type[T], key: str, default: Optional[T] = None
+) -> Optional[T]:
     """Get value from dictionary and verify expected type."""
     if key not in d:
         return default
@@ -37,16 +38,16 @@ def _get(d, expected_type, key, default=None):
     return value
 
 
-def _get_required(d, expected_type, key, default=None):
-    # type: (Dict[str, Any], Type[T], str, Optional[T]) -> T
+def _get_required(
+    d: Dict[str, Any], expected_type: Type[T], key: str, default: Optional[T] = None
+) -> T:
     value = _get(d, expected_type, key, default)
     if value is None:
         raise DirectUrlValidationError(f"{key} must have a value")
     return value
 
 
-def _exactly_one_of(infos):
-    # type: (Iterable[Optional[InfoType]]) -> InfoType
+def _exactly_one_of(infos: Iterable[Optional["InfoType"]]) -> "InfoType":
     infos = [info for info in infos if info is not None]
     if not infos:
         raise DirectUrlValidationError(
@@ -60,8 +61,7 @@ def _exactly_one_of(infos):
     return infos[0]
 
 
-def _filter_none(**kwargs):
-    # type: (Any) -> Dict[str, Any]
+def _filter_none(**kwargs: Any) -> Dict[str, Any]:
     """Make dict excluding None values."""
     return {k: v for k, v in kwargs.items() if v is not None}
 
@@ -71,39 +71,29 @@ class VcsInfo:
 
     def __init__(
         self,
-        vcs,  # type: str
-        commit_id,  # type: str
-        requested_revision=None,  # type: Optional[str]
-        resolved_revision=None,  # type: Optional[str]
-        resolved_revision_type=None,  # type: Optional[str]
-    ):
+        vcs: str,
+        commit_id: str,
+        requested_revision: Optional[str] = None,
+    ) -> None:
         self.vcs = vcs
         self.requested_revision = requested_revision
         self.commit_id = commit_id
-        self.resolved_revision = resolved_revision
-        self.resolved_revision_type = resolved_revision_type
 
     @classmethod
-    def _from_dict(cls, d):
-        # type: (Optional[Dict[str, Any]]) -> Optional[VcsInfo]
+    def _from_dict(cls, d: Optional[Dict[str, Any]]) -> Optional["VcsInfo"]:
         if d is None:
             return None
         return cls(
             vcs=_get_required(d, str, "vcs"),
             commit_id=_get_required(d, str, "commit_id"),
             requested_revision=_get(d, str, "requested_revision"),
-            resolved_revision=_get(d, str, "resolved_revision"),
-            resolved_revision_type=_get(d, str, "resolved_revision_type"),
         )
 
-    def _to_dict(self):
-        # type: () -> Dict[str, Any]
+    def _to_dict(self) -> Dict[str, Any]:
         return _filter_none(
             vcs=self.vcs,
             requested_revision=self.requested_revision,
             commit_id=self.commit_id,
-            resolved_revision=self.resolved_revision,
-            resolved_revision_type=self.resolved_revision_type,
         )
 
 
@@ -112,19 +102,17 @@ class ArchiveInfo:
 
     def __init__(
         self,
-        hash=None,  # type: Optional[str]
-    ):
+        hash: Optional[str] = None,
+    ) -> None:
         self.hash = hash
 
     @classmethod
-    def _from_dict(cls, d):
-        # type: (Optional[Dict[str, Any]]) -> Optional[ArchiveInfo]
+    def _from_dict(cls, d: Optional[Dict[str, Any]]) -> Optional["ArchiveInfo"]:
         if d is None:
             return None
         return cls(hash=_get(d, str, "hash"))
 
-    def _to_dict(self):
-        # type: () -> Dict[str, Any]
+    def _to_dict(self) -> Dict[str, Any]:
         return _filter_none(hash=self.hash)
 
 
@@ -133,21 +121,17 @@ class DirInfo:
 
     def __init__(
         self,
-        editable=False,  # type: bool
-    ):
+        editable: bool = False,
+    ) -> None:
         self.editable = editable
 
     @classmethod
-    def _from_dict(cls, d):
-        # type: (Optional[Dict[str, Any]]) -> Optional[DirInfo]
+    def _from_dict(cls, d: Optional[Dict[str, Any]]) -> Optional["DirInfo"]:
         if d is None:
             return None
-        return cls(
-            editable=_get_required(d, bool, "editable", default=False)
-        )
+        return cls(editable=_get_required(d, bool, "editable", default=False))
 
-    def _to_dict(self):
-        # type: () -> Dict[str, Any]
+    def _to_dict(self) -> Dict[str, Any]:
         return _filter_none(editable=self.editable or None)
 
 
@@ -155,26 +139,24 @@ InfoType = Union[ArchiveInfo, DirInfo, VcsInfo]
 
 
 class DirectUrl:
-
     def __init__(
         self,
-        url,  # type: str
-        info,  # type: InfoType
-        subdirectory=None,  # type: Optional[str]
-    ):
+        url: str,
+        info: InfoType,
+        subdirectory: Optional[str] = None,
+    ) -> None:
         self.url = url
         self.info = info
         self.subdirectory = subdirectory
 
-    def _remove_auth_from_netloc(self, netloc):
-        # type: (str) -> str
+    def _remove_auth_from_netloc(self, netloc: str) -> str:
         if "@" not in netloc:
             return netloc
         user_pass, netloc_no_user_pass = netloc.split("@", 1)
         if (
-            isinstance(self.info, VcsInfo) and
-            self.info.vcs == "git" and
-            user_pass == "git"
+            isinstance(self.info, VcsInfo)
+            and self.info.vcs == "git"
+            and user_pass == "git"
         ):
             return netloc
         if ENV_VAR_RE.match(user_pass):
@@ -182,8 +164,7 @@ class DirectUrl:
         return netloc_no_user_pass
 
     @property
-    def redacted_url(self):
-        # type: () -> str
+    def redacted_url(self) -> str:
         """url with user:password part removed unless it is formed with
         environment variables as specified in PEP 610, or it is ``git``
         in the case of a git URL.
@@ -195,13 +176,11 @@ class DirectUrl:
         )
         return surl
 
-    def validate(self):
-        # type: () -> None
+    def validate(self) -> None:
         self.from_dict(self.to_dict())
 
     @classmethod
-    def from_dict(cls, d):
-        # type: (Dict[str, Any]) -> DirectUrl
+    def from_dict(cls, d: Dict[str, Any]) -> "DirectUrl":
         return DirectUrl(
             url=_get_required(d, str, "url"),
             subdirectory=_get(d, str, "subdirectory"),
@@ -214,8 +193,7 @@ class DirectUrl:
             ),
         )
 
-    def to_dict(self):
-        # type: () -> Dict[str, Any]
+    def to_dict(self) -> Dict[str, Any]:
         res = _filter_none(
             url=self.redacted_url,
             subdirectory=self.subdirectory,
@@ -224,10 +202,11 @@ class DirectUrl:
         return res
 
     @classmethod
-    def from_json(cls, s):
-        # type: (str) -> DirectUrl
+    def from_json(cls, s: str) -> "DirectUrl":
         return cls.from_dict(json.loads(s))
 
-    def to_json(self):
-        # type: () -> str
+    def to_json(self) -> str:
         return json.dumps(self.to_dict(), sort_keys=True)
+
+    def is_local_editable(self) -> bool:
+        return isinstance(self.info, DirInfo) and self.info.editable

venv/Lib/site-packages/pip/_internal/models/format_control.py

@@ -6,13 +6,15 @@ from pip._internal.exceptions import CommandError
 
 
 class FormatControl:
-    """Helper for managing formats from which a package can be installed.
-    """
+    """Helper for managing formats from which a package can be installed."""
 
     __slots__ = ["no_binary", "only_binary"]
 
-    def __init__(self, no_binary=None, only_binary=None):
-        # type: (Optional[Set[str]], Optional[Set[str]]) -> None
+    def __init__(
+        self,
+        no_binary: Optional[Set[str]] = None,
+        only_binary: Optional[Set[str]] = None,
+    ) -> None:
         if no_binary is None:
             no_binary = set()
         if only_binary is None:
@@ -21,66 +23,58 @@ class FormatControl:
         self.no_binary = no_binary
         self.only_binary = only_binary
 
-    def __eq__(self, other):
-        # type: (object) -> bool
+    def __eq__(self, other: object) -> bool:
         if not isinstance(other, self.__class__):
             return NotImplemented
 
         if self.__slots__ != other.__slots__:
             return False
 
-        return all(
-            getattr(self, k) == getattr(other, k)
-            for k in self.__slots__
-        )
+        return all(getattr(self, k) == getattr(other, k) for k in self.__slots__)
 
-    def __repr__(self):
-        # type: () -> str
+    def __repr__(self) -> str:
         return "{}({}, {})".format(
-            self.__class__.__name__,
-            self.no_binary,
-            self.only_binary
+            self.__class__.__name__, self.no_binary, self.only_binary
         )
 
     @staticmethod
-    def handle_mutual_excludes(value, target, other):
-        # type: (str, Set[str], Set[str]) -> None
-        if value.startswith('-'):
+    def handle_mutual_excludes(value: str, target: Set[str], other: Set[str]) -> None:
+        if value.startswith("-"):
             raise CommandError(
                 "--no-binary / --only-binary option requires 1 argument."
             )
-        new = value.split(',')
-        while ':all:' in new:
+        new = value.split(",")
+        while ":all:" in new:
             other.clear()
             target.clear()
-            target.add(':all:')
-            del new[:new.index(':all:') + 1]
+            target.add(":all:")
+            del new[: new.index(":all:") + 1]
             # Without a none, we want to discard everything as :all: covers it
-            if ':none:' not in new:
+            if ":none:" not in new:
                 return
         for name in new:
-            if name == ':none:':
+            if name == ":none:":
                 target.clear()
                 continue
             name = canonicalize_name(name)
             other.discard(name)
             target.add(name)
 
-    def get_allowed_formats(self, canonical_name):
-        # type: (str) -> FrozenSet[str]
+    def get_allowed_formats(self, canonical_name: str) -> FrozenSet[str]:
         result = {"binary", "source"}
         if canonical_name in self.only_binary:
-            result.discard('source')
+            result.discard("source")
         elif canonical_name in self.no_binary:
-            result.discard('binary')
-        elif ':all:' in self.only_binary:
-            result.discard('source')
-        elif ':all:' in self.no_binary:
-            result.discard('binary')
+            result.discard("binary")
+        elif ":all:" in self.only_binary:
+            result.discard("source")
+        elif ":all:" in self.no_binary:
+            result.discard("binary")
         return frozenset(result)
 
-    def disallow_binaries(self):
-        # type: () -> None
+    def disallow_binaries(self) -> None:
         self.handle_mutual_excludes(
-            ':all:', self.no_binary, self.only_binary,
+            ":all:",
+            self.no_binary,
+            self.only_binary,
         )

venv/Lib/site-packages/pip/_internal/models/index.py

@@ -2,33 +2,27 @@ import urllib.parse
 
 
 class PackageIndex:
-    """Represents a Package Index and provides easier access to endpoints
-    """
+    """Represents a Package Index and provides easier access to endpoints"""
 
-    __slots__ = ['url', 'netloc', 'simple_url', 'pypi_url',
-                 'file_storage_domain']
+    __slots__ = ["url", "netloc", "simple_url", "pypi_url", "file_storage_domain"]
 
-    def __init__(self, url, file_storage_domain):
-        # type: (str, str) -> None
+    def __init__(self, url: str, file_storage_domain: str) -> None:
         super().__init__()
         self.url = url
         self.netloc = urllib.parse.urlsplit(url).netloc
-        self.simple_url = self._url_for_path('simple')
-        self.pypi_url = self._url_for_path('pypi')
+        self.simple_url = self._url_for_path("simple")
+        self.pypi_url = self._url_for_path("pypi")
 
         # This is part of a temporary hack used to block installs of PyPI
         # packages which depend on external urls only necessary until PyPI can
         # block such packages themselves
         self.file_storage_domain = file_storage_domain
 
-    def _url_for_path(self, path):
-        # type: (str) -> str
+    def _url_for_path(self, path: str) -> str:
         return urllib.parse.urljoin(self.url, path)
 
 
-PyPI = PackageIndex(
-    'https://pypi.org/', file_storage_domain='files.pythonhosted.org'
-)
+PyPI = PackageIndex("https://pypi.org/", file_storage_domain="files.pythonhosted.org")
 TestPyPI = PackageIndex(
-    'https://test.pypi.org/', file_storage_domain='test-files.pythonhosted.org'
+    "https://test.pypi.org/", file_storage_domain="test-files.pythonhosted.org"
 )

venv/Lib/site-packages/pip/_internal/models/link.py

@@ -1,8 +1,10 @@
+import functools
+import logging
 import os
 import posixpath
 import re
 import urllib.parse
-from typing import TYPE_CHECKING, Optional, Tuple, Union
+from typing import TYPE_CHECKING, Dict, List, NamedTuple, Optional, Tuple, Union
 
 from pip._internal.utils.filetypes import WHEEL_EXTENSION
 from pip._internal.utils.hashes import Hashes
@@ -17,10 +19,14 @@ from pip._internal.utils.urls import path_to_url, url_to_path
 if TYPE_CHECKING:
     from pip._internal.index.collector import HTMLPage
 
+logger = logging.getLogger(__name__)
+
+
+_SUPPORTED_HASHES = ("sha1", "sha224", "sha384", "sha256", "sha512", "md5")
+
 
 class Link(KeyBasedCompareMixin):
-    """Represents a parsed link from a Package Index's simple URL
-    """
+    """Represents a parsed link from a Package Index's simple URL"""
 
     __slots__ = [
         "_parsed_url",
@@ -33,13 +39,12 @@ class Link(KeyBasedCompareMixin):
 
     def __init__(
         self,
-        url,                   # type: str
-        comes_from=None,       # type: Optional[Union[str, HTMLPage]]
-        requires_python=None,  # type: Optional[str]
-        yanked_reason=None,    # type: Optional[str]
-        cache_link_parsing=True,  # type: bool
-    ):
-        # type: (...) -> None
+        url: str,
+        comes_from: Optional[Union[str, "HTMLPage"]] = None,
+        requires_python: Optional[str] = None,
+        yanked_reason: Optional[str] = None,
+        cache_link_parsing: bool = True,
+    ) -> None:
         """
         :param url: url of the resource pointed to (href of the link)
         :param comes_from: instance of HTMLPage where the link was found,
@@ -62,7 +67,7 @@ class Link(KeyBasedCompareMixin):
         """
 
         # url can be a UNC windows share
-        if url.startswith('\\\\'):
+        if url.startswith("\\\\"):
             url = path_to_url(url)
 
         self._parsed_url = urllib.parse.urlsplit(url)
@@ -78,31 +83,28 @@ class Link(KeyBasedCompareMixin):
 
         self.cache_link_parsing = cache_link_parsing
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         if self.requires_python:
-            rp = f' (requires-python:{self.requires_python})'
+            rp = f" (requires-python:{self.requires_python})"
         else:
-            rp = ''
+            rp = ""
         if self.comes_from:
-            return '{} (from {}){}'.format(
-                redact_auth_from_url(self._url), self.comes_from, rp)
+            return "{} (from {}){}".format(
+                redact_auth_from_url(self._url), self.comes_from, rp
+            )
         else:
             return redact_auth_from_url(str(self._url))
 
-    def __repr__(self):
-        # type: () -> str
-        return f'<Link {self}>'
+    def __repr__(self) -> str:
+        return f"<Link {self}>"
 
     @property
-    def url(self):
-        # type: () -> str
+    def url(self) -> str:
         return self._url
 
     @property
-    def filename(self):
-        # type: () -> str
-        path = self.path.rstrip('/')
+    def filename(self) -> str:
+        path = self.path.rstrip("/")
         name = posixpath.basename(path)
         if not name:
             # Make sure we don't leak auth information if the netloc
@@ -111,125 +113,106 @@ class Link(KeyBasedCompareMixin):
             return netloc
 
         name = urllib.parse.unquote(name)
-        assert name, f'URL {self._url!r} produced no filename'
+        assert name, f"URL {self._url!r} produced no filename"
         return name
 
     @property
-    def file_path(self):
-        # type: () -> str
+    def file_path(self) -> str:
         return url_to_path(self.url)
 
     @property
-    def scheme(self):
-        # type: () -> str
+    def scheme(self) -> str:
         return self._parsed_url.scheme
 
     @property
-    def netloc(self):
-        # type: () -> str
+    def netloc(self) -> str:
         """
         This can contain auth information.
         """
         return self._parsed_url.netloc
 
     @property
-    def path(self):
-        # type: () -> str
+    def path(self) -> str:
         return urllib.parse.unquote(self._parsed_url.path)
 
-    def splitext(self):
-        # type: () -> Tuple[str, str]
-        return splitext(posixpath.basename(self.path.rstrip('/')))
+    def splitext(self) -> Tuple[str, str]:
+        return splitext(posixpath.basename(self.path.rstrip("/")))
 
     @property
-    def ext(self):
-        # type: () -> str
+    def ext(self) -> str:
         return self.splitext()[1]
 
     @property
-    def url_without_fragment(self):
-        # type: () -> str
+    def url_without_fragment(self) -> str:
         scheme, netloc, path, query, fragment = self._parsed_url
-        return urllib.parse.urlunsplit((scheme, netloc, path, query, None))
+        return urllib.parse.urlunsplit((scheme, netloc, path, query, ""))
 
-    _egg_fragment_re = re.compile(r'[#&]egg=([^&]*)')
+    _egg_fragment_re = re.compile(r"[#&]egg=([^&]*)")
 
     @property
-    def egg_fragment(self):
-        # type: () -> Optional[str]
+    def egg_fragment(self) -> Optional[str]:
         match = self._egg_fragment_re.search(self._url)
         if not match:
             return None
         return match.group(1)
 
-    _subdirectory_fragment_re = re.compile(r'[#&]subdirectory=([^&]*)')
+    _subdirectory_fragment_re = re.compile(r"[#&]subdirectory=([^&]*)")
 
     @property
-    def subdirectory_fragment(self):
-        # type: () -> Optional[str]
+    def subdirectory_fragment(self) -> Optional[str]:
         match = self._subdirectory_fragment_re.search(self._url)
         if not match:
             return None
         return match.group(1)
 
     _hash_re = re.compile(
-        r'(sha1|sha224|sha384|sha256|sha512|md5)=([a-f0-9]+)'
+        r"({choices})=([a-f0-9]+)".format(choices="|".join(_SUPPORTED_HASHES))
     )
 
     @property
-    def hash(self):
-        # type: () -> Optional[str]
+    def hash(self) -> Optional[str]:
         match = self._hash_re.search(self._url)
         if match:
             return match.group(2)
         return None
 
     @property
-    def hash_name(self):
-        # type: () -> Optional[str]
+    def hash_name(self) -> Optional[str]:
         match = self._hash_re.search(self._url)
         if match:
             return match.group(1)
         return None
 
     @property
-    def show_url(self):
-        # type: () -> str
-        return posixpath.basename(self._url.split('#', 1)[0].split('?', 1)[0])
+    def show_url(self) -> str:
+        return posixpath.basename(self._url.split("#", 1)[0].split("?", 1)[0])
 
     @property
-    def is_file(self):
-        # type: () -> bool
-        return self.scheme == 'file'
+    def is_file(self) -> bool:
+        return self.scheme == "file"
 
-    def is_existing_dir(self):
-        # type: () -> bool
+    def is_existing_dir(self) -> bool:
         return self.is_file and os.path.isdir(self.file_path)
 
     @property
-    def is_wheel(self):
-        # type: () -> bool
+    def is_wheel(self) -> bool:
         return self.ext == WHEEL_EXTENSION
 
     @property
-    def is_vcs(self):
-        # type: () -> bool
+    def is_vcs(self) -> bool:
         from pip._internal.vcs import vcs
 
         return self.scheme in vcs.all_schemes
 
     @property
-    def is_yanked(self):
-        # type: () -> bool
+    def is_yanked(self) -> bool:
         return self.yanked_reason is not None
 
     @property
-    def has_hash(self):
-        # type: () -> bool
+    def has_hash(self) -> bool:
         return self.hash_name is not None
 
-    def is_hash_allowed(self, hashes):
-        # type: (Optional[Hashes]) -> bool
+    def is_hash_allowed(self, hashes: Optional[Hashes]) -> bool:
         """
         Return True if the link has a hash and it is allowed.
         """
@@ -242,7 +225,64 @@ class Link(KeyBasedCompareMixin):
         return hashes.is_hash_allowed(self.hash_name, hex_digest=self.hash)
 
 
-# TODO: Relax this comparison logic to ignore, for example, fragments.
-def links_equivalent(link1, link2):
-    # type: (Link, Link) -> bool
-    return link1 == link2
+class _CleanResult(NamedTuple):
+    """Convert link for equivalency check.
+
+    This is used in the resolver to check whether two URL-specified requirements
+    likely point to the same distribution and can be considered equivalent. This
+    equivalency logic avoids comparing URLs literally, which can be too strict
+    (e.g. "a=1&b=2" vs "b=2&a=1") and produce conflicts unexpecting to users.
+
+    Currently this does three things:
+
+    1. Drop the basic auth part. This is technically wrong since a server can
+       serve different content based on auth, but if it does that, it is even
+       impossible to guarantee two URLs without auth are equivalent, since
+       the user can input different auth information when prompted. So the
+       practical solution is to assume the auth doesn't affect the response.
+    2. Parse the query to avoid the ordering issue. Note that ordering under the
+       same key in the query are NOT cleaned; i.e. "a=1&a=2" and "a=2&a=1" are
+       still considered different.
+    3. Explicitly drop most of the fragment part, except ``subdirectory=`` and
+       hash values, since it should have no impact the downloaded content. Note
+       that this drops the "egg=" part historically used to denote the requested
+       project (and extras), which is wrong in the strictest sense, but too many
+       people are supplying it inconsistently to cause superfluous resolution
+       conflicts, so we choose to also ignore them.
+    """
+
+    parsed: urllib.parse.SplitResult
+    query: Dict[str, List[str]]
+    subdirectory: str
+    hashes: Dict[str, str]
+
+
+def _clean_link(link: Link) -> _CleanResult:
+    parsed = link._parsed_url
+    netloc = parsed.netloc.rsplit("@", 1)[-1]
+    # According to RFC 8089, an empty host in file: means localhost.
+    if parsed.scheme == "file" and not netloc:
+        netloc = "localhost"
+    fragment = urllib.parse.parse_qs(parsed.fragment)
+    if "egg" in fragment:
+        logger.debug("Ignoring egg= fragment in %s", link)
+    try:
+        # If there are multiple subdirectory values, use the first one.
+        # This matches the behavior of Link.subdirectory_fragment.
+        subdirectory = fragment["subdirectory"][0]
+    except (IndexError, KeyError):
+        subdirectory = ""
+    # If there are multiple hash values under the same algorithm, use the
+    # first one. This matches the behavior of Link.hash_value.
+    hashes = {k: fragment[k][0] for k in _SUPPORTED_HASHES if k in fragment}
+    return _CleanResult(
+        parsed=parsed._replace(netloc=netloc, query="", fragment=""),
+        query=urllib.parse.parse_qs(parsed.query),
+        subdirectory=subdirectory,
+        hashes=hashes,
+    )
+
+
+@functools.lru_cache(maxsize=None)
+def links_equivalent(link1: Link, link2: Link) -> bool:
+    return _clean_link(link1) == _clean_link(link2)

venv/Lib/site-packages/pip/_internal/models/scheme.py

@@ -6,7 +6,7 @@ https://docs.python.org/3/install/index.html#alternate-installation.
 """
 
 
-SCHEME_KEYS = ['platlib', 'purelib', 'headers', 'scripts', 'data']
+SCHEME_KEYS = ["platlib", "purelib", "headers", "scripts", "data"]
 
 
 class Scheme:
@@ -18,12 +18,12 @@ class Scheme:
 
     def __init__(
         self,
-        platlib,  # type: str
-        purelib,  # type: str
-        headers,  # type: str
-        scripts,  # type: str
-        data,  # type: str
-    ):
+        platlib: str,
+        purelib: str,
+        headers: str,
+        scripts: str,
+        data: str,
+    ) -> None:
         self.platlib = platlib
         self.purelib = purelib
         self.headers = headers

venv/Lib/site-packages/pip/_internal/models/search_scope.py

@@ -25,10 +25,9 @@ class SearchScope:
     @classmethod
     def create(
         cls,
-        find_links,  # type: List[str]
-        index_urls,  # type: List[str]
-    ):
-        # type: (...) -> SearchScope
+        find_links: List[str],
+        index_urls: List[str],
+    ) -> "SearchScope":
         """
         Create a SearchScope object after normalizing the `find_links`.
         """
@@ -37,9 +36,9 @@ class SearchScope:
         # it and if it exists, use the normalized version.
         # This is deliberately conservative - it might be fine just to
         # blindly normalize anything starting with a ~...
-        built_find_links = []  # type: List[str]
+        built_find_links: List[str] = []
         for link in find_links:
-            if link.startswith('~'):
+            if link.startswith("~"):
                 new_link = normalize_path(link)
                 if os.path.exists(new_link):
                     link = new_link
@@ -50,11 +49,11 @@ class SearchScope:
         if not has_tls():
             for link in itertools.chain(index_urls, built_find_links):
                 parsed = urllib.parse.urlparse(link)
-                if parsed.scheme == 'https':
+                if parsed.scheme == "https":
                     logger.warning(
-                        'pip is configured with locations that require '
-                        'TLS/SSL, however the ssl module in Python is not '
-                        'available.'
+                        "pip is configured with locations that require "
+                        "TLS/SSL, however the ssl module in Python is not "
+                        "available."
                     )
                     break
 
@@ -65,15 +64,13 @@ class SearchScope:
 
     def __init__(
         self,
-        find_links,  # type: List[str]
-        index_urls,  # type: List[str]
-    ):
-        # type: (...) -> None
+        find_links: List[str],
+        index_urls: List[str],
+    ) -> None:
         self.find_links = find_links
         self.index_urls = index_urls
 
-    def get_formatted_locations(self):
-        # type: () -> str
+    def get_formatted_locations(self) -> str:
         lines = []
         redacted_index_urls = []
         if self.index_urls and self.index_urls != [PyPI.simple_url]:
@@ -91,41 +88,42 @@ class SearchScope:
                 # exceptions for malformed URLs
                 if not purl.scheme and not purl.netloc:
                     logger.warning(
-                        'The index url "%s" seems invalid, '
-                        'please provide a scheme.', redacted_index_url)
+                        'The index url "%s" seems invalid, please provide a scheme.',
+                        redacted_index_url,
+                    )
 
                 redacted_index_urls.append(redacted_index_url)
 
-            lines.append('Looking in indexes: {}'.format(
-                ', '.join(redacted_index_urls)))
+            lines.append(
+                "Looking in indexes: {}".format(", ".join(redacted_index_urls))
+            )
 
         if self.find_links:
             lines.append(
-                'Looking in links: {}'.format(', '.join(
-                    redact_auth_from_url(url) for url in self.find_links))
+                "Looking in links: {}".format(
+                    ", ".join(redact_auth_from_url(url) for url in self.find_links)
+                )
             )
-        return '\n'.join(lines)
+        return "\n".join(lines)
 
-    def get_index_urls_locations(self, project_name):
-        # type: (str) -> List[str]
+    def get_index_urls_locations(self, project_name: str) -> List[str]:
         """Returns the locations found via self.index_urls
 
         Checks the url_name on the main (first in the list) index and
         use this url_name to produce all locations
         """
 
-        def mkurl_pypi_url(url):
-            # type: (str) -> str
+        def mkurl_pypi_url(url: str) -> str:
             loc = posixpath.join(
-                url,
-                urllib.parse.quote(canonicalize_name(project_name)))
+                url, urllib.parse.quote(canonicalize_name(project_name))
+            )
             # For maximum compatibility with easy_install, ensure the path
             # ends in a trailing slash.  Although this isn't in the spec
             # (and PyPI can handle it without the slash) some other index
             # implementations might break if they relied on easy_install's
             # behavior.
-            if not loc.endswith('/'):
-                loc = loc + '/'
+            if not loc.endswith("/"):
+                loc = loc + "/"
             return loc
 
         return [mkurl_pypi_url(url) for url in self.index_urls]

venv/Lib/site-packages/pip/_internal/models/selection_prefs.py

@@ -9,8 +9,13 @@ class SelectionPreferences:
     and installing files.
     """
 
-    __slots__ = ['allow_yanked', 'allow_all_prereleases', 'format_control',
-                 'prefer_binary', 'ignore_requires_python']
+    __slots__ = [
+        "allow_yanked",
+        "allow_all_prereleases",
+        "format_control",
+        "prefer_binary",
+        "ignore_requires_python",
+    ]
 
     # Don't include an allow_yanked default value to make sure each call
     # site considers whether yanked releases are allowed. This also causes
@@ -18,13 +23,12 @@ class SelectionPreferences:
     # people when reading the code.
     def __init__(
         self,
-        allow_yanked,  # type: bool
-        allow_all_prereleases=False,  # type: bool
-        format_control=None,          # type: Optional[FormatControl]
-        prefer_binary=False,          # type: bool
-        ignore_requires_python=None,  # type: Optional[bool]
-    ):
-        # type: (...) -> None
+        allow_yanked: bool,
+        allow_all_prereleases: bool = False,
+        format_control: Optional[FormatControl] = None,
+        prefer_binary: bool = False,
+        ignore_requires_python: Optional[bool] = None,
+    ) -> None:
         """Create a SelectionPreferences object.
 
         :param allow_yanked: Whether files marked as yanked (in the sense

venv/Lib/site-packages/pip/_internal/models/target_python.py

@@ -26,12 +26,11 @@ class TargetPython:
 
     def __init__(
         self,
-        platforms=None,  # type: Optional[List[str]]
-        py_version_info=None,  # type: Optional[Tuple[int, ...]]
-        abis=None,  # type: Optional[List[str]]
-        implementation=None,  # type: Optional[str]
-    ):
-        # type: (...) -> None
+        platforms: Optional[List[str]] = None,
+        py_version_info: Optional[Tuple[int, ...]] = None,
+        abis: Optional[List[str]] = None,
+        implementation: Optional[str] = None,
+    ) -> None:
         """
         :param platforms: A list of strings or None. If None, searches for
             packages that are supported by the current system. Otherwise, will
@@ -54,7 +53,7 @@ class TargetPython:
         else:
             py_version_info = normalize_version_info(py_version_info)
 
-        py_version = '.'.join(map(str, py_version_info[:2]))
+        py_version = ".".join(map(str, py_version_info[:2]))
 
         self.abis = abis
         self.implementation = implementation
@@ -63,32 +62,29 @@ class TargetPython:
         self.py_version_info = py_version_info
 
         # This is used to cache the return value of get_tags().
-        self._valid_tags = None  # type: Optional[List[Tag]]
+        self._valid_tags: Optional[List[Tag]] = None
 
-    def format_given(self):
-        # type: () -> str
+    def format_given(self) -> str:
         """
         Format the given, non-None attributes for display.
         """
         display_version = None
         if self._given_py_version_info is not None:
-            display_version = '.'.join(
+            display_version = ".".join(
                 str(part) for part in self._given_py_version_info
             )
 
         key_values = [
-            ('platforms', self.platforms),
-            ('version_info', display_version),
-            ('abis', self.abis),
-            ('implementation', self.implementation),
+            ("platforms", self.platforms),
+            ("version_info", display_version),
+            ("abis", self.abis),
+            ("implementation", self.implementation),
         ]
-        return ' '.join(
-            f'{key}={value!r}' for key, value in key_values
-            if value is not None
+        return " ".join(
+            f"{key}={value!r}" for key, value in key_values if value is not None
         )
 
-    def get_tags(self):
-        # type: () -> List[Tag]
+    def get_tags(self) -> List[Tag]:
         """
         Return the supported PEP 425 tags to check wheel candidates against.
 

venv/Lib/site-packages/pip/_internal/models/wheel.py

@@ -16,42 +16,36 @@ class Wheel:
         r"""^(?P<namever>(?P<name>.+?)-(?P<ver>.*?))
         ((-(?P<build>\d[^-]*?))?-(?P<pyver>.+?)-(?P<abi>.+?)-(?P<plat>.+?)
         \.whl|\.dist-info)$""",
-        re.VERBOSE
+        re.VERBOSE,
     )
 
-    def __init__(self, filename):
-        # type: (str) -> None
+    def __init__(self, filename: str) -> None:
         """
         :raises InvalidWheelFilename: when the filename is invalid for a wheel
         """
         wheel_info = self.wheel_file_re.match(filename)
         if not wheel_info:
-            raise InvalidWheelFilename(
-                f"{filename} is not a valid wheel filename."
-            )
+            raise InvalidWheelFilename(f"{filename} is not a valid wheel filename.")
         self.filename = filename
-        self.name = wheel_info.group('name').replace('_', '-')
+        self.name = wheel_info.group("name").replace("_", "-")
         # we'll assume "_" means "-" due to wheel naming scheme
         # (https://github.com/pypa/pip/issues/1150)
-        self.version = wheel_info.group('ver').replace('_', '-')
-        self.build_tag = wheel_info.group('build')
-        self.pyversions = wheel_info.group('pyver').split('.')
-        self.abis = wheel_info.group('abi').split('.')
-        self.plats = wheel_info.group('plat').split('.')
+        self.version = wheel_info.group("ver").replace("_", "-")
+        self.build_tag = wheel_info.group("build")
+        self.pyversions = wheel_info.group("pyver").split(".")
+        self.abis = wheel_info.group("abi").split(".")
+        self.plats = wheel_info.group("plat").split(".")
 
