# The following comment should be removed at some point in the future.
# mypy: strict-optional=False

from __future__ import absolute_import

import logging
import os
import shutil
import sys
import uuid
import zipfile

from pip._vendor import pkg_resources, six
from pip._vendor.packaging.requirements import Requirement
from pip._vendor.packaging.utils import canonicalize_name
from pip._vendor.packaging.version import Version
from pip._vendor.packaging.version import parse as parse_version
from pip._vendor.pep517.wrappers import Pep517HookCaller

from pip._internal.build_env import NoOpBuildEnvironment
from pip._internal.exceptions import InstallationError
from pip._internal.locations import get_scheme
from pip._internal.models.link import Link
from pip._internal.operations.build.metadata import generate_metadata
from pip._internal.operations.build.metadata_legacy import (
    generate_metadata as generate_metadata_legacy,
)
from pip._internal.operations.install.editable_legacy import (
    install_editable as install_editable_legacy,
)
from pip._internal.operations.install.legacy import LegacyInstallFailure
from pip._internal.operations.install.legacy import install as install_legacy
from pip._internal.operations.install.wheel import install_wheel
from pip._internal.pyproject import load_pyproject_toml, make_pyproject_path
from pip._internal.req.req_uninstall import UninstallPathSet
from pip._internal.utils.deprecation import deprecated
from pip._internal.utils.direct_url_helpers import direct_url_from_link
from pip._internal.utils.hashes import Hashes
from pip._internal.utils.logging import indent_log
from pip._internal.utils.misc import (
    ask_path_exists,
    backup_dir,
    display_path,
    dist_in_site_packages,
    dist_in_usersite,
    get_distribution,
    get_installed_version,
    hide_url,
    redact_auth_from_url,
)
from pip._internal.utils.packaging import get_metadata
from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
from pip._internal.utils.typing import MYPY_CHECK_RUNNING
from pip._internal.utils.virtualenv import running_under_virtualenv
from pip._internal.vcs import vcs

if MYPY_CHECK_RUNNING:
    from typing import Any, Dict, Iterable, List, Optional, Sequence, Union

    from pip._vendor.packaging.markers import Marker
    from pip._vendor.packaging.specifiers import SpecifierSet
    from pip._vendor.pkg_resources import Distribution

    from pip._internal.build_env import BuildEnvironment


logger = logging.getLogger(__name__)


def _get_dist(metadata_directory):
    # type: (str) -> Distribution
    """Return a pkg_resources.Distribution for the provided
    metadata directory.
    """
    dist_dir = metadata_directory.rstrip(os.sep)

    # Build a PathMetadata object, from path to metadata. :wink:
    base_dir, dist_dir_name = os.path.split(dist_dir)
    metadata = pkg_resources.PathMetadata(base_dir, dist_dir)

    # Determine the correct Distribution object type.
    if dist_dir.endswith(".egg-info"):
        dist_cls = pkg_resources.Distribution
        dist_name = os.path.splitext(dist_dir_name)[0]
    else:
        assert dist_dir.endswith(".dist-info")
        dist_cls = pkg_resources.DistInfoDistribution
        dist_name = os.path.splitext(dist_dir_name)[0].split("-")[0]

    return dist_cls(
        base_dir,
        project_name=dist_name,
        metadata=metadata,
    )


class InstallRequirement(object):
    """
    Represents something that may be installed later on, may have information
    about where to fetch the relevant requirement and also contains logic for
    installing the said requirement.
    """

    def __init__(
        self,
        req,  # type: Optional[Requirement]
        comes_from,  # type: Optional[Union[str, InstallRequirement]]
        editable=False,  # type: bool
        link=None,  # type: Optional[Link]
        markers=None,  # type: Optional[Marker]
        use_pep517=None,  # type: Optional[bool]
        isolated=False,  # type: bool
        install_options=None,  # type: Optional[List[str]]
        global_options=None,  # type: Optional[List[str]]
        hash_options=None,  # type: Optional[Dict[str, List[str]]]
        constraint=False,  # type: bool
        extras=(),  # type: Iterable[str]
        user_supplied=False,  # type: bool
    ):
        # type: (...) -> None
        assert req is None or isinstance(req, Requirement), req
        self.req = req
        self.comes_from = comes_from
        self.constraint = constraint
        self.editable = editable
        self.legacy_install_reason = None  # type: Optional[int]

