Created starter files for the project.

venv/Lib/site-packages/pip/_internal/resolution/resolvelib/candidates.py

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+import logging
+import sys
+
+from pip._vendor.contextlib2 import suppress
+from pip._vendor.packaging.specifiers import InvalidSpecifier, SpecifierSet
+from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.packaging.version import Version
+
+from pip._internal.exceptions import HashError, MetadataInconsistent
+from pip._internal.network.lazy_wheel import (
+    HTTPRangeRequestUnsupported,
+    dist_from_wheel_url,
+)
+from pip._internal.req.constructors import (
+    install_req_from_editable,
+    install_req_from_line,
+)
+from pip._internal.req.req_install import InstallRequirement
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.misc import dist_is_editable, normalize_version_info
+from pip._internal.utils.packaging import get_requires_python
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+from .base import Candidate, format_name
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, FrozenSet, Iterable, Optional, Tuple, Union
+
+    from pip._vendor.packaging.version import _BaseVersion
+    from pip._vendor.pkg_resources import Distribution
+
+    from pip._internal.distributions import AbstractDistribution
+    from pip._internal.models.link import Link
+
+    from .base import Requirement
+    from .factory import Factory
+
+    BaseCandidate = Union[
+        "AlreadyInstalledCandidate",
+        "EditableCandidate",
+        "LinkCandidate",
+    ]
+
+
+logger = logging.getLogger(__name__)
+
+
+def make_install_req_from_link(link, template):
+    # type: (Link, InstallRequirement) -> InstallRequirement
+    assert not template.editable, "template is editable"
+    if template.req:
+        line = str(template.req)
+    else:
+        line = link.url
+    ireq = install_req_from_line(
+        line,
+        user_supplied=template.user_supplied,
+        comes_from=template.comes_from,
+        use_pep517=template.use_pep517,
+        isolated=template.isolated,
+        constraint=template.constraint,
+        options=dict(
+            install_options=template.install_options,
+            global_options=template.global_options,
+            hashes=template.hash_options
+        ),
+    )
+    ireq.original_link = template.original_link
+    ireq.link = link
+    return ireq
+
+
+def make_install_req_from_editable(link, template):
+    # type: (Link, InstallRequirement) -> InstallRequirement
+    assert template.editable, "template not editable"
+    return install_req_from_editable(
+        link.url,
+        user_supplied=template.user_supplied,
+        comes_from=template.comes_from,
+        use_pep517=template.use_pep517,
+        isolated=template.isolated,
+        constraint=template.constraint,
+        options=dict(
+            install_options=template.install_options,
+            global_options=template.global_options,
+            hashes=template.hash_options
+        ),
+    )
+
+
+def make_install_req_from_dist(dist, template):
+    # type: (Distribution, InstallRequirement) -> InstallRequirement
+    project_name = canonicalize_name(dist.project_name)
+    if template.req:
+        line = str(template.req)
+    elif template.link:
+        line = "{} @ {}".format(project_name, template.link.url)
+    else:
+        line = "{}=={}".format(project_name, dist.parsed_version)
+    ireq = install_req_from_line(
+        line,
+        user_supplied=template.user_supplied,
+        comes_from=template.comes_from,
+        use_pep517=template.use_pep517,
+        isolated=template.isolated,
+        constraint=template.constraint,
+        options=dict(
+            install_options=template.install_options,
+            global_options=template.global_options,
+            hashes=template.hash_options
+        ),
+    )
+    ireq.satisfied_by = dist
+    return ireq
+
+
+class _InstallRequirementBackedCandidate(Candidate):
+    """A candidate backed by an ``InstallRequirement``.
+
+    This represents a package request with the target not being already
+    in the environment, and needs to be fetched and installed. The backing
+    ``InstallRequirement`` is responsible for most of the leg work; this
+    class exposes appropriate information to the resolver.
+
+    :param link: The link passed to the ``InstallRequirement``. The backing
+        ``InstallRequirement`` will use this link to fetch the distribution.
+    :param source_link: The link this candidate "originates" from. This is
+        different from ``link`` when the link is found in the wheel cache.
+        ``link`` would point to the wheel cache, while this points to the
+        found remote link (e.g. from pypi.org).