         # All the tag combinations from this file
         self.file_tags = {
-            Tag(x, y, z) for x in self.pyversions
-            for y in self.abis for z in self.plats
+            Tag(x, y, z) for x in self.pyversions for y in self.abis for z in self.plats
         }
 
-    def get_formatted_file_tags(self):
-        # type: () -> List[str]
+    def get_formatted_file_tags(self) -> List[str]:
         """Return the wheel's tags as a sorted list of strings."""
         return sorted(str(tag) for tag in self.file_tags)
 
-    def support_index_min(self, tags):
-        # type: (List[Tag]) -> int
+    def support_index_min(self, tags: List[Tag]) -> int:
         """Return the lowest index that one of the wheel's file_tag combinations
         achieves in the given list of supported tags.
 
@@ -66,10 +60,11 @@ class Wheel:
         """
         return min(tags.index(tag) for tag in self.file_tags if tag in tags)
 
-    def find_most_preferred_tag(self, tags, tag_to_priority):
-        # type: (List[Tag], Dict[Tag, int]) -> int
+    def find_most_preferred_tag(
+        self, tags: List[Tag], tag_to_priority: Dict[Tag, int]
+    ) -> int:
         """Return the priority of the most preferred tag that one of the wheel's file
-        tag combinations acheives in the given list of supported tags using the given
+        tag combinations achieves in the given list of supported tags using the given
         tag_to_priority mapping, where lower priorities are more-preferred.
 
         This is used in place of support_index_min in some cases in order to avoid
@@ -86,8 +81,7 @@ class Wheel:
             tag_to_priority[tag] for tag in self.file_tags if tag in tag_to_priority
         )
 
-    def supported(self, tags):
-        # type: (Iterable[Tag]) -> bool
+    def supported(self, tags: Iterable[Tag]) -> bool:
         """Return whether the wheel is compatible with one of the given tags.
 
         :param tags: the PEP 425 tags to check the wheel against.

venv/Lib/site-packages/pip/_internal/network/auth.py

@@ -4,7 +4,6 @@ Contains interface (MultiDomainBasicAuth) and associated glue code for
 providing credentials in the context of network requests.
 """
 
-import logging
 import urllib.parse
 from typing import Any, Dict, List, Optional, Tuple
 
@@ -12,6 +11,7 @@ from pip._vendor.requests.auth import AuthBase, HTTPBasicAuth
 from pip._vendor.requests.models import Request, Response
 from pip._vendor.requests.utils import get_netrc_auth
 
+from pip._internal.utils.logging import getLogger
 from pip._internal.utils.misc import (
     ask,
     ask_input,
@@ -21,23 +21,23 @@ from pip._internal.utils.misc import (
 )
 from pip._internal.vcs.versioncontrol import AuthInfo
 
-logger = logging.getLogger(__name__)
+logger = getLogger(__name__)
 
 Credentials = Tuple[str, str, str]
 
 try:
     import keyring
 except ImportError:
-    keyring = None
+    keyring = None  # type: ignore[assignment]
 except Exception as exc:
     logger.warning(
-        "Keyring is skipped due to an exception: %s", str(exc),
+        "Keyring is skipped due to an exception: %s",
+        str(exc),
     )
-    keyring = None
+    keyring = None  # type: ignore[assignment]
 
 
-def get_keyring_auth(url, username):
-    # type: (Optional[str], Optional[str]) -> Optional[AuthInfo]
+def get_keyring_auth(url: Optional[str], username: Optional[str]) -> Optional[AuthInfo]:
     """Return the tuple auth for a given url from keyring."""
     global keyring
     if not url or not keyring:
@@ -63,28 +63,28 @@ def get_keyring_auth(url, username):
 
     except Exception as exc:
         logger.warning(
-            "Keyring is skipped due to an exception: %s", str(exc),
+            "Keyring is skipped due to an exception: %s",
+            str(exc),
         )
-        keyring = None
+        keyring = None  # type: ignore[assignment]
     return None
 
 
 class MultiDomainBasicAuth(AuthBase):
-
-    def __init__(self, prompting=True, index_urls=None):
-        # type: (bool, Optional[List[str]]) -> None
+    def __init__(
+        self, prompting: bool = True, index_urls: Optional[List[str]] = None
+    ) -> None:
         self.prompting = prompting
         self.index_urls = index_urls
-        self.passwords = {}  # type: Dict[str, AuthInfo]
+        self.passwords: Dict[str, AuthInfo] = {}
         # When the user is prompted to enter credentials and keyring is
         # available, we will offer to save them. If the user accepts,
         # this value is set to the credentials they entered. After the
         # request authenticates, the caller should call
         # ``save_credentials`` to save these.
-        self._credentials_to_save = None  # type: Optional[Credentials]
+        self._credentials_to_save: Optional[Credentials] = None
 
-    def _get_index_url(self, url):
-        # type: (str) -> Optional[str]
+    def _get_index_url(self, url: str) -> Optional[str]:
         """Return the original index URL matching the requested URL.
 
         Cached or dynamically generated credentials may work against
@@ -106,9 +106,12 @@ class MultiDomainBasicAuth(AuthBase):
                 return u
         return None
 
-    def _get_new_credentials(self, original_url, allow_netrc=True,
-                             allow_keyring=False):
-        # type: (str, bool, bool) -> AuthInfo
+    def _get_new_credentials(
+        self,
+        original_url: str,
+        allow_netrc: bool = True,
+        allow_keyring: bool = False,
+    ) -> AuthInfo:
         """Find and return credentials for the specified URL."""
         # Split the credentials and netloc from the url.
         url, netloc, url_user_password = split_auth_netloc_from_url(
@@ -147,18 +150,21 @@ class MultiDomainBasicAuth(AuthBase):
         # If we don't have a password and keyring is available, use it.
         if allow_keyring:
             # The index url is more specific than the netloc, so try it first
+            # fmt: off
             kr_auth = (
                 get_keyring_auth(index_url, username) or
                 get_keyring_auth(netloc, username)
             )
+            # fmt: on
             if kr_auth:
                 logger.debug("Found credentials in keyring for %s", netloc)
                 return kr_auth
 
         return username, password
 
-    def _get_url_and_credentials(self, original_url):
-        # type: (str) -> Tuple[str, Optional[str], Optional[str]]
+    def _get_url_and_credentials(
+        self, original_url: str
+    ) -> Tuple[str, Optional[str], Optional[str]]:
         """Return the credentials to use for the provided URL.
 
         If allowed, netrc and keyring may be used to obtain the
@@ -170,13 +176,19 @@ class MultiDomainBasicAuth(AuthBase):
         """
         url, netloc, _ = split_auth_netloc_from_url(original_url)
 
-        # Use any stored credentials that we have for this netloc
-        username, password = self.passwords.get(netloc, (None, None))
+        # Try to get credentials from original url
+        username, password = self._get_new_credentials(original_url)
 
-        if username is None and password is None:
-            # No stored credentials. Acquire new credentials without prompting
-            # the user. (e.g. from netrc, keyring, or the URL itself)
-            username, password = self._get_new_credentials(original_url)
+        # If credentials not found, use any stored credentials for this netloc.
+        # Do this if either the username or the password is missing.
+        # This accounts for the situation in which the user has specified
+        # the username in the index url, but the password comes from keyring.
+        if (username is None or password is None) and netloc in self.passwords:
+            un, pw = self.passwords[netloc]
+            # It is possible that the cached credentials are for a different username,
+            # in which case the cache should be ignored.
+            if username is None or username == un:
+                username, password = un, pw
 
         if username is not None or password is not None:
             # Convert the username and password if they're None, so that
@@ -191,15 +203,14 @@ class MultiDomainBasicAuth(AuthBase):
 
         assert (
             # Credentials were found
-            (username is not None and password is not None) or
+            (username is not None and password is not None)
             # Credentials were not found
-            (username is None and password is None)
+            or (username is None and password is None)
         ), f"Could not load credentials from url: {original_url}"
 
         return url, username, password
 
-    def __call__(self, req):
-        # type: (Request) -> Request
+    def __call__(self, req: Request) -> Request:
         # Get credentials for this request
         url, username, password = self._get_url_and_credentials(req.url)
 
@@ -216,8 +227,9 @@ class MultiDomainBasicAuth(AuthBase):
         return req
 
     # Factored out to allow for easy patching in tests
-    def _prompt_for_password(self, netloc):
-        # type: (str) -> Tuple[Optional[str], Optional[str], bool]
+    def _prompt_for_password(
+        self, netloc: str
+    ) -> Tuple[Optional[str], Optional[str], bool]:
         username = ask_input(f"User for {netloc}: ")
         if not username:
             return None, None, False
@@ -228,14 +240,12 @@ class MultiDomainBasicAuth(AuthBase):
         return username, password, True
 
     # Factored out to allow for easy patching in tests
-    def _should_save_password_to_keyring(self):
-        # type: () -> bool
+    def _should_save_password_to_keyring(self) -> bool:
         if not keyring:
             return False
         return ask("Save credentials to keyring [y/N]: ", ["y", "n"]) == "y"
 
-    def handle_401(self, resp, **kwargs):
-        # type: (Response, **Any) -> Response
+    def handle_401(self, resp: Response, **kwargs: Any) -> Response:
         # We only care about 401 responses, anything else we want to just
         #   pass through the actual response
         if resp.status_code != 401:
@@ -248,9 +258,11 @@ class MultiDomainBasicAuth(AuthBase):
         parsed = urllib.parse.urlparse(resp.url)
 
         # Query the keyring for credentials:
-        username, password = self._get_new_credentials(resp.url,
-                                                       allow_netrc=False,
-                                                       allow_keyring=True)
+        username, password = self._get_new_credentials(
+            resp.url,
+            allow_netrc=False,
+            allow_keyring=True,
+        )
 
         # Prompt the user for a new username and password
         save = False
@@ -287,16 +299,15 @@ class MultiDomainBasicAuth(AuthBase):
 
         return new_resp
 
-    def warn_on_401(self, resp, **kwargs):
-        # type: (Response, **Any) -> None
+    def warn_on_401(self, resp: Response, **kwargs: Any) -> None:
         """Response callback to warn about incorrect credentials."""
         if resp.status_code == 401:
             logger.warning(
-                '401 Error, Credentials not correct for %s', resp.request.url,
+                "401 Error, Credentials not correct for %s",
+                resp.request.url,
             )
 
-    def save_credentials(self, resp, **kwargs):
-        # type: (Response, **Any) -> None
+    def save_credentials(self, resp: Response, **kwargs: Any) -> None:
         """Response callback to save credentials on success."""
         assert keyring is not None, "should never reach here without keyring"
         if not keyring:
@@ -306,7 +317,7 @@ class MultiDomainBasicAuth(AuthBase):
         self._credentials_to_save = None
         if creds and resp.status_code < 400:
             try:
-                logger.info('Saving credentials to keyring')
+                logger.info("Saving credentials to keyring")
                 keyring.set_password(*creds)
             except Exception:
-                logger.exception('Failed to save credentials')
+                logger.exception("Failed to save credentials")

venv/Lib/site-packages/pip/_internal/network/cache.py

@@ -3,7 +3,7 @@
 
 import os
 from contextlib import contextmanager
-from typing import Iterator, Optional
+from typing import Generator, Optional
 
 from pip._vendor.cachecontrol.cache import BaseCache
 from pip._vendor.cachecontrol.caches import FileCache
@@ -13,14 +13,12 @@ from pip._internal.utils.filesystem import adjacent_tmp_file, replace
 from pip._internal.utils.misc import ensure_dir
 
 
-def is_from_cache(response):
-    # type: (Response) -> bool
+def is_from_cache(response: Response) -> bool:
     return getattr(response, "from_cache", False)
 
 
 @contextmanager
-def suppressed_cache_errors():
-    # type: () -> Iterator[None]
+def suppressed_cache_errors() -> Generator[None, None, None]:
     """If we can't access the cache then we can just skip caching and process
     requests as if caching wasn't enabled.
     """
@@ -36,14 +34,12 @@ class SafeFileCache(BaseCache):
     not be accessible or writable.
     """
 
-    def __init__(self, directory):
-        # type: (str) -> None
+    def __init__(self, directory: str) -> None:
         assert directory is not None, "Cache directory must not be None."
         super().__init__()
         self.directory = directory
 
-    def _get_cache_path(self, name):
-        # type: (str) -> str
+    def _get_cache_path(self, name: str) -> str:
         # From cachecontrol.caches.file_cache.FileCache._fn, brought into our
         # class for backwards-compatibility and to avoid using a non-public
         # method.
@@ -51,15 +47,13 @@ class SafeFileCache(BaseCache):
         parts = list(hashed[:5]) + [hashed]
         return os.path.join(self.directory, *parts)
 
-    def get(self, key):
-        # type: (str) -> Optional[bytes]
+    def get(self, key: str) -> Optional[bytes]:
         path = self._get_cache_path(key)
         with suppressed_cache_errors():
-            with open(path, 'rb') as f:
+            with open(path, "rb") as f:
                 return f.read()
 
-    def set(self, key, value):
-        # type: (str, bytes) -> None
+    def set(self, key: str, value: bytes, expires: Optional[int] = None) -> None:
         path = self._get_cache_path(key)
         with suppressed_cache_errors():
             ensure_dir(os.path.dirname(path))
@@ -69,8 +63,7 @@ class SafeFileCache(BaseCache):
 
             replace(f.name, path)
 
-    def delete(self, key):
-        # type: (str) -> None
+    def delete(self, key: str) -> None:
         path = self._get_cache_path(key)
         with suppressed_cache_errors():
             os.remove(path)

venv/Lib/site-packages/pip/_internal/network/download.py

@@ -8,7 +8,7 @@ from typing import Iterable, Optional, Tuple
 
 from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response
 
-from pip._internal.cli.progress_bars import DownloadProgressProvider
+from pip._internal.cli.progress_bars import get_download_progress_renderer
 from pip._internal.exceptions import NetworkConnectionError
 from pip._internal.models.index import PyPI
 from pip._internal.models.link import Link
@@ -20,20 +20,18 @@ from pip._internal.utils.misc import format_size, redact_auth_from_url, splitext
 logger = logging.getLogger(__name__)
 
 
-def _get_http_response_size(resp):
-    # type: (Response) -> Optional[int]
+def _get_http_response_size(resp: Response) -> Optional[int]:
     try:
-        return int(resp.headers['content-length'])
+        return int(resp.headers["content-length"])
     except (ValueError, KeyError, TypeError):
         return None
 
 
 def _prepare_download(
-    resp,  # type: Response
-    link,  # type: Link
-    progress_bar  # type: str
-):
-    # type: (...) -> Iterable[bytes]
+    resp: Response,
+    link: Link,
+    progress_bar: str,
+) -> Iterable[bytes]:
     total_length = _get_http_response_size(resp)
 
     if link.netloc == PyPI.file_storage_domain:
@@ -44,7 +42,7 @@ def _prepare_download(
     logged_url = redact_auth_from_url(url)
 
     if total_length:
-        logged_url = '{} ({})'.format(logged_url, format_size(total_length))
+        logged_url = "{} ({})".format(logged_url, format_size(total_length))
 
     if is_from_cache(resp):
         logger.info("Using cached %s", logged_url)
@@ -67,27 +65,24 @@ def _prepare_download(
     if not show_progress:
         return chunks
 
-    return DownloadProgressProvider(
-        progress_bar, max=total_length
-    )(chunks)
+    renderer = get_download_progress_renderer(bar_type=progress_bar, size=total_length)
+    return renderer(chunks)
 
 
-def sanitize_content_filename(filename):
-    # type: (str) -> str
+def sanitize_content_filename(filename: str) -> str:
     """
     Sanitize the "filename" value from a Content-Disposition header.
     """
     return os.path.basename(filename)
 
 
-def parse_content_disposition(content_disposition, default_filename):
-    # type: (str, str) -> str
+def parse_content_disposition(content_disposition: str, default_filename: str) -> str:
     """
     Parse the "filename" value from a Content-Disposition header, and
     return the default filename if the result is empty.
     """
     _type, params = cgi.parse_header(content_disposition)
-    filename = params.get('filename')
+    filename = params.get("filename")
     if filename:
         # We need to sanitize the filename to prevent directory traversal
         # in case the filename contains ".." path parts.
@@ -95,21 +90,18 @@ def parse_content_disposition(content_disposition, default_filename):
     return filename or default_filename
 
 
-def _get_http_response_filename(resp, link):
-    # type: (Response, Link) -> str
+def _get_http_response_filename(resp: Response, link: Link) -> str:
     """Get an ideal filename from the given HTTP response, falling back to
     the link filename if not provided.
     """
     filename = link.filename  # fallback
     # Have a look at the Content-Disposition header for a better guess
-    content_disposition = resp.headers.get('content-disposition')
+    content_disposition = resp.headers.get("content-disposition")
     if content_disposition:
         filename = parse_content_disposition(content_disposition, filename)
-    ext = splitext(filename)[1]  # type: Optional[str]
+    ext: Optional[str] = splitext(filename)[1]
     if not ext:
-        ext = mimetypes.guess_extension(
-            resp.headers.get('content-type', '')
-        )
+        ext = mimetypes.guess_extension(resp.headers.get("content-type", ""))
         if ext:
             filename += ext
     if not ext and link.url != resp.url:
@@ -119,9 +111,8 @@ def _get_http_response_filename(resp, link):
     return filename
 
 
-def _http_get_download(session, link):
-    # type: (PipSession, Link) -> Response
-    target_url = link.url.split('#', 1)[0]
+def _http_get_download(session: PipSession, link: Link) -> Response:
+    target_url = link.url.split("#", 1)[0]
     resp = session.get(target_url, headers=HEADERS, stream=True)
     raise_for_status(resp)
     return resp
@@ -130,15 +121,13 @@ def _http_get_download(session, link):
 class Downloader:
     def __init__(
         self,
-        session,  # type: PipSession
-        progress_bar,  # type: str
-    ):
-        # type: (...) -> None
+        session: PipSession,
+        progress_bar: str,
+    ) -> None:
         self._session = session
         self._progress_bar = progress_bar
 
-    def __call__(self, link, location):
-        # type: (Link, str) -> Tuple[str, str]
+    def __call__(self, link: Link, location: str) -> Tuple[str, str]:
         """Download the file given by link into location."""
         try:
             resp = _http_get_download(self._session, link)
@@ -153,26 +142,25 @@ class Downloader:
         filepath = os.path.join(location, filename)
 
         chunks = _prepare_download(resp, link, self._progress_bar)
-        with open(filepath, 'wb') as content_file:
+        with open(filepath, "wb") as content_file:
             for chunk in chunks:
                 content_file.write(chunk)
-        content_type = resp.headers.get('Content-Type', '')
+        content_type = resp.headers.get("Content-Type", "")
         return filepath, content_type
 
 
 class BatchDownloader:
-
     def __init__(
         self,
-        session,  # type: PipSession
-        progress_bar,  # type: str
-    ):
-        # type: (...) -> None
+        session: PipSession,
+        progress_bar: str,
+    ) -> None:
         self._session = session
         self._progress_bar = progress_bar
 
-    def __call__(self, links, location):
-        # type: (Iterable[Link], str) -> Iterable[Tuple[Link, Tuple[str, str]]]
+    def __call__(
+        self, links: Iterable[Link], location: str
+    ) -> Iterable[Tuple[Link, Tuple[str, str]]]:
         """Download the files given by links into location."""
         for link in links:
             try:
@@ -181,7 +169,8 @@ class BatchDownloader:
                 assert e.response is not None
                 logger.critical(
                     "HTTP error %s while getting %s",
-                    e.response.status_code, link,
+                    e.response.status_code,
+                    link,
                 )
                 raise
 
@@ -189,8 +178,8 @@ class BatchDownloader:
             filepath = os.path.join(location, filename)
 
             chunks = _prepare_download(resp, link, self._progress_bar)
-            with open(filepath, 'wb') as content_file:
+            with open(filepath, "wb") as content_file:
                 for chunk in chunks:
                     content_file.write(chunk)
-            content_type = resp.headers.get('Content-Type', '')
+            content_type = resp.headers.get("Content-Type", "")
             yield link, (filepath, content_type)

venv/Lib/site-packages/pip/_internal/network/lazy_wheel.py

@@ -1,41 +1,40 @@
 """Lazy ZIP over HTTP"""
 
-__all__ = ['HTTPRangeRequestUnsupported', 'dist_from_wheel_url']
+__all__ = ["HTTPRangeRequestUnsupported", "dist_from_wheel_url"]
 
 from bisect import bisect_left, bisect_right
 from contextlib import contextmanager
 from tempfile import NamedTemporaryFile
-from typing import Any, Dict, Iterator, List, Optional, Tuple
+from typing import Any, Dict, Generator, List, Optional, Tuple
 from zipfile import BadZipfile, ZipFile
 
-from pip._vendor.pkg_resources import Distribution
+from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response
 
+from pip._internal.metadata import BaseDistribution, MemoryWheel, get_wheel_distribution
 from pip._internal.network.session import PipSession
 from pip._internal.network.utils import HEADERS, raise_for_status, response_chunks
-from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
 
 
 class HTTPRangeRequestUnsupported(Exception):
     pass
 
 
-def dist_from_wheel_url(name, url, session):
-    # type: (str, str, PipSession) -> Distribution
-    """Return a pkg_resources.Distribution from the given wheel URL.
+def dist_from_wheel_url(name: str, url: str, session: PipSession) -> BaseDistribution:
+    """Return a distribution object from the given wheel URL.
 
     This uses HTTP range requests to only fetch the potion of the wheel
     containing metadata, just enough for the object to be constructed.
     If such requests are not supported, HTTPRangeRequestUnsupported
     is raised.
     """
-    with LazyZipOverHTTP(url, session) as wheel:
+    with LazyZipOverHTTP(url, session) as zf:
         # For read-only ZIP files, ZipFile only needs methods read,
         # seek, seekable and tell, not the whole IO protocol.
-        zip_file = ZipFile(wheel)  # type: ignore
+        wheel = MemoryWheel(zf.name, zf)  # type: ignore
         # After context manager exit, wheel.name
         # is an invalid file by intention.
-        return pkg_resources_distribution_for_wheel(zip_file, name, wheel.name)
+        return get_wheel_distribution(wheel, canonicalize_name(name))
 
 
 class LazyZipOverHTTP:
@@ -47,51 +46,46 @@ class LazyZipOverHTTP:
     during initialization.
     """
 
-    def __init__(self, url, session, chunk_size=CONTENT_CHUNK_SIZE):
-        # type: (str, PipSession, int) -> None
+    def __init__(
+        self, url: str, session: PipSession, chunk_size: int = CONTENT_CHUNK_SIZE
+    ) -> None:
         head = session.head(url, headers=HEADERS)
         raise_for_status(head)
         assert head.status_code == 200
         self._session, self._url, self._chunk_size = session, url, chunk_size
-        self._length = int(head.headers['Content-Length'])
+        self._length = int(head.headers["Content-Length"])
         self._file = NamedTemporaryFile()
         self.truncate(self._length)
-        self._left = []  # type: List[int]
-        self._right = []  # type: List[int]
-        if 'bytes' not in head.headers.get('Accept-Ranges', 'none'):
-            raise HTTPRangeRequestUnsupported('range request is not supported')
+        self._left: List[int] = []
+        self._right: List[int] = []
+        if "bytes" not in head.headers.get("Accept-Ranges", "none"):
+            raise HTTPRangeRequestUnsupported("range request is not supported")
         self._check_zip()
 
     @property
-    def mode(self):
-        # type: () -> str
+    def mode(self) -> str:
         """Opening mode, which is always rb."""
-        return 'rb'
+        return "rb"
 
     @property
-    def name(self):
-        # type: () -> str
+    def name(self) -> str:
         """Path to the underlying file."""
         return self._file.name
 
-    def seekable(self):
-        # type: () -> bool
+    def seekable(self) -> bool:
         """Return whether random access is supported, which is True."""
         return True
 
-    def close(self):
-        # type: () -> None
+    def close(self) -> None:
         """Close the file."""
         self._file.close()
 
     @property
-    def closed(self):
-        # type: () -> bool
+    def closed(self) -> bool:
         """Whether the file is closed."""
         return self._file.closed
 
-    def read(self, size=-1):
-        # type: (int) -> bytes
+    def read(self, size: int = -1) -> bytes:
         """Read up to size bytes from the object and return them.
 
         As a convenience, if size is unspecified or -1,
@@ -100,18 +94,16 @@ class LazyZipOverHTTP:
         """
         download_size = max(size, self._chunk_size)
         start, length = self.tell(), self._length
-        stop = length if size < 0 else min(start+download_size, length)
-        start = max(0, stop-download_size)
-        self._download(start, stop-1)
+        stop = length if size < 0 else min(start + download_size, length)
+        start = max(0, stop - download_size)
+        self._download(start, stop - 1)
         return self._file.read(size)
 
-    def readable(self):
-        # type: () -> bool
+    def readable(self) -> bool:
         """Return whether the file is readable, which is True."""
         return True
 
-    def seek(self, offset, whence=0):
-        # type: (int, int) -> int
+    def seek(self, offset: int, whence: int = 0) -> int:
         """Change stream position and return the new absolute position.
 
         Seek to offset relative position indicated by whence:
@@ -121,13 +113,11 @@ class LazyZipOverHTTP:
         """
         return self._file.seek(offset, whence)
 
-    def tell(self):
-        # type: () -> int
-        """Return the current possition."""
+    def tell(self) -> int:
+        """Return the current position."""
         return self._file.tell()
 
-    def truncate(self, size=None):
-        # type: (Optional[int]) -> int
+    def truncate(self, size: Optional[int] = None) -> int:
         """Resize the stream to the given size in bytes.
 
         If size is unspecified resize to the current position.
@@ -137,23 +127,19 @@ class LazyZipOverHTTP:
         """
         return self._file.truncate(size)
 
-    def writable(self):
-        # type: () -> bool
+    def writable(self) -> bool:
         """Return False."""
         return False
 
-    def __enter__(self):
-        # type: () -> LazyZipOverHTTP
+    def __enter__(self) -> "LazyZipOverHTTP":
         self._file.__enter__()
         return self
 
-    def __exit__(self, *exc):
-        # type: (*Any) -> Optional[bool]
+    def __exit__(self, *exc: Any) -> Optional[bool]:
         return self._file.__exit__(*exc)
 
     @contextmanager
-    def _stay(self):
-        # type: ()-> Iterator[None]
+    def _stay(self) -> Generator[None, None, None]:
         """Return a context manager keeping the position.
 
         At the end of the block, seek back to original position.
@@ -164,8 +150,7 @@ class LazyZipOverHTTP:
         finally:
             self.seek(pos)
 
-    def _check_zip(self):
-        # type: () -> None
+    def _check_zip(self) -> None:
         """Check and download until the file is a valid ZIP."""
         end = self._length - 1
         for start in reversed(range(0, end, self._chunk_size)):
@@ -180,18 +165,20 @@ class LazyZipOverHTTP:
                 else:
                     break
 
-    def _stream_response(self, start, end, base_headers=HEADERS):
-        # type: (int, int, Dict[str, str]) -> Response
+    def _stream_response(
+        self, start: int, end: int, base_headers: Dict[str, str] = HEADERS
+    ) -> Response:
         """Return HTTP response to a range request from start to end."""
         headers = base_headers.copy()
-        headers['Range'] = f'bytes={start}-{end}'
+        headers["Range"] = f"bytes={start}-{end}"
         # TODO: Get range requests to be correctly cached
-        headers['Cache-Control'] = 'no-cache'
+        headers["Cache-Control"] = "no-cache"
         return self._session.get(self._url, headers=headers, stream=True)
 
-    def _merge(self, start, end, left, right):
-        # type: (int, int, int, int) -> Iterator[Tuple[int, int]]
-        """Return an iterator of intervals to be fetched.
+    def _merge(
+        self, start: int, end: int, left: int, right: int
+    ) -> Generator[Tuple[int, int], None, None]:
+        """Return a generator of intervals to be fetched.
 
