Ejemplo n.º 1
0
        def make_data_scheme_file(record_path):
            # type: (RecordPath) -> File
            normed_path = os.path.normpath(record_path)
            try:
                _, scheme_key, dest_subpath = normed_path.split(os.path.sep, 2)
            except ValueError:
                message = (
                    "Unexpected file in {}: {!r}. .data directory contents"
                    " should be named like: '<scheme key>/<path>'.").format(
                        wheel_path, record_path)
                raise InstallationError(message)

            try:
                scheme_path = scheme_paths[scheme_key]
            except KeyError:
                valid_scheme_keys = ", ".join(sorted(scheme_paths))
                message = (
                    "Unknown scheme key used in {}: {} (for file {!r}). .data"
                    " directory contents should be in subdirectories named"
                    " with a valid scheme key ({})").format(
                        wheel_path, scheme_key, record_path, valid_scheme_keys)
                raise InstallationError(message)

            dest_path = os.path.join(scheme_path, dest_subpath)
            assert_no_path_traversal(scheme_path, dest_path)
            return ZipBackedFile(record_path, dest_path, zip_file)
Ejemplo n.º 2
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def install_req_from_req_string(
        req_string,  # type: str
        comes_from=None,  # type: Optional[InstallRequirement]
        isolated=False,  # type: bool
        use_pep517=None,  # type: Optional[bool]
        user_supplied=False,  # type: bool
):
    # type: (...) -> InstallRequirement
    try:
        req = Requirement(req_string)
    except InvalidRequirement:
        raise InstallationError("Invalid requirement: '{}'".format(req_string))

    domains_not_allowed = [
        PyPI.file_storage_domain,
        TestPyPI.file_storage_domain,
    ]
    if (req.url and comes_from and comes_from.link
            and comes_from.link.netloc in domains_not_allowed):
        # Explicitly disallow pypi packages that depend on external urls
        raise InstallationError(
            "Packages installed from PyPI cannot depend on packages "
            "which are not also hosted on PyPI.\n"
            "{} depends on {} ".format(comes_from.name, req))

    return InstallRequirement(
        req,
        comes_from,
        isolated=isolated,
        use_pep517=use_pep517,
        user_supplied=user_supplied,
    )
Ejemplo n.º 3
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 def assert_no_path_traversal(dest_dir_path, target_path):
     # type: (text_type, text_type) -> None
     if not is_within_directory(dest_dir_path, target_path):
         message = ("The wheel {!r} has a file {!r} trying to install"
                    " outside the target directory {!r}")
         raise InstallationError(
             message.format(wheel_path, target_path, dest_dir_path))
Ejemplo n.º 4
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def _get_url_from_path(path, name):
    # type: (str, str) -> Optional[str]
    """
    First, it checks whether a provided path is an installable directory
    (e.g. it has a setup.py). If it is, returns the path.

    If false, check if the path is an archive file (such as a .whl).
    The function checks if the path is a file. If false, if the path has
    an @, it will treat it as a PEP 440 URL requirement and return the path.
    """
    if _looks_like_path(name) and os.path.isdir(path):
        if is_installable_dir(path):
            return path_to_url(path)
        raise InstallationError(
            "Directory {name!r} is not installable. Neither 'setup.py' "
            "nor 'pyproject.toml' found.".format(**locals()))
    if not is_archive_file(path):
        return None
    if os.path.isfile(path):
        return path_to_url(path)
    urlreq_parts = name.split('@', 1)
    if len(urlreq_parts) >= 2 and not _looks_like_path(urlreq_parts[0]):
        # If the path contains '@' and the part before it does not look
        # like a path, try to treat it as a PEP 440 URL req instead.
        return None
    logger.warning(
        'Requirement %r looks like a filename, but the '
        'file does not exist', name)
    return path_to_url(path)
Ejemplo n.º 5
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    def prepare_editable_requirement(
            self,
            req,  # type: InstallRequirement
    ):
        # type: (...) -> Distribution
        """Prepare an editable requirement
        """
        assert req.editable, "cannot prepare a non-editable req as editable"

        logger.info('Obtaining %s', req)

        with indent_log():
            if self.require_hashes:
                raise InstallationError(
                    'The editable requirement {} cannot be installed when '
                    'requiring hashes, because there is no single file to '
                    'hash.'.format(req))
            req.ensure_has_source_dir(self.src_dir)
            req.update_editable(not self._download_should_save)

            dist = _get_prepared_distribution(
                req,
                self.req_tracker,
                self.finder,
                self.build_isolation,
            )

            if self._download_should_save:
                req.archive(self.download_dir)
            req.check_if_exists(self.use_user_site)

        return dist
Ejemplo n.º 6
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    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
Ejemplo n.º 7
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    def get_url_rev_and_auth(cls, url):
        # type: (str) -> Tuple[str, Optional[str], AuthInfo]
        """
        Parse the repository URL to use, and return the URL, revision,
        and auth info to use.

