Merge branch 'master' into sysconfig

.pre-commit-config.yaml

@@ -23,9 +23,7 @@ repos:
     exclude: |
       (?x)
         ^docs/|
-        ^src/pip/_internal/cli|
         ^src/pip/_internal/commands|
-        ^src/pip/_internal/distributions|
         ^src/pip/_internal/index|
         ^src/pip/_internal/models|
         ^src/pip/_internal/network|

docs/html/development/ci.rst

@@ -133,11 +133,11 @@ Actual testing
 |           |          +-------+---------------+-----------------+
 |           |          | PyPy3 |               |                 |
 |   MacOS   +----------+-------+---------------+-----------------+
-|           |          | CP3.6 |   Azure       |   Azure         |
+|           |          | CP3.6 |   Github      |   Github        |
 |           |          +-------+---------------+-----------------+
-|           |   x64    | CP3.7 |   Azure       |   Azure         |
+|           |   x64    | CP3.7 |   Github      |   Github        |
 |           |          +-------+---------------+-----------------+
-|           |          | CP3.8 |   Azure       |   Azure         |
+|           |          | CP3.8 |   Github      |   Github        |
 |           |          +-------+---------------+-----------------+
 |           |          | PyPy3 |               |                 |
 +-----------+----------+-------+---------------+-----------------+

docs/html/reference/pip_install.rst

@@ -561,8 +561,12 @@ See the :ref:`pip install Examples<pip install Examples>`.
 SSL Certificate Verification
 ----------------------------
 
-Starting with v1.3, pip provides SSL certificate verification over https, to
+Starting with v1.3, pip provides SSL certificate verification over HTTP, to
-prevent man-in-the-middle attacks against PyPI downloads.
+prevent man-in-the-middle attacks against PyPI downloads. This does not use
+the system certificate store but instead uses a bundled CA certificate
+store. The default bundled CA certificate store certificate store may be
+overridden by using ``--cert`` option or by using ``PIP_CERT``,
+``REQUESTS_CA_BUNDLE``, or ``CURL_CA_BUNDLE`` environment variables.
 
 
 .. _`Caching`:
@@ -808,7 +812,15 @@ You can install local projects by specifying the project path to pip:
 During regular installation, pip will copy the entire project directory to a
 temporary location and install from there. The exception is that pip will
 exclude .tox and .nox directories present in the top level of the project from
-being copied.
+being copied. This approach is the cause of several performance and correctness
+issues, so it is planned that pip 21.3 will change to install directly from the
+local project directory. Depending on the build backend used by the project,
+this may generate secondary build artifacts in the project directory, such as
+the ``.egg-info`` and ``build`` directories in the case of the setuptools
+backend.
+
+To opt in to the future behavior, specify the ``--use-feature=in-tree-build``
+option in pip's command line.
 
 
 .. _`editable-installs`:

docs/html/user_guide.rst

@@ -1857,9 +1857,11 @@ We plan for the resolver changeover to proceed as follows, using
      environments, pip defaults to the old resolver, and the new one is
      available using the flag ``--use-feature=2020-resolver``.
 
-*    pip 21.0: pip uses new resolver, and the old resolver is no longer
+*    pip 21.0: pip uses new resolver by default, and the old resolver is
-     available. Python 2 support is removed per our :ref:`Python 2
+     no longer supported. It will be removed after a currently undecided
-     Support` policy.
+     amount of time, as the removal is dependent on pip's volunteer
+     maintainers' availability. Python 2 support is removed per our
+     :ref:`Python 2 Support` policy.
 
 Since this work will not change user-visible behavior described in the
 pip documentation, this change is not covered by the :ref:`Deprecation

news/6720.doc.rst

@@ -0,0 +1 @@
+Improve SSL Certificate Verification docs and ``--cert`` help text.

news/8733.bugfix.rst

@@ -0,0 +1 @@
+Correctly uninstall script files (from setuptools' ``scripts`` argument), when installed with ``--user``.

news/9091.feature.rst

@@ -0,0 +1,4 @@
+Add a feature ``--use-feature=in-tree-build`` to build local projects in-place
+when installing. This is expected to become the default behavior in pip 21.3;
+see `Installing from local packages <https://pip.pypa.io/en/stable/user_guide/#installing-from-local-packages>`_
+for more information.

news/9300.bugfix.rst

@@ -0,0 +1,2 @@
+New resolver: Show relevant entries from user-supplied constraint files in the
+error message to improve debuggability.

noxfile.py

@@ -174,11 +174,14 @@ def vendoring(session):
 
     def pinned_requirements(path):
         # type: (Path) -> Iterator[Tuple[str, str]]
-        for line in path.read_text().splitlines():
+        for line in path.read_text().splitlines(keepends=False):
-            one, two = line.split("==", 1)
+            one, sep, two = line.partition("==")
+            if not sep:
+                continue
             name = one.strip()
-            version = two.split("#")[0].strip()
+            version = two.split("#", 1)[0].strip()
-            yield name, version
+            if name and version:
+                yield name, version
 
     vendor_txt = Path("src/pip/_vendor/vendor.txt")
     for name, old_version in pinned_requirements(vendor_txt):

setup.py

@@ -1,6 +1,3 @@
-# The following comment should be removed at some point in the future.
-# mypy: disallow-untyped-defs=False
-
 import os
 import sys
 
@@ -8,14 +5,16 @@ from setuptools import find_packages, setup
 
 
 def read(rel_path):
+    # type: (str) -> str
     here = os.path.abspath(os.path.dirname(__file__))
     # intentionally *not* adding an encoding option to open, See:
     #   https://github.com/pypa/virtualenv/issues/201#issuecomment-3145690
-    with open(os.path.join(here, rel_path), 'r') as fp:
+    with open(os.path.join(here, rel_path)) as fp:
         return fp.read()
 
 
 def get_version(rel_path):
+    # type: (str) -> str
     for line in read(rel_path).splitlines():
         if line.startswith('__version__'):
             # __version__ = "0.9"

src/pip/_internal/cli/autocompletion.py

@@ -14,17 +14,16 @@ from pip._internal.utils.misc import get_installed_distributions
 
 def autocomplete():
     # type: () -> None
-    """Entry Point for completion of main and subcommand options.
+    """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:
+    if "PIP_AUTO_COMPLETE" not in os.environ:
         return
-    cwords = os.environ['COMP_WORDS'].split()[1:]
+    cwords = os.environ["COMP_WORDS"].split()[1:]
-    cword = int(os.environ['COMP_CWORD'])
+    cword = int(os.environ["COMP_CWORD"])
     try:
         current = cwords[cword - 1]
     except IndexError:
-        current = ''
+        current = ""
 
     parser = create_main_parser()
     subcommands = list(commands_dict)
@@ -39,13 +38,13 @@ def autocomplete():
     # subcommand options
     if subcommand_name is not None:
         # special case: 'help' subcommand has no options
-        if subcommand_name == 'help':
+        if subcommand_name == "help":
             sys.exit(1)
         # special case: list locally installed dists for show and uninstall
-        should_list_installed = (
+        should_list_installed = not current.startswith("-") and subcommand_name in [
-            subcommand_name in ['show', 'uninstall'] and
+            "show",
-            not current.startswith('-')
+            "uninstall",
-        )
+        ]
         if should_list_installed:
             lc = current.lower()
             installed = [
@@ -67,13 +66,15 @@ def autocomplete():
                     options.append((opt_str, opt.nargs))
 
         # filter out previously specified options from available options
-        prev_opts = [x.split('=')[0] for x in cwords[1:cword - 1]]
+        prev_opts = [x.split("=")[0] for x in cwords[1 : cword - 1]]
         options = [(x, v) for (x, v) in options if x not in prev_opts]
         # filter options by current input
         options = [(k, v) for k, v in options if k.startswith(current)]
         # get completion type given cwords and available subcommand options
         completion_type = get_path_completion_type(
-            cwords, cword, subcommand.parser.option_list_all,
+            cwords,
+            cword,
+            subcommand.parser.option_list_all,
         )
         # get completion files and directories if ``completion_type`` is
         # ``<file>``, ``<dir>`` or ``<path>``
@@ -84,7 +85,7 @@ def autocomplete():
             opt_label = option[0]
             # append '=' to options which require args
             if option[1] and option[0][:2] == "--":
-                opt_label += '='
+                opt_label += "="
             print(opt_label)
     else:
         # show main parser options only when necessary
@@ -92,19 +93,17 @@ def autocomplete():
         opts = [i.option_list for i in parser.option_groups]
         opts.append(parser.option_list)
         flattened_opts = chain.from_iterable(opts)
-        if current.startswith('-'):
+        if current.startswith("-"):
             for opt in flattened_opts:
                 if opt.help != optparse.SUPPRESS_HELP:
                     subcommands += opt._long_opts + opt._short_opts
         else:
             # get completion type given cwords and all available options
-            completion_type = get_path_completion_type(cwords, cword,
+            completion_type = get_path_completion_type(cwords, cword, flattened_opts)
-                                                       flattened_opts)
             if completion_type:
-                subcommands = list(auto_complete_paths(current,
+                subcommands = list(auto_complete_paths(current, completion_type))
-                                                       completion_type))
 
-        print(' '.join([x for x in subcommands if x.startswith(current)]))
+        print(" ".join([x for x in subcommands if x.startswith(current)]))
     sys.exit(1)
 
 
@@ -117,16 +116,16 @@ def get_path_completion_type(cwords, cword, opts):
     :param opts: The available options to check
     :return: path completion type (``file``, ``dir``, ``path`` or None)
     """
-    if cword < 2 or not cwords[cword - 2].startswith('-'):
+    if cword < 2 or not cwords[cword - 2].startswith("-"):
         return None
     for opt in opts:
         if opt.help == optparse.SUPPRESS_HELP:
             continue
-        for o in str(opt).split('/'):
+        for o in str(opt).split("/"):
-            if cwords[cword - 2].split('=')[0] == o:
+            if cwords[cword - 2].split("=")[0] == o:
                 if not opt.metavar or any(
-                        x in ('path', 'file', 'dir')
+                    x in ("path", "file", "dir") for x in opt.metavar.split("/")
-                        for x in opt.metavar.split('/')):
+                ):
                     return opt.metavar
     return None
 
@@ -148,15 +147,16 @@ def auto_complete_paths(current, completion_type):
         return
     filename = os.path.normcase(filename)
     # list all files that start with ``filename``
-    file_list = (x for x in os.listdir(current_path)
+    file_list = (
-                 if os.path.normcase(x).startswith(filename))
+        x for x in os.listdir(current_path) if os.path.normcase(x).startswith(filename)
+    )
     for f in file_list:
         opt = os.path.join(current_path, f)
         comp_file = os.path.normcase(os.path.join(directory, f))
         # complete regular files when there is not ``<dir>`` after option
         # complete directories when there is ``<file>``, ``<path>`` or
         # ``<dir>``after option
-        if completion_type != 'dir' and os.path.isfile(opt):
+        if completion_type != "dir" and os.path.isfile(opt):
             yield comp_file
         elif os.path.isdir(opt):
-            yield os.path.join(comp_file, '')
+            yield os.path.join(comp_file, "")

src/pip/_internal/cli/base_command.py

@@ -34,7 +34,7 @@ from pip._internal.utils.temp_dir import TempDirectoryTypeRegistry as TempDirReg
 from pip._internal.utils.temp_dir import global_tempdir_manager, tempdir_registry
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
-__all__ = ['Command']
+__all__ = ["Command"]
 
 logger = logging.getLogger(__name__)
 