        # source_dir is the local directory where the linked requirement is
        # located, or unpacked. In case unpacking is needed, creating and
        # populating source_dir is done by the RequirementPreparer. Note this
        # is not necessarily the directory where pyproject.toml or setup.py is
        # located - that one is obtained via unpacked_source_directory.
        self.source_dir = None  # type: Optional[str]
        if self.editable:
            assert link
            if link.is_file:
                self.source_dir = os.path.normpath(
                    os.path.abspath(link.file_path)
                )

        if link is None and req and req.url:
            # PEP 508 URL requirement
            link = Link(req.url)
        self.link = self.original_link = link
        self.original_link_is_in_wheel_cache = False

        # Path to any downloaded or already-existing package.
        self.local_file_path = None  # type: Optional[str]
        if self.link and self.link.is_file:
            self.local_file_path = self.link.file_path

        if extras:
            self.extras = extras
        elif req:
            self.extras = {
                pkg_resources.safe_extra(extra) for extra in req.extras
            }
        else:
            self.extras = set()
        if markers is None and req:
            markers = req.marker
        self.markers = markers

        # This holds the pkg_resources.Distribution object if this requirement
        # is already available:
        self.satisfied_by = None  # type: Optional[Distribution]
        # Whether the installation process should try to uninstall an existing
        # distribution before installing this requirement.
        self.should_reinstall = False
        # Temporary build location
        self._temp_build_dir = None  # type: Optional[TempDirectory]
        # Set to True after successful installation
        self.install_succeeded = None  # type: Optional[bool]
        # Supplied options
        self.install_options = install_options if install_options else []
        self.global_options = global_options if global_options else []
        self.hash_options = hash_options if hash_options else {}
        # Set to True after successful preparation of this requirement
        self.prepared = False
        # User supplied requirement are explicitly requested for installation
        # by the user via CLI arguments or requirements files, as opposed to,
        # e.g. dependencies, extras or constraints.
        self.user_supplied = user_supplied

        self.isolated = isolated
        self.build_env = NoOpBuildEnvironment()  # type: BuildEnvironment

        # For PEP 517, the directory where we request the project metadata
        # gets stored. We need this to pass to build_wheel, so the backend
        # can ensure that the wheel matches the metadata (see the PEP for
        # details).
        self.metadata_directory = None  # type: Optional[str]

        # The static build requirements (from pyproject.toml)
        self.pyproject_requires = None  # type: Optional[List[str]]

        # Build requirements that we will check are available
        self.requirements_to_check = []  # type: List[str]

        # The PEP 517 backend we should use to build the project
        self.pep517_backend = None  # type: Optional[Pep517HookCaller]

        # Are we using PEP 517 for this requirement?
        # After pyproject.toml has been loaded, the only valid values are True
        # and False. Before loading, None is valid (meaning "use the default").
        # Setting an explicit value before loading pyproject.toml is supported,
        # but after loading this flag should be treated as read only.
        self.use_pep517 = use_pep517