        Returns: (url, rev, (username, password)).
        """
        scheme, netloc, path, query, frag = urllib_parse.urlsplit(url)
        if '+' not in scheme:
            raise ValueError(
                "Sorry, {!r} is a malformed VCS url. "
                "The format is <vcs>+<protocol>://<url>, "
                "e.g. svn+http://myrepo/svn/MyApp#egg=MyApp".format(url))
        # Remove the vcs prefix.
        scheme = scheme.split('+', 1)[1]
        netloc, user_pass = cls.get_netloc_and_auth(netloc, scheme)
        rev = None
        if '@' in path:
            path, rev = path.rsplit('@', 1)
            if not rev:
                raise InstallationError(
                    "The URL {!r} has an empty revision (after @) "
                    "which is not supported. Include a revision after @ "
                    "or remove @ from the URL.".format(url))
        url = urllib_parse.urlunsplit((scheme, netloc, path, query, ''))
        return url, rev, user_pass
Ejemplo n.º 8
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def req_error_context(req_description):
    # type: (str) -> Iterator[None]
    try:
        yield
    except InstallationError as e:
        message = "For req: {}. {}".format(req_description, e.args[0])
        reraise(InstallationError, InstallationError(message),
                sys.exc_info()[2])
Ejemplo n.º 9
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def decide_user_install(
    use_user_site,  # type: Optional[bool]
    prefix_path=None,  # type: Optional[str]
    target_dir=None,  # type: Optional[str]
    root_path=None,  # type: Optional[str]
    isolated_mode=False,  # type: bool
):
    # type: (...) -> bool
    """Determine whether to do a user install based on the input options.

    If use_user_site is False, no additional checks are done.
    If use_user_site is True, it is checked for compatibility with other
    options.
    If use_user_site is None, the default behaviour depends on the environment,
    which is provided by the other arguments.
    """
    # In some cases (config from tox), use_user_site can be set to an integer
    # rather than a bool, which 'use_user_site is False' wouldn't catch.
    if (use_user_site is not None) and (not use_user_site):
        logger.debug("Non-user install by explicit request")
        return False

    if use_user_site:
        if prefix_path:
            raise CommandError(
                "Can not combine '--user' and '--prefix' as they imply "
                "different installation locations"
            )
        if virtualenv_no_global():
            raise InstallationError(
                "Can not perform a '--user' install. User site-packages "
                "are not visible in this virtualenv."
            )
        logger.debug("User install by explicit request")
        return True

    # If we are here, user installs have not been explicitly requested/avoided
    assert use_user_site is None

    # user install incompatible with --prefix/--target
    if prefix_path or target_dir:
        logger.debug("Non-user install due to --prefix or --target option")
        return False

    # If user installs are not enabled, choose a non-user install
    if not site.ENABLE_USER_SITE:
        logger.debug("Non-user install because user site-packages disabled")
        return False

    # If we have permission for a non-user install, do that,
    # otherwise do a user install.
    if site_packages_writable(root=root_path, isolated=isolated_mode):
        logger.debug("Non-user install because site-packages writeable")
        return False

    logger.info("Defaulting to user installation because normal site-packages "
                "is not writeable")
    return True
Ejemplo n.º 10
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    def _prepare_linked_requirement(self, req, parallel_builds):
        # type: (InstallRequirement, bool) -> Distribution
        assert req.link
        link = req.link
        download_dir = self._get_download_dir(link)

        with indent_log():
            self._ensure_link_req_src_dir(req, download_dir, parallel_builds)
            hashes = self._get_linked_req_hashes(req)
            if link.url not in self._downloaded:
                try:
                    local_file = unpack_url(
                        link,
                        req.source_dir,
                        self._download,
                        download_dir,
                        hashes,
                    )
                except NetworkConnectionError as exc:
                    raise InstallationError(
                        'Could not install requirement {} because of HTTP '
                        'error {} for URL {}'.format(req, exc, link))
            else:
                file_path, content_type = self._downloaded[link.url]
                if hashes:
                    hashes.check_against_path(file_path)
                local_file = File(file_path, content_type)