@@ -51,7 +51,7 @@ class Command(CommandContextMixIn):
         self.summary = summary
         self.parser = ConfigOptionParser(
             usage=self.usage,
-            prog=f'{get_prog()} {name}',
+            prog=f"{get_prog()} {name}",
             formatter=UpdatingDefaultsHelpFormatter(),
             add_help_option=False,
             name=name,
@@ -62,7 +62,7 @@ class Command(CommandContextMixIn):
         self.tempdir_registry = None  # type: Optional[TempDirRegistry]
 
         # Commands should add options to this option group
-        optgroup_name = f'{self.name.capitalize()} Options'
+        optgroup_name = f"{self.name.capitalize()} Options"
         self.cmd_opts = optparse.OptionGroup(self.parser, optgroup_name)
 
         # Add the general options
@@ -86,7 +86,7 @@ class Command(CommandContextMixIn):
         """
         # Make sure we do the pip version check if the index_group options
         # are present.
-        assert not hasattr(options, 'no_index')
+        assert not hasattr(options, "no_index")
 
     def run(self, options, args):
         # type: (Values, List[Any]) -> int
@@ -131,17 +131,15 @@ class Command(CommandContextMixIn):
         #       This also affects isolated builds and it should.
 
         if options.no_input:
-            os.environ['PIP_NO_INPUT'] = '1'
+            os.environ["PIP_NO_INPUT"] = "1"
 
         if options.exists_action:
-            os.environ['PIP_EXISTS_ACTION'] = ' '.join(options.exists_action)
+            os.environ["PIP_EXISTS_ACTION"] = " ".join(options.exists_action)
 
         if options.require_venv and not self.ignore_require_venv:
             # If a venv is required check if it can really be found
             if not running_under_virtualenv():
-                logger.critical(
+                logger.critical("Could not find an activated virtualenv (required).")
-                    'Could not find an activated virtualenv (required).'
-                )
                 sys.exit(VIRTUALENV_NOT_FOUND)
 
         if options.cache_dir:
@@ -171,7 +169,7 @@ class Command(CommandContextMixIn):
                 issue=8333,
             )
 
-        if '2020-resolver' in options.features_enabled:
+        if "2020-resolver" in options.features_enabled:
             logger.warning(
                 "--use-feature=2020-resolver no longer has any effect, "
                 "since it is now the default dependency resolver in pip. "
@@ -184,35 +182,39 @@ class Command(CommandContextMixIn):
             return status
         except PreviousBuildDirError as exc:
             logger.critical(str(exc))
-            logger.debug('Exception information:', exc_info=True)
+            logger.debug("Exception information:", exc_info=True)
 
             return PREVIOUS_BUILD_DIR_ERROR
-        except (InstallationError, UninstallationError, BadCommand,
+        except (
-                NetworkConnectionError) as exc:
+            InstallationError,
+            UninstallationError,
+            BadCommand,
+            NetworkConnectionError,
+        ) as exc:
             logger.critical(str(exc))
-            logger.debug('Exception information:', exc_info=True)
+            logger.debug("Exception information:", exc_info=True)
 
             return ERROR
         except CommandError as exc:
-            logger.critical('%s', exc)
+            logger.critical("%s", exc)
-            logger.debug('Exception information:', exc_info=True)
+            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)
+            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.critical("Operation cancelled by user")
-            logger.debug('Exception information:', exc_info=True)
+            logger.debug("Exception information:", exc_info=True)
 
             return ERROR
         except BaseException:
-            logger.critical('Exception:', exc_info=True)
+            logger.critical("Exception:", exc_info=True)
 
             return UNKNOWN_ERROR
         finally:

src/pip/_internal/cli/command_context.py

@@ -1,7 +1,7 @@
 from contextlib import ExitStack, contextmanager
 from typing import ContextManager, Iterator, TypeVar
 
-_T = TypeVar('_T', covariant=True)
+_T = TypeVar("_T", covariant=True)
 
 
 class CommandContextMixIn:

src/pip/_internal/cli/main.py

@@ -41,6 +41,7 @@ logger = logging.getLogger(__name__)
 # call to main. As it is not safe to do any processing after calling
 # main, this should not be an issue in practice.
 
+
 def main(args=None):
     # type: (Optional[List[str]]) -> int
     if args is None:
@@ -61,7 +62,7 @@ def main(args=None):
     # Needed for locale.getpreferredencoding(False) to work
     # in pip._internal.utils.encoding.auto_decode
     try:
-        locale.setlocale(locale.LC_ALL, '')
+        locale.setlocale(locale.LC_ALL, "")
     except locale.Error as e:
         # setlocale can apparently crash if locale are uninitialized
         logger.debug("Ignoring error %s when setting locale", e)

src/pip/_internal/cli/main_parser.py

@@ -16,14 +16,13 @@ __all__ = ["create_main_parser", "parse_command"]
 
 def create_main_parser():
     # type: () -> ConfigOptionParser
-    """Creates and returns the main parser for pip's CLI
+    """Creates and returns the main parser for pip's CLI"""
-    """
 
     parser = ConfigOptionParser(
-        usage='\n%prog <command> [options]',
+        usage="\n%prog <command> [options]",
         add_help_option=False,
         formatter=UpdatingDefaultsHelpFormatter(),
-        name='global',
+        name="global",
         prog=get_prog(),
     )
     parser.disable_interspersed_args()
@@ -38,11 +37,11 @@ def create_main_parser():
     parser.main = True  # type: ignore
 
     # create command listing for description
-    description = [''] + [
+    description = [""] + [
-        f'{name:27} {command_info.summary}'
+        f"{name:27} {command_info.summary}"
         for name, command_info in commands_dict.items()
     ]
-    parser.description = '\n'.join(description)
+    parser.description = "\n".join(description)
 
     return parser
 
@@ -67,7 +66,7 @@ def parse_command(args):
         sys.exit()
 
     # pip || pip help -> print_help()
-    if not args_else or (args_else[0] == 'help' and len(args_else) == 1):
+    if not args_else or (args_else[0] == "help" and len(args_else) == 1):
         parser.print_help()
         sys.exit()
 
@@ -81,7 +80,7 @@ def parse_command(args):
         if guess:
             msg.append(f'maybe you meant "{guess}"')
 
-        raise CommandError(' - '.join(msg))
+        raise CommandError(" - ".join(msg))
 
     # all the args without the subcommand
     cmd_args = args[:]

src/pip/_internal/cli/parser.py

@@ -1,15 +1,12 @@
 """Base option parser setup"""
 
-# The following comment should be removed at some point in the future.
-# mypy: disallow-untyped-defs=False
-
 import logging
 import optparse
 import shutil
 import sys
 import textwrap
 from contextlib import suppress
-from typing import Any
+from typing import Any, Dict, Iterator, List, Tuple
 
 from pip._internal.cli.status_codes import UNKNOWN_ERROR
 from pip._internal.configuration import Configuration, ConfigurationError
@@ -22,16 +19,19 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
     """A prettier/less verbose help formatter for optparse."""
 
     def __init__(self, *args, **kwargs):
+        # type: (*Any, **Any) -> None
         # help position must be aligned with __init__.parseopts.description
-        kwargs['max_help_position'] = 30
+        kwargs["max_help_position"] = 30
-        kwargs['indent_increment'] = 1
+        kwargs["indent_increment"] = 1
-        kwargs['width'] = shutil.get_terminal_size()[0] - 2
+        kwargs["width"] = shutil.get_terminal_size()[0] - 2
         super().__init__(*args, **kwargs)
 
     def format_option_strings(self, option):
+        # type: (optparse.Option) -> str
         return self._format_option_strings(option)
 
-    def _format_option_strings(self, option, mvarfmt=' <{}>', optsep=', '):
+    def _format_option_strings(self, option, mvarfmt=" <{}>", optsep=", "):
+        # type: (optparse.Option, str, str) -> str
         """
         Return a comma-separated list of option strings and metavars.
 
@@ -49,52 +49,57 @@ class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
             opts.insert(1, optsep)
 
         if option.takes_value():
+            assert option.dest is not None
             metavar = option.metavar or option.dest.lower()
             opts.append(mvarfmt.format(metavar.lower()))
 
-        return ''.join(opts)
+        return "".join(opts)
 
     def format_heading(self, heading):
-        if heading == 'Options':
+        # type: (str) -> str
-            return ''
+        if heading == "Options":
-        return heading + ':\n'
+            return ""
+        return heading + ":\n"
 
     def format_usage(self, usage):
+        # type: (str) -> str
         """
         Ensure there is only one newline between usage and the first heading
         if there is no description.
         """
-        msg = '\nUsage: {}\n'.format(
+        msg = "\nUsage: {}\n".format(self.indent_lines(textwrap.dedent(usage), "  "))
-            self.indent_lines(textwrap.dedent(usage), "  "))
         return msg
 
     def format_description(self, description):
+        # type: (str) -> str
         # leave full control over description to us
         if description:
-            if hasattr(self.parser, 'main'):
+            if hasattr(self.parser, "main"):
-                label = 'Commands'
+                label = "Commands"
             else:
-                label = 'Description'
+                label = "Description"
             # some doc strings have initial newlines, some don't
-            description = description.lstrip('\n')
+            description = description.lstrip("\n")
             # some doc strings have final newlines and spaces, some don't
             description = description.rstrip()
             # dedent, then reindent
             description = self.indent_lines(textwrap.dedent(description), "  ")
-            description = f'{label}:\n{description}\n'
+            description = f"{label}:\n{description}\n"
             return description
         else:
-            return ''
+            return ""
 
     def format_epilog(self, epilog):
+        # type: (str) -> str
         # leave full control over epilog to us
         if epilog:
             return epilog
         else:
-            return ''
+            return ""
 
     def indent_lines(self, text, indent):
-        new_lines = [indent + line for line in text.split('\n')]
+        # type: (str, str) -> str
+        new_lines = [indent + line for line in text.split("\n")]
         return "\n".join(new_lines)
 
 
@@ -108,13 +113,16 @@ class UpdatingDefaultsHelpFormatter(PrettyHelpFormatter):
     """
 
     def expand_default(self, option):
+        # type: (optparse.Option) -> str
         default_values = None
         if self.parser is not None:
+            assert isinstance(self.parser, ConfigOptionParser)
             self.parser._update_defaults(self.parser.defaults)
+            assert option.dest is not None
             default_values = self.parser.defaults.get(option.dest)
         help_text = super().expand_default(option)
 