         Args:
             start (int): Start of needed interval
@@ -200,18 +187,17 @@ class LazyZipOverHTTP:
             right (int): Index after last overlapping downloaded data
         """
         lslice, rslice = self._left[left:right], self._right[left:right]
-        i = start = min([start]+lslice[:1])
-        end = max([end]+rslice[-1:])
+        i = start = min([start] + lslice[:1])
+        end = max([end] + rslice[-1:])
         for j, k in zip(lslice, rslice):
             if j > i:
-                yield i, j-1
+                yield i, j - 1
             i = k + 1
         if i <= end:
             yield i, end
         self._left[left:right], self._right[left:right] = [start], [end]
 
-    def _download(self, start, end):
-        # type: (int, int) -> None
+    def _download(self, start: int, end: int) -> None:
         """Download bytes from start to end inclusively."""
         with self._stay():
             left = bisect_left(self._right, start)

venv/Lib/site-packages/pip/_internal/network/session.py

@@ -2,27 +2,20 @@
 network request configuration and behavior.
 """
 
-# When mypy runs on Windows the call to distro.linux_distribution() is skipped
-# resulting in the failure:
-#
-#     error: unused 'type: ignore' comment
-#
-# If the upstream module adds typing, this comment should be removed. See
-# https://github.com/nir0s/distro/pull/269
-#
-# mypy: warn-unused-ignores=False
-
 import email.utils
+import io
 import ipaddress
 import json
 import logging
 import mimetypes
 import os
 import platform
+import shutil
+import subprocess
 import sys
 import urllib.parse
 import warnings
-from typing import Any, Dict, Iterator, List, Mapping, Optional, Sequence, Tuple, Union
+from typing import Any, Dict, Generator, List, Mapping, Optional, Sequence, Tuple, Union
 
 from pip._vendor import requests, urllib3
 from pip._vendor.cachecontrol import CacheControlAdapter
@@ -53,7 +46,7 @@ SecureOrigin = Tuple[str, str, Optional[Union[int, str]]]
 warnings.filterwarnings("ignore", category=InsecureRequestWarning)
 
 
-SECURE_ORIGINS = [
+SECURE_ORIGINS: List[SecureOrigin] = [
     # protocol, hostname, port
     # Taken from Chrome's list of secure origins (See: http://bit.ly/1qrySKC)
     ("https", "*", "*"),
@@ -63,7 +56,7 @@ SECURE_ORIGINS = [
     ("file", "*", None),
     # ssh is always secure.
     ("ssh", "*", "*"),
-]  # type: List[SecureOrigin]
+]
 
 
 # These are environment variables present when running under various
@@ -75,18 +68,17 @@ SECURE_ORIGINS = [
 # For more background, see: https://github.com/pypa/pip/issues/5499
 CI_ENVIRONMENT_VARIABLES = (
     # Azure Pipelines
-    'BUILD_BUILDID',
+    "BUILD_BUILDID",
     # Jenkins
-    'BUILD_ID',
+    "BUILD_ID",
     # AppVeyor, CircleCI, Codeship, Gitlab CI, Shippable, Travis CI
-    'CI',
+    "CI",
     # Explicit environment variable.
-    'PIP_IS_CI',
+    "PIP_IS_CI",
 )
 
 
-def looks_like_ci():
-    # type: () -> bool
+def looks_like_ci() -> bool:
     """
     Return whether it looks like pip is running under CI.
     """
@@ -96,48 +88,50 @@ def looks_like_ci():
     return any(name in os.environ for name in CI_ENVIRONMENT_VARIABLES)
 
 
-def user_agent():
-    # type: () -> str
+def user_agent() -> str:
     """
     Return a string representing the user agent.
     """
-    data = {
+    data: Dict[str, Any] = {
         "installer": {"name": "pip", "version": __version__},
         "python": platform.python_version(),
         "implementation": {
             "name": platform.python_implementation(),
         },
-    }  # type: Dict[str, Any]
+    }
 
-    if data["implementation"]["name"] == 'CPython':
+    if data["implementation"]["name"] == "CPython":
         data["implementation"]["version"] = platform.python_version()
-    elif data["implementation"]["name"] == 'PyPy':
+    elif data["implementation"]["name"] == "PyPy":
         pypy_version_info = sys.pypy_version_info  # type: ignore
-        if pypy_version_info.releaselevel == 'final':
+        if pypy_version_info.releaselevel == "final":
             pypy_version_info = pypy_version_info[:3]
         data["implementation"]["version"] = ".".join(
             [str(x) for x in pypy_version_info]
         )
-    elif data["implementation"]["name"] == 'Jython':
+    elif data["implementation"]["name"] == "Jython":
         # Complete Guess
         data["implementation"]["version"] = platform.python_version()
-    elif data["implementation"]["name"] == 'IronPython':
+    elif data["implementation"]["name"] == "IronPython":
         # Complete Guess
         data["implementation"]["version"] = platform.python_version()
 
     if sys.platform.startswith("linux"):
         from pip._vendor import distro
 
-        # https://github.com/nir0s/distro/pull/269
-        linux_distribution = distro.linux_distribution()  # type: ignore
-        distro_infos = dict(filter(
-            lambda x: x[1],
-            zip(["name", "version", "id"], linux_distribution),
-        ))
-        libc = dict(filter(
-            lambda x: x[1],
-            zip(["lib", "version"], libc_ver()),
-        ))
+        linux_distribution = distro.name(), distro.version(), distro.codename()
+        distro_infos: Dict[str, Any] = dict(
+            filter(
+                lambda x: x[1],
+                zip(["name", "version", "id"], linux_distribution),
+            )
+        )
+        libc = dict(
+            filter(
+                lambda x: x[1],
+                zip(["lib", "version"], libc_ver()),
+            )
+        )
         if libc:
             distro_infos["libc"] = libc
         if distro_infos:
@@ -157,12 +151,28 @@ def user_agent():
 
     if has_tls():
         import _ssl as ssl
+
         data["openssl_version"] = ssl.OPENSSL_VERSION
 
     setuptools_dist = get_default_environment().get_distribution("setuptools")
     if setuptools_dist is not None:
         data["setuptools_version"] = str(setuptools_dist.version)
 
+    if shutil.which("rustc") is not None:
+        # If for any reason `rustc --version` fails, silently ignore it
+        try:
+            rustc_output = subprocess.check_output(
+                ["rustc", "--version"], stderr=subprocess.STDOUT, timeout=0.5
+            )
+        except Exception:
+            pass
+        else:
+            if rustc_output.startswith(b"rustc "):
+                # The format of `rustc --version` is:
+                # `b'rustc 1.52.1 (9bc8c42bb 2021-05-09)\n'`
+                # We extract just the middle (1.52.1) part
+                data["rustc_version"] = rustc_output.split(b" ")[1].decode()
+
     # Use None rather than False so as not to give the impression that
     # pip knows it is not being run under CI.  Rather, it is a null or
     # inconclusive result.  Also, we include some value rather than no
@@ -180,17 +190,15 @@ def user_agent():
 
 
 class LocalFSAdapter(BaseAdapter):
-
     def send(
         self,
-        request,  # type: PreparedRequest
-        stream=False,  # type: bool
-        timeout=None,  # type: Optional[Union[float, Tuple[float, float]]]
-        verify=True,  # type: Union[bool, str]
-        cert=None,  # type: Optional[Union[str, Tuple[str, str]]]
-        proxies=None,  # type:Optional[Mapping[str, str]]
-    ):
-        # type: (...) -> Response
+        request: PreparedRequest,
+        stream: bool = False,
+        timeout: Optional[Union[float, Tuple[float, float]]] = None,
+        verify: Union[bool, str] = True,
+        cert: Optional[Union[str, Tuple[str, str]]] = None,
+        proxies: Optional[Mapping[str, str]] = None,
+    ) -> Response:
         pathname = url_to_path(request.url)
 
         resp = Response()
@@ -200,67 +208,66 @@ class LocalFSAdapter(BaseAdapter):
         try:
             stats = os.stat(pathname)
         except OSError as exc:
+            # format the exception raised as a io.BytesIO object,
+            # to return a better error message:
             resp.status_code = 404
-            resp.raw = exc
+            resp.reason = type(exc).__name__
+            resp.raw = io.BytesIO(f"{resp.reason}: {exc}".encode("utf8"))
         else:
             modified = email.utils.formatdate(stats.st_mtime, usegmt=True)
             content_type = mimetypes.guess_type(pathname)[0] or "text/plain"
-            resp.headers = CaseInsensitiveDict({
-                "Content-Type": content_type,
-                "Content-Length": stats.st_size,
-                "Last-Modified": modified,
-            })
+            resp.headers = CaseInsensitiveDict(
+                {
+                    "Content-Type": content_type,
+                    "Content-Length": stats.st_size,
+                    "Last-Modified": modified,
+                }
+            )
 
             resp.raw = open(pathname, "rb")
             resp.close = resp.raw.close
 
         return resp
 
-    def close(self):
-        # type: () -> None
+    def close(self) -> None:
         pass
 
 
 class InsecureHTTPAdapter(HTTPAdapter):
-
     def cert_verify(
         self,
-        conn,  # type: ConnectionPool
-        url,  # type: str
-        verify,  # type: Union[bool, str]
-        cert,  # type: Optional[Union[str, Tuple[str, str]]]
-    ):
-        # type: (...) -> None
+        conn: ConnectionPool,
+        url: str,
+        verify: Union[bool, str],
+        cert: Optional[Union[str, Tuple[str, str]]],
+    ) -> None:
         super().cert_verify(conn=conn, url=url, verify=False, cert=cert)
 
 
 class InsecureCacheControlAdapter(CacheControlAdapter):
-
     def cert_verify(
         self,
-        conn,  # type: ConnectionPool
-        url,  # type: str
-        verify,  # type: Union[bool, str]
-        cert,  # type: Optional[Union[str, Tuple[str, str]]]
-    ):
-        # type: (...) -> None
+        conn: ConnectionPool,
+        url: str,
+        verify: Union[bool, str],
+        cert: Optional[Union[str, Tuple[str, str]]],
+    ) -> None:
         super().cert_verify(conn=conn, url=url, verify=False, cert=cert)
 
 
 class PipSession(requests.Session):
 
-    timeout = None  # type: Optional[int]
+    timeout: Optional[int] = None
 
     def __init__(
         self,
-        *args,  # type: Any
-        retries=0,  # type: int
-        cache=None,  # type: Optional[str]
-        trusted_hosts=(),  # type: Sequence[str]
-        index_urls=None,  # type: Optional[List[str]]
-        **kwargs,  # type: Any
-    ):
-        # type: (...) -> None
+        *args: Any,
+        retries: int = 0,
+        cache: Optional[str] = None,
+        trusted_hosts: Sequence[str] = (),
+        index_urls: Optional[List[str]] = None,
+        **kwargs: Any,
+    ) -> None:
         """
         :param trusted_hosts: Domains not to emit warnings for when not using
             HTTPS.
@@ -269,7 +276,7 @@ class PipSession(requests.Session):
 
         # Namespace the attribute with "pip_" just in case to prevent
         # possible conflicts with the base class.
-        self.pip_trusted_origins = []  # type: List[Tuple[str, Optional[int]]]
+        self.pip_trusted_origins: List[Tuple[str, Optional[int]]] = []
 
         # Attach our User Agent to the request
         self.headers["User-Agent"] = user_agent()
@@ -283,7 +290,6 @@ class PipSession(requests.Session):
             # Set the total number of retries that a particular request can
             # have.
             total=retries,
-
             # A 503 error from PyPI typically means that the Fastly -> Origin
             # connection got interrupted in some way. A 503 error in general
             # is typically considered a transient error so we'll go ahead and
@@ -291,7 +297,6 @@ class PipSession(requests.Session):
             # A 500 may indicate transient error in Amazon S3
             # A 520 or 527 - may indicate transient error in CloudFlare
             status_forcelist=[500, 503, 520, 527],
-
             # Add a small amount of back off between failed requests in
             # order to prevent hammering the service.
             backoff_factor=0.25,
@@ -331,16 +336,16 @@ class PipSession(requests.Session):
         for host in trusted_hosts:
             self.add_trusted_host(host, suppress_logging=True)
 
-    def update_index_urls(self, new_index_urls):
-        # type: (List[str]) -> None
+    def update_index_urls(self, new_index_urls: List[str]) -> None:
         """
         :param new_index_urls: New index urls to update the authentication
             handler with.
         """
         self.auth.index_urls = new_index_urls
 
-    def add_trusted_host(self, host, source=None, suppress_logging=False):
-        # type: (str, Optional[str], bool) -> None
+    def add_trusted_host(
+        self, host: str, source: Optional[str] = None, suppress_logging: bool = False
+    ) -> None:
         """
         :param host: It is okay to provide a host that has previously been
             added.
@@ -348,9 +353,9 @@ class PipSession(requests.Session):
             string came from.
         """
         if not suppress_logging:
-            msg = f'adding trusted host: {host!r}'
+            msg = f"adding trusted host: {host!r}"
             if source is not None:
-                msg += f' (from {source})'
+                msg += f" (from {source})"
             logger.info(msg)
 
         host_port = parse_netloc(host)
@@ -358,35 +363,36 @@ class PipSession(requests.Session):
             self.pip_trusted_origins.append(host_port)
 
         self.mount(
-            build_url_from_netloc(host) + '/',
-            self._trusted_host_adapter
+            build_url_from_netloc(host, scheme="http") + "/", self._trusted_host_adapter
         )
+        self.mount(build_url_from_netloc(host) + "/", self._trusted_host_adapter)
         if not host_port[1]:
-            # Mount wildcard ports for the same host.
             self.mount(
-                build_url_from_netloc(host) + ':',
-                self._trusted_host_adapter
+                build_url_from_netloc(host, scheme="http") + ":",
+                self._trusted_host_adapter,
             )
+            # Mount wildcard ports for the same host.
+            self.mount(build_url_from_netloc(host) + ":", self._trusted_host_adapter)
 
-    def iter_secure_origins(self):
-        # type: () -> Iterator[SecureOrigin]
+    def iter_secure_origins(self) -> Generator[SecureOrigin, None, None]:
         yield from SECURE_ORIGINS
         for host, port in self.pip_trusted_origins:
-            yield ('*', host, '*' if port is None else port)
+            yield ("*", host, "*" if port is None else port)
 
-    def is_secure_origin(self, location):
-        # type: (Link) -> bool
+    def is_secure_origin(self, location: Link) -> bool:
         # Determine if this url used a secure transport mechanism
         parsed = urllib.parse.urlparse(str(location))
         origin_protocol, origin_host, origin_port = (
-            parsed.scheme, parsed.hostname, parsed.port,
+            parsed.scheme,
+            parsed.hostname,
+            parsed.port,
         )
 
         # The protocol to use to see if the protocol matches.
         # Don't count the repository type as part of the protocol: in
         # cases such as "git+ssh", only use "ssh". (I.e., Only verify against
         # the last scheme.)
-        origin_protocol = origin_protocol.rsplit('+', 1)[-1]
+        origin_protocol = origin_protocol.rsplit("+", 1)[-1]
 
         # Determine if our origin is a secure origin by looking through our
         # hardcoded list of secure origins, as well as any additional ones
@@ -403,9 +409,9 @@ class PipSession(requests.Session):
                 # We don't have both a valid address or a valid network, so
                 # we'll check this origin against hostnames.
                 if (
-                    origin_host and
-                    origin_host.lower() != secure_host.lower() and
-                    secure_host != "*"
+                    origin_host
+                    and origin_host.lower() != secure_host.lower()
+                    and secure_host != "*"
                 ):
                     continue
             else:
@@ -416,9 +422,9 @@ class PipSession(requests.Session):
 
             # Check to see if the port matches.
             if (
-                origin_port != secure_port and
-                secure_port != "*" and
-                secure_port is not None
+                origin_port != secure_port
+                and secure_port != "*"
+                and secure_port is not None
             ):
                 continue
 
@@ -440,10 +446,11 @@ class PipSession(requests.Session):
 
         return False
 
-    def request(self, method, url, *args, **kwargs):
-        # type: (str, str, *Any, **Any) -> Response
+    def request(self, method: str, url: str, *args: Any, **kwargs: Any) -> Response:
         # Allow setting a default timeout on a session
         kwargs.setdefault("timeout", self.timeout)
+        # Allow setting a default proxies on a session
+        kwargs.setdefault("proxies", self.proxies)
 
         # Dispatch the actual request
         return super().request(method, url, *args, **kwargs)

venv/Lib/site-packages/pip/_internal/network/utils.py

@@ -1,4 +1,4 @@
-from typing import Dict, Iterator
+from typing import Dict, Generator
 
 from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response
 
@@ -23,40 +23,41 @@ from pip._internal.exceptions import NetworkConnectionError
 # you're not asking for a compressed file and will then decompress it
 # before sending because if that's the case I don't think it'll ever be
 # possible to make this work.
-HEADERS = {'Accept-Encoding': 'identity'}  # type: Dict[str, str]
+HEADERS: Dict[str, str] = {"Accept-Encoding": "identity"}
 
 
-def raise_for_status(resp):
-    # type: (Response) -> None
-    http_error_msg = ''
+def raise_for_status(resp: Response) -> None:
+    http_error_msg = ""
     if isinstance(resp.reason, bytes):
         # We attempt to decode utf-8 first because some servers
         # choose to localize their reason strings. If the string
         # isn't utf-8, we fall back to iso-8859-1 for all other
         # encodings.
         try:
-            reason = resp.reason.decode('utf-8')
+            reason = resp.reason.decode("utf-8")
         except UnicodeDecodeError:
-            reason = resp.reason.decode('iso-8859-1')
+            reason = resp.reason.decode("iso-8859-1")
     else:
         reason = resp.reason
 
     if 400 <= resp.status_code < 500:
         http_error_msg = (
-            f'{resp.status_code} Client Error: {reason} for url: {resp.url}')
+            f"{resp.status_code} Client Error: {reason} for url: {resp.url}"
+        )
 
     elif 500 <= resp.status_code < 600:
         http_error_msg = (
-            f'{resp.status_code} Server Error: {reason} for url: {resp.url}')
+            f"{resp.status_code} Server Error: {reason} for url: {resp.url}"
+        )
 
     if http_error_msg:
         raise NetworkConnectionError(http_error_msg, response=resp)
 
 
-def response_chunks(response, chunk_size=CONTENT_CHUNK_SIZE):
-    # type: (Response, int) -> Iterator[bytes]
-    """Given a requests Response, provide the data chunks.
-    """
+def response_chunks(
+    response: Response, chunk_size: int = CONTENT_CHUNK_SIZE
+) -> Generator[bytes, None, None]:
+    """Given a requests Response, provide the data chunks."""
     try:
         # Special case for urllib3.
         for chunk in response.raw.stream(

venv/Lib/site-packages/pip/_internal/network/xmlrpc.py

@@ -21,22 +21,32 @@ class PipXmlrpcTransport(xmlrpc.client.Transport):
     object.
     """
 
-    def __init__(self, index_url, session, use_datetime=False):
-        # type: (str, PipSession, bool) -> None
+    def __init__(
+        self, index_url: str, session: PipSession, use_datetime: bool = False
+    ) -> None:
         super().__init__(use_datetime)
         index_parts = urllib.parse.urlparse(index_url)
         self._scheme = index_parts.scheme
         self._session = session
 
-    def request(self, host, handler, request_body, verbose=False):
-        # type: (_HostType, str, bytes, bool) -> Tuple[_Marshallable, ...]
+    def request(
+        self,
+        host: "_HostType",
+        handler: str,
+        request_body: bytes,
+        verbose: bool = False,
+    ) -> Tuple["_Marshallable", ...]:
         assert isinstance(host, str)
         parts = (self._scheme, host, handler, None, None, None)
         url = urllib.parse.urlunparse(parts)
         try:
-            headers = {'Content-Type': 'text/xml'}
-            response = self._session.post(url, data=request_body,
-                                          headers=headers, stream=True)
+            headers = {"Content-Type": "text/xml"}
+            response = self._session.post(
+                url,
+                data=request_body,
+                headers=headers,
+                stream=True,
+            )
             raise_for_status(response)
             self.verbose = verbose
             return self.parse_response(response.raw)
@@ -44,6 +54,7 @@ class PipXmlrpcTransport(xmlrpc.client.Transport):
             assert exc.response
             logger.critical(
                 "HTTP error %s while getting %s",
-                exc.response.status_code, url,
+                exc.response.status_code,
+                url,
             )
             raise

venv/Lib/site-packages/pip/_internal/operations/build/metadata.py

@@ -6,19 +6,22 @@ import os
 from pip._vendor.pep517.wrappers import Pep517HookCaller
 
 from pip._internal.build_env import BuildEnvironment
+from pip._internal.exceptions import (
+    InstallationSubprocessError,
+    MetadataGenerationFailed,
+)
 from pip._internal.utils.subprocess import runner_with_spinner_message
 from pip._internal.utils.temp_dir import TempDirectory
 
 
-def generate_metadata(build_env, backend):
-    # type: (BuildEnvironment, Pep517HookCaller) -> str
+def generate_metadata(
+    build_env: BuildEnvironment, backend: Pep517HookCaller, details: str
+) -> str:
     """Generate metadata using mechanisms described in PEP 517.
 
     Returns the generated metadata directory.
     """
-    metadata_tmpdir = TempDirectory(
-        kind="modern-metadata", globally_managed=True
-    )
+    metadata_tmpdir = TempDirectory(kind="modern-metadata", globally_managed=True)
 
     metadata_dir = metadata_tmpdir.path
 
@@ -26,10 +29,11 @@ def generate_metadata(build_env, backend):
         # Note that Pep517HookCaller implements a fallback for
         # prepare_metadata_for_build_wheel, so we don't have to
         # consider the possibility that this hook doesn't exist.
-        runner = runner_with_spinner_message("Preparing wheel metadata")
+        runner = runner_with_spinner_message("Preparing metadata (pyproject.toml)")
         with backend.subprocess_runner(runner):
-            distinfo_dir = backend.prepare_metadata_for_build_wheel(
-                metadata_dir
-            )
+            try:
+                distinfo_dir = backend.prepare_metadata_for_build_wheel(metadata_dir)
+            except InstallationSubprocessError as error:
+                raise MetadataGenerationFailed(package_details=details) from error
 
     return os.path.join(metadata_dir, distinfo_dir)

venv/Lib/site-packages/pip/_internal/operations/build/metadata_legacy.py

@@ -5,7 +5,12 @@ import logging
 import os
 
 from pip._internal.build_env import BuildEnvironment
-from pip._internal.exceptions import InstallationError
+from pip._internal.cli.spinners import open_spinner
+from pip._internal.exceptions import (
+    InstallationError,
+    InstallationSubprocessError,
+    MetadataGenerationFailed,
+)
 from pip._internal.utils.setuptools_build import make_setuptools_egg_info_args
 from pip._internal.utils.subprocess import call_subprocess
 from pip._internal.utils.temp_dir import TempDirectory
@@ -13,49 +18,39 @@ from pip._internal.utils.temp_dir import TempDirectory
 logger = logging.getLogger(__name__)
 
 
-def _find_egg_info(directory):
-    # type: (str) -> str
-    """Find an .egg-info subdirectory in `directory`.
-    """
-    filenames = [
-        f for f in os.listdir(directory) if f.endswith(".egg-info")
-    ]
+def _find_egg_info(directory: str) -> str:
+    """Find an .egg-info subdirectory in `directory`."""
+    filenames = [f for f in os.listdir(directory) if f.endswith(".egg-info")]
 
     if not filenames:
-        raise InstallationError(
-            f"No .egg-info directory found in {directory}"
-        )
+        raise InstallationError(f"No .egg-info directory found in {directory}")
 
     if len(filenames) > 1:
         raise InstallationError(
-            "More than one .egg-info directory found in {}".format(
-                directory
-            )
+            "More than one .egg-info directory found in {}".format(directory)
         )
 
     return os.path.join(directory, filenames[0])
 
 
 def generate_metadata(
-    build_env,  # type: BuildEnvironment
-    setup_py_path,  # type: str
-    source_dir,  # type: str
-    isolated,  # type: bool
-    details,  # type: str
-):
-    # type: (...) -> str
+    build_env: BuildEnvironment,
+    setup_py_path: str,
+    source_dir: str,
+    isolated: bool,
+    details: str,
+) -> str:
     """Generate metadata using setup.py-based defacto mechanisms.
 
     Returns the generated metadata directory.
     """
     logger.debug(
-        'Running setup.py (path:%s) egg_info for package %s',
-        setup_py_path, details,
+        "Running setup.py (path:%s) egg_info for package %s",
+        setup_py_path,
+        details,
     )
 
-    egg_info_dir = TempDirectory(
-        kind="pip-egg-info", globally_managed=True
-    ).path
+    egg_info_dir = TempDirectory(kind="pip-egg-info", globally_managed=True).path
 
     args = make_setuptools_egg_info_args(
         setup_py_path,
@@ -64,11 +59,16 @@ def generate_metadata(
     )
 
     with build_env:
-        call_subprocess(
-            args,
-            cwd=source_dir,
-            command_desc='python setup.py egg_info',
-        )
+        with open_spinner("Preparing metadata (setup.py)") as spinner:
+            try:
+                call_subprocess(
+                    args,
+                    cwd=source_dir,
+                    command_desc="python setup.py egg_info",
+                    spinner=spinner,
+                )
+            except InstallationSubprocessError as error:
+                raise MetadataGenerationFailed(package_details=details) from error
 
     # Return the .egg-info directory.
     return _find_egg_info(egg_info_dir)

venv/Lib/site-packages/pip/_internal/operations/build/wheel.py

@@ -10,22 +10,21 @@ logger = logging.getLogger(__name__)
 
 
 def build_wheel_pep517(
-    name,  # type: str
-    backend,  # type: Pep517HookCaller
-    metadata_directory,  # type: str
-    tempd,  # type: str
-):
-    # type: (...) -> Optional[str]
+    name: str,
+    backend: Pep517HookCaller,
+    metadata_directory: str,
+    tempd: str,
+) -> Optional[str]:
     """Build one InstallRequirement using the PEP 517 build process.
 
     Returns path to wheel if successfully built. Otherwise, returns None.
     """
     assert metadata_directory is not None
     try:
-        logger.debug('Destination directory: %s', tempd)
+        logger.debug("Destination directory: %s", tempd)
 
         runner = runner_with_spinner_message(
-            f'Building wheel for {name} (PEP 517)'
+            f"Building wheel for {name} (pyproject.toml)"
         )
         with backend.subprocess_runner(runner):
             wheel_name = backend.build_wheel(
@@ -33,6 +32,6 @@ def build_wheel_pep517(
                 metadata_directory=metadata_directory,
             )
     except Exception:
-        logger.error('Failed building wheel for %s', name)
+        logger.error("Failed building wheel for %s", name)
         return None
     return os.path.join(tempd, wheel_name)

venv/Lib/site-packages/pip/_internal/operations/build/wheel_legacy.py

@@ -4,59 +4,51 @@ from typing import List, Optional
 
 from pip._internal.cli.spinners import open_spinner
 from pip._internal.utils.setuptools_build import make_setuptools_bdist_wheel_args
-from pip._internal.utils.subprocess import (
-    LOG_DIVIDER,
-    call_subprocess,
-    format_command_args,
-)
+from pip._internal.utils.subprocess import call_subprocess, format_command_args
 
 logger = logging.getLogger(__name__)
 
 
 def format_command_result(
-    command_args,  # type: List[str]
-    command_output,  # type: str
-):
-    # type: (...) -> str
+    command_args: List[str],
+    command_output: str,
+) -> str:
     """Format command information for logging."""
     command_desc = format_command_args(command_args)
-    text = f'Command arguments: {command_desc}\n'
+    text = f"Command arguments: {command_desc}\n"
 
     if not command_output:
-        text += 'Command output: None'
+        text += "Command output: None"
     elif logger.getEffectiveLevel() > logging.DEBUG:
-        text += 'Command output: [use --verbose to show]'
+        text += "Command output: [use --verbose to show]"
     else:
-        if not command_output.endswith('\n'):
-            command_output += '\n'
-        text += f'Command output:\n{command_output}{LOG_DIVIDER}'
+        if not command_output.endswith("\n"):
+            command_output += "\n"
+        text += f"Command output:\n{command_output}"
 
     return text
 
 
 def get_legacy_build_wheel_path(
-    names,  # type: List[str]
-    temp_dir,  # type: str
-    name,  # type: str
-    command_args,  # type: List[str]
-    command_output,  # type: str
-):
-    # type: (...) -> Optional[str]
+    names: List[str],
+    temp_dir: str,
+    name: str,
+    command_args: List[str],
+    command_output: str,
+) -> Optional[str]:
     """Return the path to the wheel in the temporary build directory."""
     # Sort for determinism.
     names = sorted(names)
     if not names:
-        msg = (
-            'Legacy build of wheel for {!r} created no files.\n'
-        ).format(name)
+        msg = ("Legacy build of wheel for {!r} created no files.\n").format(name)
         msg += format_command_result(command_args, command_output)
         logger.warning(msg)
         return None
 
     if len(names) > 1:
         msg = (
-            'Legacy build of wheel for {!r} created more than one file.\n'
-            'Filenames (choosing first): {}\n'
+            "Legacy build of wheel for {!r} created more than one file.\n"
+            "Filenames (choosing first): {}\n"
         ).format(name, names)
         msg += format_command_result(command_args, command_output)
         logger.warning(msg)
@@ -65,14 +57,13 @@ def get_legacy_build_wheel_path(
 
 
 def build_wheel_legacy(
-    name,  # type: str
-    setup_py_path,  # type: str
-    source_dir,  # type: str
-    global_options,  # type: List[str]
-    build_options,  # type: List[str]
-    tempd,  # type: str
-):
-    # type: (...) -> Optional[str]
+    name: str,
+    setup_py_path: str,
+    source_dir: str,
+    global_options: List[str],
+    build_options: List[str],
+    tempd: str,
+) -> Optional[str]:
     """Build one unpacked package using the "legacy" build process.
 
     Returns path to wheel if successfully built. Otherwise, returns None.
@@ -84,19 +75,20 @@ def build_wheel_legacy(
         destination_dir=tempd,
     )
 
-    spin_message = f'Building wheel for {name} (setup.py)'
+    spin_message = f"Building wheel for {name} (setup.py)"
     with open_spinner(spin_message) as spinner:
-        logger.debug('Destination directory: %s', tempd)
+        logger.debug("Destination directory: %s", tempd)
 
         try:
             output = call_subprocess(
                 wheel_args,
+                command_desc="python setup.py bdist_wheel",
                 cwd=source_dir,
                 spinner=spinner,
             )
         except Exception:
             spinner.finish("error")
-            logger.error('Failed building wheel for %s', name)
+            logger.error("Failed building wheel for %s", name)
             return None
 
         names = os.listdir(tempd)

venv/Lib/site-packages/pip/_internal/operations/check.py

@@ -2,56 +2,55 @@
 """
 
 import logging
-from collections import namedtuple
-from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Set, Tuple
+from typing import Callable, Dict, List, NamedTuple, Optional, Set, Tuple
 
-from pip._vendor.packaging.utils import canonicalize_name
-from pip._vendor.pkg_resources import RequirementParseError
+from pip._vendor.packaging.requirements import Requirement
+from pip._vendor.packaging.utils import NormalizedName, canonicalize_name
 
 from pip._internal.distributions import make_distribution_for_install_requirement
+from pip._internal.metadata import get_default_environment
+from pip._internal.metadata.base import DistributionVersion
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.utils.misc import get_installed_distributions
-
-if TYPE_CHECKING:
-    from pip._vendor.packaging.utils import NormalizedName
 
 logger = logging.getLogger(__name__)
 
-# Shorthands
-PackageSet = Dict['NormalizedName', 'PackageDetails']
-Missing = Tuple[str, Any]
-Conflicting = Tuple[str, str, Any]
 
-MissingDict = Dict['NormalizedName', List[Missing]]
-ConflictingDict = Dict['NormalizedName', List[Conflicting]]
+class PackageDetails(NamedTuple):
+    version: DistributionVersion
+    dependencies: List[Requirement]
+
+
+# Shorthands
+PackageSet = Dict[NormalizedName, PackageDetails]
+Missing = Tuple[NormalizedName, Requirement]
+Conflicting = Tuple[NormalizedName, DistributionVersion, Requirement]
+
+MissingDict = Dict[NormalizedName, List[Missing]]
+ConflictingDict = Dict[NormalizedName, List[Conflicting]]
 CheckResult = Tuple[MissingDict, ConflictingDict]
 ConflictDetails = Tuple[PackageSet, CheckResult]
 
-PackageDetails = namedtuple('PackageDetails', ['version', 'requires'])
-
-
-def create_package_set_from_installed(**kwargs: Any) -> Tuple["PackageSet", bool]:
-    """Converts a list of distributions into a PackageSet.
-    """
-    # Default to using all packages installed on the system
-    if kwargs == {}:
-        kwargs = {"local_only": False, "skip": ()}
 
+def create_package_set_from_installed() -> Tuple[PackageSet, bool]:
+    """Converts a list of distributions into a PackageSet."""
     package_set = {}
     problems = False
-    for dist in get_installed_distributions(**kwargs):
-        name = canonicalize_name(dist.project_name)
+    env = get_default_environment()
+    for dist in env.iter_installed_distributions(local_only=False, skip=()):
+        name = dist.canonical_name
         try:
-            package_set[name] = PackageDetails(dist.version, dist.requires())
-        except (OSError, RequirementParseError) as e:
-            # Don't crash on unreadable or broken metadata
+            dependencies = list(dist.iter_dependencies())
+            package_set[name] = PackageDetails(dist.version, dependencies)
+        except (OSError, ValueError) as e:
+            # Don't crash on unreadable or broken metadata.
             logger.warning("Error parsing requirements for %s: %s", name, e)
             problems = True
     return package_set, problems
 
 
-def check_package_set(package_set, should_ignore=None):
-    # type: (PackageSet, Optional[Callable[[str], bool]]) -> CheckResult
+def check_package_set(
+    package_set: PackageSet, should_ignore: Optional[Callable[[str], bool]] = None
+) -> CheckResult:
     """Check if a package set is consistent
 
     If should_ignore is passed, it should be a callable that takes a
@@ -63,14 +62,14 @@ def check_package_set(package_set, should_ignore=None):
 
     for package_name, package_detail in package_set.items():
         # Info about dependencies of package_name
-        missing_deps = set()  # type: Set[Missing]
-        conflicting_deps = set()  # type: Set[Conflicting]
+        missing_deps: Set[Missing] = set()
+        conflicting_deps: Set[Conflicting] = set()
 
         if should_ignore and should_ignore(package_name):
             continue
 
-        for req in package_detail.requires:
-            name = canonicalize_name(req.project_name)
+        for req in package_detail.dependencies:
+            name = canonicalize_name(req.name)
 
             # Check if it's missing
             if name not in package_set:
@@ -82,7 +81,7 @@ def check_package_set(package_set, should_ignore=None):
                 continue
 
             # Check if there's a conflict
-            version = package_set[name].version  # type: str
+            version = package_set[name].version
             if not req.specifier.contains(version, prereleases=True):
                 conflicting_deps.add((name, version, req))
 
@@ -94,8 +93,7 @@ def check_package_set(package_set, should_ignore=None):
     return missing, conflicting
 
 
-def check_install_conflicts(to_install):
-    # type: (List[InstallRequirement]) -> ConflictDetails
+def check_install_conflicts(to_install: List[InstallRequirement]) -> ConflictDetails:
     """For checking if the dependency graph would be consistent after \
     installing given requirements
     """
@@ -111,41 +109,39 @@ def check_install_conflicts(to_install):
         package_set,
         check_package_set(
             package_set, should_ignore=lambda name: name not in whitelist
-        )
+        ),
     )
 
 
-def _simulate_installation_of(to_install, package_set):
-    # type: (List[InstallRequirement], PackageSet) -> Set[NormalizedName]
-    """Computes the version of packages after installing to_install.
-    """
-
+def _simulate_installation_of(
+    to_install: List[InstallRequirement], package_set: PackageSet
+) -> Set[NormalizedName]:
+    """Computes the version of packages after installing to_install."""
     # Keep track of packages that were installed
     installed = set()
 