            # For use in later processing, preserve the file path on the
            # requirement.
            if local_file:
                req.local_file_path = local_file.path

            dist = _get_prepared_distribution(
                req,
                self.req_tracker,
                self.finder,
                self.build_isolation,
            )

            if download_dir:
                if link.is_existing_dir():
                    logger.info('Link is a directory, ignoring download_dir')
                elif local_file:
                    download_location = os.path.join(download_dir,
                                                     link.filename)
                    if not os.path.exists(download_location):
                        shutil.copy(local_file.path, download_location)
                        download_path = display_path(download_location)
                        logger.info('Saved %s', download_path)

            if self._download_should_save:
                # Make a .zip of the source_dir we already created.
                if link.is_vcs:
                    req.archive(self.download_dir)
        return dist
Ejemplo n.º 11
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    def _download_should_save(self):
        # type: () -> bool
        if not self.download_dir:
            return False

        if os.path.exists(self.download_dir):
            return True

        logger.critical('Could not find download directory')
        raise InstallationError(
            "Could not find or access download directory '{}'".format(
                self.download_dir))
Ejemplo n.º 12
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 def _raise_conflicts(conflicting_with, conflicting_reqs):
     # type: (str, Set[Tuple[str, str]]) -> None
     format_string = (
         "Some build dependencies for {requirement} "
         "conflict with {conflicting_with}: {description}.")
     error_message = format_string.format(
         requirement=self.req,
         conflicting_with=conflicting_with,
         description=', '.join(
             '{} is incompatible with {}'.format(installed, wanted)
             for installed, wanted in sorted(conflicting)))
     raise InstallationError(error_message)
Ejemplo n.º 13
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def get_file_content(url, session, comes_from=None):
    # type: (str, PipSession, Optional[str]) -> Tuple[str, Text]
    """Gets the content of a file; it may be a filename, file: URL, or
    http: URL.  Returns (location, content).  Content is unicode.
    Respects # -*- coding: declarations on the retrieved files.

    :param url:         File path or url.
    :param session:     PipSession instance.
    :param comes_from:  Origin description of requirements.
    """
    scheme = get_url_scheme(url)

    if scheme in ['http', 'https']:
        # FIXME: catch some errors
        resp = session.get(url)
        raise_for_status(resp)
        return resp.url, resp.text

    elif scheme == 'file':
        if comes_from and comes_from.startswith('http'):
            raise InstallationError('Requirements file {} references URL {}, '
                                    'which is local'.format(comes_from, url))

        path = url.split(':', 1)[1]
        path = path.replace('\\', '/')
        match = _url_slash_drive_re.match(path)
        if match:
            path = match.group(1) + ':' + path.split('|', 1)[1]
        path = urllib_parse.unquote(path)
        if path.startswith('/'):
            path = '/' + path.lstrip('/')
        url = path

    try:
        with open(url, 'rb') as f:
            content = auto_decode(f.read())
    except IOError as exc:
        raise InstallationError(
            'Could not open requirements file: {}'.format(exc))
    return url, content
Ejemplo n.º 14
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def parse_req_from_editable(editable_req):
    # type: (str) -> RequirementParts
    name, url, extras_override = parse_editable(editable_req)

    if name is not None:
        try:
            req = Requirement(name)
        except InvalidRequirement:
            raise InstallationError("Invalid requirement: '{}'".format(name))
    else:
        req = None

    link = Link(url)