        # This requirement needs more preparation before it can be built
        self.needs_more_preparation = False

    def __str__(self):
        # type: () -> str
        if self.req:
            s = str(self.req)
            if self.link:
                s += ' from {}'.format(redact_auth_from_url(self.link.url))
        elif self.link:
            s = redact_auth_from_url(self.link.url)
        else:
            s = '<InstallRequirement>'
        if self.satisfied_by is not None:
            s += ' in {}'.format(display_path(self.satisfied_by.location))
        if self.comes_from:
            if isinstance(self.comes_from, six.string_types):
                comes_from = self.comes_from  # type: Optional[str]
            else:
                comes_from = self.comes_from.from_path()
            if comes_from:
                s += ' (from {})'.format(comes_from)
        return s

    def __repr__(self):
        # type: () -> str
        return '<{} object: {} editable={!r}>'.format(
            self.__class__.__name__, str(self), self.editable)

    def format_debug(self):
        # type: () -> str
        """An un-tested helper for getting state, for debugging.
        """
        attributes = vars(self)
        names = sorted(attributes)

        state = (
            "{}={!r}".format(attr, attributes[attr]) for attr in sorted(names)
        )
        return '<{name} object: {{{state}}}>'.format(
            name=self.__class__.__name__,
            state=", ".join(state),
        )

    # Things that are valid for all kinds of requirements?
    @property
    def name(self):
        # type: () -> Optional[str]
        if self.req is None:
            return None
        return six.ensure_str(pkg_resources.safe_name(self.req.name))

    @property
    def specifier(self):
        # type: () -> SpecifierSet
        return self.req.specifier

    @property
    def is_pinned(self):
        # type: () -> bool
        """Return whether I am pinned to an exact version.

        For example, some-package==1.2 is pinned; some-package>1.2 is not.
        """
        specifiers = self.specifier
        return (len(specifiers) == 1 and
                next(iter(specifiers)).operator in {'==', '==='})

    @property
    def installed_version(self):
        # type: () -> Optional[str]
        return get_installed_version(self.name)

    def match_markers(self, extras_requested=None):
        # type: (Optional[Iterable[str]]) -> bool
        if not extras_requested:
            # Provide an extra to safely evaluate the markers
            # without matching any extra
            extras_requested = ('',)
        if self.markers is not None:
            return any(
                self.markers.evaluate({'extra': extra})
                for extra in extras_requested)
        else:
            return True

    @property
    def has_hash_options(self):
        # type: () -> bool
        """Return whether any known-good hashes are specified as options.

        These activate --require-hashes mode; hashes specified as part of a
        URL do not.

        """
        return bool(self.hash_options)

    def hashes(self, trust_internet=True):
        # type: (bool) -> Hashes
        """Return a hash-comparer that considers my option- and URL-based
        hashes to be known-good.

        Hashes in URLs--ones embedded in the requirements file, not ones
        downloaded from an index server--are almost peers with ones from
        flags. They satisfy --require-hashes (whether it was implicitly or
        explicitly activated) but do not activate it. md5 and sha224 are not
        allowed in flags, which should nudge people toward good algos. We
        always OR all hashes together, even ones from URLs.

        :param trust_internet: Whether to trust URL-based (#md5=...) hashes
            downloaded from the internet, as by populate_link()

        """
        good_hashes = self.hash_options.copy()
        link = self.link if trust_internet else self.original_link
        if link and link.hash:
            good_hashes.setdefault(link.hash_name, []).append(link.hash)
        return Hashes(good_hashes)

    def from_path(self):
        # type: () -> Optional[str]
        """Format a nice indicator to show where this "comes from"
        """
        if self.req is None:
            return None
        s = str(self.req)
        if self.comes_from:
            if isinstance(self.comes_from, six.string_types):
                comes_from = self.comes_from
            else:
                comes_from = self.comes_from.from_path()
            if comes_from:
                s += '->' + comes_from
        return s

    def ensure_build_location(self, build_dir, autodelete, parallel_builds):
        # type: (str, bool, bool) -> str
        assert build_dir is not None
        if self._temp_build_dir is not None:
            assert self._temp_build_dir.path
            return self._temp_build_dir.path
        if self.req is None:
            # Some systems have /tmp as a symlink which confuses custom
            # builds (such as numpy). Thus, we ensure that the real path
            # is returned.
            self._temp_build_dir = TempDirectory(
                kind=tempdir_kinds.REQ_BUILD, globally_managed=True
            )

            return self._temp_build_dir.path

        # This is the only remaining place where we manually determine the path
        # for the temporary directory. It is only needed for editables where
        # it is the value of the --src option.