     # Modify it as installing requirement_set would (assuming no errors)
     for inst_req in to_install:
         abstract_dist = make_distribution_for_install_requirement(inst_req)
-        dist = abstract_dist.get_pkg_resources_distribution()
-
-        assert dist is not None
-        name = canonicalize_name(dist.key)
-        package_set[name] = PackageDetails(dist.version, dist.requires())
+        dist = abstract_dist.get_metadata_distribution()
+        name = dist.canonical_name
+        package_set[name] = PackageDetails(dist.version, list(dist.iter_dependencies()))
 
         installed.add(name)
 
     return installed
 
 
-def _create_whitelist(would_be_installed, package_set):
-    # type: (Set[NormalizedName], PackageSet) -> Set[NormalizedName]
+def _create_whitelist(
+    would_be_installed: Set[NormalizedName], package_set: PackageSet
+) -> Set[NormalizedName]:
     packages_affected = set(would_be_installed)
 
     for package_name in package_set:
         if package_name in packages_affected:
             continue
 
-        for req in package_set[package_name].requires:
+        for req in package_set[package_name].dependencies:
             if canonicalize_name(req.name) in packages_affected:
                 packages_affected.add(package_name)
                 break

venv/Lib/site-packages/pip/_internal/operations/freeze.py

@@ -1,73 +1,46 @@
 import collections
 import logging
 import os
-from typing import (
-    Container,
-    Dict,
-    Iterable,
-    Iterator,
-    List,
-    Optional,
-    Set,
-    Tuple,
-    Union,
-)
+from typing import Container, Dict, Generator, Iterable, List, NamedTuple, Optional, Set
 
 from pip._vendor.packaging.utils import canonicalize_name
-from pip._vendor.pkg_resources import Distribution, Requirement, RequirementParseError
+from pip._vendor.packaging.version import Version
 
 from pip._internal.exceptions import BadCommand, InstallationError
+from pip._internal.metadata import BaseDistribution, get_environment
 from pip._internal.req.constructors import (
     install_req_from_editable,
     install_req_from_line,
 )
 from pip._internal.req.req_file import COMMENT_RE
-from pip._internal.utils.direct_url_helpers import (
-    direct_url_as_pep440_direct_reference,
-    dist_get_direct_url,
-)
-from pip._internal.utils.misc import dist_is_editable, get_installed_distributions
+from pip._internal.utils.direct_url_helpers import direct_url_as_pep440_direct_reference
 
 logger = logging.getLogger(__name__)
 
-RequirementInfo = Tuple[Optional[Union[str, Requirement]], bool, List[str]]
+
+class _EditableInfo(NamedTuple):
+    requirement: str
+    comments: List[str]
 
 
 def freeze(
-    requirement=None,  # type: Optional[List[str]]
-    find_links=None,  # type: Optional[List[str]]
-    local_only=False,  # type: bool
-    user_only=False,  # type: bool
-    paths=None,  # type: Optional[List[str]]
-    isolated=False,  # type: bool
-    exclude_editable=False,  # type: bool
-    skip=()  # type: Container[str]
-):
-    # type: (...) -> Iterator[str]
-    find_links = find_links or []
+    requirement: Optional[List[str]] = None,
+    local_only: bool = False,
+    user_only: bool = False,
+    paths: Optional[List[str]] = None,
+    isolated: bool = False,
+    exclude_editable: bool = False,
+    skip: Container[str] = (),
+) -> Generator[str, None, None]:
+    installations: Dict[str, FrozenRequirement] = {}
 
-    for link in find_links:
-        yield f'-f {link}'
-    installations = {}  # type: Dict[str, FrozenRequirement]
-
-    for dist in get_installed_distributions(
-            local_only=local_only,
-            skip=(),
-            user_only=user_only,
-            paths=paths
-    ):
-        try:
-            req = FrozenRequirement.from_dist(dist)
-        except RequirementParseError as exc:
-            # We include dist rather than dist.project_name because the
-            # dist string includes more information, like the version and
-            # location. We also include the exception message to aid
-            # troubleshooting.
-            logger.warning(
-                'Could not generate requirement for distribution %r: %s',
-                dist, exc
-            )
-            continue
+    dists = get_environment(paths).iter_installed_distributions(
+        local_only=local_only,
+        skip=(),
+        user_only=user_only,
+    )
+    for dist in dists:
+        req = FrozenRequirement.from_dist(dist)
         if exclude_editable and req.editable:
             continue
         installations[req.canonical_name] = req
@@ -77,42 +50,50 @@ def freeze(
         # should only be emitted once, even if the same option is in multiple
         # requirements files, so we need to keep track of what has been emitted
         # so that we don't emit it again if it's seen again
-        emitted_options = set()  # type: Set[str]
+        emitted_options: Set[str] = set()
         # keep track of which files a requirement is in so that we can
         # give an accurate warning if a requirement appears multiple times.
-        req_files = collections.defaultdict(list)  # type: Dict[str, List[str]]
+        req_files: Dict[str, List[str]] = collections.defaultdict(list)
         for req_file_path in requirement:
             with open(req_file_path) as req_file:
                 for line in req_file:
-                    if (not line.strip() or
-                            line.strip().startswith('#') or
-                            line.startswith((
-                                '-r', '--requirement',
-                                '-f', '--find-links',
-                                '-i', '--index-url',
-                                '--pre',
-                                '--trusted-host',
-                                '--process-dependency-links',
-                                '--extra-index-url',
-                                '--use-feature'))):
+                    if (
+                        not line.strip()
+                        or line.strip().startswith("#")
+                        or line.startswith(
+                            (
+                                "-r",
+                                "--requirement",
+                                "-f",
+                                "--find-links",
+                                "-i",
+                                "--index-url",
+                                "--pre",
+                                "--trusted-host",
+                                "--process-dependency-links",
+                                "--extra-index-url",
+                                "--use-feature",
+                            )
+                        )
+                    ):
                         line = line.rstrip()
                         if line not in emitted_options:
                             emitted_options.add(line)
                             yield line
                         continue
 
-                    if line.startswith('-e') or line.startswith('--editable'):
-                        if line.startswith('-e'):
+                    if line.startswith("-e") or line.startswith("--editable"):
+                        if line.startswith("-e"):
                             line = line[2:].strip()
                         else:
-                            line = line[len('--editable'):].strip().lstrip('=')
+                            line = line[len("--editable") :].strip().lstrip("=")
                         line_req = install_req_from_editable(
                             line,
                             isolated=isolated,
                         )
                     else:
                         line_req = install_req_from_line(
-                            COMMENT_RE.sub('', line).strip(),
+                            COMMENT_RE.sub("", line).strip(),
                             isolated=isolated,
                         )
 
@@ -120,15 +101,15 @@ def freeze(
                         logger.info(
                             "Skipping line in requirement file [%s] because "
                             "it's not clear what it would install: %s",
-                            req_file_path, line.strip(),
+                            req_file_path,
+                            line.strip(),
                         )
                         logger.info(
                             "  (add #egg=PackageName to the URL to avoid"
                             " this warning)"
                         )
                     else:
-                        line_req_canonical_name = canonicalize_name(
-                            line_req.name)
+                        line_req_canonical_name = canonicalize_name(line_req.name)
                         if line_req_canonical_name not in installations:
                             # either it's not installed, or it is installed
                             # but has been processed already
@@ -137,14 +118,13 @@ def freeze(
                                     "Requirement file [%s] contains %s, but "
                                     "package %r is not installed",
                                     req_file_path,
-                                    COMMENT_RE.sub('', line).strip(),
-                                    line_req.name
+                                    COMMENT_RE.sub("", line).strip(),
+                                    line_req.name,
                                 )
                             else:
                                 req_files[line_req.name].append(req_file_path)
                         else:
-                            yield str(installations[
-                                line_req_canonical_name]).rstrip()
+                            yield str(installations[line_req_canonical_name]).rstrip()
                             del installations[line_req_canonical_name]
                             req_files[line_req.name].append(req_file_path)
 
@@ -152,83 +132,98 @@ def freeze(
         # single requirements file or in different requirements files).
         for name, files in req_files.items():
             if len(files) > 1:
-                logger.warning("Requirement %s included multiple times [%s]",
-                               name, ', '.join(sorted(set(files))))
+                logger.warning(
+                    "Requirement %s included multiple times [%s]",
+                    name,
+                    ", ".join(sorted(set(files))),
+                )
 
-        yield(
-            '## The following requirements were added by '
-            'pip freeze:'
-        )
-    for installation in sorted(
-            installations.values(), key=lambda x: x.name.lower()):
+        yield ("## The following requirements were added by pip freeze:")
+    for installation in sorted(installations.values(), key=lambda x: x.name.lower()):
         if installation.canonical_name not in skip:
             yield str(installation).rstrip()
 
 
-def get_requirement_info(dist):
-    # type: (Distribution) -> RequirementInfo
+def _format_as_name_version(dist: BaseDistribution) -> str:
+    if isinstance(dist.version, Version):
+        return f"{dist.raw_name}=={dist.version}"
+    return f"{dist.raw_name}==={dist.version}"
+
+
+def _get_editable_info(dist: BaseDistribution) -> _EditableInfo:
     """
-    Compute and return values (req, editable, comments) for use in
+    Compute and return values (req, comments) for use in
     FrozenRequirement.from_dist().
     """
-    if not dist_is_editable(dist):
-        return (None, False, [])
+    editable_project_location = dist.editable_project_location
+    assert editable_project_location
+    location = os.path.normcase(os.path.abspath(editable_project_location))
 
-    location = os.path.normcase(os.path.abspath(dist.location))
+    from pip._internal.vcs import RemoteNotFoundError, RemoteNotValidError, vcs
 
-    from pip._internal.vcs import RemoteNotFoundError, vcs
     vcs_backend = vcs.get_backend_for_dir(location)
 
     if vcs_backend is None:
-        req = dist.as_requirement()
+        display = _format_as_name_version(dist)
         logger.debug(
-            'No VCS found for editable requirement "%s" in: %r', req,
+            'No VCS found for editable requirement "%s" in: %r',
+            display,
             location,
         )
-        comments = [
-            f'# Editable install with no version control ({req})'
-        ]
-        return (location, True, comments)
+        return _EditableInfo(
+            requirement=location,
+            comments=[f"# Editable install with no version control ({display})"],
+        )
+
+    vcs_name = type(vcs_backend).__name__
 
     try:
-        req = vcs_backend.get_src_requirement(location, dist.project_name)
+        req = vcs_backend.get_src_requirement(location, dist.raw_name)
     except RemoteNotFoundError:
-        req = dist.as_requirement()
-        comments = [
-            '# Editable {} install with no remote ({})'.format(
-                type(vcs_backend).__name__, req,
-            )
-        ]
-        return (location, True, comments)
-
+        display = _format_as_name_version(dist)
+        return _EditableInfo(
+            requirement=location,
+            comments=[f"# Editable {vcs_name} install with no remote ({display})"],
+        )
+    except RemoteNotValidError as ex:
+        display = _format_as_name_version(dist)
+        return _EditableInfo(
+            requirement=location,
+            comments=[
+                f"# Editable {vcs_name} install ({display}) with either a deleted "
+                f"local remote or invalid URI:",
+                f"# '{ex.url}'",
+            ],
+        )
     except BadCommand:
         logger.warning(
-            'cannot determine version of editable source in %s '
-            '(%s command not found in path)',
+            "cannot determine version of editable source in %s "
+            "(%s command not found in path)",
             location,
             vcs_backend.name,
         )
-        return (None, True, [])
-
+        return _EditableInfo(requirement=location, comments=[])
     except InstallationError as exc:
-        logger.warning(
-            "Error when trying to get requirement for VCS system %s, "
-            "falling back to uneditable format", exc
-        )
+        logger.warning("Error when trying to get requirement for VCS system %s", exc)
     else:
-        return (req, True, [])
+        return _EditableInfo(requirement=req, comments=[])
 
-    logger.warning(
-        'Could not determine repository location of %s', location
+    logger.warning("Could not determine repository location of %s", location)
+
+    return _EditableInfo(
+        requirement=location,
+        comments=["## !! Could not determine repository location"],
     )
-    comments = ['## !! Could not determine repository location']
-
-    return (None, False, comments)
 
 
 class FrozenRequirement:
-    def __init__(self, name, req, editable, comments=()):
-        # type: (str, Union[str, Requirement], bool, Iterable[str]) -> None
+    def __init__(
+        self,
+        name: str,
+        req: str,
+        editable: bool,
+        comments: Iterable[str] = (),
+    ) -> None:
         self.name = name
         self.canonical_name = canonicalize_name(name)
         self.req = req
@@ -236,29 +231,24 @@ class FrozenRequirement:
         self.comments = comments
 
     @classmethod
-    def from_dist(cls, dist):
-        # type: (Distribution) -> FrozenRequirement
-        # TODO `get_requirement_info` is taking care of editable requirements.
-        # TODO This should be refactored when we will add detection of
-        #      editable that provide .dist-info metadata.
-        req, editable, comments = get_requirement_info(dist)
-        if req is None and not editable:
-            # if PEP 610 metadata is present, attempt to use it
-            direct_url = dist_get_direct_url(dist)
+    def from_dist(cls, dist: BaseDistribution) -> "FrozenRequirement":
+        editable = dist.editable
+        if editable:
+            req, comments = _get_editable_info(dist)
+        else:
+            comments = []
+            direct_url = dist.direct_url
             if direct_url:
-                req = direct_url_as_pep440_direct_reference(
-                    direct_url, dist.project_name
-                )
-                comments = []
-        if req is None:
-            # name==version requirement
-            req = dist.as_requirement()
+                # if PEP 610 metadata is present, use it
+                req = direct_url_as_pep440_direct_reference(direct_url, dist.raw_name)
+            else:
+                # name==version requirement
+                req = _format_as_name_version(dist)
 
-        return cls(dist.project_name, req, editable, comments=comments)
+        return cls(dist.raw_name, req, editable, comments=comments)
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         req = self.req
         if self.editable:
-            req = f'-e {req}'
-        return '\n'.join(list(self.comments) + [str(req)]) + '\n'
+            req = f"-e {req}"
+        return "\n".join(list(self.comments) + [str(req)]) + "\n"

venv/Lib/site-packages/pip/_internal/operations/install/editable_legacy.py

@@ -12,22 +12,21 @@ logger = logging.getLogger(__name__)
 
 
 def install_editable(
-    install_options,  # type: List[str]
-    global_options,  # type: Sequence[str]
-    prefix,  # type: Optional[str]
-    home,  # type: Optional[str]
-    use_user_site,  # type: bool
-    name,  # type: str
-    setup_py_path,  # type: str
-    isolated,  # type: bool
-    build_env,  # type: BuildEnvironment
-    unpacked_source_directory,  # type: str
-):
-    # type: (...) -> None
+    install_options: List[str],
+    global_options: Sequence[str],
+    prefix: Optional[str],
+    home: Optional[str],
+    use_user_site: bool,
+    name: str,
+    setup_py_path: str,
+    isolated: bool,
+    build_env: BuildEnvironment,
+    unpacked_source_directory: str,
+) -> None:
     """Install a package in editable mode. Most arguments are pass-through
     to setuptools.
     """
-    logger.info('Running setup.py develop for %s', name)
+    logger.info("Running setup.py develop for %s", name)
 
     args = make_setuptools_develop_args(
         setup_py_path,
@@ -43,5 +42,6 @@ def install_editable(
         with build_env:
             call_subprocess(
                 args,
+                command_desc="python setup.py develop",
                 cwd=unpacked_source_directory,
             )

venv/Lib/site-packages/pip/_internal/operations/install/legacy.py

@@ -3,14 +3,12 @@
 
 import logging
 import os
-import sys
 from distutils.util import change_root
 from typing import List, Optional, Sequence
 
 from pip._internal.build_env import BuildEnvironment
-from pip._internal.exceptions import InstallationError
+from pip._internal.exceptions import InstallationError, LegacyInstallFailure
 from pip._internal.models.scheme import Scheme
-from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import ensure_dir
 from pip._internal.utils.setuptools_build import make_setuptools_install_args
 from pip._internal.utils.subprocess import runner_with_spinner_message
@@ -19,35 +17,65 @@ from pip._internal.utils.temp_dir import TempDirectory
 logger = logging.getLogger(__name__)
 
 
-class LegacyInstallFailure(Exception):
-    def __init__(self):
-        # type: () -> None
-        self.parent = sys.exc_info()
+def write_installed_files_from_setuptools_record(
+    record_lines: List[str],
+    root: Optional[str],
+    req_description: str,
+) -> None:
+    def prepend_root(path: str) -> str:
+        if root is None or not os.path.isabs(path):
+            return path
+        else:
+            return change_root(root, path)
+
+    for line in record_lines:
+        directory = os.path.dirname(line)
+        if directory.endswith(".egg-info"):
+            egg_info_dir = prepend_root(directory)
+            break
+    else:
+        message = (
+            "{} did not indicate that it installed an "
+            ".egg-info directory. Only setup.py projects "
+            "generating .egg-info directories are supported."
+        ).format(req_description)
+        raise InstallationError(message)
+
+    new_lines = []
+    for line in record_lines:
+        filename = line.strip()
+        if os.path.isdir(filename):
+            filename += os.path.sep
+        new_lines.append(os.path.relpath(prepend_root(filename), egg_info_dir))
+    new_lines.sort()
+    ensure_dir(egg_info_dir)
+    inst_files_path = os.path.join(egg_info_dir, "installed-files.txt")
+    with open(inst_files_path, "w") as f:
+        f.write("\n".join(new_lines) + "\n")
 
 
 def install(
-    install_options,  # type: List[str]
-    global_options,  # type: Sequence[str]
-    root,  # type: Optional[str]
-    home,  # type: Optional[str]
-    prefix,  # type: Optional[str]
-    use_user_site,  # type: bool
-    pycompile,  # type: bool
-    scheme,  # type: Scheme
-    setup_py_path,  # type: str
-    isolated,  # type: bool
-    req_name,  # type: str
-    build_env,  # type: BuildEnvironment
-    unpacked_source_directory,  # type: str
-    req_description,  # type: str
-):
-    # type: (...) -> bool
+    install_options: List[str],
+    global_options: Sequence[str],
+    root: Optional[str],
+    home: Optional[str],
+    prefix: Optional[str],
+    use_user_site: bool,
+    pycompile: bool,
+    scheme: Scheme,
+    setup_py_path: str,
+    isolated: bool,
+    req_name: str,
+    build_env: BuildEnvironment,
+    unpacked_source_directory: str,
+    req_description: str,
+) -> bool:
 
     header_dir = scheme.headers
 
     with TempDirectory(kind="record") as temp_dir:
         try:
-            record_filename = os.path.join(temp_dir.path, 'install-record.txt')
+            record_filename = os.path.join(temp_dir.path, "install-record.txt")
             install_args = make_setuptools_install_args(
                 setup_py_path,
                 global_options=global_options,
@@ -65,20 +93,20 @@ def install(
             runner = runner_with_spinner_message(
                 f"Running setup.py install for {req_name}"
             )
-            with indent_log(), build_env:
+            with build_env:
                 runner(
                     cmd=install_args,
                     cwd=unpacked_source_directory,
                 )
 
             if not os.path.exists(record_filename):
-                logger.debug('Record file %s not found', record_filename)
+                logger.debug("Record file %s not found", record_filename)
                 # Signal to the caller that we didn't install the new package
                 return False
 
-        except Exception:
+        except Exception as e:
             # Signal to the caller that we didn't install the new package
-            raise LegacyInstallFailure
+            raise LegacyInstallFailure(package_details=req_name) from e
 
         # At this point, we have successfully installed the requirement.
 
@@ -88,38 +116,5 @@ def install(
         with open(record_filename) as f:
             record_lines = f.read().splitlines()
 
-    def prepend_root(path):
-        # type: (str) -> str
-        if root is None or not os.path.isabs(path):
-            return path
-        else:
-            return change_root(root, path)
-
-    for line in record_lines:
-        directory = os.path.dirname(line)
-        if directory.endswith('.egg-info'):
-            egg_info_dir = prepend_root(directory)
-            break
-    else:
-        message = (
-            "{} did not indicate that it installed an "
-            ".egg-info directory. Only setup.py projects "
-            "generating .egg-info directories are supported."
-        ).format(req_description)
-        raise InstallationError(message)
-
-    new_lines = []
-    for line in record_lines:
-        filename = line.strip()
-        if os.path.isdir(filename):
-            filename += os.path.sep
-        new_lines.append(
-            os.path.relpath(prepend_root(filename), egg_info_dir)
-        )
-    new_lines.sort()
-    ensure_dir(egg_info_dir)
-    inst_files_path = os.path.join(egg_info_dir, 'installed-files.txt')
-    with open(inst_files_path, 'w') as f:
-        f.write('\n'.join(new_lines) + '\n')
-
+    write_installed_files_from_setuptools_record(record_lines, root, req_description)
     return True

venv/Lib/site-packages/pip/_internal/operations/install/wheel.py

@@ -22,6 +22,7 @@ from typing import (
     BinaryIO,
     Callable,
     Dict,
+    Generator,
     Iterable,
     Iterator,
     List,
@@ -35,14 +36,17 @@ from typing import (
 )
 from zipfile import ZipFile, ZipInfo
 
-from pip._vendor import pkg_resources
 from pip._vendor.distlib.scripts import ScriptMaker
 from pip._vendor.distlib.util import get_export_entry
-from pip._vendor.pkg_resources import Distribution
-from pip._vendor.six import ensure_str, ensure_text, reraise
+from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.exceptions import InstallationError
 from pip._internal.locations import get_major_minor_version
+from pip._internal.metadata import (
+    BaseDistribution,
+    FilesystemWheel,
+    get_wheel_distribution,
+)
 from pip._internal.models.direct_url import DIRECT_URL_METADATA_NAME, DirectUrl
 from pip._internal.models.scheme import SCHEME_KEYS, Scheme
 from pip._internal.utils.filesystem import adjacent_tmp_file, replace
@@ -53,98 +57,76 @@ from pip._internal.utils.unpacking import (
     set_extracted_file_to_default_mode_plus_executable,
     zip_item_is_executable,
 )
-from pip._internal.utils.wheel import parse_wheel, pkg_resources_distribution_for_wheel
+from pip._internal.utils.wheel import parse_wheel
 
 if TYPE_CHECKING:
     from typing import Protocol
 
     class File(Protocol):
-        src_record_path = None  # type: RecordPath
-        dest_path = None  # type: str
-        changed = None  # type: bool
+        src_record_path: "RecordPath"
+        dest_path: str
+        changed: bool
 
-        def save(self):
-            # type: () -> None
+        def save(self) -> None:
             pass
 
 
 logger = logging.getLogger(__name__)
 
-RecordPath = NewType('RecordPath', str)
+RecordPath = NewType("RecordPath", str)
 InstalledCSVRow = Tuple[RecordPath, str, Union[int, str]]
 
 
-def rehash(path, blocksize=1 << 20):
-    # type: (str, int) -> Tuple[str, str]
+def rehash(path: str, blocksize: int = 1 << 20) -> Tuple[str, str]:
     """Return (encoded_digest, length) for path using hashlib.sha256()"""
     h, length = hash_file(path, blocksize)
-    digest = 'sha256=' + urlsafe_b64encode(
-        h.digest()
-    ).decode('latin1').rstrip('=')
+    digest = "sha256=" + urlsafe_b64encode(h.digest()).decode("latin1").rstrip("=")
     return (digest, str(length))
 
 
-def csv_io_kwargs(mode):
-    # type: (str) -> Dict[str, Any]
+def csv_io_kwargs(mode: str) -> Dict[str, Any]:
     """Return keyword arguments to properly open a CSV file
     in the given mode.
     """
-    return {'mode': mode, 'newline': '', 'encoding': 'utf-8'}
+    return {"mode": mode, "newline": "", "encoding": "utf-8"}
 
 
-def fix_script(path):
-    # type: (str) -> bool
+def fix_script(path: str) -> bool:
     """Replace #!python with #!/path/to/python
     Return True if file was changed.
     """
     # XXX RECORD hashes will need to be updated
     assert os.path.isfile(path)
 
-    with open(path, 'rb') as script:
+    with open(path, "rb") as script:
         firstline = script.readline()
-        if not firstline.startswith(b'#!python'):
+        if not firstline.startswith(b"#!python"):
             return False
         exename = sys.executable.encode(sys.getfilesystemencoding())
-        firstline = b'#!' + exename + os.linesep.encode("ascii")
+        firstline = b"#!" + exename + os.linesep.encode("ascii")
         rest = script.read()
-    with open(path, 'wb') as script:
+    with open(path, "wb") as script:
         script.write(firstline)
         script.write(rest)
     return True
 
 
-def wheel_root_is_purelib(metadata):
-    # type: (Message) -> bool
+def wheel_root_is_purelib(metadata: Message) -> bool:
     return metadata.get("Root-Is-Purelib", "").lower() == "true"
 
 
-def get_entrypoints(distribution):
-    # type: (Distribution) -> Tuple[Dict[str, str], Dict[str, str]]
-    # get the entry points and then the script names
-    try:
-        console = distribution.get_entry_map('console_scripts')
-        gui = distribution.get_entry_map('gui_scripts')
-    except KeyError:
-        # Our dict-based Distribution raises KeyError if entry_points.txt
-        # doesn't exist.
-        return {}, {}
-
-    def _split_ep(s):
-        # type: (pkg_resources.EntryPoint) -> Tuple[str, str]
-        """get the string representation of EntryPoint,
-        remove space and split on '='
-        """
-        split_parts = str(s).replace(" ", "").split("=")
-        return split_parts[0], split_parts[1]
-
-    # convert the EntryPoint objects into strings with module:function
-    console = dict(_split_ep(v) for v in console.values())
-    gui = dict(_split_ep(v) for v in gui.values())
-    return console, gui
+def get_entrypoints(dist: BaseDistribution) -> Tuple[Dict[str, str], Dict[str, str]]:
+    console_scripts = {}
+    gui_scripts = {}
+    for entry_point in dist.iter_entry_points():
+        if entry_point.group == "console_scripts":
+            console_scripts[entry_point.name] = entry_point.value
+        elif entry_point.group == "gui_scripts":
+            gui_scripts[entry_point.name] = entry_point.value
+    return console_scripts, gui_scripts
 
 
-def message_about_scripts_not_on_PATH(scripts):
-    # type: (Sequence[str]) -> Optional[str]
+def message_about_scripts_not_on_PATH(scripts: Sequence[str]) -> Optional[str]:
     """Determine if any scripts are not on PATH and format a warning.
     Returns a warning message if one or more scripts are not on PATH,
     otherwise None.
@@ -153,7 +135,7 @@ def message_about_scripts_not_on_PATH(scripts):
         return None
 
     # Group scripts by the path they were installed in
-    grouped_by_dir = collections.defaultdict(set)  # type: Dict[str, Set[str]]
+    grouped_by_dir: Dict[str, Set[str]] = collections.defaultdict(set)
     for destfile in scripts:
         parent_dir = os.path.dirname(destfile)
         script_name = os.path.basename(destfile)
@@ -161,23 +143,24 @@ def message_about_scripts_not_on_PATH(scripts):
 
     # We don't want to warn for directories that are on PATH.
     not_warn_dirs = [
-        os.path.normcase(i).rstrip(os.sep) for i in
-        os.environ.get("PATH", "").split(os.pathsep)
+        os.path.normcase(i).rstrip(os.sep)
+        for i in os.environ.get("PATH", "").split(os.pathsep)
     ]
     # If an executable sits with sys.executable, we don't warn for it.
     #     This covers the case of venv invocations without activating the venv.
     not_warn_dirs.append(os.path.normcase(os.path.dirname(sys.executable)))
-    warn_for = {
-        parent_dir: scripts for parent_dir, scripts in grouped_by_dir.items()
+    warn_for: Dict[str, Set[str]] = {
+        parent_dir: scripts
+        for parent_dir, scripts in grouped_by_dir.items()
         if os.path.normcase(parent_dir) not in not_warn_dirs
-    }  # type: Dict[str, Set[str]]
+    }
     if not warn_for:
         return None
 
     # Format a message
     msg_lines = []
     for parent_dir, dir_scripts in warn_for.items():
-        sorted_scripts = sorted(dir_scripts)  # type: List[str]
+        sorted_scripts: List[str] = sorted(dir_scripts)
         if len(sorted_scripts) == 1:
             start_text = "script {} is".format(sorted_scripts[0])
         else:
@@ -186,8 +169,9 @@ def message_about_scripts_not_on_PATH(scripts):
             )
 
         msg_lines.append(
-            "The {} installed in '{}' which is not on PATH."
-            .format(start_text, parent_dir)
+            "The {} installed in '{}' which is not on PATH.".format(
+                start_text, parent_dir
+            )
         )
 
     last_line_fmt = (
@@ -214,8 +198,9 @@ def message_about_scripts_not_on_PATH(scripts):
     return "\n".join(msg_lines)
 
 
-def _normalized_outrows(outrows):
-    # type: (Iterable[InstalledCSVRow]) -> List[Tuple[str, str, str]]
+def _normalized_outrows(
+    outrows: Iterable[InstalledCSVRow],
+) -> List[Tuple[str, str, str]]:
     """Normalize the given rows of a RECORD file.
 