-        if default_values and option.metavar == 'URL':
+        if default_values and option.metavar == "URL":
             if isinstance(default_values, str):
                 default_values = [default_values]
 
@@ -123,15 +131,14 @@ class UpdatingDefaultsHelpFormatter(PrettyHelpFormatter):
                 default_values = []
 
             for val in default_values:
-                help_text = help_text.replace(
+                help_text = help_text.replace(val, redact_auth_from_url(val))
-                    val, redact_auth_from_url(val))
 
         return help_text
 
 
 class CustomOptionParser(optparse.OptionParser):
-
     def insert_option_group(self, idx, *args, **kwargs):
+        # type: (int, Any, Any) -> optparse.OptionGroup
         """Insert an OptionGroup at a given position."""
         group = self.add_option_group(*args, **kwargs)
 
@@ -142,6 +149,7 @@ class CustomOptionParser(optparse.OptionParser):
 
     @property
     def option_list_all(self):
+        # type: () -> List[optparse.Option]
         """Get a list of all options, including those in option groups."""
         res = self.option_list[:]
         for i in self.option_groups:
@@ -169,6 +177,7 @@ class ConfigOptionParser(CustomOptionParser):
         super().__init__(*args, **kwargs)
 
     def check_default(self, option, key, val):
+        # type: (optparse.Option, str, Any) -> Any
         try:
             return option.check_value(key, val)
         except optparse.OptionValueError as exc:
@@ -176,17 +185,20 @@ class ConfigOptionParser(CustomOptionParser):
             sys.exit(3)
 
     def _get_ordered_configuration_items(self):
+        # type: () -> Iterator[Tuple[str, Any]]
         # Configuration gives keys in an unordered manner. Order them.
         override_order = ["global", self.name, ":env:"]
 
         # Pool the options into different groups
-        section_items = {name: [] for name in override_order}
+        section_items = {
+            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:
                 logger.debug(
                     "Ignoring configuration key '%s' as it's value is empty.",
-                    section_key
+                    section_key,
                 )
                 continue
 
@@ -200,6 +212,7 @@ class ConfigOptionParser(CustomOptionParser):
                 yield key, val
 
     def _update_defaults(self, defaults):
+        # type: (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)."""
@@ -210,7 +223,7 @@ class ConfigOptionParser(CustomOptionParser):
         # Then set the options with those values
         for key, val in self._get_ordered_configuration_items():
             # '--' because configuration supports only long names
-            option = self.get_option('--' + key)
+            option = self.get_option("--" + key)
 
             # Ignore options not present in this parser. E.g. non-globals put
             # in [global] by users that want them to apply to all applicable
@@ -218,31 +231,34 @@ class ConfigOptionParser(CustomOptionParser):
             if option is None:
                 continue
 
-            if option.action in ('store_true', 'store_false'):
+            assert option.dest is not None
+
+            if option.action in ("store_true", "store_false"):
                 try:
                     val = strtobool(val)
                 except ValueError:
                     self.error(
-                        '{} is not a valid value for {} option, '  # noqa
+                        "{} is not a valid value for {} option, "  # noqa
-                        'please specify a boolean value like yes/no, '
+                        "please specify a boolean value like yes/no, "
-                        'true/false or 1/0 instead.'.format(val, key)
+                        "true/false or 1/0 instead.".format(val, key)
                     )
-            elif option.action == 'count':
+            elif option.action == "count":
                 with suppress(ValueError):
                     val = strtobool(val)
                 with suppress(ValueError):
                     val = int(val)
                 if not isinstance(val, int) or val < 0:
                     self.error(
-                        '{} is not a valid value for {} option, '  # noqa
+                        "{} is not a valid value for {} option, "  # noqa
-                        'please instead specify either a non-negative integer '
+                        "please instead specify either a non-negative integer "
-                        'or a boolean value like yes/no or false/true '
+                        "or a boolean value like yes/no or false/true "
-                        'which is equivalent to 1/0.'.format(val, key)
+                        "which is equivalent to 1/0.".format(val, key)
                     )
-            elif option.action == 'append':
+            elif option.action == "append":
                 val = val.split()
                 val = [self.check_default(option, key, v) for v in val]
-            elif option.action == 'callback':
+            elif option.action == "callback":
+                assert option.callback is not None
                 late_eval.add(option.dest)
                 opt_str = option.get_opt_string()
                 val = option.convert_value(opt_str, val)
@@ -261,6 +277,7 @@ class ConfigOptionParser(CustomOptionParser):
         return defaults
 
     def get_default_values(self):
+        # type: () -> 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:
@@ -275,6 +292,7 @@ class ConfigOptionParser(CustomOptionParser):
 
         defaults = self._update_defaults(self.defaults.copy())  # ours
         for option in self._get_all_options():
+            assert option.dest is not None
             default = defaults.get(option.dest)
             if isinstance(default, str):
                 opt_str = option.get_opt_string()
@@ -282,5 +300,6 @@ class ConfigOptionParser(CustomOptionParser):
         return optparse.Values(defaults)
 
     def error(self, msg):
+        # type: (str) -> None
         self.print_usage(sys.stderr)
         self.exit(UNKNOWN_ERROR, f"{msg}\n")

src/pip/_internal/cli/progress_bars.py

@@ -108,7 +108,6 @@ class InterruptibleMixin:
 
 
 class SilentBar(Bar):
-
     def update(self):
         # type: () -> None
         pass
@@ -123,14 +122,11 @@ class BlueEmojiBar(IncrementalBar):
 
 
 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 = (" " * (
+        self.message = (" " * (get_indentation() + 2)) + self.message  # type: str
-            get_indentation() + 2
-        )) + self.message  # type: str
 
     @property
     def downloaded(self):
@@ -162,7 +158,6 @@ class DownloadProgressMixin:
 
 
 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
@@ -192,16 +187,14 @@ class WindowsMixin:
             self.file.flush = lambda: self.file.wrapped.flush()
 
 
-class BaseDownloadProgressBar(WindowsMixin, InterruptibleMixin,
+class BaseDownloadProgressBar(WindowsMixin, InterruptibleMixin, DownloadProgressMixin):
-                              DownloadProgressMixin):
 
     file = sys.stdout
     message = "%(percent)d%%"
     suffix = "%(downloaded)s %(download_speed)s %(pretty_eta)s"
 
 
-class DefaultDownloadProgressBar(BaseDownloadProgressBar,
+class DefaultDownloadProgressBar(BaseDownloadProgressBar, _BaseBar):
-                                 _BaseBar):
     pass
 
 
@@ -209,23 +202,21 @@ class DownloadSilentBar(BaseDownloadProgressBar, SilentBar):
     pass
 
 
-class DownloadBar(BaseDownloadProgressBar,
+class DownloadBar(BaseDownloadProgressBar, Bar):
-                  Bar):
     pass
 
 
-class DownloadFillingCirclesBar(BaseDownloadProgressBar,
+class DownloadFillingCirclesBar(BaseDownloadProgressBar, FillingCirclesBar):
-                                FillingCirclesBar):
     pass
 
 
-class DownloadBlueEmojiProgressBar(BaseDownloadProgressBar,
+class DownloadBlueEmojiProgressBar(BaseDownloadProgressBar, BlueEmojiBar):
-                                   BlueEmojiBar):
     pass
 
 
-class DownloadProgressSpinner(WindowsMixin, InterruptibleMixin,
+class DownloadProgressSpinner(
-                              DownloadProgressMixin, Spinner):
+    WindowsMixin, InterruptibleMixin, DownloadProgressMixin, Spinner
+):
 
     file = sys.stdout
     suffix = "%(downloaded)s %(download_speed)s"
@@ -241,13 +232,15 @@ class DownloadProgressSpinner(WindowsMixin, InterruptibleMixin,
         message = self.message % self
         phase = self.next_phase()
         suffix = self.suffix % self
-        line = ''.join([
+        line = "".join(
-            message,
+            [
-            " " if message else "",
+                message,
-            phase,
+                " " if message else "",
-            " " if suffix else "",
+                phase,
-            suffix,
+                " " if suffix else "",
-        ])
+                suffix,
+            ]
+        )
 
         self.writeln(line)
 
@@ -257,7 +250,7 @@ BAR_TYPES = {
     "on": (DefaultDownloadProgressBar, DownloadProgressSpinner),
     "ascii": (DownloadBar, DownloadProgressSpinner),
     "pretty": (DownloadFillingCirclesBar, DownloadProgressSpinner),
-    "emoji": (DownloadBlueEmojiProgressBar, DownloadProgressSpinner)
+    "emoji": (DownloadBlueEmojiProgressBar, DownloadProgressSpinner),
 }
 
 

src/pip/_internal/cli/req_command.py

@@ -47,6 +47,7 @@ class SessionCommandMixin(CommandContextMixIn):
     """
     A class mixin for command classes needing _build_session().
     """
+
     def __init__(self):
         # type: () -> None
         super().__init__()
@@ -83,8 +84,7 @@ class SessionCommandMixin(CommandContextMixIn):
         assert not options.cache_dir or os.path.isabs(options.cache_dir)
         session = PipSession(
             cache=(
-                os.path.join(options.cache_dir, "http")
+                os.path.join(options.cache_dir, "http") if options.cache_dir else None
-                if options.cache_dir else None
             ),
             retries=retries if retries is not None else options.retries,
             trusted_hosts=options.trusted_hosts,
@@ -101,9 +101,7 @@ class SessionCommandMixin(CommandContextMixIn):
 
         # Handle timeouts
         if options.timeout or timeout:
-            session.timeout = (
+            session.timeout = timeout if timeout is not None else options.timeout
-                timeout if timeout is not None else options.timeout
-            )
 
