--- a/lib/python3.8/site-packages/pip/_internal/req/req_set.py	Mon Jul 27 03:47:31 2020 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,209 +0,0 @@
-# The following comment should be removed at some point in the future.
-# mypy: strict-optional=False
-
-from __future__ import absolute_import
-
-import logging
-from collections import OrderedDict
-
-from pip._vendor.packaging.utils import canonicalize_name
-
-from pip._internal import pep425tags
-from pip._internal.exceptions import InstallationError
-from pip._internal.models.wheel import Wheel
-from pip._internal.utils.logging import indent_log
-from pip._internal.utils.typing import MYPY_CHECK_RUNNING
-
-if MYPY_CHECK_RUNNING:
-    from typing import Dict, Iterable, List, Optional, Tuple
-    from pip._internal.req.req_install import InstallRequirement
-
-
-logger = logging.getLogger(__name__)
-
-
-class RequirementSet(object):
-
-    def __init__(self, check_supported_wheels=True):
-        # type: (bool) -> None
-        """Create a RequirementSet.
-        """
-
-        self.requirements = OrderedDict()  # type: Dict[str, InstallRequirement]  # noqa: E501
-        self.check_supported_wheels = check_supported_wheels
-
-        self.unnamed_requirements = []  # type: List[InstallRequirement]
-        self.successfully_downloaded = []  # type: List[InstallRequirement]
-        self.reqs_to_cleanup = []  # type: List[InstallRequirement]
-
-    def __str__(self):
-        # type: () -> str
-        requirements = sorted(
-            (req for req in self.requirements.values() if not req.comes_from),
-            key=lambda req: canonicalize_name(req.name),
-        )
-        return ' '.join(str(req.req) for req in requirements)
-
-    def __repr__(self):
-        # type: () -> str
-        requirements = sorted(
-            self.requirements.values(),
-            key=lambda req: canonicalize_name(req.name),
-        )
-
-        format_string = '<{classname} object; {count} requirement(s): {reqs}>'
-        return format_string.format(
-            classname=self.__class__.__name__,
-            count=len(requirements),
-            reqs=', '.join(str(req.req) for req in requirements),
-        )
-
-    def add_unnamed_requirement(self, install_req):
-        # type: (InstallRequirement) -> None
-        assert not install_req.name
-        self.unnamed_requirements.append(install_req)
-
-    def add_named_requirement(self, install_req):
-        # type: (InstallRequirement) -> None
-        assert install_req.name
-
-        project_name = canonicalize_name(install_req.name)
-        self.requirements[project_name] = install_req
-
-    def add_requirement(
-        self,
-        install_req,  # type: InstallRequirement
-        parent_req_name=None,  # type: Optional[str]
-        extras_requested=None  # type: Optional[Iterable[str]]
-    ):
-        # type: (...) -> Tuple[List[InstallRequirement], Optional[InstallRequirement]]  # noqa: E501
-        """Add install_req as a requirement to install.
-
-        :param parent_req_name: The name of the requirement that needed this
-            added. The name is used because when multiple unnamed requirements
-            resolve to the same name, we could otherwise end up with dependency
-            links that point outside the Requirements set. parent_req must
-            already be added. Note that None implies that this is a user
-            supplied requirement, vs an inferred one.
-        :param extras_requested: an iterable of extras used to evaluate the
-            environment markers.
-        :return: Additional requirements to scan. That is either [] if
-            the requirement is not applicable, or [install_req] if the
-            requirement is applicable and has just been added.
-        """
-        # If the markers do not match, ignore this requirement.
-        if not install_req.match_markers(extras_requested):
-            logger.info(
-                "Ignoring %s: markers '%s' don't match your environment",
-                install_req.name, install_req.markers,
-            )
-            return [], None
-
-        # If the wheel is not supported, raise an error.
-        # Should check this after filtering out based on environment markers to
-        # allow specifying different wheels based on the environment/OS, in a
-        # single requirements file.
-        if install_req.link and install_req.link.is_wheel:
-            wheel = Wheel(install_req.link.filename)
-            tags = pep425tags.get_supported()
-            if (self.check_supported_wheels and not wheel.supported(tags)):
-                raise InstallationError(
-                    "%s is not a supported wheel on this platform." %
-                    wheel.filename
-                )
-
-        # This next bit is really a sanity check.
-        assert install_req.is_direct == (parent_req_name is None), (
-            "a direct req shouldn't have a parent and also, "
-            "a non direct req should have a parent"
-        )
-
-        # Unnamed requirements are scanned again and the requirement won't be
-        # added as a dependency until after scanning.
-        if not install_req.name:
-            self.add_unnamed_requirement(install_req)
-            return [install_req], None
-
-        try:
-            existing_req = self.get_requirement(install_req.name)
-        except KeyError:
-            existing_req = None
-
-        has_conflicting_requirement = (
-            parent_req_name is None and
-            existing_req and
-            not existing_req.constraint and
-            existing_req.extras == install_req.extras and
-            existing_req.req.specifier != install_req.req.specifier
-        )
-        if has_conflicting_requirement:
-            raise InstallationError(
-                "Double requirement given: %s (already in %s, name=%r)"
-                % (install_req, existing_req, install_req.name)
-            )
-
-        # When no existing requirement exists, add the requirement as a
-        # dependency and it will be scanned again after.
-        if not existing_req:
-            self.add_named_requirement(install_req)
-            # We'd want to rescan this requirement later
-            return [install_req], install_req
-
-        # Assume there's no need to scan, and that we've already
-        # encountered this for scanning.
-        if install_req.constraint or not existing_req.constraint:
-            return [], existing_req
-
-        does_not_satisfy_constraint = (
-            install_req.link and
-            not (
-                existing_req.link and
-                install_req.link.path == existing_req.link.path
-            )
-        )
-        if does_not_satisfy_constraint:
-            self.reqs_to_cleanup.append(install_req)
-            raise InstallationError(
-                "Could not satisfy constraints for '%s': "
-                "installation from path or url cannot be "
-                "constrained to a version" % install_req.name,
-            )
-        # If we're now installing a constraint, mark the existing
-        # object for real installation.
-        existing_req.constraint = False
-        existing_req.extras = tuple(sorted(
-            set(existing_req.extras) | set(install_req.extras)
-        ))
-        logger.debug(
-            "Setting %s extras to: %s",
-            existing_req, existing_req.extras,
-        )
-        # Return the existing requirement for addition to the parent and
-        # scanning again.
-        return [existing_req], existing_req
-
-    def has_requirement(self, name):
-        # type: (str) -> bool
-        project_name = canonicalize_name(name)
-
-        return (
-            project_name in self.requirements and
-            not self.requirements[project_name].constraint
-        )
-
-    def get_requirement(self, name):
-        # type: (str) -> InstallRequirement
-        project_name = canonicalize_name(name)
-
-        if project_name in self.requirements:
-            return self.requirements[project_name]
-
-        raise KeyError("No project with the name %r" % name)
-
-    def cleanup_files(self):
-        # type: () -> None
-        """Clean up files, remove builds."""
-        logger.debug('Cleaning up...')
-        with indent_log():
-            for req in self.reqs_to_cleanup:
-                req.remove_temporary_source()