        # When parallel builds are enabled, add a UUID to the build directory
        # name so multiple builds do not interfere with each other.
        dir_name = canonicalize_name(self.name)
        if parallel_builds:
            dir_name = "{}_{}".format(dir_name, uuid.uuid4().hex)

        # FIXME: Is there a better place to create the build_dir? (hg and bzr
        # need this)
        if not os.path.exists(build_dir):
            logger.debug('Creating directory %s', build_dir)
            os.makedirs(build_dir)
        actual_build_dir = os.path.join(build_dir, dir_name)
        # `None` indicates that we respect the globally-configured deletion
        # settings, which is what we actually want when auto-deleting.
        delete_arg = None if autodelete else False
        return TempDirectory(
            path=actual_build_dir,
            delete=delete_arg,
            kind=tempdir_kinds.REQ_BUILD,
            globally_managed=True,
        ).path

    def _set_requirement(self):
        # type: () -> None
        """Set requirement after generating metadata.
        """
        assert self.req is None
        assert self.metadata is not None
        assert self.source_dir is not None

        # Construct a Requirement object from the generated metadata
        if isinstance(parse_version(self.metadata["Version"]), Version):
            op = "=="
        else:
            op = "==="

        self.req = Requirement(
            "".join([
                self.metadata["Name"],
                op,
                self.metadata["Version"],
            ])
        )

    def warn_on_mismatching_name(self):
        # type: () -> None
        metadata_name = canonicalize_name(self.metadata["Name"])
        if canonicalize_name(self.req.name) == metadata_name:
            # Everything is fine.
            return

        # If we're here, there's a mismatch. Log a warning about it.
        logger.warning(
            'Generating metadata for package %s '
            'produced metadata for project name %s. Fix your '
            '#egg=%s fragments.',
            self.name, metadata_name, self.name
        )
        self.req = Requirement(metadata_name)

    def check_if_exists(self, use_user_site):
        # type: (bool) -> None
        """Find an installed distribution that satisfies or conflicts
        with this requirement, and set self.satisfied_by or
        self.should_reinstall appropriately.
        """
        if self.req is None:
            return
        existing_dist = get_distribution(self.req.name)
        if not existing_dist:
            return

        existing_version = existing_dist.parsed_version
        if not self.req.specifier.contains(existing_version, prereleases=True):
            self.satisfied_by = None
            if use_user_site:
                if dist_in_usersite(existing_dist):
                    self.should_reinstall = True
                elif (running_under_virtualenv() and
                        dist_in_site_packages(existing_dist)):
                    raise InstallationError(
                        "Will not install to the user site because it will "
                        "lack sys.path precedence to {} in {}".format(
                            existing_dist.project_name, existing_dist.location)
                    )
            else:
                self.should_reinstall = True
        else:
            if self.editable:
                self.should_reinstall = True
                # when installing editables, nothing pre-existing should ever
                # satisfy
                self.satisfied_by = None
            else:
                self.satisfied_by = existing_dist

    # Things valid for wheels
    @property
    def is_wheel(self):
        # type: () -> bool
        if not self.link:
            return False
        return self.link.is_wheel

    # Things valid for sdists
    @property
    def unpacked_source_directory(self):
        # type: () -> str
        return os.path.join(
            self.source_dir,
            self.link and self.link.subdirectory_fragment or '')

    @property
    def setup_py_path(self):
        # type: () -> str
        assert self.source_dir, "No source dir for {}".format(self)
        setup_py = os.path.join(self.unpacked_source_directory, 'setup.py')

        # Python2 __file__ should not be unicode
        if six.PY2 and isinstance(setup_py, six.text_type):
            setup_py = setup_py.encode(sys.getfilesystemencoding())

        return setup_py

    @property
    def pyproject_toml_path(self):
        # type: () -> str
        assert self.source_dir, "No source dir for {}".format(self)
        return make_pyproject_path(self.unpacked_source_directory)

    def load_pyproject_toml(self):
        # type: () -> None
        """Load the pyproject.toml file.