    return RequirementParts(req, link, None, extras_override)
Ejemplo n.º 15
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def unzip_file(filename, location, flatten=True):
    # type: (str, str, bool) -> None
    """
    Unzip the file (with path `filename`) to the destination `location`.  All
    files are written based on system defaults and umask (i.e. permissions are
    not preserved), except that regular file members with any execute
    permissions (user, group, or world) have "chmod +x" applied after being
    written. Note that for windows, any execute changes using os.chmod are
    no-ops per the python docs.
    """
    ensure_dir(location)
    zipfp = open(filename, 'rb')
    try:
        zip = zipfile.ZipFile(zipfp, allowZip64=True)
        leading = has_leading_dir(zip.namelist()) and flatten
        for info in zip.infolist():
            name = info.filename
            fn = name
            if leading:
                fn = split_leading_dir(name)[1]
            fn = os.path.join(location, fn)
            dir = os.path.dirname(fn)
            if not is_within_directory(location, fn):
                message = (
                    'The zip file ({}) has a file ({}) trying to install '
                    'outside target directory ({})'
                )
                raise InstallationError(message.format(filename, fn, location))
            if fn.endswith('/') or fn.endswith('\\'):
                # A directory
                ensure_dir(fn)
            else:
                ensure_dir(dir)
                # Don't use read() to avoid allocating an arbitrarily large
                # chunk of memory for the file's content
                fp = zip.open(name)
                try:
                    with open(fn, 'wb') as destfp:
                        shutil.copyfileobj(fp, destfp)
                finally:
                    fp.close()
                    if zip_item_is_executable(info):
                        set_extracted_file_to_default_mode_plus_executable(fn)
    finally:
        zipfp.close()
Ejemplo n.º 16
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    def run(self, options, args):
        # type: (Values, List[str]) -> int
        session = self.get_default_session(options)

        reqs_to_uninstall = {}
        for name in args:
            req = install_req_from_line(
                name,
                isolated=options.isolated_mode,
            )
            if req.name:
                reqs_to_uninstall[canonicalize_name(req.name)] = req
        for filename in options.requirements:
            for parsed_req in parse_requirements(filename,
                                                 options=options,
                                                 session=session):
                req = install_req_from_parsed_requirement(
                    parsed_req, isolated=options.isolated_mode)
                if req.name:
                    reqs_to_uninstall[canonicalize_name(req.name)] = req
        if not reqs_to_uninstall:
            raise InstallationError(
                'You must give at least one requirement to {self.name} (see '
                '"pip help {self.name}")'.format(**locals()))

        protect_pip_from_modification_on_windows(
            modifying_pip="pip" in reqs_to_uninstall)

        for req in reqs_to_uninstall.values():
            uninstall_pathset = req.uninstall(
                auto_confirm=options.yes,
                verbose=self.verbosity > 0,
            )
            if uninstall_pathset:
                uninstall_pathset.commit()

        return SUCCESS
Ejemplo n.º 17
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def unpack_file(
        filename,  # type: str
        location,  # type: str
        content_type=None,  # type: Optional[str]
):
    # type: (...) -> None
    filename = os.path.realpath(filename)
    if (
        content_type == 'application/zip' or
        filename.lower().endswith(ZIP_EXTENSIONS) or
        zipfile.is_zipfile(filename)
    ):
        unzip_file(
            filename,
            location,
            flatten=not filename.endswith('.whl')
        )
    elif (
        content_type == 'application/x-gzip' or
        tarfile.is_tarfile(filename) or
        filename.lower().endswith(
            TAR_EXTENSIONS + BZ2_EXTENSIONS + XZ_EXTENSIONS
        )
    ):
        untar_file(filename, location)
    else:
        # FIXME: handle?
        # FIXME: magic signatures?
        logger.critical(
            'Cannot unpack file %s (downloaded from %s, content-type: %s); '
            'cannot detect archive format',
            filename, location, content_type,
        )
        raise InstallationError(
            'Cannot determine archive format of {}'.format(location)
        )
Ejemplo n.º 18
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    def check_against_chunks(self, chunks):
        # type: (Iterator[bytes]) -> None
        """Check good hashes against ones built from iterable of chunks of
        data.

        Raise HashMismatch if none match.

        """
        gots = {}
        for hash_name in iterkeys(self._allowed):
            try:
                gots[hash_name] = hashlib.new(hash_name)
            except (ValueError, TypeError):
                raise InstallationError(
                    'Unknown hash name: {}'.format(hash_name))

        for chunk in chunks:
            for hash in itervalues(gots):
                hash.update(chunk)

        for hash_name, got in iteritems(gots):
            if got.hexdigest() in self._allowed[hash_name]:
                return
        self._raise(gots)
Ejemplo n.º 19
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def parse_editable(editable_req):
    # type: (str) -> Tuple[Optional[str], str, Set[str]]
    """Parses an editable requirement into:
        - a requirement name
        - an URL
        - extras
        - editable options
    Accepted requirements:
        svn+http://blahblah@rev#egg=Foobar[baz]&subdirectory=version_subdir
        .[some_extra]
    """