+    """
+    is_installed = False
+
+    def __init__(
+        self,
+        link,          # type: Link
+        source_link,   # type: Link
+        ireq,          # type: InstallRequirement
+        factory,       # type: Factory
+        name=None,     # type: Optional[str]
+        version=None,  # type: Optional[_BaseVersion]
+    ):
+        # type: (...) -> None
+        self._link = link
+        self._source_link = source_link
+        self._factory = factory
+        self._ireq = ireq
+        self._name = name
+        self._version = version
+        self._dist = None  # type: Optional[Distribution]
+        self._prepared = False
+
+    def __repr__(self):
+        # type: () -> str
+        return "{class_name}({link!r})".format(
+            class_name=self.__class__.__name__,
+            link=str(self._link),
+        )
+
+    def __hash__(self):
+        # type: () -> int
+        return hash((self.__class__, self._link))
+
+    def __eq__(self, other):
+        # type: (Any) -> bool
+        if isinstance(other, self.__class__):
+            return self._link == other._link
+        return False
+
+    # Needed for Python 2, which does not implement this by default
+    def __ne__(self, other):
+        # type: (Any) -> bool
+        return not self.__eq__(other)
+
+    @property
+    def source_link(self):
+        # type: () -> Optional[Link]
+        return self._source_link
+
+    @property
+    def name(self):
+        # type: () -> str
+        """The normalised name of the project the candidate refers to"""
+        if self._name is None:
+            self._name = canonicalize_name(self.dist.project_name)
+        return self._name
+
+    @property
+    def version(self):
+        # type: () -> _BaseVersion
+        if self._version is None:
+            self._version = self.dist.parsed_version
+        return self._version
+
+    def format_for_error(self):
+        # type: () -> str
+        return "{} {} (from {})".format(
+            self.name,
+            self.version,
+            self._link.file_path if self._link.is_file else self._link
+        )
+
+    def _prepare_abstract_distribution(self):
+        # type: () -> AbstractDistribution
+        raise NotImplementedError("Override in subclass")
+
+    def _check_metadata_consistency(self):
+        # type: () -> None
+        """Check for consistency of project name and version of dist."""
+        # TODO: (Longer term) Rather than abort, reject this candidate
+        #       and backtrack. This would need resolvelib support.
+        dist = self._dist  # type: Distribution
+        name = canonicalize_name(dist.project_name)
+        if self._name is not None and self._name != name:
+            raise MetadataInconsistent(self._ireq, "name", dist.project_name)
+        version = dist.parsed_version
+        if self._version is not None and self._version != version:
+            raise MetadataInconsistent(self._ireq, "version", dist.version)
+
+    def _prepare(self):
+        # type: () -> None
+        if self._prepared:
+            return
+        try:
+            abstract_dist = self._prepare_abstract_distribution()
+        except HashError as e:
+            e.req = self._ireq
+            raise
+
+        self._dist = abstract_dist.get_pkg_resources_distribution()
+        assert self._dist is not None, "Distribution already installed"
+        self._check_metadata_consistency()
+        self._prepared = True
+
+    def _fetch_metadata(self):
+        # type: () -> None
+        """Fetch metadata, using lazy wheel if possible."""
+        preparer = self._factory.preparer
+        use_lazy_wheel = self._factory.use_lazy_wheel
+        remote_wheel = self._link.is_wheel and not self._link.is_file
+        if use_lazy_wheel and remote_wheel and not preparer.require_hashes:
+            assert self._name is not None
+            logger.info('Collecting %s', self._ireq.req or self._ireq)
+            # If HTTPRangeRequestUnsupported is raised, fallback silently.
+            with indent_log(), suppress(HTTPRangeRequestUnsupported):
+                logger.info(
+                    'Obtaining dependency information from %s %s',
+                    self._name, self._version,
+                )
+                url = self._link.url.split('#', 1)[0]
+                session = preparer.downloader._session
+                self._dist = dist_from_wheel_url(self._name, url, session)
+                self._check_metadata_consistency()
+        if self._dist is None:
+            self._prepare()
+
+    @property
+    def dist(self):
+        # type: () -> Distribution
+        if self._dist is None:
+            self._fetch_metadata()
+        return self._dist
+
+    def _get_requires_python_specifier(self):
+        # type: () -> Optional[SpecifierSet]
+        requires_python = get_requires_python(self.dist)
+        if requires_python is None:
+            return None
+        try:
+            spec = SpecifierSet(requires_python)
+        except InvalidSpecifier as e:
+            logger.warning(
+                "Package %r has an invalid Requires-Python: %s", self.name, e,
+            )
+            return None
+        return spec
+
+    def iter_dependencies(self, with_requires):
+        # type: (bool) -> Iterable[Optional[Requirement]]
+        if not with_requires:
+            return
+        for r in self.dist.requires():
+            yield self._factory.make_requirement_from_spec(str(r), self._ireq)