        After calling this routine, all of the attributes related to PEP 517
        processing for this requirement have been set. In particular, the
        use_pep517 attribute can be used to determine whether we should
        follow the PEP 517 or legacy (setup.py) code path.
        """
        pyproject_toml_data = load_pyproject_toml(
            self.use_pep517,
            self.pyproject_toml_path,
            self.setup_py_path,
            str(self)
        )

        if pyproject_toml_data is None:
            self.use_pep517 = False
            return

        self.use_pep517 = True
        requires, backend, check, backend_path = pyproject_toml_data
        self.requirements_to_check = check
        self.pyproject_requires = requires
        self.pep517_backend = Pep517HookCaller(
            self.unpacked_source_directory, backend, backend_path=backend_path,
        )

    def _generate_metadata(self):
        # type: () -> str
        """Invokes metadata generator functions, with the required arguments.
        """
        if not self.use_pep517:
            assert self.unpacked_source_directory

            return generate_metadata_legacy(
                build_env=self.build_env,
                setup_py_path=self.setup_py_path,
                source_dir=self.unpacked_source_directory,
                isolated=self.isolated,
                details=self.name or "from {}".format(self.link)
            )

        assert self.pep517_backend is not None

        return generate_metadata(
            build_env=self.build_env,
            backend=self.pep517_backend,
        )

    def prepare_metadata(self):
        # type: () -> None
        """Ensure that project metadata is available.

        Under PEP 517, call the backend hook to prepare the metadata.
        Under legacy processing, call setup.py egg-info.
        """
        assert self.source_dir

        with indent_log():
            self.metadata_directory = self._generate_metadata()

        # Act on the newly generated metadata, based on the name and version.
        if not self.name:
            self._set_requirement()
        else:
            self.warn_on_mismatching_name()

        self.assert_source_matches_version()

    @property
    def metadata(self):
        # type: () -> Any
        if not hasattr(self, '_metadata'):
            self._metadata = get_metadata(self.get_dist())

        return self._metadata

    def get_dist(self):
        # type: () -> Distribution
        return _get_dist(self.metadata_directory)

    def assert_source_matches_version(self):
        # type: () -> None
        assert self.source_dir
        version = self.metadata['version']
        if self.req.specifier and version not in self.req.specifier:
            logger.warning(
                'Requested %s, but installing version %s',
                self,
                version,
            )
        else:
            logger.debug(
                'Source in %s has version %s, which satisfies requirement %s',
                display_path(self.source_dir),
                version,
                self,
            )

    # For both source distributions and editables
    def ensure_has_source_dir(
        self,
        parent_dir,
        autodelete=False,
        parallel_builds=False,
    ):
        # type: (str, bool, bool) -> None
        """Ensure that a source_dir is set.

        This will create a temporary build dir if the name of the requirement
        isn't known yet.

        :param parent_dir: The ideal pip parent_dir for the source_dir.
            Generally src_dir for editables and build_dir for sdists.
        :return: self.source_dir
        """
        if self.source_dir is None:
            self.source_dir = self.ensure_build_location(
                parent_dir,
                autodelete=autodelete,
                parallel_builds=parallel_builds,
            )