         # Handle configured proxies
         if options.proxy:
@@ -134,16 +132,14 @@ class IndexGroupCommand(Command, SessionCommandMixin):
         This overrides the default behavior of not doing the check.
         """
         # Make sure the index_group options are present.
-        assert hasattr(options, 'no_index')
+        assert hasattr(options, "no_index")
 
         if options.disable_pip_version_check or options.no_index:
             return
 
         # Otherwise, check if we're using the latest version of pip available.
         session = self._build_session(
-            options,
+            options, retries=0, timeout=min(5, options.timeout)
-            retries=0,
-            timeout=min(5, options.timeout)
         )
         with session:
             pip_self_version_check(session, options)
@@ -161,6 +157,7 @@ def with_cleanup(func):
     """Decorator for common logic related to managing temporary
     directories.
     """
+
     def configure_tempdir_registry(registry):
         # type: (TempDirectoryTypeRegistry) -> None
         for t in KEEPABLE_TEMPDIR_TYPES:
@@ -185,7 +182,6 @@ def with_cleanup(func):
 
 
 class RequirementCommand(IndexGroupCommand):
-
     def __init__(self, *args, **kw):
         # type: (Any, Any) -> None
         super().__init__(*args, **kw)
@@ -204,13 +200,13 @@ class RequirementCommand(IndexGroupCommand):
     @classmethod
     def make_requirement_preparer(
         cls,
-        temp_build_dir,           # type: TempDirectory
+        temp_build_dir,  # type: TempDirectory
-        options,                  # type: Values
+        options,  # type: Values
-        req_tracker,              # type: RequirementTracker
+        req_tracker,  # type: RequirementTracker
-        session,                  # type: PipSession
+        session,  # type: PipSession
-        finder,                   # type: PackageFinder
+        finder,  # type: PackageFinder
-        use_user_site,            # type: bool
+        use_user_site,  # type: bool
-        download_dir=None,        # type: str
+        download_dir=None,  # type: str
     ):
         # type: (...) -> RequirementPreparer
         """
@@ -221,20 +217,20 @@ class RequirementCommand(IndexGroupCommand):
 
         resolver_variant = cls.determine_resolver_variant(options)
         if resolver_variant == "2020-resolver":
-            lazy_wheel = 'fast-deps' in options.features_enabled
+            lazy_wheel = "fast-deps" in options.features_enabled
             if lazy_wheel:
                 logger.warning(
-                    'pip is using lazily downloaded wheels using HTTP '
+                    "pip is using lazily downloaded wheels using HTTP "
-                    'range requests to obtain dependency information. '
+                    "range requests to obtain dependency information. "
-                    'This experimental feature is enabled through '
+                    "This experimental feature is enabled through "
-                    '--use-feature=fast-deps and it is not ready for '
+                    "--use-feature=fast-deps and it is not ready for "
-                    'production.'
+                    "production."
                 )
         else:
             lazy_wheel = False
-            if 'fast-deps' in options.features_enabled:
+            if "fast-deps" in options.features_enabled:
                 logger.warning(
-                    'fast-deps has no effect when used with the legacy resolver.'
+                    "fast-deps has no effect when used with the legacy resolver."
                 )
 
         return RequirementPreparer(
@@ -249,22 +245,23 @@ class RequirementCommand(IndexGroupCommand):
             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,
         )
 
     @classmethod
     def make_resolver(
         cls,
-        preparer,                            # type: RequirementPreparer
+        preparer,  # type: RequirementPreparer
-        finder,                              # type: PackageFinder
+        finder,  # type: PackageFinder
-        options,                             # type: Values
+        options,  # type: Values
-        wheel_cache=None,                    # type: Optional[WheelCache]
+        wheel_cache=None,  # type: Optional[WheelCache]
-        use_user_site=False,                 # type: bool
+        use_user_site=False,  # type: bool
-        ignore_installed=True,               # type: bool
+        ignore_installed=True,  # type: bool
-        ignore_requires_python=False,        # type: bool
+        ignore_requires_python=False,  # type: bool
-        force_reinstall=False,               # type: bool
+        force_reinstall=False,  # type: bool
         upgrade_strategy="to-satisfy-only",  # type: str
-        use_pep517=None,                     # type: Optional[bool]
+        use_pep517=None,  # type: Optional[bool]
-        py_version_info=None,                # type: Optional[Tuple[int, ...]]
+        py_version_info=None,  # type: Optional[Tuple[int, ...]]
     ):
         # type: (...) -> BaseResolver
         """
@@ -296,6 +293,7 @@ class RequirementCommand(IndexGroupCommand):
                 py_version_info=py_version_info,
             )
         import pip._internal.resolution.legacy.resolver
+
         return pip._internal.resolution.legacy.resolver.Resolver(
             preparer=preparer,
             finder=finder,
@@ -312,10 +310,10 @@ class RequirementCommand(IndexGroupCommand):
 
     def get_requirements(
         self,
-        args,             # type: List[str]
+        args,  # type: List[str]
-        options,          # type: Values
+        options,  # type: Values
-        finder,           # type: PackageFinder
+        finder,  # type: PackageFinder
-        session,          # type: PipSession
+        session,  # type: PipSession
     ):
         # type: (...) -> List[InstallRequirement]
         """
@@ -324,9 +322,12 @@ class RequirementCommand(IndexGroupCommand):
         requirements = []  # type: List[InstallRequirement]
         for filename in options.constraints:
             for parsed_req in parse_requirements(
-                    filename,
+                filename,
-                    constraint=True, finder=finder, options=options,
+                constraint=True,
-                    session=session):
+                finder=finder,
+                options=options,
+                session=session,
+            ):
                 req_to_add = install_req_from_parsed_requirement(
                     parsed_req,
                     isolated=options.isolated_mode,
@@ -336,7 +337,9 @@ class RequirementCommand(IndexGroupCommand):
 
         for req in args:
             req_to_add = install_req_from_line(
-                req, None, isolated=options.isolated_mode,
+                req,
+                None,
+                isolated=options.isolated_mode,
                 use_pep517=options.use_pep517,
                 user_supplied=True,
             )
@@ -354,8 +357,8 @@ class RequirementCommand(IndexGroupCommand):
         # NOTE: options.require_hashes may be set if --require-hashes is True
         for filename in options.requirements:
             for parsed_req in parse_requirements(
-                    filename,
+                filename, finder=finder, options=options, session=session
-                    finder=finder, options=options, session=session):
+            ):
                 req_to_add = install_req_from_parsed_requirement(
                     parsed_req,
                     isolated=options.isolated_mode,
@@ -369,16 +372,19 @@ class RequirementCommand(IndexGroupCommand):
             options.require_hashes = True
 
         if not (args or options.editables or options.requirements):
-            opts = {'name': self.name}
+            opts = {"name": self.name}
             if options.find_links:
                 raise CommandError(
-                    'You must give at least one requirement to {name} '
+                    "You must give at least one requirement to {name} "
                     '(maybe you meant "pip {name} {links}"?)'.format(
-                        **dict(opts, links=' '.join(options.find_links))))
+                        **dict(opts, links=" ".join(options.find_links))
+                    )
+                )
             else:
                 raise CommandError(
-                    'You must give at least one requirement to {name} '
+                    "You must give at least one requirement to {name} "
-                    '(see "pip help {name}")'.format(**opts))
+                    '(see "pip help {name}")'.format(**opts)
+                )
 
         return requirements
 
@@ -396,9 +402,9 @@ class RequirementCommand(IndexGroupCommand):
 
     def _build_package_finder(
         self,
-        options,               # type: Values
+        options,  # type: Values
-        session,               # type: PipSession
+        session,  # type: PipSession
-        target_python=None,    # type: Optional[TargetPython]
+        target_python=None,  # type: Optional[TargetPython]
         ignore_requires_python=None,  # type: Optional[bool]
     ):
         # type: (...) -> PackageFinder

src/pip/_internal/cli/spinners.py

@@ -24,9 +24,14 @@ class SpinnerInterface:
 
 
 class InteractiveSpinner(SpinnerInterface):
-    def __init__(self, message, file=None, spin_chars="-\\|/",
+    def __init__(
-                 # Empirically, 8 updates/second looks nice
+        self,
-                 min_update_interval_seconds=0.125):
+        message,
+        file=None,
+        spin_chars="-\\|/",
+        # Empirically, 8 updates/second looks nice
+        min_update_interval_seconds=0.125,
+    ):
         # type: (str, IO[str], str, float) -> None
         self._message = message
         if file is None:

src/pip/_internal/commands/search.py

@@ -22,10 +22,10 @@ from pip._internal.utils.misc import write_output
 if TYPE_CHECKING:
     from typing import TypedDict
 
-    TransformedHit = TypedDict(
+    class TransformedHit(TypedDict):
-        'TransformedHit',
+        name: str
-        {'name': str, 'summary': str, 'versions': List[str]},
+        summary: str
-    )
+        versions: List[str]
 
 logger = logging.getLogger(__name__)
 

src/pip/_internal/distributions/__init__.py

@@ -6,8 +6,7 @@ from pip._internal.req.req_install import InstallRequirement
 
 def make_distribution_for_install_requirement(install_req):
     # type: (InstallRequirement) -> AbstractDistribution
-    """Returns a Distribution for the given InstallRequirement
+    """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.
     if install_req.editable:

src/pip/_internal/distributions/base.py

@@ -22,6 +22,7 @@ class AbstractDistribution(metaclass=abc.ABCMeta):
      - we must be able to create a Distribution object exposing the
        above metadata.
     """
+
     def __init__(self, req):
         # type: (InstallRequirement) -> None
         super().__init__()

src/pip/_internal/distributions/sdist.py

@@ -46,10 +46,10 @@ class SourceDistribution(AbstractDistribution):
             error_message = format_string.format(
                 requirement=self.req,
                 conflicting_with=conflicting_with,
-                description=', '.join(
+                description=", ".join(
-                    f'{installed} is incompatible with {wanted}'
+                    f"{installed} is incompatible with {wanted}"
                     for installed, wanted in sorted(conflicting)
-                )
+                ),
             )
             raise InstallationError(error_message)
 
@@ -60,15 +60,13 @@ class SourceDistribution(AbstractDistribution):
 
         self.req.build_env = BuildEnvironment()
         self.req.build_env.install_requirements(
-            finder, pyproject_requires, 'overlay',
+            finder, pyproject_requires, "overlay", "Installing build dependencies"
-            "Installing build dependencies"
         )
         conflicting, missing = self.req.build_env.check_requirements(
             self.req.requirements_to_check
         )
         if conflicting:
-            _raise_conflicts("PEP 517/518 supported requirements",
+            _raise_conflicts("PEP 517/518 supported requirements", conflicting)
-                             conflicting)
         if missing:
             logger.warning(
                 "Missing build requirements in pyproject.toml for %s.",
@@ -77,15 +75,13 @@ class SourceDistribution(AbstractDistribution):
             logger.warning(
                 "The project does not specify a build backend, and "
                 "pip cannot fall back to setuptools without %s.",
-                " and ".join(map(repr, sorted(missing)))
+                " 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.
         with self.req.build_env:
-            runner = runner_with_spinner_message(
+            runner = runner_with_spinner_message("Getting requirements to build wheel")
-                "Getting requirements to build wheel"
-            )
             backend = self.req.pep517_backend
             assert backend is not None
             with backend.subprocess_runner(runner):
@@ -95,6 +91,5 @@ class SourceDistribution(AbstractDistribution):
         if conflicting:
             _raise_conflicts("the backend dependencies", conflicting)
         self.req.build_env.install_requirements(
-            finder, missing, 'normal',
+            finder, missing, "normal", "Installing backend dependencies"
-            "Installing backend dependencies"
         )

src/pip/_internal/locations/__init__.py

@@ -8,7 +8,6 @@ from pip._internal.models.scheme import SCHEME_KEYS, Scheme
 from . import _distutils, _sysconfig
 from .base import (
     USER_CACHE_DIR,
-    get_bin_user,
     get_major_minor_version,
     get_src_prefix,
     site_packages,
@@ -119,6 +118,11 @@ def get_bin_prefix():
     return old
 