     Items in each row are converted into str. Rows are then sorted to make
@@ -235,69 +220,60 @@ def _normalized_outrows(outrows):
     # For additional background, see--
     # https://github.com/pypa/pip/issues/5868
     return sorted(
-        (ensure_str(record_path, encoding='utf-8'), hash_, str(size))
-        for record_path, hash_, size in outrows
+        (record_path, hash_, str(size)) for record_path, hash_, size in outrows
     )
 
 
-def _record_to_fs_path(record_path):
-    # type: (RecordPath) -> str
+def _record_to_fs_path(record_path: RecordPath) -> str:
     return record_path
 
 
-def _fs_to_record_path(path, relative_to=None):
-    # type: (str, Optional[str]) -> RecordPath
+def _fs_to_record_path(path: str, relative_to: Optional[str] = None) -> RecordPath:
     if relative_to is not None:
         # On Windows, do not handle relative paths if they belong to different
         # logical disks
-        if os.path.splitdrive(path)[0].lower() == \
-                os.path.splitdrive(relative_to)[0].lower():
+        if (
+            os.path.splitdrive(path)[0].lower()
+            == os.path.splitdrive(relative_to)[0].lower()
+        ):
             path = os.path.relpath(path, relative_to)
-    path = path.replace(os.path.sep, '/')
-    return cast('RecordPath', path)
-
-
-def _parse_record_path(record_column):
-    # type: (str) -> RecordPath
-    p = ensure_text(record_column, encoding='utf-8')
-    return cast('RecordPath', p)
+    path = path.replace(os.path.sep, "/")
+    return cast("RecordPath", path)
 
 
 def get_csv_rows_for_installed(
-    old_csv_rows,  # type: List[List[str]]
-    installed,  # type: Dict[RecordPath, RecordPath]
-    changed,  # type: Set[RecordPath]
-    generated,  # type: List[str]
-    lib_dir,  # type: str
-):
-    # type: (...) -> List[InstalledCSVRow]
+    old_csv_rows: List[List[str]],
+    installed: Dict[RecordPath, RecordPath],
+    changed: Set[RecordPath],
+    generated: List[str],
+    lib_dir: str,
+) -> List[InstalledCSVRow]:
     """
     :param installed: A map from archive RECORD path to installation RECORD
         path.
     """
-    installed_rows = []  # type: List[InstalledCSVRow]
+    installed_rows: List[InstalledCSVRow] = []
     for row in old_csv_rows:
         if len(row) > 3:
-            logger.warning('RECORD line has more than three elements: %s', row)
-        old_record_path = _parse_record_path(row[0])
+            logger.warning("RECORD line has more than three elements: %s", row)
+        old_record_path = cast("RecordPath", row[0])
         new_record_path = installed.pop(old_record_path, old_record_path)
         if new_record_path in changed:
             digest, length = rehash(_record_to_fs_path(new_record_path))
         else:
-            digest = row[1] if len(row) > 1 else ''
-            length = row[2] if len(row) > 2 else ''
+            digest = row[1] if len(row) > 1 else ""
+            length = row[2] if len(row) > 2 else ""
         installed_rows.append((new_record_path, digest, length))
     for f in generated:
         path = _fs_to_record_path(f, lib_dir)
         digest, length = rehash(f)
         installed_rows.append((path, digest, length))
     for installed_record_path in installed.values():
-        installed_rows.append((installed_record_path, '', ''))
+        installed_rows.append((installed_record_path, "", ""))
     return installed_rows
 
 
-def get_console_script_specs(console):
-    # type: (Dict[str, str]) -> List[str]
+def get_console_script_specs(console: Dict[str, str]) -> List[str]:
     """
     Given the mapping from entrypoint name to callable, return the relevant
     console script specs.
@@ -340,62 +316,57 @@ def get_console_script_specs(console):
     # DEFAULT
     #   - The default behavior is to install pip, pipX, pipX.Y, easy_install
     #     and easy_install-X.Y.
-    pip_script = console.pop('pip', None)
+    pip_script = console.pop("pip", None)
     if pip_script:
         if "ENSUREPIP_OPTIONS" not in os.environ:
-            scripts_to_generate.append('pip = ' + pip_script)
+            scripts_to_generate.append("pip = " + pip_script)
 
         if os.environ.get("ENSUREPIP_OPTIONS", "") != "altinstall":
             scripts_to_generate.append(
-                'pip{} = {}'.format(sys.version_info[0], pip_script)
+                "pip{} = {}".format(sys.version_info[0], pip_script)
             )
 
-        scripts_to_generate.append(
-            f'pip{get_major_minor_version()} = {pip_script}'
-        )
+        scripts_to_generate.append(f"pip{get_major_minor_version()} = {pip_script}")
         # Delete any other versioned pip entry points
-        pip_ep = [k for k in console if re.match(r'pip(\d(\.\d)?)?$', k)]
+        pip_ep = [k for k in console if re.match(r"pip(\d(\.\d)?)?$", k)]
         for k in pip_ep:
             del console[k]
-    easy_install_script = console.pop('easy_install', None)
+    easy_install_script = console.pop("easy_install", None)
     if easy_install_script:
         if "ENSUREPIP_OPTIONS" not in os.environ:
-            scripts_to_generate.append(
-                'easy_install = ' + easy_install_script
-            )
+            scripts_to_generate.append("easy_install = " + easy_install_script)
 
         scripts_to_generate.append(
-            'easy_install-{} = {}'.format(
+            "easy_install-{} = {}".format(
                 get_major_minor_version(), easy_install_script
             )
         )
         # Delete any other versioned easy_install entry points
         easy_install_ep = [
-            k for k in console if re.match(r'easy_install(-\d\.\d)?$', k)
+            k for k in console if re.match(r"easy_install(-\d\.\d)?$", k)
         ]
         for k in easy_install_ep:
             del console[k]
 
     # Generate the console entry points specified in the wheel
-    scripts_to_generate.extend(starmap('{} = {}'.format, console.items()))
+    scripts_to_generate.extend(starmap("{} = {}".format, console.items()))
 
     return scripts_to_generate
 
 
 class ZipBackedFile:
-    def __init__(self, src_record_path, dest_path, zip_file):
-        # type: (RecordPath, str, ZipFile) -> None
+    def __init__(
+        self, src_record_path: RecordPath, dest_path: str, zip_file: ZipFile
+    ) -> None:
         self.src_record_path = src_record_path
         self.dest_path = dest_path
         self._zip_file = zip_file
         self.changed = False
 
-    def _getinfo(self):
-        # type: () -> ZipInfo
+    def _getinfo(self) -> ZipInfo:
         return self._zip_file.getinfo(self.src_record_path)
 
-    def save(self):
-        # type: () -> None
+    def save(self) -> None:
         # directory creation is lazy and after file filtering
         # to ensure we don't install empty dirs; empty dirs can't be
         # uninstalled.
@@ -424,22 +395,19 @@ class ZipBackedFile:
 
 
 class ScriptFile:
-    def __init__(self, file):
-        # type: (File) -> None
+    def __init__(self, file: "File") -> None:
         self._file = file
         self.src_record_path = self._file.src_record_path
         self.dest_path = self._file.dest_path
         self.changed = False
 
-    def save(self):
-        # type: () -> None
+    def save(self) -> None:
         self._file.save()
         self.changed = fix_script(self.dest_path)
 
 
 class MissingCallableSuffix(InstallationError):
-    def __init__(self, entry_point):
-        # type: (str) -> None
+    def __init__(self, entry_point: str) -> None:
         super().__init__(
             "Invalid script entry point: {} - A callable "
             "suffix is required. Cf https://packaging.python.org/"
@@ -448,31 +416,28 @@ class MissingCallableSuffix(InstallationError):
         )
 
 
-def _raise_for_invalid_entrypoint(specification):
-    # type: (str) -> None
+def _raise_for_invalid_entrypoint(specification: str) -> None:
     entry = get_export_entry(specification)
     if entry is not None and entry.suffix is None:
         raise MissingCallableSuffix(str(entry))
 
 
 class PipScriptMaker(ScriptMaker):
-    def make(self, specification, options=None):
-        # type: (str, Dict[str, Any]) -> List[str]
+    def make(self, specification: str, options: Dict[str, Any] = None) -> List[str]:
         _raise_for_invalid_entrypoint(specification)
         return super().make(specification, options)
 
 
 def _install_wheel(
-    name,  # type: str
-    wheel_zip,  # type: ZipFile
-    wheel_path,  # type: str
-    scheme,  # type: Scheme
-    pycompile=True,  # type: bool
-    warn_script_location=True,  # type: bool
-    direct_url=None,  # type: Optional[DirectUrl]
-    requested=False,  # type: bool
-):
-    # type: (...) -> None
+    name: str,
+    wheel_zip: ZipFile,
+    wheel_path: str,
+    scheme: Scheme,
+    pycompile: bool = True,
+    warn_script_location: bool = True,
+    direct_url: Optional[DirectUrl] = None,
+    requested: bool = False,
+) -> None:
     """Install a wheel.
 
     :param name: Name of the project to install
@@ -499,33 +464,23 @@ def _install_wheel(
     #   installed = files copied from the wheel to the destination
     #   changed = files changed while installing (scripts #! line typically)
     #   generated = files newly generated during the install (script wrappers)
-    installed = {}  # type: Dict[RecordPath, RecordPath]
-    changed = set()  # type: Set[RecordPath]
-    generated = []  # type: List[str]
+    installed: Dict[RecordPath, RecordPath] = {}
+    changed: Set[RecordPath] = set()
+    generated: List[str] = []
 
-    def record_installed(srcfile, destfile, modified=False):
-        # type: (RecordPath, str, bool) -> None
+    def record_installed(
+        srcfile: RecordPath, destfile: str, modified: bool = False
+    ) -> None:
         """Map archive RECORD paths to installation RECORD paths."""
         newpath = _fs_to_record_path(destfile, lib_dir)
         installed[srcfile] = newpath
         if modified:
             changed.add(_fs_to_record_path(destfile))
 
-    def all_paths():
-        # type: () -> Iterable[RecordPath]
-        names = wheel_zip.namelist()
-        # If a flag is set, names may be unicode in Python 2. We convert to
-        # text explicitly so these are valid for lookup in RECORD.
-        decoded_names = map(ensure_text, names)
-        for name in decoded_names:
-            yield cast("RecordPath", name)
-
-    def is_dir_path(path):
-        # type: (RecordPath) -> bool
+    def is_dir_path(path: RecordPath) -> bool:
         return path.endswith("/")
 
-    def assert_no_path_traversal(dest_dir_path, target_path):
-        # type: (str, str) -> None
+    def assert_no_path_traversal(dest_dir_path: str, target_path: str) -> None:
         if not is_within_directory(dest_dir_path, target_path):
             message = (
                 "The wheel {!r} has a file {!r} trying to install"
@@ -535,10 +490,10 @@ def _install_wheel(
                 message.format(wheel_path, target_path, dest_dir_path)
             )
 
-    def root_scheme_file_maker(zip_file, dest):
-        # type: (ZipFile, str) -> Callable[[RecordPath], File]
-        def make_root_scheme_file(record_path):
-            # type: (RecordPath) -> File
+    def root_scheme_file_maker(
+        zip_file: ZipFile, dest: str
+    ) -> Callable[[RecordPath], "File"]:
+        def make_root_scheme_file(record_path: RecordPath) -> "File":
             normed_path = os.path.normpath(record_path)
             dest_path = os.path.join(dest, normed_path)
             assert_no_path_traversal(dest, dest_path)
@@ -546,17 +501,12 @@ def _install_wheel(
 
         return make_root_scheme_file
 
-    def data_scheme_file_maker(zip_file, scheme):
-        # type: (ZipFile, Scheme) -> Callable[[RecordPath], File]
-        scheme_paths = {}
-        for key in SCHEME_KEYS:
-            encoded_key = ensure_text(key)
-            scheme_paths[encoded_key] = ensure_text(
-                getattr(scheme, key), encoding=sys.getfilesystemencoding()
-            )
+    def data_scheme_file_maker(
+        zip_file: ZipFile, scheme: Scheme
+    ) -> Callable[[RecordPath], "File"]:
+        scheme_paths = {key: getattr(scheme, key) for key in SCHEME_KEYS}
 
-        def make_data_scheme_file(record_path):
-            # type: (RecordPath) -> File
+        def make_data_scheme_file(record_path: RecordPath) -> "File":
             normed_path = os.path.normpath(record_path)
             try:
                 _, scheme_key, dest_subpath = normed_path.split(os.path.sep, 2)
@@ -575,9 +525,7 @@ def _install_wheel(
                     "Unknown scheme key used in {}: {} (for file {!r}). .data"
                     " directory contents should be in subdirectories named"
                     " with a valid scheme key ({})"
-                ).format(
-                    wheel_path, scheme_key, record_path, valid_scheme_keys
-                )
+                ).format(wheel_path, scheme_key, record_path, valid_scheme_keys)
                 raise InstallationError(message)
 
             dest_path = os.path.join(scheme_path, dest_subpath)
@@ -586,30 +534,19 @@ def _install_wheel(
 
         return make_data_scheme_file
 
-    def is_data_scheme_path(path):
-        # type: (RecordPath) -> bool
+    def is_data_scheme_path(path: RecordPath) -> bool:
         return path.split("/", 1)[0].endswith(".data")
 
-    paths = all_paths()
+    paths = cast(List[RecordPath], wheel_zip.namelist())
     file_paths = filterfalse(is_dir_path, paths)
-    root_scheme_paths, data_scheme_paths = partition(
-        is_data_scheme_path, file_paths
-    )
+    root_scheme_paths, data_scheme_paths = partition(is_data_scheme_path, file_paths)
 
-    make_root_scheme_file = root_scheme_file_maker(
-        wheel_zip,
-        ensure_text(lib_dir, encoding=sys.getfilesystemencoding()),
-    )
-    files = map(make_root_scheme_file, root_scheme_paths)
+    make_root_scheme_file = root_scheme_file_maker(wheel_zip, lib_dir)
+    files: Iterator[File] = map(make_root_scheme_file, root_scheme_paths)
 
-    def is_script_scheme_path(path):
-        # type: (RecordPath) -> bool
+    def is_script_scheme_path(path: RecordPath) -> bool:
         parts = path.split("/", 2)
-        return (
-            len(parts) > 2 and
-            parts[0].endswith(".data") and
-            parts[1] == "scripts"
-        )
+        return len(parts) > 2 and parts[0].endswith(".data") and parts[1] == "scripts"
 
     other_scheme_paths, script_scheme_paths = partition(
         is_script_scheme_path, data_scheme_paths
@@ -620,32 +557,32 @@ def _install_wheel(
     files = chain(files, other_scheme_files)
 
     # Get the defined entry points
-    distribution = pkg_resources_distribution_for_wheel(
-        wheel_zip, name, wheel_path
+    distribution = get_wheel_distribution(
+        FilesystemWheel(wheel_path),
+        canonicalize_name(name),
     )
     console, gui = get_entrypoints(distribution)
 
-    def is_entrypoint_wrapper(file):
-        # type: (File) -> bool
+    def is_entrypoint_wrapper(file: "File") -> bool:
         # EP, EP.exe and EP-script.py are scripts generated for
         # entry point EP by setuptools
         path = file.dest_path
         name = os.path.basename(path)
-        if name.lower().endswith('.exe'):
+        if name.lower().endswith(".exe"):
             matchname = name[:-4]
-        elif name.lower().endswith('-script.py'):
+        elif name.lower().endswith("-script.py"):
             matchname = name[:-10]
         elif name.lower().endswith(".pya"):
             matchname = name[:-4]
         else:
             matchname = name
         # Ignore setuptools-generated scripts
-        return (matchname in console or matchname in gui)
+        return matchname in console or matchname in gui
 
-    script_scheme_files = map(make_data_scheme_file, script_scheme_paths)
-    script_scheme_files = filterfalse(
-        is_entrypoint_wrapper, script_scheme_files
+    script_scheme_files: Iterator[File] = map(
+        make_data_scheme_file, script_scheme_paths
     )
+    script_scheme_files = filterfalse(is_entrypoint_wrapper, script_scheme_files)
     script_scheme_files = map(ScriptFile, script_scheme_files)
     files = chain(files, script_scheme_files)
 
@@ -653,8 +590,7 @@ def _install_wheel(
         file.save()
         record_installed(file.src_record_path, file.dest_path, file.changed)
 
-    def pyc_source_file_paths():
-        # type: () -> Iterator[str]
+    def pyc_source_file_paths() -> Generator[str, None, None]:
         # We de-duplicate installation paths, since there can be overlap (e.g.
         # file in .data maps to same location as file in wheel root).
         # Sorting installation paths makes it easier to reproduce and debug
@@ -663,30 +599,21 @@ def _install_wheel(
             full_installed_path = os.path.join(lib_dir, installed_path)
             if not os.path.isfile(full_installed_path):
                 continue
-            if not full_installed_path.endswith('.py'):
+            if not full_installed_path.endswith(".py"):
                 continue
             yield full_installed_path
 
-    def pyc_output_path(path):
-        # type: (str) -> str
-        """Return the path the pyc file would have been written to.
-        """
+    def pyc_output_path(path: str) -> str:
+        """Return the path the pyc file would have been written to."""
         return importlib.util.cache_from_source(path)
 
     # Compile all of the pyc files for the installed files
     if pycompile:
         with captured_stdout() as stdout:
             with warnings.catch_warnings():
-                warnings.filterwarnings('ignore')
+                warnings.filterwarnings("ignore")
                 for path in pyc_source_file_paths():
-                    # Python 2's `compileall.compile_file` requires a str in
-                    # error cases, so we must convert to the native type.
-                    path_arg = ensure_str(
-                        path, encoding=sys.getfilesystemencoding()
-                    )
-                    success = compileall.compile_file(
-                        path_arg, force=True, quiet=True
-                    )
+                    success = compileall.compile_file(path, force=True, quiet=True)
                     if success:
                         pyc_path = pyc_output_path(path)
                         assert os.path.exists(pyc_path)
@@ -705,7 +632,7 @@ def _install_wheel(
     # Ensure we don't generate any variants for scripts because this is almost
     # never what somebody wants.
     # See https://bitbucket.org/pypa/distlib/issue/35/
-    maker.variants = {''}
+    maker.variants = {""}
 
     # This is required because otherwise distlib creates scripts that are not
     # executable.
@@ -715,14 +642,12 @@ def _install_wheel(
     # Generate the console and GUI entry points specified in the wheel
     scripts_to_generate = get_console_script_specs(console)
 
-    gui_scripts_to_generate = list(starmap('{} = {}'.format, gui.items()))
+    gui_scripts_to_generate = list(starmap("{} = {}".format, gui.items()))
 
     generated_console_scripts = maker.make_multiple(scripts_to_generate)
     generated.extend(generated_console_scripts)
 
-    generated.extend(
-        maker.make_multiple(gui_scripts_to_generate, {'gui': True})
-    )
+    generated.extend(maker.make_multiple(gui_scripts_to_generate, {"gui": True}))
 
     if warn_script_location:
         msg = message_about_scripts_not_on_PATH(generated_console_scripts)
@@ -732,8 +657,7 @@ def _install_wheel(
     generated_file_mode = 0o666 & ~current_umask()
 
     @contextlib.contextmanager
-    def _generate_file(path, **kwargs):
-        # type: (str, **Any) -> Iterator[BinaryIO]
+    def _generate_file(path: str, **kwargs: Any) -> Generator[BinaryIO, None, None]:
         with adjacent_tmp_file(path, **kwargs) as f:
             yield f
         os.chmod(f.name, generated_file_mode)
@@ -742,9 +666,9 @@ def _install_wheel(
     dest_info_dir = os.path.join(lib_dir, info_dir)
 
     # Record pip as the installer
-    installer_path = os.path.join(dest_info_dir, 'INSTALLER')
+    installer_path = os.path.join(dest_info_dir, "INSTALLER")
     with _generate_file(installer_path) as installer_file:
-        installer_file.write(b'pip\n')
+        installer_file.write(b"pip\n")
     generated.append(installer_path)
 
     # Record the PEP 610 direct URL reference
@@ -756,12 +680,12 @@ def _install_wheel(
 
     # Record the REQUESTED file
     if requested:
-        requested_path = os.path.join(dest_info_dir, 'REQUESTED')
+        requested_path = os.path.join(dest_info_dir, "REQUESTED")
         with open(requested_path, "wb"):
             pass
         generated.append(requested_path)
 
-    record_text = distribution.get_metadata('RECORD')
+    record_text = distribution.read_text("RECORD")
     record_rows = list(csv.reader(record_text.splitlines()))
 
     rows = get_csv_rows_for_installed(
@@ -769,42 +693,38 @@ def _install_wheel(
         installed=installed,
         changed=changed,
         generated=generated,
-        lib_dir=lib_dir)
+        lib_dir=lib_dir,
+    )
 
     # Record details of all files installed
-    record_path = os.path.join(dest_info_dir, 'RECORD')
+    record_path = os.path.join(dest_info_dir, "RECORD")
 
-    with _generate_file(record_path, **csv_io_kwargs('w')) as record_file:
-        # The type mypy infers for record_file is different for Python 3
-        # (typing.IO[Any]) and Python 2 (typing.BinaryIO). We explicitly
-        # cast to typing.IO[str] as a workaround.
-        writer = csv.writer(cast('IO[str]', record_file))
+    with _generate_file(record_path, **csv_io_kwargs("w")) as record_file:
+        # Explicitly cast to typing.IO[str] as a workaround for the mypy error:
+        # "writer" has incompatible type "BinaryIO"; expected "_Writer"
+        writer = csv.writer(cast("IO[str]", record_file))
         writer.writerows(_normalized_outrows(rows))
 
 
 @contextlib.contextmanager
-def req_error_context(req_description):
-    # type: (str) -> Iterator[None]
+def req_error_context(req_description: str) -> Generator[None, None, None]:
     try:
         yield
     except InstallationError as e:
         message = "For req: {}. {}".format(req_description, e.args[0])
-        reraise(
-            InstallationError, InstallationError(message), sys.exc_info()[2]
-        )
+        raise InstallationError(message) from e
 
 
 def install_wheel(
-    name,  # type: str
-    wheel_path,  # type: str
-    scheme,  # type: Scheme
-    req_description,  # type: str
-    pycompile=True,  # type: bool
-    warn_script_location=True,  # type: bool
-    direct_url=None,  # type: Optional[DirectUrl]
-    requested=False,  # type: bool
-):
-    # type: (...) -> None
+    name: str,
+    wheel_path: str,
+    scheme: Scheme,
+    req_description: str,
+    pycompile: bool = True,
+    warn_script_location: bool = True,
+    direct_url: Optional[DirectUrl] = None,
+    requested: bool = False,
+) -> None:
     with ZipFile(wheel_path, allowZip64=True) as z:
         with req_error_context(req_description):
             _install_wheel(

venv/Lib/site-packages/pip/_internal/operations/prepare.py

@@ -8,10 +8,9 @@ import logging
 import mimetypes
 import os
 import shutil
-from typing import Dict, Iterable, List, Optional, Tuple
+from typing import Dict, Iterable, List, Optional
 
 from pip._vendor.packaging.utils import canonicalize_name
-from pip._vendor.pkg_resources import Distribution
 
 from pip._internal.distributions import make_distribution_for_install_requirement
 from pip._internal.distributions.installed import InstalledDistribution
@@ -25,6 +24,7 @@ from pip._internal.exceptions import (
     VcsHashUnsupported,
 )
 from pip._internal.index.package_finder import PackageFinder
+from pip._internal.metadata import BaseDistribution
 from pip._internal.models.link import Link
 from pip._internal.models.wheel import Wheel
 from pip._internal.network.download import BatchDownloader, Downloader
@@ -33,13 +33,11 @@ from pip._internal.network.lazy_wheel import (
     dist_from_wheel_url,
 )
 from pip._internal.network.session import PipSession
+from pip._internal.operations.build.build_tracker import BuildTracker
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_tracker import RequirementTracker
-from pip._internal.utils.deprecation import deprecated
-from pip._internal.utils.filesystem import copy2_fixed
 from pip._internal.utils.hashes import Hashes, MissingHashes
 from pip._internal.utils.logging import indent_log
-from pip._internal.utils.misc import display_path, hide_url, rmtree
+from pip._internal.utils.misc import display_path, hide_url, is_installable_dir
 from pip._internal.utils.temp_dir import TempDirectory
 from pip._internal.utils.unpacking import unpack_file
 from pip._internal.vcs import vcs
@@ -48,30 +46,29 @@ logger = logging.getLogger(__name__)
 
 
 def _get_prepared_distribution(
-    req,  # type: InstallRequirement
-    req_tracker,  # type: RequirementTracker
-    finder,  # type: PackageFinder
-    build_isolation,  # type: bool
-):
-    # type: (...) -> Distribution
+    req: InstallRequirement,
+    build_tracker: BuildTracker,
+    finder: PackageFinder,
+    build_isolation: bool,
+    check_build_deps: bool,
+) -> BaseDistribution:
     """Prepare a distribution for installation."""
     abstract_dist = make_distribution_for_install_requirement(req)
-    with req_tracker.track(req):
-        abstract_dist.prepare_distribution_metadata(finder, build_isolation)
-    return abstract_dist.get_pkg_resources_distribution()
+    with build_tracker.track(req):
+        abstract_dist.prepare_distribution_metadata(
+            finder, build_isolation, check_build_deps
+        )
+    return abstract_dist.get_metadata_distribution()
 
 
-def unpack_vcs_link(link, location):
-    # type: (Link, str) -> None
+def unpack_vcs_link(link: Link, location: str, verbosity: int) -> None:
     vcs_backend = vcs.get_backend_for_scheme(link.scheme)
     assert vcs_backend is not None
-    vcs_backend.unpack(location, url=hide_url(link.url))
+    vcs_backend.unpack(location, url=hide_url(link.url), verbosity=verbosity)
 
 
 class File:
-
-    def __init__(self, path, content_type):
-        # type: (str, Optional[str]) -> None
+    def __init__(self, path: str, content_type: Optional[str]) -> None:
         self.path = path
         if content_type is None:
             self.content_type = mimetypes.guess_type(path)[0]
@@ -80,19 +77,16 @@ class File:
 
 
 def get_http_url(
-    link,  # type: Link
-    download,  # type: Downloader
-    download_dir=None,  # type: Optional[str]
-    hashes=None,  # type: Optional[Hashes]
-):
-    # type: (...) -> File
+    link: Link,
+    download: Downloader,
+    download_dir: Optional[str] = None,
+    hashes: Optional[Hashes] = None,
+) -> File:
     temp_dir = TempDirectory(kind="unpack", globally_managed=True)
     # If a download dir is specified, is the file already downloaded there?
     already_downloaded_path = None
     if download_dir:
-        already_downloaded_path = _check_download_dir(
-            link, download_dir, hashes
-        )
+        already_downloaded_path = _check_download_dir(link, download_dir, hashes)
 
     if already_downloaded_path:
         from_path = already_downloaded_path
@@ -106,72 +100,14 @@ def get_http_url(
     return File(from_path, content_type)
 
 
-def _copy2_ignoring_special_files(src, dest):
-    # type: (str, str) -> None
-    """Copying special files is not supported, but as a convenience to users
-    we skip errors copying them. This supports tools that may create e.g.
-    socket files in the project source directory.
-    """
-    try:
-        copy2_fixed(src, dest)
-    except shutil.SpecialFileError as e:
-        # SpecialFileError may be raised due to either the source or
-        # destination. If the destination was the cause then we would actually
-        # care, but since the destination directory is deleted prior to
-        # copy we ignore all of them assuming it is caused by the source.
-        logger.warning(
-            "Ignoring special file error '%s' encountered copying %s to %s.",
-            str(e),
-            src,
-            dest,
-        )
-
-
-def _copy_source_tree(source, target):
-    # type: (str, str) -> None
-    target_abspath = os.path.abspath(target)
-    target_basename = os.path.basename(target_abspath)
-    target_dirname = os.path.dirname(target_abspath)
-
-    def ignore(d, names):
-        # type: (str, List[str]) -> List[str]
-        skipped = []  # type: List[str]
-        if d == source:
-            # Pulling in those directories can potentially be very slow,
-            # exclude the following directories if they appear in the top
-            # level dir (and only it).
-            # See discussion at https://github.com/pypa/pip/pull/6770
-            skipped += ['.tox', '.nox']
-        if os.path.abspath(d) == target_dirname:
-            # Prevent an infinite recursion if the target is in source.
-            # This can happen when TMPDIR is set to ${PWD}/...
-            # and we copy PWD to TMPDIR.
-            skipped += [target_basename]
-        return skipped
-
-    shutil.copytree(
-        source,
-        target,
-        ignore=ignore,
-        symlinks=True,
-        copy_function=_copy2_ignoring_special_files,
-    )
-
-
 def get_file_url(
-    link,  # type: Link
-    download_dir=None,  # type: Optional[str]
-    hashes=None  # type: Optional[Hashes]
-):
-    # type: (...) -> File
-    """Get file and optionally check its hash.
-    """
+    link: Link, download_dir: Optional[str] = None, hashes: Optional[Hashes] = None
+) -> File:
+    """Get file and optionally check its hash."""
     # If a download dir is specified, is the file already there and valid?
     already_downloaded_path = None
     if download_dir:
-        already_downloaded_path = _check_download_dir(
-            link, download_dir, hashes
-        )
+        already_downloaded_path = _check_download_dir(link, download_dir, hashes)
 
     if already_downloaded_path:
         from_path = already_downloaded_path
@@ -189,13 +125,13 @@ def get_file_url(
 
 
 def unpack_url(
-    link,  # type: Link
-    location,  # type: str
-    download,  # type: Downloader
-    download_dir=None,  # type: Optional[str]
-    hashes=None,  # type: Optional[Hashes]
-):
-    # type: (...) -> Optional[File]
+    link: Link,
+    location: str,
+    download: Downloader,
+    verbosity: int,
+    download_dir: Optional[str] = None,
+    hashes: Optional[Hashes] = None,
+) -> Optional[File]:
     """Unpack link into location, downloading if required.
 
     :param hashes: A Hashes object, one of whose embedded hashes must match,
@@ -205,30 +141,10 @@ def unpack_url(
     """
     # non-editable vcs urls
     if link.is_vcs:
-        unpack_vcs_link(link, location)
+        unpack_vcs_link(link, location, verbosity=verbosity)
         return None
 
-    # Once out-of-tree-builds are no longer supported, could potentially
-    # replace the below condition with `assert not link.is_existing_dir`
-    # - unpack_url does not need to be called for in-tree-builds.
-    #
-    # As further cleanup, _copy_source_tree and accompanying tests can
-    # be removed.
-    if link.is_existing_dir():
-        deprecated(
-            "A future pip version will change local packages to be built "
-            "in-place without first copying to a temporary directory. "
-            "We recommend you use --use-feature=in-tree-build to test "
-            "your packages with this new behavior before it becomes the "
-            "default.\n",
-            replacement=None,
-            gone_in="21.3",
-            issue=7555
-        )
-        if os.path.isdir(location):
-            rmtree(location)
-        _copy_source_tree(link.file_path, location)
-        return None
+    assert not link.is_existing_dir()
 
     # file urls
     if link.is_file:
@@ -251,10 +167,11 @@ def unpack_url(
     return file
 
 
-def _check_download_dir(link, download_dir, hashes):
-    # type: (Link, str, Optional[Hashes]) -> Optional[str]
-    """ Check download_dir for previously downloaded file with correct hash
-        If a correct file is found return its path else None
+def _check_download_dir(
+    link: Link, download_dir: str, hashes: Optional[Hashes]
+) -> Optional[str]:
+    """Check download_dir for previously downloaded file with correct hash
+    If a correct file is found return its path else None
     """
     download_path = os.path.join(download_dir, link.filename)
 
@@ -262,15 +179,14 @@ def _check_download_dir(link, download_dir, hashes):
         return None
 
     # If already downloaded, does its hash match?
-    logger.info('File was already downloaded %s', download_path)
+    logger.info("File was already downloaded %s", download_path)
     if hashes:
         try:
             hashes.check_against_path(download_path)
         except HashMismatch:
             logger.warning(
-                'Previously-downloaded file %s has bad hash. '
-                'Re-downloading.',
-                download_path
+                "Previously-downloaded file %s has bad hash. Re-downloading.",
+                download_path,
             )
             os.unlink(download_path)
             return None
@@ -278,30 +194,29 @@ def _check_download_dir(link, download_dir, hashes):
 
 
 class RequirementPreparer:
-    """Prepares a Requirement
-    """
+    """Prepares a Requirement"""
 
     def __init__(
         self,
-        build_dir,  # type: str
-        download_dir,  # type: Optional[str]
-        src_dir,  # type: str
-        build_isolation,  # type: bool
-        req_tracker,  # type: RequirementTracker
-        session,  # type: PipSession
-        progress_bar,  # type: str
-        finder,  # type: PackageFinder
-        require_hashes,  # type: bool
-        use_user_site,  # type: bool
-        lazy_wheel,  # type: bool
-        in_tree_build,  # type: bool
-    ):
-        # type: (...) -> None
+        build_dir: str,
+        download_dir: Optional[str],
+        src_dir: str,
+        build_isolation: bool,
+        check_build_deps: bool,
+        build_tracker: BuildTracker,
+        session: PipSession,
+        progress_bar: str,
+        finder: PackageFinder,
+        require_hashes: bool,
+        use_user_site: bool,
+        lazy_wheel: bool,
+        verbosity: int,
+    ) -> None:
         super().__init__()
 
         self.src_dir = src_dir
         self.build_dir = build_dir
-        self.req_tracker = req_tracker
+        self.build_tracker = build_tracker
         self._session = session
         self._download = Downloader(session, progress_bar)
         self._batch_download = BatchDownloader(session, progress_bar)
@@ -314,6 +229,9 @@ class RequirementPreparer:
         # Is build isolation allowed?
         self.build_isolation = build_isolation
 
+        # Should check build dependencies?
+        self.check_build_deps = check_build_deps
+
         # Should hash-checking be required?
         self.require_hashes = require_hashes
 
@@ -323,17 +241,16 @@ class RequirementPreparer:
         # Should wheels be downloaded lazily?
         self.use_lazy_wheel = lazy_wheel
 
-        # Should in-tree builds be used for local paths?
-        self.in_tree_build = in_tree_build
+        # How verbose should underlying tooling be?
+        self.verbosity = verbosity
 
-        # Memoized downloaded files, as mapping of url: (path, mime type)
-        self._downloaded = {}  # type: Dict[str, Tuple[str, str]]
+        # Memoized downloaded files, as mapping of url: path.
+        self._downloaded: Dict[str, str] = {}
 
         # Previous "header" printed for a link-based InstallRequirement
         self._previous_requirement_header = ("", "")
 
-    def _log_preparing_link(self, req):
-        # type: (InstallRequirement) -> None
+    def _log_preparing_link(self, req: InstallRequirement) -> None:
         """Provide context for the requirement being prepared."""
         if req.link.is_file and not req.original_link_is_in_wheel_cache:
             message = "Processing %s"
@@ -350,8 +267,9 @@ class RequirementPreparer:
             with indent_log():
                 logger.info("Using cached %s", req.link.filename)
 
-    def _ensure_link_req_src_dir(self, req, parallel_builds):
-        # type: (InstallRequirement, bool) -> None
+    def _ensure_link_req_src_dir(
+        self, req: InstallRequirement, parallel_builds: bool
+    ) -> None:
         """Ensure source_dir of a linked InstallRequirement."""
         # Since source_dir is only set for editable requirements.
         if req.link.is_wheel:
@@ -359,7 +277,7 @@ class RequirementPreparer:
             # directory.
             return
         assert req.source_dir is None
-        if req.link.is_existing_dir() and self.in_tree_build:
+        if req.link.is_existing_dir():
             # build local directories in-tree
             req.source_dir = req.link.file_path
             return
@@ -376,7 +294,8 @@ class RequirementPreparer:
         # installation.
         # FIXME: this won't upgrade when there's an existing
         # package unpacked in `req.source_dir`
-        if os.path.exists(os.path.join(req.source_dir, 'setup.py')):
+        # TODO: this check is now probably dead code
+        if is_installable_dir(req.source_dir):
             raise PreviousBuildDirError(
                 "pip can't proceed with requirements '{}' due to a"
                 "pre-existing build directory ({}). This is likely "
@@ -385,8 +304,7 @@ class RequirementPreparer:
                 "Please delete it and try again.".format(req, req.source_dir)
             )
 