+        python_dep = self._factory.make_requires_python_requirement(
+            self._get_requires_python_specifier(),
+        )
+        if python_dep:
+            yield python_dep
+
+    def get_install_requirement(self):
+        # type: () -> Optional[InstallRequirement]
+        self._prepare()
+        return self._ireq
+
+
+class LinkCandidate(_InstallRequirementBackedCandidate):
+    is_editable = False
+
+    def __init__(
+        self,
+        link,          # type: Link
+        template,        # type: InstallRequirement
+        factory,       # type: Factory
+        name=None,     # type: Optional[str]
+        version=None,  # type: Optional[_BaseVersion]
+    ):
+        # type: (...) -> None
+        source_link = link
+        cache_entry = factory.get_wheel_cache_entry(link, name)
+        if cache_entry is not None:
+            logger.debug("Using cached wheel link: %s", cache_entry.link)
+            link = cache_entry.link
+        ireq = make_install_req_from_link(link, template)
+
+        if (cache_entry is not None and
+                cache_entry.persistent and
+                template.link is template.original_link):
+            ireq.original_link_is_in_wheel_cache = True
+
+        super(LinkCandidate, self).__init__(
+            link=link,
+            source_link=source_link,
+            ireq=ireq,
+            factory=factory,
+            name=name,
+            version=version,
+        )
+
+    def _prepare_abstract_distribution(self):
+        # type: () -> AbstractDistribution
+        return self._factory.preparer.prepare_linked_requirement(
+            self._ireq, parallel_builds=True,
+        )
+
+
+class EditableCandidate(_InstallRequirementBackedCandidate):
+    is_editable = True
+
+    def __init__(
+        self,
+        link,          # type: Link
+        template,        # type: InstallRequirement
+        factory,       # type: Factory
+        name=None,     # type: Optional[str]
+        version=None,  # type: Optional[_BaseVersion]
+    ):
+        # type: (...) -> None
+        super(EditableCandidate, self).__init__(
+            link=link,
+            source_link=link,
+            ireq=make_install_req_from_editable(link, template),
+            factory=factory,
+            name=name,
+            version=version,
+        )
+
+    def _prepare_abstract_distribution(self):
+        # type: () -> AbstractDistribution
+        return self._factory.preparer.prepare_editable_requirement(self._ireq)
+
+
+class AlreadyInstalledCandidate(Candidate):
+    is_installed = True
+    source_link = None
+
+    def __init__(
+        self,
+        dist,  # type: Distribution
+        template,  # type: InstallRequirement
+        factory,  # type: Factory
+    ):
+        # type: (...) -> None
+        self.dist = dist
+        self._ireq = make_install_req_from_dist(dist, template)
+        self._factory = factory
+
+        # This is just logging some messages, so we can do it eagerly.
+        # The returned dist would be exactly the same as self.dist because we
+        # set satisfied_by in make_install_req_from_dist.
+        # TODO: Supply reason based on force_reinstall and upgrade_strategy.
+        skip_reason = "already satisfied"
+        factory.preparer.prepare_installed_requirement(self._ireq, skip_reason)
+
+    def __repr__(self):
+        # type: () -> str
+        return "{class_name}({distribution!r})".format(
+            class_name=self.__class__.__name__,
+            distribution=self.dist,
+        )
+
+    def __hash__(self):
+        # type: () -> int
+        return hash((self.__class__, self.name, self.version))
+
+    def __eq__(self, other):
+        # type: (Any) -> bool
+        if isinstance(other, self.__class__):
+            return self.name == other.name and self.version == other.version
+        return False
+
+    # Needed for Python 2, which does not implement this by default
+    def __ne__(self, other):
+        # type: (Any) -> bool
+        return not self.__eq__(other)
+
+    @property
+    def name(self):
+        # type: () -> str
+        return canonicalize_name(self.dist.project_name)
+
+    @property
+    def version(self):
+        # type: () -> _BaseVersion
+        return self.dist.parsed_version
+
+    @property
+    def is_editable(self):
+        # type: () -> bool
+        return dist_is_editable(self.dist)
+
+    def format_for_error(self):
+        # type: () -> str
+        return "{} {} (Installed)".format(self.name, self.version)
+
+    def iter_dependencies(self, with_requires):
+        # type: (bool) -> Iterable[Optional[Requirement]]
+        if not with_requires:
+            return
+        for r in self.dist.requires():
+            yield self._factory.make_requirement_from_spec(str(r), self._ireq)
+
+    def get_install_requirement(self):
+        # type: () -> Optional[InstallRequirement]
+        return None
+
+
+class ExtrasCandidate(Candidate):
+    """A candidate that has 'extras', indicating additional dependencies.
+
+    Requirements can be for a project with dependencies, something like
+    foo[extra].  The extras don't affect the project/version being installed
+    directly, but indicate that we need additional dependencies. We model that
+    by having an artificial ExtrasCandidate that wraps the "base" candidate.
+
+    The ExtrasCandidate differs from the base in the following ways:
+
+    1. It has a unique name, of the form foo[extra]. This causes the resolver
+       to treat it as a separate node in the dependency graph.