 
+def get_bin_user():
+    # type: () -> str
+    return _sysconfig.get_scheme("", user=True).scripts
+
+
 def get_purelib():
     # type: () -> str
     """Return the default pure-Python lib location."""

src/pip/_internal/locations/_sysconfig.py

@@ -137,7 +137,7 @@ def get_scheme(
         paths["include"] = os.path.join(base, "include", "site", python_xy)
 
     # Special user scripts path on Windows for compatibility to distutils.
-    # See ``distutils.commands.install.INSTALL_SCHEMES["nt_user"]["scritps"]``.
+    # See ``distutils.commands.install.INSTALL_SCHEMES["nt_user"]["scripts"]``.
     if scheme_name == "nt_user":
         base = variables.get("userbase", sys.prefix)
         python_xy = f"Python{sys.version_info.major}{sys.version_info.minor}"

src/pip/_internal/locations/base.py

@@ -4,9 +4,7 @@ import sys
 import sysconfig
 import typing
 
-from pip._internal.exceptions import UserInstallationInvalid
 from pip._internal.utils import appdirs
-from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.virtualenv import running_under_virtualenv
 
 # Application Directories
@@ -48,21 +46,3 @@ try:
     user_site = site.getusersitepackages()  # type: typing.Optional[str]
 except AttributeError:
     user_site = site.USER_SITE
-
-
-def get_bin_user():
-    # type: () -> str
-    """Get the user-site scripts directory.
-
-    Pip puts the scripts directory in site-packages, not under userbase.
-    I'm honestly not sure if this is a bug (because ``get_scheme()`` puts it
-    correctly under userbase), but we need to keep backwards compatibility.
-    """
-    if user_site is None:
-        raise UserInstallationInvalid()
-    if not WINDOWS:
-        return os.path.join(user_site, "bin")
-    # Special case for buildout, which uses 'bin' on Windows too?
-    if not os.path.exists(os.path.join(sys.prefix, "Scripts")):
-        os.path.join(user_site, "bin")
-    return os.path.join(user_site, "Scripts")

src/pip/_internal/network/auth.py

@@ -37,7 +37,7 @@ except Exception as exc:
 
 
 def get_keyring_auth(url, username):
-    # type: (str, str) -> Optional[AuthInfo]
+    # type: (Optional[str], Optional[str]) -> Optional[AuthInfo]
     """Return the tuple auth for a given url from keyring."""
     global keyring
     if not url or not keyring:

src/pip/_internal/network/session.py

@@ -2,8 +2,15 @@
 network request configuration and behavior.
 """
 
-# The following comment should be removed at some point in the future.
+# When mypy runs on Windows the call to distro.linux_distribution() is skipped
-# mypy: disallow-untyped-defs=False
+# 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 ipaddress
@@ -15,13 +22,14 @@ import platform
 import sys
 import urllib.parse
 import warnings
-from typing import Any, Iterator, List, Optional, Sequence, Tuple, Union
+from typing import Any, Dict, Iterator, List, Mapping, Optional, Sequence, Tuple, Union
 
 from pip._vendor import requests, urllib3
 from pip._vendor.cachecontrol import CacheControlAdapter
 from pip._vendor.requests.adapters import BaseAdapter, HTTPAdapter
-from pip._vendor.requests.models import Response
+from pip._vendor.requests.models import PreparedRequest, Response
 from pip._vendor.requests.structures import CaseInsensitiveDict
+from pip._vendor.urllib3.connectionpool import ConnectionPool
 from pip._vendor.urllib3.exceptions import InsecureRequestWarning
 
 from pip import __version__
@@ -89,6 +97,7 @@ def looks_like_ci():
 
 
 def user_agent():
+    # type: () -> str
     """
     Return a string representing the user agent.
     """
@@ -98,15 +107,14 @@ def user_agent():
         "implementation": {
             "name": platform.python_implementation(),
         },
-    }
+    }  # type: Dict[str, Any]
 
     if data["implementation"]["name"] == 'CPython':
         data["implementation"]["version"] = platform.python_version()
     elif data["implementation"]["name"] == 'PyPy':
-        if sys.pypy_version_info.releaselevel == 'final':
+        pypy_version_info = sys.pypy_version_info  # type: ignore
-            pypy_version_info = sys.pypy_version_info[:3]
+        if pypy_version_info.releaselevel == 'final':
-        else:
+            pypy_version_info = pypy_version_info[:3]
-            pypy_version_info = sys.pypy_version_info
         data["implementation"]["version"] = ".".join(
             [str(x) for x in pypy_version_info]
         )
@@ -119,9 +127,12 @@ def user_agent():
 
     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"], distro.linux_distribution()),
+            zip(["name", "version", "id"], linux_distribution),
         ))
         libc = dict(filter(
             lambda x: x[1],
@@ -170,8 +181,16 @@ def user_agent():
 
 class LocalFSAdapter(BaseAdapter):
 
-    def send(self, request, stream=None, timeout=None, verify=None, cert=None,
+    def send(
-             proxies=None):
+        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
         pathname = url_to_path(request.url)
 
         resp = Response()
@@ -198,18 +217,33 @@ class LocalFSAdapter(BaseAdapter):
         return resp
 
     def close(self):
+        # type: () -> None
         pass
 
 
 class InsecureHTTPAdapter(HTTPAdapter):
 
-    def cert_verify(self, conn, url, verify, cert):
+    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
         super().cert_verify(conn=conn, url=url, verify=False, cert=cert)
 
 
 class InsecureCacheControlAdapter(CacheControlAdapter):
 
-    def cert_verify(self, conn, url, verify, cert):
+    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
         super().cert_verify(conn=conn, url=url, verify=False, cert=cert)
 
 
@@ -407,6 +441,7 @@ class PipSession(requests.Session):
         return False
 
     def request(self, method, url, *args, **kwargs):
+        # type: (str, str, *Any, **Any) -> Response
         # Allow setting a default timeout on a session
         kwargs.setdefault("timeout", self.timeout)
 

src/pip/_internal/operations/prepare.py

@@ -35,6 +35,7 @@ from pip._internal.network.lazy_wheel import (
 from pip._internal.network.session import PipSession
 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
@@ -207,8 +208,23 @@ def unpack_url(
         unpack_vcs_link(link, location)
         return None
 
-    # If it's a url to a local directory
+    # 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)
@@ -278,6 +294,7 @@ class RequirementPreparer:
         require_hashes,  # type: bool
         use_user_site,  # type: bool
         lazy_wheel,  # type: bool
+        in_tree_build,  # type: bool
     ):
         # type: (...) -> None
         super().__init__()
@@ -306,6 +323,9 @@ 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
+
         # Memoized downloaded files, as mapping of url: (path, mime type)
         self._downloaded = {}  # type: Dict[str, Tuple[str, str]]
 
@@ -339,6 +359,11 @@ class RequirementPreparer:
             # directory.
             return
         assert req.source_dir is None
+        if req.link.is_existing_dir() and self.in_tree_build:
+            # build local directories in-tree
+            req.source_dir = req.link.file_path
+            return
+
         # We always delete unpacked sdists after pip runs.
         req.ensure_has_source_dir(
             self.build_dir,
@@ -517,11 +542,14 @@ class RequirementPreparer:
 
         self._ensure_link_req_src_dir(req, parallel_builds)
         hashes = self._get_linked_req_hashes(req)
-        if link.url not in self._downloaded:
+
+        if link.is_existing_dir() and self.in_tree_build:
+            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,
+                    self.download_dir, hashes
                 )
             except NetworkConnectionError as exc:
                 raise InstallationError(

src/pip/_internal/req/constructors.py

@@ -140,7 +140,7 @@ def deduce_helpful_msg(req):
         msg = " The path does exist. "
         # Try to parse and check if it is a requirements file.
         try:
-            with open(req, 'r') as fp:
+            with open(req) as fp:
                 # parse first line only
                 next(parse_requirements(fp.read()))
                 msg += (

src/pip/_internal/req/req_file.py

@@ -17,7 +17,6 @@ from typing import (
     List,
     NoReturn,
     Optional,
-    Text,
     Tuple,
 )
 
@@ -34,9 +33,9 @@ if TYPE_CHECKING:
 
 __all__ = ['parse_requirements']
 
-ReqFileLines = Iterator[Tuple[int, Text]]
+ReqFileLines = Iterator[Tuple[int, str]]
 
-LineParser = Callable[[Text], Tuple[str, Values]]
+LineParser = Callable[[str], Tuple[str, Values]]
 
 SCHEME_RE = re.compile(r'^(http|https|file):', re.I)
 COMMENT_RE = re.compile(r'(^|\s+)#.*$')

src/pip/_internal/req/req_uninstall.py

@@ -529,7 +529,7 @@ class UninstallPathSet:
 
         elif develop_egg_link:
             # develop egg
-            with open(develop_egg_link, 'r') as fh:
+            with open(develop_egg_link) as fh:
                 link_pointer = os.path.normcase(fh.readline().strip())
             assert (link_pointer == dist.location), (
                 'Egg-link {} does not match installed location of {} '

src/pip/_internal/resolution/legacy/resolver.py

@@ -12,13 +12,12 @@ for sub-dependencies
 
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
-# mypy: disallow-untyped-defs=False
 
 import logging
 import sys
 from collections import defaultdict
 from itertools import chain
-from typing import DefaultDict, List, Optional, Set, Tuple
+from typing import DefaultDict, Iterable, List, Optional, Set, Tuple
 
 from pip._vendor.packaging import specifiers
 from pip._vendor.pkg_resources import Distribution
@@ -388,6 +387,7 @@ class Resolver(BaseResolver):
         more_reqs = []  # type: List[InstallRequirement]
 
         def add_req(subreq, extras_requested):
+            # type: (Distribution, Iterable[str]) -> None
             sub_install_req = self._make_install_req(
                 str(subreq),
                 req_to_install,
@@ -447,6 +447,7 @@ class Resolver(BaseResolver):
         ordered_reqs = set()  # type: Set[InstallRequirement]
 
         def schedule(req):
+            # type: (InstallRequirement) -> None
             if req.satisfied_by or req in ordered_reqs:
                 return
             if req.constraint:

src/pip/_internal/resolution/resolvelib/factory.py

@@ -404,8 +404,24 @@ class Factory:
         )
         return UnsupportedPythonVersion(message)
 
-    def get_installation_error(self, e):
+    def _report_single_requirement_conflict(self, req, parent):
-        # type: (ResolutionImpossible) -> InstallationError
+        # type: (Requirement, Candidate) -> DistributionNotFound
+        if parent is None:
+            req_disp = str(req)
+        else:
+            req_disp = f"{req} (from {parent.name})"
+        logger.critical(
+            "Could not find a version that satisfies the requirement %s",
+            req_disp,
+        )
+        return DistributionNotFound(f"No matching distribution found for {req}")
+
+    def get_installation_error(
+        self,
+        e,  # type: ResolutionImpossible
+        constraints,  # type: Dict[str, Constraint]
+    ):
+        # type: (...) -> InstallationError
 
         assert e.causes, "Installation error reported with no cause"
 