    # For editable installations
    def update_editable(self, obtain=True):
        # type: (bool) -> None
        if not self.link:
            logger.debug(
                "Cannot update repository at %s; repository location is "
                "unknown",
                self.source_dir,
            )
            return
        assert self.editable
        assert self.source_dir
        if self.link.scheme == 'file':
            # Static paths don't get updated
            return
        assert '+' in self.link.url, \
            "bad url: {self.link.url!r}".format(**locals())
        vc_type, url = self.link.url.split('+', 1)
        vcs_backend = vcs.get_backend(vc_type)
        if vcs_backend:
            if not self.link.is_vcs:
                reason = (
                    "This form of VCS requirement is being deprecated: {}."
                ).format(
                    self.link.url
                )
                replacement = None
                if self.link.url.startswith("git+git@"):
                    replacement = (
                        "git+https://git@example.com/..., "
                        "git+ssh://git@example.com/..., "
                        "or the insecure git+git://git@example.com/..."
                    )
                deprecated(reason, replacement, gone_in="21.0", issue=7554)
            hidden_url = hide_url(self.link.url)
            if obtain:
                vcs_backend.obtain(self.source_dir, url=hidden_url)
            else:
                vcs_backend.export(self.source_dir, url=hidden_url)
        else:
            assert 0, (
                'Unexpected version control type (in {}): {}'.format(
                    self.link, vc_type))

    # Top-level Actions
    def uninstall(self, auto_confirm=False, verbose=False):
        # type: (bool, bool) -> Optional[UninstallPathSet]
        """
        Uninstall the distribution currently satisfying this requirement.

        Prompts before removing or modifying files unless
        ``auto_confirm`` is True.

        Refuses to delete or modify files outside of ``sys.prefix`` -
        thus uninstallation within a virtual environment can only
        modify that virtual environment, even if the virtualenv is
        linked to global site-packages.

        """
        assert self.req
        dist = get_distribution(self.req.name)
        if not dist:
            logger.warning("Skipping %s as it is not installed.", self.name)
            return None
        logger.info('Found existing installation: %s', dist)

        uninstalled_pathset = UninstallPathSet.from_dist(dist)
        uninstalled_pathset.remove(auto_confirm, verbose)
        return uninstalled_pathset

    def _get_archive_name(self, path, parentdir, rootdir):
        # type: (str, str, str) -> str

        def _clean_zip_name(name, prefix):
            # type: (str, str) -> str
            assert name.startswith(prefix + os.path.sep), (
                "name {name!r} doesn't start with prefix {prefix!r}"
                .format(**locals())
            )
            name = name[len(prefix) + 1:]
            name = name.replace(os.path.sep, '/')
            return name

        path = os.path.join(parentdir, path)
        name = _clean_zip_name(path, rootdir)
        return self.name + '/' + name

    def archive(self, build_dir):
        # type: (Optional[str]) -> None
        """Saves archive to provided build_dir.

        Used for saving downloaded VCS requirements as part of `pip download`.
        """
        assert self.source_dir
        if build_dir is None:
            return

        create_archive = True
        archive_name = '{}-{}.zip'.format(self.name, self.metadata["version"])
        archive_path = os.path.join(build_dir, archive_name)

        if os.path.exists(archive_path):
            response = ask_path_exists(
                'The file {} exists. (i)gnore, (w)ipe, '
                '(b)ackup, (a)bort '.format(
                    display_path(archive_path)),
                ('i', 'w', 'b', 'a'))
            if response == 'i':
                create_archive = False
            elif response == 'w':
                logger.warning('Deleting %s', display_path(archive_path))
                os.remove(archive_path)
            elif response == 'b':
                dest_file = backup_dir(archive_path)
                logger.warning(
                    'Backing up %s to %s',
                    display_path(archive_path),
                    display_path(dest_file),
                )
                shutil.move(archive_path, dest_file)
            elif response == 'a':
                sys.exit(-1)

        if not create_archive:
            return

        zip_output = zipfile.ZipFile(
            archive_path, 'w', zipfile.ZIP_DEFLATED, allowZip64=True,
        )
        with zip_output:
            dir = os.path.normcase(
                os.path.abspath(self.unpacked_source_directory)
            )
            for dirpath, dirnames, filenames in os.walk(dir):
                for dirname in dirnames:
                    dir_arcname = self._get_archive_name(
                        dirname, parentdir=dirpath, rootdir=dir,
                    )
                    zipdir = zipfile.ZipInfo(dir_arcname + '/')
                    zipdir.external_attr = 0x1ED << 16  # 0o755
                    zip_output.writestr(zipdir, '')
                for filename in filenames:
                    file_arcname = self._get_archive_name(
                        filename, parentdir=dirpath, rootdir=dir,
                    )
                    filename = os.path.join(dirpath, filename)
                    zip_output.write(filename, file_arcname)