-    def _get_linked_req_hashes(self, req):
-        # type: (InstallRequirement) -> Hashes
+    def _get_linked_req_hashes(self, req: InstallRequirement) -> Hashes:
         # By the time this is called, the requirement's link should have
         # been checked so we can tell what kind of requirements req is
         # and raise some more informative errors than otherwise.
@@ -418,18 +336,19 @@ class RequirementPreparer:
         # showing the user what the hash should be.
         return req.hashes(trust_internet=False) or MissingHashes()
 
-    def _fetch_metadata_using_lazy_wheel(self, link):
-        # type: (Link) -> Optional[Distribution]
+    def _fetch_metadata_using_lazy_wheel(
+        self,
+        link: Link,
+    ) -> Optional[BaseDistribution]:
         """Fetch metadata using lazy wheel, if possible."""
         if not self.use_lazy_wheel:
             return None
         if self.require_hashes:
-            logger.debug('Lazy wheel is not used as hash checking is required')
+            logger.debug("Lazy wheel is not used as hash checking is required")
             return None
         if link.is_file or not link.is_wheel:
             logger.debug(
-                'Lazy wheel is not used as '
-                '%r does not points to a remote wheel',
+                "Lazy wheel is not used as %r does not points to a remote wheel",
                 link,
             )
             return None
@@ -437,22 +356,22 @@ class RequirementPreparer:
         wheel = Wheel(link.filename)
         name = canonicalize_name(wheel.name)
         logger.info(
-            'Obtaining dependency information from %s %s',
-            name, wheel.version,
+            "Obtaining dependency information from %s %s",
+            name,
+            wheel.version,
         )
-        url = link.url.split('#', 1)[0]
+        url = link.url.split("#", 1)[0]
         try:
             return dist_from_wheel_url(name, url, self._session)
         except HTTPRangeRequestUnsupported:
-            logger.debug('%s does not support range requests', url)
+            logger.debug("%s does not support range requests", url)
             return None
 
     def _complete_partial_requirements(
         self,
-        partially_downloaded_reqs,  # type: Iterable[InstallRequirement]
-        parallel_builds=False,      # type: bool
-    ):
-        # type: (...) -> None
+        partially_downloaded_reqs: Iterable[InstallRequirement],
+        parallel_builds: bool = False,
+    ) -> None:
         """Download any requirements which were only fetched by metadata."""
         # Download to a temporary directory. These will be copied over as
         # needed for downstream 'download', 'wheel', and 'install' commands.
@@ -461,7 +380,7 @@ class RequirementPreparer:
         # Map each link to the requirement that owns it. This allows us to set
         # `req.local_file_path` on the appropriate requirement after passing
         # all the links at once into BatchDownloader.
-        links_to_fully_download = {}  # type: Dict[Link, InstallRequirement]
+        links_to_fully_download: Dict[Link, InstallRequirement] = {}
         for req in partially_downloaded_reqs:
             assert req.link
             links_to_fully_download[req.link] = req
@@ -480,8 +399,9 @@ class RequirementPreparer:
         for req in partially_downloaded_reqs:
             self._prepare_linked_requirement(req, parallel_builds)
 
-    def prepare_linked_requirement(self, req, parallel_builds=False):
-        # type: (InstallRequirement, bool) -> Distribution
+    def prepare_linked_requirement(
+        self, req: InstallRequirement, parallel_builds: bool = False
+    ) -> BaseDistribution:
         """Prepare a requirement to be obtained from req.link."""
         assert req.link
         link = req.link
@@ -496,7 +416,7 @@ class RequirementPreparer:
 
             if file_path is not None:
                 # The file is already available, so mark it as downloaded
-                self._downloaded[req.link.url] = file_path, None
+                self._downloaded[req.link.url] = file_path
             else:
                 # The file is not available, attempt to fetch only metadata
                 wheel_dist = self._fetch_metadata_using_lazy_wheel(link)
@@ -507,8 +427,9 @@ class RequirementPreparer:
             # None of the optimizations worked, fully prepare the requirement
             return self._prepare_linked_requirement(req, parallel_builds)
 
-    def prepare_linked_requirements_more(self, reqs, parallel_builds=False):
-        # type: (Iterable[InstallRequirement], bool) -> None
+    def prepare_linked_requirements_more(
+        self, reqs: Iterable[InstallRequirement], parallel_builds: bool = False
+    ) -> None:
         """Prepare linked requirements more, if needed."""
         reqs = [req for req in reqs if req.needs_more_preparation]
         for req in reqs:
@@ -517,12 +438,12 @@ class RequirementPreparer:
                 hashes = self._get_linked_req_hashes(req)
                 file_path = _check_download_dir(req.link, self.download_dir, hashes)
                 if file_path is not None:
-                    self._downloaded[req.link.url] = file_path, None
+                    self._downloaded[req.link.url] = file_path
                     req.needs_more_preparation = False
 
         # Prepare requirements we found were already downloaded for some
         # reason. The other downloads will be completed separately.
-        partially_downloaded_reqs = []  # type: List[InstallRequirement]
+        partially_downloaded_reqs: List[InstallRequirement] = []
         for req in reqs:
             if req.needs_more_preparation:
                 partially_downloaded_reqs.append(req)
@@ -532,35 +453,41 @@ class RequirementPreparer:
         # TODO: separate this part out from RequirementPreparer when the v1
         # resolver can be removed!
         self._complete_partial_requirements(
-            partially_downloaded_reqs, parallel_builds=parallel_builds,
+            partially_downloaded_reqs,
+            parallel_builds=parallel_builds,
         )
 
-    def _prepare_linked_requirement(self, req, parallel_builds):
-        # type: (InstallRequirement, bool) -> Distribution
+    def _prepare_linked_requirement(
+        self, req: InstallRequirement, parallel_builds: bool
+    ) -> BaseDistribution:
         assert req.link
         link = req.link
 
         self._ensure_link_req_src_dir(req, parallel_builds)
         hashes = self._get_linked_req_hashes(req)
 
-        if link.is_existing_dir() and self.in_tree_build:
+        if link.is_existing_dir():
             local_file = None
         elif link.url not in self._downloaded:
             try:
                 local_file = unpack_url(
-                    link, req.source_dir, self._download,
-                    self.download_dir, hashes
+                    link,
+                    req.source_dir,
+                    self._download,
+                    self.verbosity,
+                    self.download_dir,
+                    hashes,
                 )
             except NetworkConnectionError as exc:
                 raise InstallationError(
-                    'Could not install requirement {} because of HTTP '
-                    'error {} for URL {}'.format(req, exc, link)
+                    "Could not install requirement {} because of HTTP "
+                    "error {} for URL {}".format(req, exc, link)
                 )
         else:
-            file_path, content_type = self._downloaded[link.url]
+            file_path = self._downloaded[link.url]
             if hashes:
                 hashes.check_against_path(file_path)
-            local_file = File(file_path, content_type)
+            local_file = File(file_path, content_type=None)
 
         # For use in later processing,
         # preserve the file path on the requirement.
@@ -568,12 +495,15 @@ class RequirementPreparer:
             req.local_file_path = local_file.path
 
         dist = _get_prepared_distribution(
-            req, self.req_tracker, self.finder, self.build_isolation,
+            req,
+            self.build_tracker,
+            self.finder,
+            self.build_isolation,
+            self.check_build_deps,
         )
         return dist
 
-    def save_linked_requirement(self, req):
-        # type: (InstallRequirement) -> None
+    def save_linked_requirement(self, req: InstallRequirement) -> None:
         assert self.download_dir is not None
         assert req.link is not None
         link = req.link
@@ -584,8 +514,9 @@ class RequirementPreparer:
 
         if link.is_existing_dir():
             logger.debug(
-                'Not copying link to destination directory '
-                'since it is a directory: %s', link,
+                "Not copying link to destination directory "
+                "since it is a directory: %s",
+                link,
             )
             return
         if req.local_file_path is None:
@@ -596,31 +527,33 @@ class RequirementPreparer:
         if not os.path.exists(download_location):
             shutil.copy(req.local_file_path, download_location)
             download_path = display_path(download_location)
-            logger.info('Saved %s', download_path)
+            logger.info("Saved %s", download_path)
 
     def prepare_editable_requirement(
         self,
-        req,  # type: InstallRequirement
-    ):
-        # type: (...) -> Distribution
-        """Prepare an editable requirement
-        """
+        req: InstallRequirement,
+    ) -> BaseDistribution:
+        """Prepare an editable requirement."""
         assert req.editable, "cannot prepare a non-editable req as editable"
 
-        logger.info('Obtaining %s', req)
+        logger.info("Obtaining %s", req)
 
         with indent_log():
             if self.require_hashes:
                 raise InstallationError(
-                    'The editable requirement {} cannot be installed when '
-                    'requiring hashes, because there is no single file to '
-                    'hash.'.format(req)
+                    "The editable requirement {} cannot be installed when "
+                    "requiring hashes, because there is no single file to "
+                    "hash.".format(req)
                 )
             req.ensure_has_source_dir(self.src_dir)
             req.update_editable()
 
             dist = _get_prepared_distribution(
-                req, self.req_tracker, self.finder, self.build_isolation,
+                req,
+                self.build_tracker,
+                self.finder,
+                self.build_isolation,
+                self.check_build_deps,
             )
 
             req.check_if_exists(self.use_user_site)
@@ -629,27 +562,24 @@ class RequirementPreparer:
 
     def prepare_installed_requirement(
         self,
-        req,  # type: InstallRequirement
-        skip_reason  # type: str
-    ):
-        # type: (...) -> Distribution
-        """Prepare an already-installed requirement
-        """
+        req: InstallRequirement,
+        skip_reason: str,
+    ) -> BaseDistribution:
+        """Prepare an already-installed requirement."""
         assert req.satisfied_by, "req should have been satisfied but isn't"
         assert skip_reason is not None, (
             "did not get skip reason skipped but req.satisfied_by "
             "is set to {}".format(req.satisfied_by)
         )
         logger.info(
-            'Requirement %s: %s (%s)',
-            skip_reason, req, req.satisfied_by.version
+            "Requirement %s: %s (%s)", skip_reason, req, req.satisfied_by.version
         )
         with indent_log():
             if self.require_hashes:
                 logger.debug(
-                    'Since it is already installed, we are trusting this '
-                    'package without checking its hash. To ensure a '
-                    'completely repeatable environment, install into an '
-                    'empty virtualenv.'
+                    "Since it is already installed, we are trusting this "
+                    "package without checking its hash. To ensure a "
+                    "completely repeatable environment, install into an "
+                    "empty virtualenv."
                 )
-            return InstalledDistribution(req).get_pkg_resources_distribution()
+            return InstalledDistribution(req).get_metadata_distribution()

venv/Lib/site-packages/pip/_internal/pyproject.py

@@ -1,38 +1,34 @@
+import importlib.util
 import os
 from collections import namedtuple
 from typing import Any, List, Optional
 
-from pip._vendor import toml
+from pip._vendor import tomli
 from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
 
-from pip._internal.exceptions import InstallationError
+from pip._internal.exceptions import (
+    InstallationError,
+    InvalidPyProjectBuildRequires,
+    MissingPyProjectBuildRequires,
+)
 
 
-def _is_list_of_str(obj):
-    # type: (Any) -> bool
-    return (
-        isinstance(obj, list) and
-        all(isinstance(item, str) for item in obj)
-    )
+def _is_list_of_str(obj: Any) -> bool:
+    return isinstance(obj, list) and all(isinstance(item, str) for item in obj)
 
 
-def make_pyproject_path(unpacked_source_directory):
-    # type: (str) -> str
-    return os.path.join(unpacked_source_directory, 'pyproject.toml')
+def make_pyproject_path(unpacked_source_directory: str) -> str:
+    return os.path.join(unpacked_source_directory, "pyproject.toml")
 
 
-BuildSystemDetails = namedtuple('BuildSystemDetails', [
-    'requires', 'backend', 'check', 'backend_path'
-])
+BuildSystemDetails = namedtuple(
+    "BuildSystemDetails", ["requires", "backend", "check", "backend_path"]
+)
 
 
 def load_pyproject_toml(
-    use_pep517,  # type: Optional[bool]
-    pyproject_toml,  # type: str
-    setup_py,  # type: str
-    req_name  # type: str
-):
-    # type: (...) -> Optional[BuildSystemDetails]
+    use_pep517: Optional[bool], pyproject_toml: str, setup_py: str, req_name: str
+) -> Optional[BuildSystemDetails]:
     """Load the pyproject.toml file.
 
     Parameters:
@@ -57,9 +53,15 @@ def load_pyproject_toml(
     has_pyproject = os.path.isfile(pyproject_toml)
     has_setup = os.path.isfile(setup_py)
 
+    if not has_pyproject and not has_setup:
+        raise InstallationError(
+            f"{req_name} does not appear to be a Python project: "
+            f"neither 'setup.py' nor 'pyproject.toml' found."
+        )
+
     if has_pyproject:
         with open(pyproject_toml, encoding="utf-8") as f:
-            pp_toml = toml.load(f)
+            pp_toml = tomli.loads(f.read())
         build_system = pp_toml.get("build-system")
     else:
         build_system = None
@@ -82,17 +84,21 @@ def load_pyproject_toml(
             raise InstallationError(
                 "Disabling PEP 517 processing is invalid: "
                 "project specifies a build backend of {} "
-                "in pyproject.toml".format(
-                    build_system["build-backend"]
-                )
+                "in pyproject.toml".format(build_system["build-backend"])
             )
         use_pep517 = True
 
     # If we haven't worked out whether to use PEP 517 yet,
     # and the user hasn't explicitly stated a preference,
-    # we do so if the project has a pyproject.toml file.
+    # we do so if the project has a pyproject.toml file
+    # or if we cannot import setuptools.
+
+    # We fallback to PEP 517 when without setuptools,
+    # so setuptools can be installed as a default build backend.
+    # For more info see:
+    # https://discuss.python.org/t/pip-without-setuptools-could-the-experience-be-improved/11810/9
     elif use_pep517 is None:
-        use_pep517 = has_pyproject
+        use_pep517 = has_pyproject or not importlib.util.find_spec("setuptools")
 
     # At this point, we know whether we're going to use PEP 517.
     assert use_pep517 is not None
@@ -124,46 +130,32 @@ def load_pyproject_toml(
 
     # Ensure that the build-system section in pyproject.toml conforms
     # to PEP 518.
-    error_template = (
-        "{package} has a pyproject.toml file that does not comply "
-        "with PEP 518: {reason}"
-    )
 
     # Specifying the build-system table but not the requires key is invalid
     if "requires" not in build_system:
-        raise InstallationError(
-            error_template.format(package=req_name, reason=(
-                "it has a 'build-system' table but not "
-                "'build-system.requires' which is mandatory in the table"
-            ))
-        )
+        raise MissingPyProjectBuildRequires(package=req_name)
 
     # Error out if requires is not a list of strings
     requires = build_system["requires"]
     if not _is_list_of_str(requires):
-        raise InstallationError(error_template.format(
+        raise InvalidPyProjectBuildRequires(
             package=req_name,
-            reason="'build-system.requires' is not a list of strings.",
-        ))
+            reason="It is not a list of strings.",
+        )
 
     # Each requirement must be valid as per PEP 508
     for requirement in requires:
         try:
             Requirement(requirement)
-        except InvalidRequirement:
-            raise InstallationError(
-                error_template.format(
-                    package=req_name,
-                    reason=(
-                        "'build-system.requires' contains an invalid "
-                        "requirement: {!r}".format(requirement)
-                    ),
-                )
-            )
+        except InvalidRequirement as error:
+            raise InvalidPyProjectBuildRequires(
+                package=req_name,
+                reason=f"It contains an invalid requirement: {requirement!r}",
+            ) from error
 
     backend = build_system.get("build-backend")
     backend_path = build_system.get("backend-path", [])
-    check = []  # type: List[str]
+    check: List[str] = []
     if backend is None:
         # If the user didn't specify a backend, we assume they want to use
         # the setuptools backend. But we can't be sure they have included

venv/Lib/site-packages/pip/_internal/req/__init__.py

@@ -1,6 +1,6 @@
 import collections
 import logging
-from typing import Iterator, List, Optional, Sequence, Tuple
+from typing import Generator, List, Optional, Sequence, Tuple
 
 from pip._internal.utils.logging import indent_log
 
@@ -9,44 +9,42 @@ from .req_install import InstallRequirement
 from .req_set import RequirementSet
 
 __all__ = [
-    "RequirementSet", "InstallRequirement",
-    "parse_requirements", "install_given_reqs",
+    "RequirementSet",
+    "InstallRequirement",
+    "parse_requirements",
+    "install_given_reqs",
 ]
 
 logger = logging.getLogger(__name__)
 
 
 class InstallationResult:
-    def __init__(self, name):
-        # type: (str) -> None
+    def __init__(self, name: str) -> None:
         self.name = name
 
-    def __repr__(self):
-        # type: () -> str
+    def __repr__(self) -> str:
         return f"InstallationResult(name={self.name!r})"
 
 
 def _validate_requirements(
-    requirements,  # type: List[InstallRequirement]
-):
-    # type: (...) -> Iterator[Tuple[str, InstallRequirement]]
+    requirements: List[InstallRequirement],
+) -> Generator[Tuple[str, InstallRequirement], None, None]:
     for req in requirements:
         assert req.name, f"invalid to-be-installed requirement: {req}"
         yield req.name, req
 
 
 def install_given_reqs(
-    requirements,  # type: List[InstallRequirement]
-    install_options,  # type: List[str]
-    global_options,  # type: Sequence[str]
-    root,  # type: Optional[str]
-    home,  # type: Optional[str]
-    prefix,  # type: Optional[str]
-    warn_script_location,  # type: bool
-    use_user_site,  # type: bool
-    pycompile,  # type: bool
-):
-    # type: (...) -> List[InstallationResult]
+    requirements: List[InstallRequirement],
+    install_options: List[str],
+    global_options: Sequence[str],
+    root: Optional[str],
+    home: Optional[str],
+    prefix: Optional[str],
+    warn_script_location: bool,
+    use_user_site: bool,
+    pycompile: bool,
+) -> List[InstallationResult]:
     """
     Install everything in the given list.
 
@@ -56,8 +54,8 @@ def install_given_reqs(
 
     if to_install:
         logger.info(
-            'Installing collected packages: %s',
-            ', '.join(to_install.keys()),
+            "Installing collected packages: %s",
+            ", ".join(to_install.keys()),
         )
 
     installed = []
@@ -65,11 +63,9 @@ def install_given_reqs(
     with indent_log():
         for req_name, requirement in to_install.items():
             if requirement.should_reinstall:
-                logger.info('Attempting uninstall: %s', req_name)
+                logger.info("Attempting uninstall: %s", req_name)
                 with indent_log():
-                    uninstalled_pathset = requirement.uninstall(
-                        auto_confirm=True
-                    )
+                    uninstalled_pathset = requirement.uninstall(auto_confirm=True)
             else:
                 uninstalled_pathset = None
 

venv/Lib/site-packages/pip/_internal/req/constructors.py

@@ -16,32 +16,31 @@ from typing import Any, Dict, Optional, Set, Tuple, Union
 from pip._vendor.packaging.markers import Marker
 from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
 from pip._vendor.packaging.specifiers import Specifier
-from pip._vendor.pkg_resources import RequirementParseError, parse_requirements
 
 from pip._internal.exceptions import InstallationError
 from pip._internal.models.index import PyPI, TestPyPI
 from pip._internal.models.link import Link
 from pip._internal.models.wheel import Wheel
-from pip._internal.pyproject import make_pyproject_path
 from pip._internal.req.req_file import ParsedRequirement
 from pip._internal.req.req_install import InstallRequirement
 from pip._internal.utils.filetypes import is_archive_file
 from pip._internal.utils.misc import is_installable_dir
+from pip._internal.utils.packaging import get_requirement
 from pip._internal.utils.urls import path_to_url
 from pip._internal.vcs import is_url, vcs
 
 __all__ = [
-    "install_req_from_editable", "install_req_from_line",
-    "parse_editable"
+    "install_req_from_editable",
+    "install_req_from_line",
+    "parse_editable",
 ]
 
 logger = logging.getLogger(__name__)
 operators = Specifier._operators.keys()
 
 
-def _strip_extras(path):
-    # type: (str) -> Tuple[str, Optional[str]]
-    m = re.match(r'^(.+)(\[[^\]]+\])$', path)
+def _strip_extras(path: str) -> Tuple[str, Optional[str]]:
+    m = re.match(r"^(.+)(\[[^\]]+\])$", path)
     extras = None
     if m:
         path_no_extras = m.group(1)
@@ -52,15 +51,13 @@ def _strip_extras(path):
     return path_no_extras, extras
 
 
-def convert_extras(extras):
-    # type: (Optional[str]) -> Set[str]
+def convert_extras(extras: Optional[str]) -> Set[str]:
     if not extras:
         return set()
-    return Requirement("placeholder" + extras.lower()).extras
+    return get_requirement("placeholder" + extras.lower()).extras
 
 
-def parse_editable(editable_req):
-    # type: (str) -> Tuple[Optional[str], str, Set[str]]
+def parse_editable(editable_req: str) -> Tuple[Optional[str], str, Set[str]]:
     """Parses an editable requirement into:
         - a requirement name
         - an URL
@@ -77,39 +74,23 @@ def parse_editable(editable_req):
     url_no_extras, extras = _strip_extras(url)
 
     if os.path.isdir(url_no_extras):
-        setup_py = os.path.join(url_no_extras, 'setup.py')
-        setup_cfg = os.path.join(url_no_extras, 'setup.cfg')
-        if not os.path.exists(setup_py) and not os.path.exists(setup_cfg):
-            msg = (
-                'File "setup.py" or "setup.cfg" not found. Directory cannot be '
-                'installed in editable mode: {}'
-                .format(os.path.abspath(url_no_extras))
-            )
-            pyproject_path = make_pyproject_path(url_no_extras)
-            if os.path.isfile(pyproject_path):
-                msg += (
-                    '\n(A "pyproject.toml" file was found, but editable '
-                    'mode currently requires a setuptools-based build.)'
-                )
-            raise InstallationError(msg)
-
         # Treating it as code that has already been checked out
         url_no_extras = path_to_url(url_no_extras)
 
-    if url_no_extras.lower().startswith('file:'):
+    if url_no_extras.lower().startswith("file:"):
         package_name = Link(url_no_extras).egg_fragment
         if extras:
             return (
                 package_name,
                 url_no_extras,
-                Requirement("placeholder" + extras.lower()).extras,
+                get_requirement("placeholder" + extras.lower()).extras,
             )
         else:
             return package_name, url_no_extras, set()
 
     for version_control in vcs:
-        if url.lower().startswith(f'{version_control}:'):
-            url = f'{version_control}+{url}'
+        if url.lower().startswith(f"{version_control}:"):
+            url = f"{version_control}+{url}"
             break
 
     link = Link(url)
@@ -117,9 +98,9 @@ def parse_editable(editable_req):
     if not link.is_vcs:
         backends = ", ".join(vcs.all_schemes)
         raise InstallationError(
-            f'{editable_req} is not a valid editable requirement. '
-            f'It should either be a path to a local project or a VCS URL '
-            f'(beginning with {backends}).'
+            f"{editable_req} is not a valid editable requirement. "
+            f"It should either be a path to a local project or a VCS URL "
+            f"(beginning with {backends})."
         )
 
     package_name = link.egg_fragment
@@ -131,44 +112,66 @@ def parse_editable(editable_req):
     return package_name, url, set()
 
 
-def deduce_helpful_msg(req):
-    # type: (str) -> str
+def check_first_requirement_in_file(filename: str) -> None:
+    """Check if file is parsable as a requirements file.
+
+    This is heavily based on ``pkg_resources.parse_requirements``, but
+    simplified to just check the first meaningful line.
+
+    :raises InvalidRequirement: If the first meaningful line cannot be parsed
+        as an requirement.
+    """
+    with open(filename, encoding="utf-8", errors="ignore") as f:
+        # Create a steppable iterator, so we can handle \-continuations.
+        lines = (
+            line
+            for line in (line.strip() for line in f)
+            if line and not line.startswith("#")  # Skip blank lines/comments.
+        )
+
+        for line in lines:
+            # Drop comments -- a hash without a space may be in a URL.
+            if " #" in line:
+                line = line[: line.find(" #")]
+            # If there is a line continuation, drop it, and append the next line.
+            if line.endswith("\\"):
+                line = line[:-2].strip() + next(lines, "")
+            Requirement(line)
+            return
+
+
+def deduce_helpful_msg(req: str) -> str:
     """Returns helpful msg in case requirements file does not exist,
     or cannot be parsed.
 
     :params req: Requirements file path
     """
-    msg = ""
-    if os.path.exists(req):
-        msg = " The path does exist. "
-        # Try to parse and check if it is a requirements file.
-        try:
-            with open(req) as fp:
-                # parse first line only
-                next(parse_requirements(fp.read()))
-                msg += (
-                    "The argument you provided "
-                    "({}) appears to be a"
-                    " requirements file. If that is the"
-                    " case, use the '-r' flag to install"
-                    " the packages specified within it."
-                ).format(req)
-        except RequirementParseError:
-            logger.debug(
-                "Cannot parse '%s' as requirements file", req, exc_info=True
-            )
+    if not os.path.exists(req):
+        return f" File '{req}' does not exist."
+    msg = " The path does exist. "
+    # Try to parse and check if it is a requirements file.
+    try:
+        check_first_requirement_in_file(req)
+    except InvalidRequirement:
+        logger.debug("Cannot parse '%s' as requirements file", req)
     else:
-        msg += f" File '{req}' does not exist."
+        msg += (
+            f"The argument you provided "
+            f"({req}) appears to be a"
+            f" requirements file. If that is the"
+            f" case, use the '-r' flag to install"
+            f" the packages specified within it."
+        )
     return msg
 
 
 class RequirementParts:
     def __init__(
-            self,
-            requirement,  # type: Optional[Requirement]
-            link,         # type: Optional[Link]
-            markers,      # type: Optional[Marker]
-            extras,       # type: Set[str]
+        self,
+        requirement: Optional[Requirement],
+        link: Optional[Link],
+        markers: Optional[Marker],
+        extras: Set[str],
     ):
         self.requirement = requirement
         self.link = link
@@ -176,13 +179,12 @@ class RequirementParts:
         self.extras = extras
 
 
-def parse_req_from_editable(editable_req):
-    # type: (str) -> RequirementParts
+def parse_req_from_editable(editable_req: str) -> RequirementParts:
     name, url, extras_override = parse_editable(editable_req)
 
     if name is not None:
         try:
-            req = Requirement(name)  # type: Optional[Requirement]
+            req: Optional[Requirement] = Requirement(name)
         except InvalidRequirement:
             raise InstallationError(f"Invalid requirement: '{name}'")
     else:
@@ -197,15 +199,16 @@ def parse_req_from_editable(editable_req):
 
 
 def install_req_from_editable(
-    editable_req,  # type: str
-    comes_from=None,  # type: Optional[Union[InstallRequirement, str]]
-    use_pep517=None,  # type: Optional[bool]
-    isolated=False,  # type: bool
-    options=None,  # type: Optional[Dict[str, Any]]
-    constraint=False,  # type: bool
-    user_supplied=False,  # type: bool
-):
-    # type: (...) -> InstallRequirement
+    editable_req: str,
+    comes_from: Optional[Union[InstallRequirement, str]] = None,
+    use_pep517: Optional[bool] = None,
+    isolated: bool = False,
+    options: Optional[Dict[str, Any]] = None,
+    constraint: bool = False,
+    user_supplied: bool = False,
+    permit_editable_wheels: bool = False,
+    config_settings: Optional[Dict[str, str]] = None,
+) -> InstallRequirement:
 
     parts = parse_req_from_editable(editable_req)
 
@@ -214,6 +217,7 @@ def install_req_from_editable(
         comes_from=comes_from,
         user_supplied=user_supplied,
         editable=True,
+        permit_editable_wheels=permit_editable_wheels,
         link=parts.link,
         constraint=constraint,
         use_pep517=use_pep517,
@@ -221,12 +225,12 @@ def install_req_from_editable(
         install_options=options.get("install_options", []) if options else [],
         global_options=options.get("global_options", []) if options else [],
         hash_options=options.get("hashes", {}) if options else {},
+        config_settings=config_settings,
         extras=parts.extras,
     )
 
 
-def _looks_like_path(name):
-    # type: (str) -> bool
+def _looks_like_path(name: str) -> bool:
     """Checks whether the string "looks like" a path on the filesystem.
 
     This does not check whether the target actually exists, only judge from the
@@ -245,11 +249,10 @@ def _looks_like_path(name):
     return False
 
 
-def _get_url_from_path(path, name):
-    # type: (str, str) -> Optional[str]
+def _get_url_from_path(path: str, name: str) -> Optional[str]:
     """
-    First, it checks whether a provided path is an installable directory
-    (e.g. it has a setup.py). If it is, returns the path.
+    First, it checks whether a provided path is an installable directory. If it
+    is, returns the path.
 
     If false, check if the path is an archive file (such as a .whl).
     The function checks if the path is a file. If false, if the path has
@@ -258,6 +261,8 @@ def _get_url_from_path(path, name):
     if _looks_like_path(name) and os.path.isdir(path):
         if is_installable_dir(path):
             return path_to_url(path)
+        # TODO: The is_installable_dir test here might not be necessary
+        #       now that it is done in load_pyproject_toml too.
         raise InstallationError(
             f"Directory {name!r} is not installable. Neither 'setup.py' "
             "nor 'pyproject.toml' found."
@@ -266,25 +271,23 @@ def _get_url_from_path(path, name):
         return None
     if os.path.isfile(path):
         return path_to_url(path)
-    urlreq_parts = name.split('@', 1)
+    urlreq_parts = name.split("@", 1)
     if len(urlreq_parts) >= 2 and not _looks_like_path(urlreq_parts[0]):
         # If the path contains '@' and the part before it does not look
         # like a path, try to treat it as a PEP 440 URL req instead.
         return None
     logger.warning(
-        'Requirement %r looks like a filename, but the '
-        'file does not exist',
-        name
+        "Requirement %r looks like a filename, but the file does not exist",
+        name,
     )
     return path_to_url(path)
 
 
-def parse_req_from_line(name, line_source):
-    # type: (str, Optional[str]) -> RequirementParts
+def parse_req_from_line(name: str, line_source: Optional[str]) -> RequirementParts:
     if is_url(name):
-        marker_sep = '; '
+        marker_sep = "; "
     else:
-        marker_sep = ';'
+        marker_sep = ";"
     if marker_sep in name:
         name, markers_as_string = name.split(marker_sep, 1)
         markers_as_string = markers_as_string.strip()
@@ -311,9 +314,8 @@ def parse_req_from_line(name, line_source):
     # it's a local file, dir, or url
     if link:
         # Handle relative file URLs
-        if link.scheme == 'file' and re.search(r'\.\./', link.url):
-            link = Link(
-                path_to_url(os.path.normpath(os.path.abspath(link.path))))
+        if link.scheme == "file" and re.search(r"\.\./", link.url):
+            link = Link(path_to_url(os.path.normpath(os.path.abspath(link.path))))
         # wheel file
         if link.is_wheel:
             wheel = Wheel(link.filename)  # can raise InvalidWheelFilename
@@ -329,29 +331,27 @@ def parse_req_from_line(name, line_source):
 
     extras = convert_extras(extras_as_string)
 
-    def with_source(text):
-        # type: (str) -> str
+    def with_source(text: str) -> str:
         if not line_source:
             return text
-        return f'{text} (from {line_source})'
+        return f"{text} (from {line_source})"
 
     def _parse_req_string(req_as_string: str) -> Requirement:
         try:
-            req = Requirement(req_as_string)
+            req = get_requirement(req_as_string)
         except InvalidRequirement:
             if os.path.sep in req_as_string:
                 add_msg = "It looks like a path."
                 add_msg += deduce_helpful_msg(req_as_string)
-            elif ('=' in req_as_string and
-                  not any(op in req_as_string for op in operators)):
+            elif "=" in req_as_string and not any(
+                op in req_as_string for op in operators
+            ):
                 add_msg = "= is not a valid operator. Did you mean == ?"
             else:
-                add_msg = ''
-            msg = with_source(
-                f'Invalid requirement: {req_as_string!r}'
-            )
+                add_msg = ""
+            msg = with_source(f"Invalid requirement: {req_as_string!r}")
             if add_msg:
-                msg += f'\nHint: {add_msg}'
+                msg += f"\nHint: {add_msg}"
             raise InstallationError(msg)
         else:
             # Deprecate extras after specifiers: "name>=1.0[extras]"
@@ -360,13 +360,13 @@ def parse_req_from_line(name, line_source):
             # RequirementParts
             for spec in req.specifier:
                 spec_str = str(spec)
-                if spec_str.endswith(']'):
+                if spec_str.endswith("]"):
                     msg = f"Extras after version '{spec_str}'."
                     raise InstallationError(msg)
         return req
 
     if req_as_string is not None:
-        req = _parse_req_string(req_as_string)  # type: Optional[Requirement]
+        req: Optional[Requirement] = _parse_req_string(req_as_string)
     else:
         req = None
 
@@ -374,16 +374,16 @@ def parse_req_from_line(name, line_source):
 
 
 def install_req_from_line(
-    name,  # type: str
-    comes_from=None,  # type: Optional[Union[str, InstallRequirement]]
-    use_pep517=None,  # type: Optional[bool]
-    isolated=False,  # type: bool
-    options=None,  # type: Optional[Dict[str, Any]]
-    constraint=False,  # type: bool
-    line_source=None,  # type: Optional[str]
-    user_supplied=False,  # type: bool
-):
-    # type: (...) -> InstallRequirement
+    name: str,
+    comes_from: Optional[Union[str, InstallRequirement]] = None,
+    use_pep517: Optional[bool] = None,
+    isolated: bool = False,
+    options: Optional[Dict[str, Any]] = None,
+    constraint: bool = False,
+    line_source: Optional[str] = None,
+    user_supplied: bool = False,
+    config_settings: Optional[Dict[str, str]] = None,
+) -> InstallRequirement:
     """Creates an InstallRequirement from a name, which might be a
     requirement, directory containing 'setup.py', filename, or URL.
 