@@ -425,15 +441,8 @@ class Factory:
         # satisfied. We just report that case.
         if len(e.causes) == 1:
             req, parent = e.causes[0]
-            if parent is None:
+            if req.name not in constraints:
-                req_disp = str(req)
+                return self._report_single_requirement_conflict(req, parent)
-            else:
-                req_disp = f"{req} (from {parent.name})"
-            logger.critical(
-                "Could not find a version that satisfies the requirement %s",
-                req_disp,
-            )
-            return DistributionNotFound(f"No matching distribution found for {req}")
 
         # OK, we now have a list of requirements that can't all be
         # satisfied at once.
@@ -475,13 +484,20 @@ class Factory:
         )
         logger.critical(msg)
         msg = "\nThe conflict is caused by:"
+
+        relevant_constraints = set()
         for req, parent in e.causes:
+            if req.name in constraints:
+                relevant_constraints.add(req.name)
             msg = msg + "\n    "
             if parent:
                 msg = msg + "{} {} depends on ".format(parent.name, parent.version)
             else:
                 msg = msg + "The user requested "
             msg = msg + req.format_for_error()
+        for key in relevant_constraints:
+            spec = constraints[key].specifier
+            msg += f"\n    The user requested (constraint) {key}{spec}"
 
         msg = (
             msg

src/pip/_internal/resolution/resolvelib/resolver.py

@@ -3,7 +3,6 @@ import logging
 import os
 from typing import TYPE_CHECKING, Dict, List, Optional, Set, Tuple
 
-from pip._vendor import six
 from pip._vendor.packaging.utils import canonicalize_name
 from pip._vendor.resolvelib import ResolutionImpossible
 from pip._vendor.resolvelib import Resolver as RLResolver
@@ -122,8 +121,8 @@ class Resolver(BaseResolver):
             )
 
         except ResolutionImpossible as e:
-            error = self.factory.get_installation_error(e)
+            error = self.factory.get_installation_error(e, constraints)
-            six.raise_from(error, e)
+            raise error from e
 
         req_set = RequirementSet(check_supported_wheels=check_supported_wheels)
         for candidate in self._result.mapping.values():

src/pip/_internal/utils/compat.py

@@ -1,9 +1,6 @@
 """Stuff that differs in different Python versions and platform
 distributions."""
 
-# The following comment should be removed at some point in the future.
-# mypy: disallow-untyped-defs=False
-
 import logging
 import os
 import sys

src/pip/_internal/utils/deprecation.py

@@ -2,12 +2,9 @@
 A module that implements tooling to enable easy warnings about deprecations.
 """
 
-# The following comment should be removed at some point in the future.
-# mypy: disallow-untyped-defs=False
-
 import logging
 import warnings
-from typing import Any, Optional
+from typing import Any, Optional, TextIO, Type, Union
 
 from pip._vendor.packaging.version import parse
 
@@ -24,7 +21,15 @@ _original_showwarning = None  # type: Any
 
 
 # Warnings <-> Logging Integration
-def _showwarning(message, category, filename, lineno, file=None, line=None):
+def _showwarning(
+    message,  # type: Union[Warning, str]
+    category,  # type: Type[Warning]
+    filename,  # type: str
+    lineno,  # type: int
+    file=None,  # type: Optional[TextIO]
+    line=None,  # type: Optional[str]
+):
+    # type: (...) -> None
     if file is not None:
         if _original_showwarning is not None:
             _original_showwarning(message, category, filename, lineno, file, line)

src/pip/_internal/utils/logging.py

@@ -1,6 +1,3 @@
-# The following comment should be removed at some point in the future.
-# mypy: disallow-untyped-defs=False
-
 import contextlib
 import errno
 import logging
@@ -8,7 +5,7 @@ import logging.handlers
 import os
 import sys
 from logging import Filter, getLogger
-from typing import Any
+from typing import IO, Any, Callable, Iterator, Optional, TextIO, Type, cast
 
 from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.deprecation import DEPRECATION_MSG_PREFIX
@@ -46,15 +43,17 @@ if WINDOWS:
     # https://bugs.python.org/issue19612
     # https://bugs.python.org/issue30418
     def _is_broken_pipe_error(exc_class, exc):
+        # type: (Type[BaseException], BaseException) -> bool
         """See the docstring for non-Windows below."""
         return (exc_class is BrokenPipeError) or (
-            exc_class is OSError and exc.errno in (errno.EINVAL, errno.EPIPE)
+            isinstance(exc, OSError) and exc.errno in (errno.EINVAL, errno.EPIPE)
         )
 
 
 else:
     # Then we are in the non-Windows case.
     def _is_broken_pipe_error(exc_class, exc):
+        # type: (Type[BaseException], BaseException) -> bool
         """
         Return whether an exception is a broken pipe error.
 
@@ -67,6 +66,7 @@ else:
 
 @contextlib.contextmanager
 def indent_log(num=2):
+    # type: (int) -> Iterator[None]
     """
     A context manager which will cause the log output to be indented for any
     log messages emitted inside it.
@@ -81,6 +81,7 @@ def indent_log(num=2):
 
 
 def get_indentation():
+    # type: () -> int
     return getattr(_log_state, "indentation", 0)
 
 
@@ -104,6 +105,7 @@ class IndentingFormatter(logging.Formatter):
         super().__init__(*args, **kwargs)
 
     def get_message_start(self, formatted, levelno):
+        # type: (str, int) -> str
         """
         Return the start of the formatted log message (not counting the
         prefix to add to each line).
@@ -120,6 +122,7 @@ class IndentingFormatter(logging.Formatter):
         return "ERROR: "
 
     def format(self, record):
+        # type: (logging.LogRecord) -> str
         """
         Calls the standard formatter, but will indent all of the log message
         lines by our current indentation level.
@@ -137,7 +140,9 @@ class IndentingFormatter(logging.Formatter):
 
 
 def _color_wrap(*colors):
+    # type: (*str) -> Callable[[str], str]
     def wrapped(inp):
+        # type: (str) -> str
         return "".join(list(colors) + [inp, colorama.Style.RESET_ALL])
 
     return wrapped
@@ -156,6 +161,7 @@ class ColorizedStreamHandler(logging.StreamHandler):
         COLORS = []
 
     def __init__(self, stream=None, no_color=None):
+        # type: (Optional[TextIO], bool) -> None
         super().__init__(stream)
         self._no_color = no_color
 
@@ -163,16 +169,19 @@ class ColorizedStreamHandler(logging.StreamHandler):
             self.stream = colorama.AnsiToWin32(self.stream)
 
     def _using_stdout(self):
+        # type: () -> bool
         """
         Return whether the handler is using sys.stdout.
         """
         if WINDOWS and colorama:
             # Then self.stream is an AnsiToWin32 object.
-            return self.stream.wrapped is sys.stdout
+            stream = cast(colorama.AnsiToWin32, self.stream)
+            return stream.wrapped is sys.stdout
 
         return self.stream is sys.stdout
 
     def should_color(self):
+        # type: () -> bool
         # Don't colorize things if we do not have colorama or if told not to
         if not colorama or self._no_color:
             return False
@@ -195,7 +204,8 @@ class ColorizedStreamHandler(logging.StreamHandler):
         return False
 
     def format(self, record):
-        msg = logging.StreamHandler.format(self, record)
+        # type: (logging.LogRecord) -> str
+        msg = super().format(record)
 
         if self.should_color():
             for level, color in self.COLORS:
@@ -207,12 +217,18 @@ class ColorizedStreamHandler(logging.StreamHandler):
 
     # The logging module says handleError() can be customized.
     def handleError(self, record):
+        # type: (logging.LogRecord) -> None
         exc_class, exc = sys.exc_info()[:2]
         # If a broken pipe occurred while calling write() or flush() on the
         # stdout stream in logging's Handler.emit(), then raise our special
         # exception so we can handle it in main() instead of logging the
         # broken pipe error and continuing.
-        if exc_class and self._using_stdout() and _is_broken_pipe_error(exc_class, exc):
+        if (
+            exc_class
+            and exc
+            and self._using_stdout()
+            and _is_broken_pipe_error(exc_class, exc)
+        ):
             raise BrokenStdoutLoggingError()
 
         return super().handleError(record)
@@ -220,15 +236,18 @@ class ColorizedStreamHandler(logging.StreamHandler):
 
 class BetterRotatingFileHandler(logging.handlers.RotatingFileHandler):
     def _open(self):
+        # type: () -> IO[Any]
         ensure_dir(os.path.dirname(self.baseFilename))
-        return logging.handlers.RotatingFileHandler._open(self)
+        return super()._open()
 
 
 class MaxLevelFilter(Filter):
     def __init__(self, level):
+        # type: (int) -> None
         self.level = level
 
     def filter(self, record):
+        # type: (logging.LogRecord) -> bool
         return record.levelno < self.level
 
 
@@ -239,12 +258,14 @@ class ExcludeLoggerFilter(Filter):
     """
 
     def filter(self, record):
+        # type: (logging.LogRecord) -> bool
         # The base Filter class allows only records from a logger (or its
         # children).
         return not super().filter(record)
 
 
 def setup_logging(verbosity, no_color, user_log_file):
+    # type: (int, bool, Optional[str]) -> int
     """Configures and sets up all of the logging
 
     Returns the requested logging level, as its integer value.

src/pip/_internal/utils/misc.py

@@ -1,6 +1,5 @@
 # The following comment should be removed at some point in the future.
 # mypy: strict-optional=False
-# mypy: disallow-untyped-defs=False
 
 import contextlib
 import errno
@@ -16,16 +15,21 @@ import sys
 import urllib.parse
 from io import StringIO
 from itertools import filterfalse, tee, zip_longest
+from types import TracebackType
 from typing import (
     Any,
     AnyStr,
+    BinaryIO,
     Callable,
     Container,
+    ContextManager,
     Iterable,
     Iterator,
     List,
     Optional,
+    TextIO,
     Tuple,
+    Type,
     TypeVar,
     cast,
 )
@@ -64,8 +68,10 @@ __all__ = [
 
 logger = logging.getLogger(__name__)
 
-VersionInfo = Tuple[int, int, int]
 T = TypeVar("T")
+ExcInfo = Tuple[Type[BaseException], BaseException, TracebackType]
+VersionInfo = Tuple[int, int, int]
+NetlocTuple = Tuple[str, Tuple[Optional[str], Optional[str]]]
 
 
 def get_pip_version():
@@ -132,6 +138,7 @@ def rmtree(dir, ignore_errors=False):
 
 
 def rmtree_errorhandler(func, path, exc_info):
+    # type: (Callable[..., Any], str, ExcInfo) -> None
     """On Windows, the files in .svn are read-only, so when rmtree() tries to
     remove them, an exception is thrown.  We catch that here, remove the
     read-only attribute, and hopefully continue without problems."""
@@ -279,6 +286,7 @@ def is_installable_dir(path):
 
 
 def read_chunks(file, size=io.DEFAULT_BUFFER_SIZE):
+    # type: (BinaryIO, int) -> Iterator[bytes]
     """Yield pieces of data from a file-like object until EOF."""
     while True:
         chunk = file.read(size)
@@ -491,19 +499,24 @@ def write_output(msg, *args):
 
 
 class StreamWrapper(StringIO):
+    orig_stream = None  # type: TextIO
+
     @classmethod
     def from_stream(cls, orig_stream):
+        # type: (TextIO) -> StreamWrapper
         cls.orig_stream = orig_stream
         return cls()
 
     # compileall.compile_dir() needs stdout.encoding to print to stdout
+    # https://github.com/python/mypy/issues/4125
     @property
-    def encoding(self):
+    def encoding(self):  # type: ignore
         return self.orig_stream.encoding
 
 
 @contextlib.contextmanager
 def captured_output(stream_name):
+    # type: (str) -> Iterator[StreamWrapper]
     """Return a context manager used by captured_stdout/stdin/stderr
     that temporarily replaces the sys stream *stream_name* with a StringIO.
 