        logger.info('Saved %s', display_path(archive_path))

    def install(
        self,
        install_options,  # type: List[str]
        global_options=None,  # type: Optional[Sequence[str]]
        root=None,  # type: Optional[str]
        home=None,  # type: Optional[str]
        prefix=None,  # type: Optional[str]
        warn_script_location=True,  # type: bool
        use_user_site=False,  # type: bool
        pycompile=True  # type: bool
    ):
        # type: (...) -> None
        scheme = get_scheme(
            self.name,
            user=use_user_site,
            home=home,
            root=root,
            isolated=self.isolated,
            prefix=prefix,
        )

        global_options = global_options if global_options is not None else []
        if self.editable:
            install_editable_legacy(
                install_options,
                global_options,
                prefix=prefix,
                home=home,
                use_user_site=use_user_site,
                name=self.name,
                setup_py_path=self.setup_py_path,
                isolated=self.isolated,
                build_env=self.build_env,
                unpacked_source_directory=self.unpacked_source_directory,
            )
            self.install_succeeded = True
            return

        if self.is_wheel:
            assert self.local_file_path
            direct_url = None
            if self.original_link:
                direct_url = direct_url_from_link(
                    self.original_link,
                    self.source_dir,
                    self.original_link_is_in_wheel_cache,
                )
            install_wheel(
                self.name,
                self.local_file_path,
                scheme=scheme,
                req_description=str(self.req),
                pycompile=pycompile,
                warn_script_location=warn_script_location,
                direct_url=direct_url,
                requested=self.user_supplied,
            )
            self.install_succeeded = True
            return

        # TODO: Why don't we do this for editable installs?

        # Extend the list of global and install options passed on to
        # the setup.py call with the ones from the requirements file.
        # Options specified in requirements file override those
        # specified on the command line, since the last option given
        # to setup.py is the one that is used.
        global_options = list(global_options) + self.global_options
        install_options = list(install_options) + self.install_options

        try:
            success = install_legacy(
                install_options=install_options,
                global_options=global_options,
                root=root,
                home=home,
                prefix=prefix,
                use_user_site=use_user_site,
                pycompile=pycompile,
                scheme=scheme,
                setup_py_path=self.setup_py_path,
                isolated=self.isolated,
                req_name=self.name,
                build_env=self.build_env,
                unpacked_source_directory=self.unpacked_source_directory,
                req_description=str(self.req),
            )
        except LegacyInstallFailure as exc:
            self.install_succeeded = False
            six.reraise(*exc.parent)
        except Exception:
            self.install_succeeded = True
            raise

        self.install_succeeded = success

        if success and self.legacy_install_reason == 8368:
            deprecated(
                reason=(
                    "{} was installed using the legacy 'setup.py install' "
                    "method, because a wheel could not be built for it.".
                    format(self.name)
                ),
                replacement="to fix the wheel build issue reported above",
                gone_in="21.0",
                issue=8368,
            )


def check_invalid_constraint_type(req):
    # type: (InstallRequirement) -> str

    # Check for unsupported forms
    problem = ""
    if not req.name:
        problem = "Unnamed requirements are not allowed as constraints"
    elif req.link:
        problem = "Links are not allowed as constraints"
    elif req.extras:
        problem = "Constraints cannot have extras"

    if problem:
        deprecated(
            reason=(
                "Constraints are only allowed to take the form of a package "
                "name and a version specifier. Other forms were originally "
                "permitted as an accident of the implementation, but were "
                "undocumented. The new implementation of the resolver no "
                "longer supports these forms."
            ),
            replacement=(
                "replacing the constraint with a requirement."
            ),
            # No plan yet for when the new resolver becomes default
            gone_in=None,
            issue=8210
        )

    return problem