@@ -393,11 +393,16 @@ def install_req_from_line(
     parts = parse_req_from_line(name, line_source)
 
     return InstallRequirement(
-        parts.requirement, comes_from, link=parts.link, markers=parts.markers,
-        use_pep517=use_pep517, isolated=isolated,
+        parts.requirement,
+        comes_from,
+        link=parts.link,
+        markers=parts.markers,
+        use_pep517=use_pep517,
+        isolated=isolated,
         install_options=options.get("install_options", []) if options else [],
         global_options=options.get("global_options", []) if options else [],
         hash_options=options.get("hashes", {}) if options else {},
+        config_settings=config_settings,
         constraint=constraint,
         extras=parts.extras,
         user_supplied=user_supplied,
@@ -405,15 +410,15 @@ def install_req_from_line(
 
 
 def install_req_from_req_string(
-    req_string,  # type: str
-    comes_from=None,  # type: Optional[InstallRequirement]
-    isolated=False,  # type: bool
-    use_pep517=None,  # type: Optional[bool]
-    user_supplied=False,  # type: bool
-):
-    # type: (...) -> InstallRequirement
+    req_string: str,
+    comes_from: Optional[InstallRequirement] = None,
+    isolated: bool = False,
+    use_pep517: Optional[bool] = None,
+    user_supplied: bool = False,
+    config_settings: Optional[Dict[str, str]] = None,
+) -> InstallRequirement:
     try:
-        req = Requirement(req_string)
+        req = get_requirement(req_string)
     except InvalidRequirement:
         raise InstallationError(f"Invalid requirement: '{req_string}'")
 
@@ -421,8 +426,12 @@ def install_req_from_req_string(
         PyPI.file_storage_domain,
         TestPyPI.file_storage_domain,
     ]
-    if (req.url and comes_from and comes_from.link and
-            comes_from.link.netloc in domains_not_allowed):
+    if (
+        req.url
+        and comes_from
+        and comes_from.link
+        and comes_from.link.netloc in domains_not_allowed
+    ):
         # Explicitly disallow pypi packages that depend on external urls
         raise InstallationError(
             "Packages installed from PyPI cannot depend on packages "
@@ -436,16 +445,17 @@ def install_req_from_req_string(
         isolated=isolated,
         use_pep517=use_pep517,
         user_supplied=user_supplied,
+        config_settings=config_settings,
     )
 
 
 def install_req_from_parsed_requirement(
-    parsed_req,  # type: ParsedRequirement
-    isolated=False,  # type: bool
-    use_pep517=None,  # type: Optional[bool]
-    user_supplied=False,  # type: bool
-):
-    # type: (...) -> InstallRequirement
+    parsed_req: ParsedRequirement,
+    isolated: bool = False,
+    use_pep517: Optional[bool] = None,
+    user_supplied: bool = False,
+    config_settings: Optional[Dict[str, str]] = None,
+) -> InstallRequirement:
     if parsed_req.is_editable:
         req = install_req_from_editable(
             parsed_req.requirement,
@@ -454,6 +464,7 @@ def install_req_from_parsed_requirement(
             constraint=parsed_req.constraint,
             isolated=isolated,
             user_supplied=user_supplied,
+            config_settings=config_settings,
         )
 
     else:
@@ -466,12 +477,14 @@ def install_req_from_parsed_requirement(
             constraint=parsed_req.constraint,
             line_source=parsed_req.line_source,
             user_supplied=user_supplied,
+            config_settings=config_settings,
         )
     return req
 
 
-def install_req_from_link_and_ireq(link, ireq):
-    # type: (Link, InstallRequirement) -> InstallRequirement
+def install_req_from_link_and_ireq(
+    link: Link, ireq: InstallRequirement
+) -> InstallRequirement:
     return InstallRequirement(
         req=ireq.req,
         comes_from=ireq.comes_from,
@@ -483,4 +496,6 @@ def install_req_from_link_and_ireq(link, ireq):
         install_options=ireq.install_options,
         global_options=ireq.global_options,
         hash_options=ireq.hash_options,
+        config_settings=ireq.config_settings,
+        user_supplied=ireq.user_supplied,
     )

venv/Lib/site-packages/pip/_internal/req/req_file.py

@@ -8,7 +8,17 @@ import re
 import shlex
 import urllib.parse
 from optparse import Values
-from typing import TYPE_CHECKING, Any, Callable, Dict, Iterator, List, Optional, Tuple
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Dict,
+    Generator,
+    Iterable,
+    List,
+    Optional,
+    Tuple,
+)
 
 from pip._internal.cli import cmdoptions
 from pip._internal.exceptions import InstallationError, RequirementsFileParseError
@@ -16,7 +26,7 @@ from pip._internal.models.search_scope import SearchScope
 from pip._internal.network.session import PipSession
 from pip._internal.network.utils import raise_for_status
 from pip._internal.utils.encoding import auto_decode
-from pip._internal.utils.urls import get_url_scheme, url_to_path
+from pip._internal.utils.urls import get_url_scheme
 
 if TYPE_CHECKING:
     # NoReturn introduced in 3.6.2; imported only for type checking to maintain
@@ -25,22 +35,22 @@ if TYPE_CHECKING:
 
     from pip._internal.index.package_finder import PackageFinder
 
-__all__ = ['parse_requirements']
+__all__ = ["parse_requirements"]
 
-ReqFileLines = Iterator[Tuple[int, str]]
+ReqFileLines = Iterable[Tuple[int, str]]
 
 LineParser = Callable[[str], Tuple[str, Values]]
 
-SCHEME_RE = re.compile(r'^(http|https|file):', re.I)
-COMMENT_RE = re.compile(r'(^|\s+)#.*$')
+SCHEME_RE = re.compile(r"^(http|https|file):", re.I)
+COMMENT_RE = re.compile(r"(^|\s+)#.*$")
 
 # Matches environment variable-style values in '${MY_VARIABLE_1}' with the
 # variable name consisting of only uppercase letters, digits or the '_'
 # (underscore). This follows the POSIX standard defined in IEEE Std 1003.1,
 # 2013 Edition.
-ENV_VAR_RE = re.compile(r'(?P<var>\$\{(?P<name>[A-Z0-9_]+)\})')
+ENV_VAR_RE = re.compile(r"(?P<var>\$\{(?P<name>[A-Z0-9_]+)\})")
 
-SUPPORTED_OPTIONS = [
+SUPPORTED_OPTIONS: List[Callable[..., optparse.Option]] = [
     cmdoptions.index_url,
     cmdoptions.extra_index_url,
     cmdoptions.no_index,
@@ -55,14 +65,14 @@ SUPPORTED_OPTIONS = [
     cmdoptions.pre,
     cmdoptions.trusted_host,
     cmdoptions.use_new_feature,
-]  # type: List[Callable[..., optparse.Option]]
+]
 
 # options to be passed to requirements
-SUPPORTED_OPTIONS_REQ = [
+SUPPORTED_OPTIONS_REQ: List[Callable[..., optparse.Option]] = [
     cmdoptions.install_options,
     cmdoptions.global_options,
     cmdoptions.hash,
-]  # type: List[Callable[..., optparse.Option]]
+]
 
 # the 'dest' string values
 SUPPORTED_OPTIONS_REQ_DEST = [str(o().dest) for o in SUPPORTED_OPTIONS_REQ]
@@ -71,14 +81,13 @@ SUPPORTED_OPTIONS_REQ_DEST = [str(o().dest) for o in SUPPORTED_OPTIONS_REQ]
 class ParsedRequirement:
     def __init__(
         self,
-        requirement,  # type:str
-        is_editable,  # type: bool
-        comes_from,  # type: str
-        constraint,  # type: bool
-        options=None,  # type: Optional[Dict[str, Any]]
-        line_source=None,  # type: Optional[str]
-    ):
-        # type: (...) -> None
+        requirement: str,
+        is_editable: bool,
+        comes_from: str,
+        constraint: bool,
+        options: Optional[Dict[str, Any]] = None,
+        line_source: Optional[str] = None,
+    ) -> None:
         self.requirement = requirement
         self.is_editable = is_editable
         self.comes_from = comes_from
@@ -90,13 +99,12 @@ class ParsedRequirement:
 class ParsedLine:
     def __init__(
         self,
-        filename,  # type: str
-        lineno,  # type: int
-        args,  # type: str
-        opts,  # type: Values
-        constraint,  # type: bool
-    ):
-        # type: (...) -> None
+        filename: str,
+        lineno: int,
+        args: str,
+        opts: Values,
+        constraint: bool,
+    ) -> None:
         self.filename = filename
         self.lineno = lineno
         self.opts = opts
@@ -116,13 +124,12 @@ class ParsedLine:
 
 
 def parse_requirements(
-    filename,  # type: str
-    session,  # type: PipSession
-    finder=None,  # type: Optional[PackageFinder]
-    options=None,  # type: Optional[optparse.Values]
-    constraint=False,  # type: bool
-):
-    # type: (...) -> Iterator[ParsedRequirement]
+    filename: str,
+    session: PipSession,
+    finder: Optional["PackageFinder"] = None,
+    options: Optional[optparse.Values] = None,
+    constraint: bool = False,
+) -> Generator[ParsedRequirement, None, None]:
     """Parse a requirements file and yield ParsedRequirement instances.
 
     :param filename:    Path or url of requirements file.
@@ -137,22 +144,18 @@ def parse_requirements(
 
     for parsed_line in parser.parse(filename, constraint):
         parsed_req = handle_line(
-            parsed_line,
-            options=options,
-            finder=finder,
-            session=session
+            parsed_line, options=options, finder=finder, session=session
         )
         if parsed_req is not None:
             yield parsed_req
 
 
-def preprocess(content):
-    # type: (str) -> ReqFileLines
+def preprocess(content: str) -> ReqFileLines:
     """Split, filter, and join lines, and return a line iterator
 
     :param content: the content of the requirements file
     """
-    lines_enum = enumerate(content.splitlines(), start=1)  # type: ReqFileLines
+    lines_enum: ReqFileLines = enumerate(content.splitlines(), start=1)
     lines_enum = join_lines(lines_enum)
     lines_enum = ignore_comments(lines_enum)
     lines_enum = expand_env_variables(lines_enum)
@@ -160,14 +163,15 @@ def preprocess(content):
 
 
 def handle_requirement_line(
-    line,  # type: ParsedLine
-    options=None,  # type: Optional[optparse.Values]
-):
-    # type: (...) -> ParsedRequirement
+    line: ParsedLine,
+    options: Optional[optparse.Values] = None,
+) -> ParsedRequirement:
 
     # preserve for the nested code path
-    line_comes_from = '{} {} (line {})'.format(
-        '-c' if line.constraint else '-r', line.filename, line.lineno,
+    line_comes_from = "{} {} (line {})".format(
+        "-c" if line.constraint else "-r",
+        line.filename,
+        line.lineno,
     )
 
     assert line.is_requirement
@@ -192,7 +196,7 @@ def handle_requirement_line(
             if dest in line.opts.__dict__ and line.opts.__dict__[dest]:
                 req_options[dest] = line.opts.__dict__[dest]
 
-        line_source = f'line {line.lineno} of {line.filename}'
+        line_source = f"line {line.lineno} of {line.filename}"
         return ParsedRequirement(
             requirement=line.requirement,
             is_editable=line.is_editable,
@@ -204,14 +208,13 @@ def handle_requirement_line(
 
 
 def handle_option_line(
-    opts,  # type: Values
-    filename,  # type: str
-    lineno,  # type: int
-    finder=None,  # type: Optional[PackageFinder]
-    options=None,  # type: Optional[optparse.Values]
-    session=None,  # type: Optional[PipSession]
-):
-    # type:  (...) -> None
+    opts: Values,
+    filename: str,
+    lineno: int,
+    finder: Optional["PackageFinder"] = None,
+    options: Optional[optparse.Values] = None,
+    session: Optional[PipSession] = None,
+) -> None:
 
     if options:
         # percolate options upward
@@ -219,8 +222,7 @@ def handle_option_line(
             options.require_hashes = opts.require_hashes
         if opts.features_enabled:
             options.features_enabled.extend(
-                f for f in opts.features_enabled
-                if f not in options.features_enabled
+                f for f in opts.features_enabled if f not in options.features_enabled
             )
 
     # set finder options
@@ -262,17 +264,16 @@ def handle_option_line(
 
         if session:
             for host in opts.trusted_hosts or []:
-                source = f'line {lineno} of {filename}'
+                source = f"line {lineno} of {filename}"
                 session.add_trusted_host(host, source=source)
 
 
 def handle_line(
-    line,  # type: ParsedLine
-    options=None,  # type: Optional[optparse.Values]
-    finder=None,  # type: Optional[PackageFinder]
-    session=None,  # type: Optional[PipSession]
-):
-    # type: (...) -> Optional[ParsedRequirement]
+    line: ParsedLine,
+    options: Optional[optparse.Values] = None,
+    finder: Optional["PackageFinder"] = None,
+    session: Optional[PipSession] = None,
+) -> Optional[ParsedRequirement]:
     """Handle a single parsed requirements line; This can result in
     creating/yielding requirements, or updating the finder.
 
@@ -314,25 +315,24 @@ def handle_line(
 class RequirementsFileParser:
     def __init__(
         self,
-        session,  # type: PipSession
-        line_parser,  # type: LineParser
-    ):
-        # type: (...) -> None
+        session: PipSession,
+        line_parser: LineParser,
+    ) -> None:
         self._session = session
         self._line_parser = line_parser
 
-    def parse(self, filename, constraint):
-        # type: (str, bool) -> Iterator[ParsedLine]
-        """Parse a given file, yielding parsed lines.
-        """
+    def parse(
+        self, filename: str, constraint: bool
+    ) -> Generator[ParsedLine, None, None]:
+        """Parse a given file, yielding parsed lines."""
         yield from self._parse_and_recurse(filename, constraint)
 
-    def _parse_and_recurse(self, filename, constraint):
-        # type: (str, bool) -> Iterator[ParsedLine]
+    def _parse_and_recurse(
+        self, filename: str, constraint: bool
+    ) -> Generator[ParsedLine, None, None]:
         for line in self._parse_file(filename, constraint):
-            if (
-                not line.is_requirement and
-                (line.opts.requirements or line.opts.constraints)
+            if not line.is_requirement and (
+                line.opts.requirements or line.opts.constraints
             ):
                 # parse a nested requirements file
                 if line.opts.requirements:
@@ -350,15 +350,17 @@ class RequirementsFileParser:
                 elif not SCHEME_RE.search(req_path):
                     # do a join so relative paths work
                     req_path = os.path.join(
-                        os.path.dirname(filename), req_path,
+                        os.path.dirname(filename),
+                        req_path,
                     )
 
                 yield from self._parse_and_recurse(req_path, nested_constraint)
             else:
                 yield line
 
-    def _parse_file(self, filename, constraint):
-        # type: (str, bool) -> Iterator[ParsedLine]
+    def _parse_file(
+        self, filename: str, constraint: bool
+    ) -> Generator[ParsedLine, None, None]:
         _, content = get_file_content(filename, self._session)
 
         lines_enum = preprocess(content)
@@ -368,7 +370,7 @@ class RequirementsFileParser:
                 args_str, opts = self._line_parser(line)
             except OptionParsingError as e:
                 # add offending line
-                msg = f'Invalid requirement: {line}\n{e.msg}'
+                msg = f"Invalid requirement: {line}\n{e.msg}"
                 raise RequirementsFileParseError(msg)
 
             yield ParsedLine(
@@ -380,10 +382,8 @@ class RequirementsFileParser:
             )
 
 
-def get_line_parser(finder):
-    # type: (Optional[PackageFinder]) -> LineParser
-    def parse_line(line):
-        # type: (str) -> Tuple[str, Values]
+def get_line_parser(finder: Optional["PackageFinder"]) -> LineParser:
+    def parse_line(line: str) -> Tuple[str, Values]:
         # Build new parser for each line since it accumulates appendable
         # options.
         parser = build_parser()
@@ -401,32 +401,29 @@ def get_line_parser(finder):
     return parse_line
 
 
-def break_args_options(line):
-    # type: (str) -> Tuple[str, str]
+def break_args_options(line: str) -> Tuple[str, str]:
     """Break up the line into an args and options string.  We only want to shlex
     (and then optparse) the options, not the args.  args can contain markers
     which are corrupted by shlex.
     """
-    tokens = line.split(' ')
+    tokens = line.split(" ")
     args = []
     options = tokens[:]
     for token in tokens:
-        if token.startswith('-') or token.startswith('--'):
+        if token.startswith("-") or token.startswith("--"):
             break
         else:
             args.append(token)
             options.pop(0)
-    return ' '.join(args), ' '.join(options)
+    return " ".join(args), " ".join(options)
 
 
 class OptionParsingError(Exception):
-    def __init__(self, msg):
-        # type: (str) -> None
+    def __init__(self, msg: str) -> None:
         self.msg = msg
 
 
-def build_parser():
-    # type: () -> optparse.OptionParser
+def build_parser() -> optparse.OptionParser:
     """
     Return a parser for parsing requirement lines
     """
@@ -439,9 +436,9 @@ def build_parser():
 
     # By default optparse sys.exits on parsing errors. We want to wrap
     # that in our own exception.
-    def parser_exit(self, msg):
-        # type: (Any, str) -> NoReturn
+    def parser_exit(self: Any, msg: str) -> "NoReturn":
         raise OptionParsingError(msg)
+
     # NOTE: mypy disallows assigning to a method
     #       https://github.com/python/mypy/issues/2427
     parser.exit = parser_exit  # type: ignore
@@ -449,52 +446,49 @@ def build_parser():
     return parser
 
 
-def join_lines(lines_enum):
-    # type: (ReqFileLines) -> ReqFileLines
+def join_lines(lines_enum: ReqFileLines) -> ReqFileLines:
     """Joins a line ending in '\' with the previous line (except when following
     comments).  The joined line takes on the index of the first line.
     """
     primary_line_number = None
-    new_line = []  # type: List[str]
+    new_line: List[str] = []
     for line_number, line in lines_enum:
-        if not line.endswith('\\') or COMMENT_RE.match(line):
+        if not line.endswith("\\") or COMMENT_RE.match(line):
             if COMMENT_RE.match(line):
                 # this ensures comments are always matched later
-                line = ' ' + line
+                line = " " + line
             if new_line:
                 new_line.append(line)
                 assert primary_line_number is not None
-                yield primary_line_number, ''.join(new_line)
+                yield primary_line_number, "".join(new_line)
                 new_line = []
             else:
                 yield line_number, line
         else:
             if not new_line:
                 primary_line_number = line_number
-            new_line.append(line.strip('\\'))
+            new_line.append(line.strip("\\"))
 
     # last line contains \
     if new_line:
         assert primary_line_number is not None
-        yield primary_line_number, ''.join(new_line)
+        yield primary_line_number, "".join(new_line)
 
     # TODO: handle space after '\'.
 
 
-def ignore_comments(lines_enum):
-    # type: (ReqFileLines) -> ReqFileLines
+def ignore_comments(lines_enum: ReqFileLines) -> ReqFileLines:
     """
     Strips comments and filter empty lines.
     """
     for line_number, line in lines_enum:
-        line = COMMENT_RE.sub('', line)
+        line = COMMENT_RE.sub("", line)
         line = line.strip()
         if line:
             yield line_number, line
 
 
-def expand_env_variables(lines_enum):
-    # type: (ReqFileLines) -> ReqFileLines
+def expand_env_variables(lines_enum: ReqFileLines) -> ReqFileLines:
     """Replace all environment variables that can be retrieved via `os.getenv`.
 
     The only allowed format for environment variables defined in the
@@ -521,8 +515,7 @@ def expand_env_variables(lines_enum):
         yield line_number, line
 
 
-def get_file_content(url, session):
-    # type: (str, PipSession) -> Tuple[str, str]
+def get_file_content(url: str, session: PipSession) -> Tuple[str, str]:
     """Gets the content of a file; it may be a filename, file: URL, or
     http: URL.  Returns (location, content).  Content is unicode.
     Respects # -*- coding: declarations on the retrieved files.
@@ -532,20 +525,16 @@ def get_file_content(url, session):
     """
     scheme = get_url_scheme(url)
 
-    if scheme in ['http', 'https']:
-        # FIXME: catch some errors
+    # Pip has special support for file:// URLs (LocalFSAdapter).
+    if scheme in ["http", "https", "file"]:
         resp = session.get(url)
         raise_for_status(resp)
         return resp.url, resp.text
 
-    elif scheme == 'file':
-        url = url_to_path(url)
-
+    # Assume this is a bare path.
     try:
-        with open(url, 'rb') as f:
+        with open(url, "rb") as f:
             content = auto_decode(f.read())
     except OSError as exc:
-        raise InstallationError(
-            f'Could not open requirements file: {exc}'
-        )
+        raise InstallationError(f"Could not open requirements file: {exc}")
     return url, content

venv/Lib/site-packages/pip/_internal/req/req_install.py

@@ -1,15 +1,15 @@
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
 
+import functools
 import logging
 import os
 import shutil
 import sys
 import uuid
 import zipfile
-from typing import Any, Dict, Iterable, List, Optional, Sequence, Union
+from typing import Any, Collection, Dict, Iterable, List, Optional, Sequence, Union
 
-from pip._vendor import pkg_resources, six
 from pip._vendor.packaging.markers import Marker
 from pip._vendor.packaging.requirements import Requirement
 from pip._vendor.packaging.specifiers import SpecifierSet
@@ -17,39 +17,44 @@ from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.packaging.version import Version
 from pip._vendor.packaging.version import parse as parse_version
 from pip._vendor.pep517.wrappers import Pep517HookCaller
-from pip._vendor.pkg_resources import Distribution
 
 from pip._internal.build_env import BuildEnvironment, NoOpBuildEnvironment
-from pip._internal.exceptions import InstallationError
+from pip._internal.exceptions import InstallationError, LegacyInstallFailure
 from pip._internal.locations import get_scheme
+from pip._internal.metadata import (
+    BaseDistribution,
+    get_default_environment,
+    get_directory_distribution,
+)
 from pip._internal.models.link import Link
 from pip._internal.operations.build.metadata import generate_metadata
+from pip._internal.operations.build.metadata_editable import generate_editable_metadata
 from pip._internal.operations.build.metadata_legacy import (
     generate_metadata as generate_metadata_legacy,
 )
 from pip._internal.operations.install.editable_legacy import (
     install_editable as install_editable_legacy,
 )
-from pip._internal.operations.install.legacy import LegacyInstallFailure
 from pip._internal.operations.install.legacy import install as install_legacy
 from pip._internal.operations.install.wheel import install_wheel
 from pip._internal.pyproject import load_pyproject_toml, make_pyproject_path
 from pip._internal.req.req_uninstall import UninstallPathSet
 from pip._internal.utils.deprecation import deprecated
-from pip._internal.utils.direct_url_helpers import direct_url_from_link
+from pip._internal.utils.direct_url_helpers import (
+    direct_url_for_editable,
+    direct_url_from_link,
+)
 from pip._internal.utils.hashes import Hashes
-from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import (
+    ConfiguredPep517HookCaller,
     ask_path_exists,
     backup_dir,
     display_path,
-    dist_in_site_packages,
-    dist_in_usersite,
-    get_distribution,
     hide_url,
     redact_auth_from_url,
 )
-from pip._internal.utils.packaging import get_metadata
+from pip._internal.utils.packaging import safe_extra
+from pip._internal.utils.subprocess import runner_with_spinner_message
 from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
 from pip._internal.utils.virtualenv import running_under_virtualenv
 from pip._internal.vcs import vcs
@@ -57,33 +62,6 @@ from pip._internal.vcs import vcs
 logger = logging.getLogger(__name__)
 
 
-def _get_dist(metadata_directory):
-    # type: (str) -> Distribution
-    """Return a pkg_resources.Distribution for the provided
-    metadata directory.
-    """
-    dist_dir = metadata_directory.rstrip(os.sep)
-
-    # Build a PathMetadata object, from path to metadata. :wink:
-    base_dir, dist_dir_name = os.path.split(dist_dir)
-    metadata = pkg_resources.PathMetadata(base_dir, dist_dir)
-
-    # Determine the correct Distribution object type.
-    if dist_dir.endswith(".egg-info"):
-        dist_cls = pkg_resources.Distribution
-        dist_name = os.path.splitext(dist_dir_name)[0]
-    else:
-        assert dist_dir.endswith(".dist-info")
-        dist_cls = pkg_resources.DistInfoDistribution
-        dist_name = os.path.splitext(dist_dir_name)[0].split("-")[0]
-
-    return dist_cls(
-        base_dir,
-        project_name=dist_name,
-        metadata=metadata,
-    )
-
-
 class InstallRequirement:
     """
     Represents something that may be installed later on, may have information
@@ -93,40 +71,40 @@ class InstallRequirement:
 
     def __init__(
         self,
-        req,  # type: Optional[Requirement]
-        comes_from,  # type: Optional[Union[str, InstallRequirement]]
-        editable=False,  # type: bool
-        link=None,  # type: Optional[Link]
-        markers=None,  # type: Optional[Marker]
-        use_pep517=None,  # type: Optional[bool]
-        isolated=False,  # type: bool
-        install_options=None,  # type: Optional[List[str]]
-        global_options=None,  # type: Optional[List[str]]
-        hash_options=None,  # type: Optional[Dict[str, List[str]]]
-        constraint=False,  # type: bool
-        extras=(),  # type: Iterable[str]
-        user_supplied=False,  # type: bool
-    ):
-        # type: (...) -> None
+        req: Optional[Requirement],
+        comes_from: Optional[Union[str, "InstallRequirement"]],
+        editable: bool = False,
+        link: Optional[Link] = None,
+        markers: Optional[Marker] = None,
+        use_pep517: Optional[bool] = None,
+        isolated: bool = False,
+        install_options: Optional[List[str]] = None,
+        global_options: Optional[List[str]] = None,
+        hash_options: Optional[Dict[str, List[str]]] = None,
+        config_settings: Optional[Dict[str, str]] = None,
+        constraint: bool = False,
+        extras: Collection[str] = (),
+        user_supplied: bool = False,
+        permit_editable_wheels: bool = False,
+    ) -> None:
         assert req is None or isinstance(req, Requirement), req
         self.req = req
         self.comes_from = comes_from
         self.constraint = constraint
         self.editable = editable
-        self.legacy_install_reason = None  # type: Optional[int]
+        self.permit_editable_wheels = permit_editable_wheels
+        self.legacy_install_reason: Optional[int] = None
 
         # source_dir is the local directory where the linked requirement is
         # located, or unpacked. In case unpacking is needed, creating and
         # populating source_dir is done by the RequirementPreparer. Note this
         # is not necessarily the directory where pyproject.toml or setup.py is
         # located - that one is obtained via unpacked_source_directory.
-        self.source_dir = None  # type: Optional[str]
+        self.source_dir: Optional[str] = None
         if self.editable:
             assert link
             if link.is_file:
-                self.source_dir = os.path.normpath(
-                    os.path.abspath(link.file_path)
-                )
+                self.source_dir = os.path.normpath(os.path.abspath(link.file_path))
 
         if link is None and req and req.url:
             # PEP 508 URL requirement
@@ -135,36 +113,34 @@ class InstallRequirement:
         self.original_link_is_in_wheel_cache = False
 
         # Path to any downloaded or already-existing package.
-        self.local_file_path = None  # type: Optional[str]
+        self.local_file_path: Optional[str] = None
         if self.link and self.link.is_file:
             self.local_file_path = self.link.file_path
 
         if extras:
             self.extras = extras
         elif req:
-            self.extras = {
-                pkg_resources.safe_extra(extra) for extra in req.extras
-            }
+            self.extras = {safe_extra(extra) for extra in req.extras}
         else:
             self.extras = set()
         if markers is None and req:
             markers = req.marker
         self.markers = markers
 
-        # This holds the pkg_resources.Distribution object if this requirement
-        # is already available:
-        self.satisfied_by = None  # type: Optional[Distribution]
+        # This holds the Distribution object if this requirement is already installed.
+        self.satisfied_by: Optional[BaseDistribution] = None
         # Whether the installation process should try to uninstall an existing
         # distribution before installing this requirement.
         self.should_reinstall = False
         # Temporary build location
-        self._temp_build_dir = None  # type: Optional[TempDirectory]
+        self._temp_build_dir: Optional[TempDirectory] = None
         # Set to True after successful installation
-        self.install_succeeded = None  # type: Optional[bool]
+        self.install_succeeded: Optional[bool] = None
         # Supplied options
         self.install_options = install_options if install_options else []
         self.global_options = global_options if global_options else []
         self.hash_options = hash_options if hash_options else {}
+        self.config_settings = config_settings
         # Set to True after successful preparation of this requirement
         self.prepared = False
         # User supplied requirement are explicitly requested for installation
@@ -173,22 +149,22 @@ class InstallRequirement:
         self.user_supplied = user_supplied
 
         self.isolated = isolated
-        self.build_env = NoOpBuildEnvironment()  # type: BuildEnvironment
+        self.build_env: BuildEnvironment = NoOpBuildEnvironment()
 
         # For PEP 517, the directory where we request the project metadata
         # gets stored. We need this to pass to build_wheel, so the backend
         # can ensure that the wheel matches the metadata (see the PEP for
         # details).
-        self.metadata_directory = None  # type: Optional[str]
+        self.metadata_directory: Optional[str] = None
 
         # The static build requirements (from pyproject.toml)
-        self.pyproject_requires = None  # type: Optional[List[str]]
+        self.pyproject_requires: Optional[List[str]] = None
 
         # Build requirements that we will check are available
-        self.requirements_to_check = []  # type: List[str]
+        self.requirements_to_check: List[str] = []
 
         # The PEP 517 backend we should use to build the project
-        self.pep517_backend = None  # type: Optional[Pep517HookCaller]
+        self.pep517_backend: Optional[Pep517HookCaller] = None
 
         # Are we using PEP 517 for this requirement?
         # After pyproject.toml has been loaded, the only valid values are True
@@ -200,87 +176,88 @@ class InstallRequirement:
         # This requirement needs more preparation before it can be built
         self.needs_more_preparation = False
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         if self.req:
             s = str(self.req)
             if self.link:
-                s += ' from {}'.format(redact_auth_from_url(self.link.url))
+                s += " from {}".format(redact_auth_from_url(self.link.url))
         elif self.link:
             s = redact_auth_from_url(self.link.url)
         else:
-            s = '<InstallRequirement>'
+            s = "<InstallRequirement>"
         if self.satisfied_by is not None:
-            s += ' in {}'.format(display_path(self.satisfied_by.location))
+            s += " in {}".format(display_path(self.satisfied_by.location))
         if self.comes_from:
             if isinstance(self.comes_from, str):
-                comes_from = self.comes_from  # type: Optional[str]
+                comes_from: Optional[str] = self.comes_from
             else:
                 comes_from = self.comes_from.from_path()
             if comes_from:
-                s += f' (from {comes_from})'
+                s += f" (from {comes_from})"
         return s
 
-    def __repr__(self):
-        # type: () -> str
-        return '<{} object: {} editable={!r}>'.format(
-            self.__class__.__name__, str(self), self.editable)
+    def __repr__(self) -> str:
+        return "<{} object: {} editable={!r}>".format(
+            self.__class__.__name__, str(self), self.editable
+        )
 
-    def format_debug(self):
-        # type: () -> str
-        """An un-tested helper for getting state, for debugging.
-        """
+    def format_debug(self) -> str:
+        """An un-tested helper for getting state, for debugging."""
         attributes = vars(self)
         names = sorted(attributes)
 
-        state = (
-            "{}={!r}".format(attr, attributes[attr]) for attr in sorted(names)
-        )
-        return '<{name} object: {{{state}}}>'.format(
+        state = ("{}={!r}".format(attr, attributes[attr]) for attr in sorted(names))
+        return "<{name} object: {{{state}}}>".format(
             name=self.__class__.__name__,
             state=", ".join(state),
         )
 
     # Things that are valid for all kinds of requirements?
     @property
-    def name(self):
-        # type: () -> Optional[str]
+    def name(self) -> Optional[str]:
         if self.req is None:
             return None
-        return pkg_resources.safe_name(self.req.name)
+        return self.req.name
+
+    @functools.lru_cache()  # use cached_property in python 3.8+
+    def supports_pyproject_editable(self) -> bool:
+        if not self.use_pep517:
+            return False
+        assert self.pep517_backend
+        with self.build_env:
+            runner = runner_with_spinner_message(
+                "Checking if build backend supports build_editable"
+            )
+            with self.pep517_backend.subprocess_runner(runner):
+                return "build_editable" in self.pep517_backend._supported_features()
 
     @property
-    def specifier(self):
-        # type: () -> SpecifierSet
+    def specifier(self) -> SpecifierSet:
         return self.req.specifier
 
     @property
-    def is_pinned(self):
-        # type: () -> bool
+    def is_pinned(self) -> bool:
         """Return whether I am pinned to an exact version.
 