@@ -518,6 +531,7 @@ def captured_output(stream_name):
 
 
 def captured_stdout():
+    # type: () -> ContextManager[StreamWrapper]
     """Capture the output of sys.stdout:
 
        with captured_stdout() as stdout:
@@ -530,6 +544,7 @@ def captured_stdout():
 
 
 def captured_stderr():
+    # type: () -> ContextManager[StreamWrapper]
     """
     See captured_stdout().
     """
@@ -538,6 +553,7 @@ def captured_stderr():
 
 # Simulates an enum
 def enum(*sequential, **named):
+    # type: (*Any, **Any) -> Type[Any]
     enums = dict(zip(sequential, range(len(sequential))), **named)
     reverse = {value: key for key, value in enums.items()}
     enums["reverse_mapping"] = reverse
@@ -579,6 +595,7 @@ def parse_netloc(netloc):
 
 
 def split_auth_from_netloc(netloc):
+    # type: (str) -> NetlocTuple
     """
     Parse out and remove the auth information from a netloc.
 
@@ -591,17 +608,20 @@ def split_auth_from_netloc(netloc):
     # behaves if more than one @ is present (which can be checked using
     # the password attribute of urlsplit()'s return value).
     auth, netloc = netloc.rsplit("@", 1)
+    pw = None  # type: Optional[str]
     if ":" in auth:
         # Split from the left because that's how urllib.parse.urlsplit()
         # behaves if more than one : is present (which again can be checked
         # using the password attribute of the return value)
-        user_pass = auth.split(":", 1)
+        user, pw = auth.split(":", 1)
     else:
-        user_pass = auth, None
+        user, pw = auth, None
 
-    user_pass = tuple(None if x is None else urllib.parse.unquote(x) for x in user_pass)
+    user = urllib.parse.unquote(user)
+    if pw is not None:
+        pw = urllib.parse.unquote(pw)
 
-    return netloc, user_pass
+    return netloc, (user, pw)
 
 
 def redact_netloc(netloc):
@@ -628,6 +648,7 @@ def redact_netloc(netloc):
 
 
 def _transform_url(url, transform_netloc):
+    # type: (str, Callable[[str], Tuple[Any, ...]]) -> Tuple[str, NetlocTuple]
     """Transform and replace netloc in a url.
 
     transform_netloc is a function taking the netloc and returning a
@@ -642,14 +663,16 @@ def _transform_url(url, transform_netloc):
     # stripped url
     url_pieces = (purl.scheme, netloc_tuple[0], purl.path, purl.query, purl.fragment)
     surl = urllib.parse.urlunsplit(url_pieces)
-    return surl, netloc_tuple
+    return surl, cast("NetlocTuple", netloc_tuple)
 
 
 def _get_netloc(netloc):
+    # type: (str) -> NetlocTuple
     return split_auth_from_netloc(netloc)
 
 
 def _redact_netloc(netloc):
+    # type: (str) -> Tuple[str,]
     return (redact_netloc(netloc),)
 
 
@@ -765,6 +788,7 @@ def hash_file(path, blocksize=1 << 20):
 
 
 def is_wheel_installed():
+    # type: () -> bool
     """
     Return whether the wheel package is installed.
     """

src/pip/_internal/utils/models.py

@@ -1,9 +1,8 @@
 """Utilities for defining models
 """
-# The following comment should be removed at some point in the future.
-# mypy: disallow-untyped-defs=False
 
 import operator
+from typing import Any, Callable, Type
 
 
 class KeyBasedCompareMixin:
@@ -12,28 +11,36 @@ class KeyBasedCompareMixin:
     __slots__ = ["_compare_key", "_defining_class"]
 
     def __init__(self, key, defining_class):
+        # type: (Any, Type[KeyBasedCompareMixin]) -> None
         self._compare_key = key
         self._defining_class = defining_class
 
     def __hash__(self):
+        # type: () -> int
         return hash(self._compare_key)
 
     def __lt__(self, other):
+        # type: (Any) -> bool
         return self._compare(other, operator.__lt__)
 
     def __le__(self, other):
+        # type: (Any) -> bool
         return self._compare(other, operator.__le__)
 
     def __gt__(self, other):
+        # type: (Any) -> bool
         return self._compare(other, operator.__gt__)
 
     def __ge__(self, other):
+        # type: (Any) -> bool
         return self._compare(other, operator.__ge__)
 
     def __eq__(self, other):
+        # type: (Any) -> bool
         return self._compare(other, operator.__eq__)
 
     def _compare(self, other, method):
+        # type: (Any, Callable[[Any, Any], bool]) -> bool
         if not isinstance(other, self._defining_class):
             return NotImplemented
 

src/pip/_internal/vcs/versioncontrol.py

@@ -18,8 +18,6 @@ from typing import (
     Union,
 )
 
-from pip._vendor import pkg_resources
-
 from pip._internal.cli.spinners import SpinnerInterface
 from pip._internal.exceptions import BadCommand, InstallationError
 from pip._internal.utils.misc import (
@@ -62,7 +60,7 @@ def make_vcs_requirement_url(repo_url, rev, project_name, subdir=None):
       repo_url: the remote VCS url, with any needed VCS prefix (e.g. "git+").
       project_name: the (unescaped) project name.
     """
-    egg_project_name = pkg_resources.to_filename(project_name)
+    egg_project_name = project_name.replace("-", "_")
     req = f'{repo_url}@{rev}#egg={egg_project_name}'
     if subdir:
         req += f'&subdirectory={subdir}'

tests/data/packages/HackedEggInfo/setup.py

@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-
 from setuptools import setup
 from setuptools.command import egg_info as orig_egg_info
 

tests/data/packages/SetupPyUTF8/setup.py

@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-
 from distutils.core import setup
 
 setup(name="SetupPyUTF8",

tests/data/src/prjwithdatafile/setup.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 from setuptools import setup
 
 setup(

tests/functional/test_install.py

@@ -23,9 +23,7 @@ from tests.lib import (
     need_svn,
     path_to_url,
     pyversion,
-    pyversion_tuple,
     requirements_file,
-    windows_workaround_7667,
 )
 from tests.lib.filesystem import make_socket_file
 from tests.lib.local_repos import local_checkout
@@ -193,16 +191,10 @@ def test_pip_second_command_line_interface_works(
     """
     # Re-install pip so we get the launchers.
     script.pip_install_local('-f', common_wheels, pip_src)
-    # On old versions of Python, urllib3/requests will raise a warning about
-    # the lack of an SSLContext.
-    kwargs = {'expect_stderr': deprecated_python}
-    if pyversion_tuple < (2, 7, 9):
-        kwargs['expect_stderr'] = True
-
     args = [f'pip{pyversion}']
     args.extend(['install', 'INITools==0.2'])
     args.extend(['-f', data.packages])
-    result = script.run(*args, **kwargs)
+    result = script.run(*args)
     dist_info_folder = (
         script.site_packages /
         'INITools-0.2.dist-info'
@@ -581,7 +573,29 @@ def test_install_from_local_directory_with_symlinks_to_directories(
     result.did_create(dist_info_folder)
 
 
-@pytest.mark.skipif("sys.platform == 'win32' or sys.version_info < (3,)")
+def test_install_from_local_directory_with_in_tree_build(
+    script, data, with_wheel
+):
+    """
+    Test installing from a local directory with --use-feature=in-tree-build.
+    """
+    to_install = data.packages.joinpath("FSPkg")
+    args = ["install", "--use-feature=in-tree-build", to_install]
+
+    in_tree_build_dir = to_install / "build"
+    assert not in_tree_build_dir.exists()
+    result = script.pip(*args)
+    fspkg_folder = script.site_packages / 'fspkg'
+    dist_info_folder = (
+        script.site_packages /
+        'FSPkg-0.1.dev0.dist-info'
+    )
+    result.did_create(fspkg_folder)
+    result.did_create(dist_info_folder)
+    assert in_tree_build_dir.exists()
+
+
+@pytest.mark.skipif("sys.platform == 'win32'")
 def test_install_from_local_directory_with_socket_file(
     script, data, tmpdir, with_wheel
 ):
@@ -742,7 +756,6 @@ def test_install_using_install_option_and_editable(script, tmpdir):
 @pytest.mark.xfail
 @pytest.mark.network
 @need_mercurial
-@windows_workaround_7667
 def test_install_global_option_using_editable(script, tmpdir):
     """
     Test using global distutils options, but in an editable installation
@@ -1291,7 +1304,7 @@ def test_install_log(script, data, tmpdir):
             'install', data.src.joinpath('chattymodule')]
     result = script.pip(*args)
     assert 0 == result.stdout.count("HELLO FROM CHATTYMODULE")
-    with open(f, 'r') as fp:
+    with open(f) as fp:
         # one from egg_info, one from install
         assert 2 == fp.read().count("HELLO FROM CHATTYMODULE")
 
@@ -1314,7 +1327,8 @@ def test_cleanup_after_failed_wheel(script, with_wheel):
     # One of the effects of not cleaning up is broken scripts:
     script_py = script.bin_path / "script.py"
     assert script_py.exists(), script_py
-    shebang = open(script_py, 'r').readline().strip()
+    with open(script_py) as f:
+        shebang = f.readline().strip()
     assert shebang != '#!python', shebang
     # OK, assert that we *said* we were cleaning up:
     # /!\ if in need to change this, also change test_pep517_no_legacy_cleanup
@@ -1385,7 +1399,6 @@ def test_install_no_binary_disables_building_wheels(script, data, with_wheel):
 
 
 @pytest.mark.network
-@windows_workaround_7667
 def test_install_no_binary_builds_pep_517_wheel(script, data, with_wheel):
     to_install = data.packages.joinpath('pep517_setup_and_pyproject')
     res = script.pip(
@@ -1400,7 +1413,6 @@ def test_install_no_binary_builds_pep_517_wheel(script, data, with_wheel):
 