+    2. When we're getting the candidate's dependencies,
+       a) We specify that we want the extra dependencies as well.
+       b) We add a dependency on the base candidate.
+          See below for why this is needed.
+    3. We return None for the underlying InstallRequirement, as the base
+       candidate will provide it, and we don't want to end up with duplicates.
+
+    The dependency on the base candidate is needed so that the resolver can't
+    decide that it should recommend foo[extra1] version 1.0 and foo[extra2]
+    version 2.0. Having those candidates depend on foo=1.0 and foo=2.0
+    respectively forces the resolver to recognise that this is a conflict.
+    """
+    def __init__(
+        self,
+        base,  # type: BaseCandidate
+        extras,  # type: FrozenSet[str]
+    ):
+        # type: (...) -> None
+        self.base = base
+        self.extras = extras
+
+    def __repr__(self):
+        # type: () -> str
+        return "{class_name}(base={base!r}, extras={extras!r})".format(
+            class_name=self.__class__.__name__,
+            base=self.base,
+            extras=self.extras,
+        )
+
+    def __hash__(self):
+        # type: () -> int
+        return hash((self.base, self.extras))
+
+    def __eq__(self, other):
+        # type: (Any) -> bool
+        if isinstance(other, self.__class__):
+            return self.base == other.base and self.extras == other.extras
+        return False
+
+    # Needed for Python 2, which does not implement this by default
+    def __ne__(self, other):
+        # type: (Any) -> bool
+        return not self.__eq__(other)
+
+    @property
+    def name(self):
+        # type: () -> str
+        """The normalised name of the project the candidate refers to"""
+        return format_name(self.base.name, self.extras)
+
+    @property
+    def version(self):
+        # type: () -> _BaseVersion
+        return self.base.version
+
+    def format_for_error(self):
+        # type: () -> str
+        return "{} [{}]".format(
+            self.base.format_for_error(),
+            ", ".join(sorted(self.extras))
+        )
+
+    @property
+    def is_installed(self):
+        # type: () -> bool
+        return self.base.is_installed
+
+    @property
+    def is_editable(self):
+        # type: () -> bool
+        return self.base.is_editable
+
+    @property
+    def source_link(self):
+        # type: () -> Optional[Link]
+        return self.base.source_link
+
+    def iter_dependencies(self, with_requires):
+        # type: (bool) -> Iterable[Optional[Requirement]]
+        factory = self.base._factory
+
+        # Add a dependency on the exact base
+        # (See note 2b in the class docstring)
+        yield factory.make_requirement_from_candidate(self.base)
+        if not with_requires:
+            return
+
+        # The user may have specified extras that the candidate doesn't
+        # support. We ignore any unsupported extras here.
+        valid_extras = self.extras.intersection(self.base.dist.extras)
+        invalid_extras = self.extras.difference(self.base.dist.extras)
+        for extra in sorted(invalid_extras):
+            logger.warning(
+                "%s %s does not provide the extra '%s'",
+                self.base.name,
+                self.version,
+                extra
+            )
+
+        for r in self.base.dist.requires(valid_extras):
+            requirement = factory.make_requirement_from_spec(
+                str(r), self.base._ireq, valid_extras,
+            )
+            if requirement:
+                yield requirement
+
+    def get_install_requirement(self):
+        # type: () -> Optional[InstallRequirement]
+        # We don't return anything here, because we always
+        # depend on the base candidate, and we'll get the
+        # install requirement from that.
+        return None
+
+
+class RequiresPythonCandidate(Candidate):
+    is_installed = False
+    source_link = None
+
+    def __init__(self, py_version_info):
+        # type: (Optional[Tuple[int, ...]]) -> None
+        if py_version_info is not None:
+            version_info = normalize_version_info(py_version_info)
+        else:
+            version_info = sys.version_info[:3]
+        self._version = Version(".".join(str(c) for c in version_info))
+
+    # We don't need to implement __eq__() and __ne__() since there is always
+    # only one RequiresPythonCandidate in a resolution, i.e. the host Python.
+    # The built-in object.__eq__() and object.__ne__() do exactly what we want.
+
+    @property
+    def name(self):
+        # type: () -> str
+        # Avoid conflicting with the PyPI package "Python".
+        return "<Python from Requires-Python>"
+
+    @property
+    def version(self):
+        # type: () -> _BaseVersion
+        return self._version
+
+    def format_for_error(self):
+        # type: () -> str
+        return "Python {}".format(self.version)
+
+    def iter_dependencies(self, with_requires):
+        # type: (bool) -> Iterable[Optional[Requirement]]
+        return ()
+
+    def get_install_requirement(self):
+        # type: () -> Optional[InstallRequirement]
+        return None