         For example, some-package==1.2 is pinned; some-package>1.2 is not.
         """
         specifiers = self.specifier
-        return (len(specifiers) == 1 and
-                next(iter(specifiers)).operator in {'==', '==='})
+        return len(specifiers) == 1 and next(iter(specifiers)).operator in {"==", "==="}
 
-    def match_markers(self, extras_requested=None):
-        # type: (Optional[Iterable[str]]) -> bool
+    def match_markers(self, extras_requested: Optional[Iterable[str]] = None) -> bool:
         if not extras_requested:
             # Provide an extra to safely evaluate the markers
             # without matching any extra
-            extras_requested = ('',)
+            extras_requested = ("",)
         if self.markers is not None:
             return any(
-                self.markers.evaluate({'extra': extra})
-                for extra in extras_requested)
+                self.markers.evaluate({"extra": extra}) for extra in extras_requested
+            )
         else:
             return True
 
     @property
-    def has_hash_options(self):
-        # type: () -> bool
+    def has_hash_options(self) -> bool:
         """Return whether any known-good hashes are specified as options.
 
         These activate --require-hashes mode; hashes specified as part of a
@@ -289,8 +266,7 @@ class InstallRequirement:
         """
         return bool(self.hash_options)
 
-    def hashes(self, trust_internet=True):
-        # type: (bool) -> Hashes
+    def hashes(self, trust_internet: bool = True) -> Hashes:
         """Return a hash-comparer that considers my option- and URL-based
         hashes to be known-good.
 
@@ -311,10 +287,8 @@ class InstallRequirement:
             good_hashes.setdefault(link.hash_name, []).append(link.hash)
         return Hashes(good_hashes)
 
-    def from_path(self):
-        # type: () -> Optional[str]
-        """Format a nice indicator to show where this "comes from"
-        """
+    def from_path(self) -> Optional[str]:
+        """Format a nice indicator to show where this "comes from" """
         if self.req is None:
             return None
         s = str(self.req)
@@ -324,11 +298,12 @@ class InstallRequirement:
             else:
                 comes_from = self.comes_from.from_path()
             if comes_from:
-                s += '->' + comes_from
+                s += "->" + comes_from
         return s
 
-    def ensure_build_location(self, build_dir, autodelete, parallel_builds):
-        # type: (str, bool, bool) -> str
+    def ensure_build_location(
+        self, build_dir: str, autodelete: bool, parallel_builds: bool
+    ) -> str:
         assert build_dir is not None
         if self._temp_build_dir is not None:
             assert self._temp_build_dir.path
@@ -349,14 +324,14 @@ class InstallRequirement:
 
         # When parallel builds are enabled, add a UUID to the build directory
         # name so multiple builds do not interfere with each other.
-        dir_name = canonicalize_name(self.name)  # type: str
+        dir_name: str = canonicalize_name(self.name)
         if parallel_builds:
             dir_name = f"{dir_name}_{uuid.uuid4().hex}"
 
         # FIXME: Is there a better place to create the build_dir? (hg and bzr
         # need this)
         if not os.path.exists(build_dir):
-            logger.debug('Creating directory %s', build_dir)
+            logger.debug("Creating directory %s", build_dir)
             os.makedirs(build_dir)
         actual_build_dir = os.path.join(build_dir, dir_name)
         # `None` indicates that we respect the globally-configured deletion
@@ -369,10 +344,8 @@ class InstallRequirement:
             globally_managed=True,
         ).path
 
-    def _set_requirement(self):
-        # type: () -> None
-        """Set requirement after generating metadata.
-        """
+    def _set_requirement(self) -> None:
+        """Set requirement after generating metadata."""
         assert self.req is None
         assert self.metadata is not None
         assert self.source_dir is not None
@@ -384,15 +357,16 @@ class InstallRequirement:
             op = "==="
 
         self.req = Requirement(
-            "".join([
-                self.metadata["Name"],
-                op,
-                self.metadata["Version"],
-            ])
+            "".join(
+                [
+                    self.metadata["Name"],
+                    op,
+                    self.metadata["Version"],
+                ]
+            )
         )
 
-    def warn_on_mismatching_name(self):
-        # type: () -> None
+    def warn_on_mismatching_name(self) -> None:
         metadata_name = canonicalize_name(self.metadata["Name"])
         if canonicalize_name(self.req.name) == metadata_name:
             # Everything is fine.
@@ -400,45 +374,40 @@ class InstallRequirement:
 
         # If we're here, there's a mismatch. Log a warning about it.
         logger.warning(
-            'Generating metadata for package %s '
-            'produced metadata for project name %s. Fix your '
-            '#egg=%s fragments.',
-            self.name, metadata_name, self.name
+            "Generating metadata for package %s "
+            "produced metadata for project name %s. Fix your "
+            "#egg=%s fragments.",
+            self.name,
+            metadata_name,
+            self.name,
         )
         self.req = Requirement(metadata_name)
 
-    def check_if_exists(self, use_user_site):
-        # type: (bool) -> None
+    def check_if_exists(self, use_user_site: bool) -> None:
         """Find an installed distribution that satisfies or conflicts
         with this requirement, and set self.satisfied_by or
         self.should_reinstall appropriately.
         """
         if self.req is None:
             return
-        existing_dist = get_distribution(self.req.name)
+        existing_dist = get_default_environment().get_distribution(self.req.name)
         if not existing_dist:
             return
 
-        # pkg_resouces may contain a different copy of packaging.version from
-        # pip in if the downstream distributor does a poor job debundling pip.
-        # We avoid existing_dist.parsed_version and let SpecifierSet.contains
-        # parses the version instead.
-        existing_version = existing_dist.version
-        version_compatible = (
-            existing_version is not None and
-            self.req.specifier.contains(existing_version, prereleases=True)
+        version_compatible = self.req.specifier.contains(
+            existing_dist.version,
+            prereleases=True,
         )
         if not version_compatible:
             self.satisfied_by = None
             if use_user_site:
-                if dist_in_usersite(existing_dist):
+                if existing_dist.in_usersite:
                     self.should_reinstall = True
-                elif (running_under_virtualenv() and
-                        dist_in_site_packages(existing_dist)):
+                elif running_under_virtualenv() and existing_dist.in_site_packages:
                     raise InstallationError(
-                        "Will not install to the user site because it will "
-                        "lack sys.path precedence to {} in {}".format(
-                            existing_dist.project_name, existing_dist.location)
+                        f"Will not install to the user site because it will "
+                        f"lack sys.path precedence to {existing_dist.raw_name} "
+                        f"in {existing_dist.location}"
                     )
             else:
                 self.should_reinstall = True
@@ -453,36 +422,38 @@ class InstallRequirement:
 
     # Things valid for wheels
     @property
-    def is_wheel(self):
-        # type: () -> bool
+    def is_wheel(self) -> bool:
         if not self.link:
             return False
         return self.link.is_wheel
 
     # Things valid for sdists
     @property
-    def unpacked_source_directory(self):
-        # type: () -> str
+    def unpacked_source_directory(self) -> str:
         return os.path.join(
-            self.source_dir,
-            self.link and self.link.subdirectory_fragment or '')
+            self.source_dir, self.link and self.link.subdirectory_fragment or ""
+        )
 
     @property
-    def setup_py_path(self):
-        # type: () -> str
+    def setup_py_path(self) -> str:
         assert self.source_dir, f"No source dir for {self}"
-        setup_py = os.path.join(self.unpacked_source_directory, 'setup.py')
+        setup_py = os.path.join(self.unpacked_source_directory, "setup.py")
 
         return setup_py
 
     @property
-    def pyproject_toml_path(self):
-        # type: () -> str
+    def setup_cfg_path(self) -> str:
+        assert self.source_dir, f"No source dir for {self}"
+        setup_cfg = os.path.join(self.unpacked_source_directory, "setup.cfg")
+
+        return setup_cfg
+
+    @property
+    def pyproject_toml_path(self) -> str:
         assert self.source_dir, f"No source dir for {self}"
         return make_pyproject_path(self.unpacked_source_directory)
 
-    def load_pyproject_toml(self):
-        # type: () -> None
+    def load_pyproject_toml(self) -> None:
         """Load the pyproject.toml file.
 
         After calling this routine, all of the attributes related to PEP 517
@@ -491,10 +462,7 @@ class InstallRequirement:
         follow the PEP 517 or legacy (setup.py) code path.
         """
         pyproject_toml_data = load_pyproject_toml(
-            self.use_pep517,
-            self.pyproject_toml_path,
-            self.setup_py_path,
-            str(self)
+            self.use_pep517, self.pyproject_toml_path, self.setup_py_path, str(self)
         )
 
         if pyproject_toml_data is None:
@@ -505,63 +473,70 @@ class InstallRequirement:
         requires, backend, check, backend_path = pyproject_toml_data
         self.requirements_to_check = check
         self.pyproject_requires = requires
-        self.pep517_backend = Pep517HookCaller(
-            self.unpacked_source_directory, backend, backend_path=backend_path,
+        self.pep517_backend = ConfiguredPep517HookCaller(
+            self,
+            self.unpacked_source_directory,
+            backend,
+            backend_path=backend_path,
         )
 
-    def _check_setup_py_or_cfg_exists(self) -> bool:
-        """Check if the requirement actually has a setuptools build file.
+    def isolated_editable_sanity_check(self) -> None:
+        """Check that an editable requirement if valid for use with PEP 517/518.
 
-        If setup.py does not exist, we also check setup.cfg in the same
-        directory and allow the directory if that exists.
+        This verifies that an editable that has a pyproject.toml either supports PEP 660
+        or as a setup.py or a setup.cfg
         """
-        if os.path.exists(self.setup_py_path):
-            return True
-        stem, ext = os.path.splitext(self.setup_py_path)
-        if ext == ".py" and os.path.exists(f"{stem}.cfg"):
-            return True
-        return False
+        if (
+            self.editable
+            and self.use_pep517
+            and not self.supports_pyproject_editable()
+            and not os.path.isfile(self.setup_py_path)
+            and not os.path.isfile(self.setup_cfg_path)
+        ):
+            raise InstallationError(
+                f"Project {self} has a 'pyproject.toml' and its build "
+                f"backend is missing the 'build_editable' hook. Since it does not "
+                f"have a 'setup.py' nor a 'setup.cfg', "
+                f"it cannot be installed in editable mode. "
+                f"Consider using a build backend that supports PEP 660."
+            )
 
-    def _generate_metadata(self):
-        # type: () -> str
-        """Invokes metadata generator functions, with the required arguments.
+    def prepare_metadata(self) -> None:
+        """Ensure that project metadata is available.
+
+        Under PEP 517 and PEP 660, call the backend hook to prepare the metadata.
+        Under legacy processing, call setup.py egg-info.
         """
-        if not self.use_pep517:
-            assert self.unpacked_source_directory
+        assert self.source_dir
+        details = self.name or f"from {self.link}"
 
-            if not self._check_setup_py_or_cfg_exists():
-                raise InstallationError(
-                    f'File "setup.py" or "setup.cfg" not found for legacy '
-                    f'project {self}.'
+        if self.use_pep517:
+            assert self.pep517_backend is not None
+            if (
+                self.editable
+                and self.permit_editable_wheels
+                and self.supports_pyproject_editable()
+            ):
+                self.metadata_directory = generate_editable_metadata(
+                    build_env=self.build_env,
+                    backend=self.pep517_backend,
+                    details=details,
                 )
-
-            return generate_metadata_legacy(
+            else:
+                self.metadata_directory = generate_metadata(
+                    build_env=self.build_env,
+                    backend=self.pep517_backend,
+                    details=details,
+                )
+        else:
+            self.metadata_directory = generate_metadata_legacy(
                 build_env=self.build_env,
                 setup_py_path=self.setup_py_path,
                 source_dir=self.unpacked_source_directory,
                 isolated=self.isolated,
-                details=self.name or f"from {self.link}"
+                details=details,
             )
 
-        assert self.pep517_backend is not None
-
-        return generate_metadata(
-            build_env=self.build_env,
-            backend=self.pep517_backend,
-        )
-
-    def prepare_metadata(self):
-        # type: () -> None
-        """Ensure that project metadata is available.
-
-        Under PEP 517, call the backend hook to prepare the metadata.
-        Under legacy processing, call setup.py egg-info.
-        """
-        assert self.source_dir
-
-        with indent_log():
-            self.metadata_directory = self._generate_metadata()
-
         # Act on the newly generated metadata, based on the name and version.
         if not self.name:
             self._set_requirement()
@@ -571,30 +546,27 @@ class InstallRequirement:
         self.assert_source_matches_version()
 
     @property
-    def metadata(self):
-        # type: () -> Any
-        if not hasattr(self, '_metadata'):
-            self._metadata = get_metadata(self.get_dist())
+    def metadata(self) -> Any:
+        if not hasattr(self, "_metadata"):
+            self._metadata = self.get_dist().metadata
 
         return self._metadata
 
-    def get_dist(self):
-        # type: () -> Distribution
-        return _get_dist(self.metadata_directory)
+    def get_dist(self) -> BaseDistribution:
+        return get_directory_distribution(self.metadata_directory)
 
-    def assert_source_matches_version(self):
-        # type: () -> None
+    def assert_source_matches_version(self) -> None:
         assert self.source_dir
-        version = self.metadata['version']
+        version = self.metadata["version"]
         if self.req.specifier and version not in self.req.specifier:
             logger.warning(
-                'Requested %s, but installing version %s',
+                "Requested %s, but installing version %s",
                 self,
                 version,
             )
         else:
             logger.debug(
-                'Source in %s has version %s, which satisfies requirement %s',
+                "Source in %s has version %s, which satisfies requirement %s",
                 display_path(self.source_dir),
                 version,
                 self,
@@ -603,11 +575,10 @@ class InstallRequirement:
     # For both source distributions and editables
     def ensure_has_source_dir(
         self,
-        parent_dir,
-        autodelete=False,
-        parallel_builds=False,
-    ):
-        # type: (str, bool, bool) -> None
+        parent_dir: str,
+        autodelete: bool = False,
+        parallel_builds: bool = False,
+    ) -> None:
         """Ensure that a source_dir is set.
 
         This will create a temporary build dir if the name of the requirement
@@ -625,18 +596,16 @@ class InstallRequirement:
             )
 
     # For editable installations
-    def update_editable(self):
-        # type: () -> None
+    def update_editable(self) -> None:
         if not self.link:
             logger.debug(
-                "Cannot update repository at %s; repository location is "
-                "unknown",
+                "Cannot update repository at %s; repository location is unknown",
                 self.source_dir,
             )
             return
         assert self.editable
         assert self.source_dir
-        if self.link.scheme == 'file':
+        if self.link.scheme == "file":
             # Static paths don't get updated
             return
         vcs_backend = vcs.get_backend_for_scheme(self.link.scheme)
@@ -644,11 +613,12 @@ class InstallRequirement:
         # So here, if it's neither a path nor a valid VCS URL, it's a bug.
         assert vcs_backend, f"Unsupported VCS URL {self.link.url}"
         hidden_url = hide_url(self.link.url)
-        vcs_backend.obtain(self.source_dir, url=hidden_url)
+        vcs_backend.obtain(self.source_dir, url=hidden_url, verbosity=0)
 
     # Top-level Actions
-    def uninstall(self, auto_confirm=False, verbose=False):
-        # type: (bool, bool) -> Optional[UninstallPathSet]
+    def uninstall(
+        self, auto_confirm: bool = False, verbose: bool = False
+    ) -> Optional[UninstallPathSet]:
         """
         Uninstall the distribution currently satisfying this requirement.
 
@@ -662,34 +632,30 @@ class InstallRequirement:
 
         """
         assert self.req
-        dist = get_distribution(self.req.name)
+        dist = get_default_environment().get_distribution(self.req.name)
         if not dist:
             logger.warning("Skipping %s as it is not installed.", self.name)
             return None
-        logger.info('Found existing installation: %s', dist)
+        logger.info("Found existing installation: %s", dist)
 
         uninstalled_pathset = UninstallPathSet.from_dist(dist)
         uninstalled_pathset.remove(auto_confirm, verbose)
         return uninstalled_pathset
 
-    def _get_archive_name(self, path, parentdir, rootdir):
-        # type: (str, str, str) -> str
-
-        def _clean_zip_name(name, prefix):
-            # type: (str, str) -> str
-            assert name.startswith(prefix + os.path.sep), (
-                f"name {name!r} doesn't start with prefix {prefix!r}"
-            )
-            name = name[len(prefix) + 1:]
-            name = name.replace(os.path.sep, '/')
+    def _get_archive_name(self, path: str, parentdir: str, rootdir: str) -> str:
+        def _clean_zip_name(name: str, prefix: str) -> str:
+            assert name.startswith(
+                prefix + os.path.sep
+            ), f"name {name!r} doesn't start with prefix {prefix!r}"
+            name = name[len(prefix) + 1 :]
+            name = name.replace(os.path.sep, "/")
             return name
 
         path = os.path.join(parentdir, path)
         name = _clean_zip_name(path, rootdir)
-        return self.name + '/' + name
+        return self.name + "/" + name
 
-    def archive(self, build_dir):
-        # type: (Optional[str]) -> None
+    def archive(self, build_dir: Optional[str]) -> None:
         """Saves archive to provided build_dir.
 
         Used for saving downloaded VCS requirements as part of `pip download`.
@@ -699,70 +665,74 @@ class InstallRequirement:
             return
 
         create_archive = True
-        archive_name = '{}-{}.zip'.format(self.name, self.metadata["version"])
+        archive_name = "{}-{}.zip".format(self.name, self.metadata["version"])
         archive_path = os.path.join(build_dir, archive_name)
 
         if os.path.exists(archive_path):
             response = ask_path_exists(
-                'The file {} exists. (i)gnore, (w)ipe, '
-                '(b)ackup, (a)bort '.format(
-                    display_path(archive_path)),
-                ('i', 'w', 'b', 'a'))
-            if response == 'i':
+                "The file {} exists. (i)gnore, (w)ipe, "
+                "(b)ackup, (a)bort ".format(display_path(archive_path)),
+                ("i", "w", "b", "a"),
+            )
+            if response == "i":
                 create_archive = False
-            elif response == 'w':
-                logger.warning('Deleting %s', display_path(archive_path))
+            elif response == "w":
+                logger.warning("Deleting %s", display_path(archive_path))
                 os.remove(archive_path)
-            elif response == 'b':
+            elif response == "b":
                 dest_file = backup_dir(archive_path)
                 logger.warning(
-                    'Backing up %s to %s',
+                    "Backing up %s to %s",
                     display_path(archive_path),
                     display_path(dest_file),
                 )
                 shutil.move(archive_path, dest_file)
-            elif response == 'a':
+            elif response == "a":
                 sys.exit(-1)
 
         if not create_archive:
             return
 
         zip_output = zipfile.ZipFile(
-            archive_path, 'w', zipfile.ZIP_DEFLATED, allowZip64=True,
+            archive_path,
+            "w",
+            zipfile.ZIP_DEFLATED,
+            allowZip64=True,
         )
         with zip_output:
-            dir = os.path.normcase(
-                os.path.abspath(self.unpacked_source_directory)
-            )
+            dir = os.path.normcase(os.path.abspath(self.unpacked_source_directory))
             for dirpath, dirnames, filenames in os.walk(dir):
                 for dirname in dirnames:
                     dir_arcname = self._get_archive_name(
-                        dirname, parentdir=dirpath, rootdir=dir,
+                        dirname,
+                        parentdir=dirpath,
+                        rootdir=dir,
                     )
-                    zipdir = zipfile.ZipInfo(dir_arcname + '/')
+                    zipdir = zipfile.ZipInfo(dir_arcname + "/")
                     zipdir.external_attr = 0x1ED << 16  # 0o755
-                    zip_output.writestr(zipdir, '')
+                    zip_output.writestr(zipdir, "")
                 for filename in filenames:
                     file_arcname = self._get_archive_name(
-                        filename, parentdir=dirpath, rootdir=dir,
+                        filename,
+                        parentdir=dirpath,
+                        rootdir=dir,
                     )
                     filename = os.path.join(dirpath, filename)
                     zip_output.write(filename, file_arcname)
 
-        logger.info('Saved %s', display_path(archive_path))
+        logger.info("Saved %s", display_path(archive_path))
 
     def install(
         self,
-        install_options,  # type: List[str]
-        global_options=None,  # type: Optional[Sequence[str]]
-        root=None,  # type: Optional[str]
-        home=None,  # type: Optional[str]
-        prefix=None,  # type: Optional[str]
-        warn_script_location=True,  # type: bool
-        use_user_site=False,  # type: bool
-        pycompile=True  # type: bool
-    ):
-        # type: (...) -> None
+        install_options: List[str],
+        global_options: Optional[Sequence[str]] = None,
+        root: Optional[str] = None,
+        home: Optional[str] = None,
+        prefix: Optional[str] = None,
+        warn_script_location: bool = True,
+        use_user_site: bool = False,
+        pycompile: bool = True,
+    ) -> None:
         scheme = get_scheme(
             self.name,
             user=use_user_site,
@@ -773,7 +743,7 @@ class InstallRequirement:
         )
 
         global_options = global_options if global_options is not None else []
-        if self.editable:
+        if self.editable and not self.is_wheel:
             install_editable_legacy(
                 install_options,
                 global_options,
@@ -792,7 +762,9 @@ class InstallRequirement:
         if self.is_wheel:
             assert self.local_file_path
             direct_url = None
-            if self.original_link:
+            if self.editable:
+                direct_url = direct_url_for_editable(self.unpacked_source_directory)
+            elif self.original_link:
                 direct_url = direct_url_from_link(
                     self.original_link,
                     self.source_dir,
@@ -840,7 +812,7 @@ class InstallRequirement:
             )
         except LegacyInstallFailure as exc:
             self.install_succeeded = False
-            six.reraise(*exc.parent)
+            raise exc
         except Exception:
             self.install_succeeded = True
             raise
@@ -851,8 +823,9 @@ class InstallRequirement:
             deprecated(
                 reason=(
                     "{} was installed using the legacy 'setup.py install' "
-                    "method, because a wheel could not be built for it.".
-                    format(self.name)
+                    "method, because a wheel could not be built for it.".format(
+                        self.name
+                    )
                 ),
                 replacement="to fix the wheel build issue reported above",
                 gone_in=None,
@@ -860,8 +833,7 @@ class InstallRequirement:
             )
 
 
-def check_invalid_constraint_type(req):
-    # type: (InstallRequirement) -> str
+def check_invalid_constraint_type(req: InstallRequirement) -> str:
 
     # Check for unsupported forms
     problem = ""
@@ -881,12 +853,10 @@ def check_invalid_constraint_type(req):
                 "undocumented. The new implementation of the resolver no "
                 "longer supports these forms."
             ),
-            replacement=(
-                "replacing the constraint with a requirement."
-            ),
+            replacement="replacing the constraint with a requirement",
             # No plan yet for when the new resolver becomes default
             gone_in=None,
-            issue=8210
+            issue=8210,
         )
 
     return problem

venv/Lib/site-packages/pip/_internal/req/req_set.py

@@ -1,191 +1,62 @@
 import logging
 from collections import OrderedDict
-from typing import Dict, Iterable, List, Optional, Tuple
+from typing import Dict, List
 
 from pip._vendor.packaging.utils import canonicalize_name
 
-from pip._internal.exceptions import InstallationError
-from pip._internal.models.wheel import Wheel
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.utils import compatibility_tags
 
 logger = logging.getLogger(__name__)
 
 
 class RequirementSet:
+    def __init__(self, check_supported_wheels: bool = True) -> None:
+        """Create a RequirementSet."""
 
-    def __init__(self, check_supported_wheels=True):
-        # type: (bool) -> None
-        """Create a RequirementSet.
-        """
-
-        self.requirements = OrderedDict()  # type: Dict[str, InstallRequirement]
+        self.requirements: Dict[str, InstallRequirement] = OrderedDict()
         self.check_supported_wheels = check_supported_wheels
 
-        self.unnamed_requirements = []  # type: List[InstallRequirement]
+        self.unnamed_requirements: List[InstallRequirement] = []
 
-    def __str__(self):
-        # type: () -> str
+    def __str__(self) -> str:
         requirements = sorted(
             (req for req in self.requirements.values() if not req.comes_from),
             key=lambda req: canonicalize_name(req.name or ""),
         )
-        return ' '.join(str(req.req) for req in requirements)
+        return " ".join(str(req.req) for req in requirements)
 
-    def __repr__(self):
-        # type: () -> str
+    def __repr__(self) -> str:
         requirements = sorted(
             self.requirements.values(),
             key=lambda req: canonicalize_name(req.name or ""),
         )
 
-        format_string = '<{classname} object; {count} requirement(s): {reqs}>'
+        format_string = "<{classname} object; {count} requirement(s): {reqs}>"
         return format_string.format(
             classname=self.__class__.__name__,
             count=len(requirements),
-            reqs=', '.join(str(req.req) for req in requirements),
+            reqs=", ".join(str(req.req) for req in requirements),
         )
 
-    def add_unnamed_requirement(self, install_req):
-        # type: (InstallRequirement) -> None
+    def add_unnamed_requirement(self, install_req: InstallRequirement) -> None:
         assert not install_req.name
         self.unnamed_requirements.append(install_req)
 
-    def add_named_requirement(self, install_req):
-        # type: (InstallRequirement) -> None
+    def add_named_requirement(self, install_req: InstallRequirement) -> None:
         assert install_req.name
 
         project_name = canonicalize_name(install_req.name)
         self.requirements[project_name] = install_req
 
-    def add_requirement(
-        self,
-        install_req,  # type: InstallRequirement
-        parent_req_name=None,  # type: Optional[str]
-        extras_requested=None  # type: Optional[Iterable[str]]
-    ):
-        # type: (...) -> Tuple[List[InstallRequirement], Optional[InstallRequirement]]
-        """Add install_req as a requirement to install.
-
-        :param parent_req_name: The name of the requirement that needed this
-            added. The name is used because when multiple unnamed requirements
-            resolve to the same name, we could otherwise end up with dependency
-            links that point outside the Requirements set. parent_req must
-            already be added. Note that None implies that this is a user
-            supplied requirement, vs an inferred one.
-        :param extras_requested: an iterable of extras used to evaluate the
-            environment markers.
-        :return: Additional requirements to scan. That is either [] if
-            the requirement is not applicable, or [install_req] if the
-            requirement is applicable and has just been added.
-        """
-        # If the markers do not match, ignore this requirement.
-        if not install_req.match_markers(extras_requested):
-            logger.info(
-                "Ignoring %s: markers '%s' don't match your environment",
-                install_req.name, install_req.markers,
-            )
-            return [], None
-
-        # If the wheel is not supported, raise an error.
-        # Should check this after filtering out based on environment markers to
-        # allow specifying different wheels based on the environment/OS, in a
-        # single requirements file.
-        if install_req.link and install_req.link.is_wheel:
-            wheel = Wheel(install_req.link.filename)
-            tags = compatibility_tags.get_supported()
-            if (self.check_supported_wheels and not wheel.supported(tags)):
-                raise InstallationError(
-                    "{} is not a supported wheel on this platform.".format(
-                        wheel.filename)
-                )
-
-        # This next bit is really a sanity check.
-        assert not install_req.user_supplied or parent_req_name is None, (
-            "a user supplied req shouldn't have a parent"
-        )
-
-        # Unnamed requirements are scanned again and the requirement won't be
-        # added as a dependency until after scanning.
-        if not install_req.name:
-            self.add_unnamed_requirement(install_req)
-            return [install_req], None
-
-        try:
-            existing_req = self.get_requirement(
-                install_req.name)  # type: Optional[InstallRequirement]
-        except KeyError:
-            existing_req = None
-
-        has_conflicting_requirement = (
-            parent_req_name is None and
-            existing_req and
-            not existing_req.constraint and
-            existing_req.extras == install_req.extras and
-            existing_req.req and
-            install_req.req and
-            existing_req.req.specifier != install_req.req.specifier
-        )
-        if has_conflicting_requirement:
-            raise InstallationError(
-                "Double requirement given: {} (already in {}, name={!r})"
-                .format(install_req, existing_req, install_req.name)
-            )
-
-        # When no existing requirement exists, add the requirement as a
-        # dependency and it will be scanned again after.
-        if not existing_req:
-            self.add_named_requirement(install_req)
-            # We'd want to rescan this requirement later
-            return [install_req], install_req
-
-        # Assume there's no need to scan, and that we've already
-        # encountered this for scanning.
-        if install_req.constraint or not existing_req.constraint:
-            return [], existing_req
-
-        does_not_satisfy_constraint = (
-            install_req.link and
-            not (
-                existing_req.link and
-                install_req.link.path == existing_req.link.path
-            )
-        )
-        if does_not_satisfy_constraint:
-            raise InstallationError(
-                "Could not satisfy constraints for '{}': "
-                "installation from path or url cannot be "
-                "constrained to a version".format(install_req.name)
-            )
-        # If we're now installing a constraint, mark the existing
-        # object for real installation.
-        existing_req.constraint = False
-        # If we're now installing a user supplied requirement,
-        # mark the existing object as such.
-        if install_req.user_supplied:
-            existing_req.user_supplied = True
-        existing_req.extras = tuple(sorted(
-            set(existing_req.extras) | set(install_req.extras)
-        ))
-        logger.debug(
-            "Setting %s extras to: %s",
-            existing_req, existing_req.extras,
-        )
-        # Return the existing requirement for addition to the parent and
-        # scanning again.
-        return [existing_req], existing_req
-
-    def has_requirement(self, name):
-        # type: (str) -> bool
+    def has_requirement(self, name: str) -> bool:
         project_name = canonicalize_name(name)
 
         return (
-            project_name in self.requirements and
-            not self.requirements[project_name].constraint
+            project_name in self.requirements
+            and not self.requirements[project_name].constraint
         )
 
-    def get_requirement(self, name):
-        # type: (str) -> InstallRequirement
+    def get_requirement(self, name: str) -> InstallRequirement:
         project_name = canonicalize_name(name)
 
         if project_name in self.requirements:
@@ -194,6 +65,5 @@ class RequirementSet:
         raise KeyError(f"No project with the name {name!r}")
 
     @property
-    def all_requirements(self):
-        # type: () -> List[InstallRequirement]
+    def all_requirements(self) -> List[InstallRequirement]:
         return self.unnamed_requirements + list(self.requirements.values())