 
 @pytest.mark.network
-@windows_workaround_7667
 def test_install_no_binary_uses_local_backend(
         script, data, with_wheel, tmpdir):
     to_install = data.packages.joinpath('pep517_wrapper_buildsys')

tests/functional/test_install_reqs.py

@@ -357,7 +357,7 @@ def test_constraints_local_editable_install_causes_error(
         assert 'Could not satisfy constraints' in result.stderr, str(result)
     else:
         # Because singlemodule only has 0.0.1 available.
-        assert 'No matching distribution found' in result.stderr, str(result)
+        assert 'Cannot install singlemodule 0.0.1' in result.stderr, str(result)
 
 
 @pytest.mark.network
@@ -386,7 +386,7 @@ def test_constraints_local_install_causes_error(
         assert 'Could not satisfy constraints' in result.stderr, str(result)
     else:
         # Because singlemodule only has 0.0.1 available.
-        assert 'No matching distribution found' in result.stderr, str(result)
+        assert 'Cannot install singlemodule 0.0.1' in result.stderr, str(result)
 
 
 def test_constraints_constrain_to_local_editable(

tests/functional/test_new_resolver.py

@@ -687,7 +687,7 @@ def test_new_resolver_constraint_on_dependency(script):
 @pytest.mark.parametrize(
     "constraint_version, expect_error, message",
     [
-        ("1.0", True, "ERROR: No matching distribution found for foo 2.0"),
+        ("1.0", True, "Cannot install foo 2.0"),
         ("2.0", False, "Successfully installed foo-2.0"),
     ],
 )

tests/functional/test_new_resolver_errors.py

@@ -24,3 +24,24 @@ def test_new_resolver_conflict_requirements_file(tmpdir, script):
 
     message = "package versions have conflicting dependencies"
     assert message in result.stderr, str(result)
+
+
+def test_new_resolver_conflict_constraints_file(tmpdir, script):
+    create_basic_wheel_for_package(script, "pkg", "1.0")
+
+    constrats_file = tmpdir.joinpath("constraints.txt")
+    constrats_file.write_text("pkg!=1.0")
+
+    result = script.pip(
+        "install",
+        "--no-cache-dir", "--no-index",
+        "--find-links", script.scratch_path,
+        "-c", constrats_file,
+        "pkg==1.0",
+        expect_error=True,
+    )
+
+    assert "ResolutionImpossible" in result.stderr, str(result)
+
+    message = "The user requested (constraint) pkg!=1.0"
+    assert message in result.stdout, str(result)

tests/functional/test_no_color.py

@@ -33,7 +33,7 @@ def test_no_color(script):
             pytest.skip("Unable to capture output using script: " + cmd)
 
         try:
-            with open("/tmp/pip-test-no-color.txt", "r") as output_file:
+            with open("/tmp/pip-test-no-color.txt") as output_file:
                 retval = output_file.read()
             return retval
         finally:

tests/functional/test_pep517.py

@@ -3,7 +3,7 @@ from pip._vendor import toml
 
 from pip._internal.build_env import BuildEnvironment
 from pip._internal.req import InstallRequirement
-from tests.lib import make_test_finder, path_to_url, windows_workaround_7667
+from tests.lib import make_test_finder, path_to_url
 
 
 def make_project(tmpdir, requires=None, backend=None, backend_path=None):
@@ -255,7 +255,6 @@ def test_explicit_setuptools_backend(script, tmpdir, data, common_wheels):
 
 
 @pytest.mark.network
-@windows_workaround_7667
 def test_pep517_and_build_options(script, tmpdir, data, common_wheels):
     """Backend generated requirements are installed in the build env"""
     project_dir, name = make_pyproject_with_setup(tmpdir)

tests/functional/test_vcs_bazaar.py

@@ -64,7 +64,7 @@ def test_export_rev(script, tmpdir):
     url = hide_url('bzr+' + _test_path_to_file_url(source_dir) + '@1')
     Bazaar().export(str(export_dir), url=url)
 
-    with open(export_dir / 'test_file', 'r') as f:
+    with open(export_dir / 'test_file') as f:
         assert f.read() == 'something initial'
 
 

tests/lib/__init__.py

@@ -31,7 +31,6 @@ DATA_DIR = Path(__file__).parent.parent.joinpath("data").resolve()
 SRC_DIR = Path(__file__).resolve().parent.parent.parent
 
 pyversion = get_major_minor_version()
-pyversion_tuple = sys.version_info
 
 CURRENT_PY_VERSION_INFO = sys.version_info[:3]
 
@@ -1145,10 +1144,3 @@ def need_mercurial(fn):
     return pytest.mark.mercurial(need_executable(
         'Mercurial', ('hg', 'version')
     )(fn))
-
-
-# Workaround for test failures after new wheel release.
-windows_workaround_7667 = pytest.mark.skipif(
-    "sys.platform == 'win32' and sys.version_info < (3,)",
-    reason="Workaround for #7667",
-)

tests/lib/path.py

@@ -22,8 +22,8 @@ class Path(str):
 
     def __new__(cls, *paths):
         if len(paths):
-            return str.__new__(cls, os.path.join(*paths))
+            return super().__new__(cls, os.path.join(*paths))
-        return str.__new__(cls)
+        return super().__new__(cls)
 
     def __div__(self, path):
         """
@@ -73,9 +73,6 @@ class Path(str):
     def __repr__(self):
         return "Path({inner})".format(inner=str.__repr__(self))
 
-    def __hash__(self):
-        return str.__hash__(self)
-
     @property
     def name(self):
         """

tests/unit/test_operations_prepare.py

@@ -102,7 +102,7 @@ def test_copy_source_tree(clean_project, tmpdir):
     assert expected_files == copied_files
 
 
-@pytest.mark.skipif("sys.platform == 'win32' or sys.version_info < (3,)")
+@pytest.mark.skipif("sys.platform == 'win32'")
 def test_copy_source_tree_with_socket(clean_project, tmpdir, caplog):
     target = tmpdir.joinpath("target")
     expected_files = get_filelist(clean_project)
@@ -121,7 +121,7 @@ def test_copy_source_tree_with_socket(clean_project, tmpdir, caplog):
     assert socket_path in record.message
 
 
-@pytest.mark.skipif("sys.platform == 'win32' or sys.version_info < (3,)")
+@pytest.mark.skipif("sys.platform == 'win32'")
 def test_copy_source_tree_with_socket_fails_with_no_socket_error(
     clean_project, tmpdir
 ):

tests/unit/test_req.py

@@ -89,6 +89,7 @@ class TestRequirementSet:
                 require_hashes=require_hashes,
                 use_user_site=False,
                 lazy_wheel=False,
+                in_tree_build=False,
             )
             yield Resolver(
                 preparer=preparer,

tests/unit/test_utils_subprocess.py

@@ -57,11 +57,6 @@ def test_make_subprocess_output_error__non_ascii_command_arg(monkeypatch):
     Test a command argument with a non-ascii character.
     """
     cmd_args = ['foo', 'déf']
-    if sys.version_info[0] == 2:
-        # Check in Python 2 that the str (bytes object) with the non-ascii
-        # character has the encoding we expect. (This comes from the source
-        # code encoding at the top of the file.)
-        assert cmd_args[1].decode('utf-8') == 'déf'
 
     # We need to monkeypatch so the encoding will be correct on Windows.
     monkeypatch.setattr(locale, 'getpreferredencoding', lambda: 'utf-8')
@@ -80,7 +75,6 @@ def test_make_subprocess_output_error__non_ascii_command_arg(monkeypatch):
     assert actual == expected, f'actual: {actual}'
 
 
-@pytest.mark.skipif("sys.version_info < (3,)")
 def test_make_subprocess_output_error__non_ascii_cwd_python_3(monkeypatch):
     """
     Test a str (text) cwd with a non-ascii character in Python 3.
@@ -102,36 +96,6 @@ def test_make_subprocess_output_error__non_ascii_cwd_python_3(monkeypatch):
     assert actual == expected, f'actual: {actual}'
 
 
-@pytest.mark.parametrize('encoding', [
-    'utf-8',
-    # Test a Windows encoding.
-    'cp1252',
-])
-@pytest.mark.skipif("sys.version_info >= (3,)")
-def test_make_subprocess_output_error__non_ascii_cwd_python_2(
-    monkeypatch, encoding,
-):
-    """
-    Test a str (bytes object) cwd with a non-ascii character in Python 2.
-    """
-    cmd_args = ['test']
-    cwd = '/path/to/cwd/déf'.encode(encoding)
-    monkeypatch.setattr(sys, 'getfilesystemencoding', lambda: encoding)
-    actual = make_subprocess_output_error(
-        cmd_args=cmd_args,
-        cwd=cwd,
-        lines=[],
-        exit_status=1,
-    )
-    expected = dedent("""\
-    Command errored out with exit status 1:
-     command: test
-         cwd: /path/to/cwd/déf
-    Complete output (0 lines):
-    ----------------------------------------""")
-    assert actual == expected, f'actual: {actual}'
-
-
 # This test is mainly important for checking unicode in Python 2.
 def test_make_subprocess_output_error__non_ascii_line():
     """

tools/automation/release/__init__.py

@@ -91,7 +91,7 @@ def generate_news(session: Session, version: str) -> None:
 
 
 def update_version_file(version: str, filepath: str) -> None:
-    with open(filepath, "r", encoding="utf-8") as f:
+    with open(filepath, encoding="utf-8") as f:
         content = list(f)
 
     file_modified = False

tools/requirements/tests.txt

@@ -1,7 +1,6 @@
 --use-feature=2020-resolver
 cryptography==2.8
 freezegun
-mock
 pretend
 pytest
 pytest-cov

tools/tox_pip.py

@@ -1,17 +1,16 @@
-# The following comment should be removed at some point in the future.
-# mypy: disallow-untyped-defs=False
-
 import os
 import shutil
 import subprocess
 import sys
 from glob import glob
+from typing import List
 
 VIRTUAL_ENV = os.environ['VIRTUAL_ENV']
 TOX_PIP_DIR = os.path.join(VIRTUAL_ENV, 'pip')
 
 
 def pip(args):
+    # type: (List[str]) -> None
     # First things first, get a recent (stable) version of pip.
     if not os.path.exists(TOX_PIP_DIR):
         subprocess.check_call([sys.executable, '-m', 'pip',
@@ -20,8 +19,8 @@ def pip(args):
                                'pip'])
         shutil.rmtree(glob(os.path.join(TOX_PIP_DIR, 'pip-*.dist-info'))[0])
     # And use that version.
-    pypath = os.environ.get('PYTHONPATH')
+    pypath_env = os.environ.get('PYTHONPATH')
-    pypath = pypath.split(os.pathsep) if pypath is not None else []
+    pypath = pypath_env.split(os.pathsep) if pypath_env is not None else []
     pypath.insert(0, TOX_PIP_DIR)
     os.environ['PYTHONPATH'] = os.pathsep.join(pypath)
     subprocess.check_call([sys.executable, '-m', 'pip'] + args)