    url = editable_req

    # If a file path is specified with extras, strip off the extras.
    url_no_extras, extras = _strip_extras(url)

    if os.path.isdir(url_no_extras):
        if not os.path.exists(os.path.join(url_no_extras, 'setup.py')):
            msg = ('File "setup.py" not found. Directory cannot be installed '
                   'in editable mode: {}'.format(
                       os.path.abspath(url_no_extras)))
            pyproject_path = make_pyproject_path(url_no_extras)
            if os.path.isfile(pyproject_path):
                msg += ('\n(A "pyproject.toml" file was found, but editable '
                        'mode currently requires a setup.py based build.)')
            raise InstallationError(msg)

        # Treating it as code that has already been checked out
        url_no_extras = path_to_url(url_no_extras)

    if url_no_extras.lower().startswith('file:'):
        package_name = Link(url_no_extras).egg_fragment
        if extras:
            return (
                package_name,
                url_no_extras,
                Requirement("placeholder" + extras.lower()).extras,
            )
        else:
            return package_name, url_no_extras, set()

    for version_control in vcs:
        if url.lower().startswith('{}:'.format(version_control)):
            url = '{}+{}'.format(version_control, url)
            break

    if '+' not in url:
        raise InstallationError(
            '{} is not a valid editable requirement. '
            'It should either be a path to a local project or a VCS URL '
            '(beginning with svn+, git+, hg+, or bzr+).'.format(editable_req))

    vc_type = url.split('+', 1)[0].lower()

    if not vcs.get_backend(vc_type):
        backends = ", ".join([bends.name + '+URL' for bends in vcs.backends])
        error_message = "For --editable={}, " \
                        "only {} are currently supported".format(
                            editable_req, backends)
        raise InstallationError(error_message)

    package_name = Link(url).egg_fragment
    if not package_name:
        raise InstallationError(
            "Could not detect requirement name for '{}', please specify one "
            "with #egg=your_package_name".format(editable_req))
    return package_name, url, set()
Ejemplo n.º 20
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def load_pyproject_toml(
    use_pep517,  # type: Optional[bool]
    pyproject_toml,  # type: str
    setup_py,  # type: str
    req_name  # type: str
):
    # type: (...) -> Optional[BuildSystemDetails]
    """Load the pyproject.toml file.

    Parameters:
        use_pep517 - Has the user requested PEP 517 processing? None
                     means the user hasn't explicitly specified.
        pyproject_toml - Location of the project's pyproject.toml file
        setup_py - Location of the project's setup.py file
        req_name - The name of the requirement we're processing (for
                   error reporting)

    Returns:
        None if we should use the legacy code path, otherwise a tuple
        (
            requirements from pyproject.toml,
            name of PEP 517 backend,
            requirements we should check are installed after setting
                up the build environment
            directory paths to import the backend from (backend-path),
                relative to the project root.
        )
    """
    has_pyproject = os.path.isfile(pyproject_toml)
    has_setup = os.path.isfile(setup_py)

    if has_pyproject:
        with io.open(pyproject_toml, encoding="utf-8") as f:
            pp_toml = toml.load(f)
        build_system = pp_toml.get("build-system")
    else:
        build_system = None

    # The following cases must use PEP 517
    # We check for use_pep517 being non-None and falsey because that means
    # the user explicitly requested --no-use-pep517.  The value 0 as
    # opposed to False can occur when the value is provided via an
    # environment variable or config file option (due to the quirk of
    # strtobool() returning an integer in pip's configuration code).
    if has_pyproject and not has_setup:
        if use_pep517 is not None and not use_pep517:
            raise InstallationError(
                "Disabling PEP 517 processing is invalid: "
                "project does not have a setup.py"
            )
        use_pep517 = True
    elif build_system and "build-backend" in build_system:
        if use_pep517 is not None and not use_pep517:
            raise InstallationError(
                "Disabling PEP 517 processing is invalid: "
                "project specifies a build backend of {} "
                "in pyproject.toml".format(
                    build_system["build-backend"]
                )
            )
        use_pep517 = True

    # If we haven't worked out whether to use PEP 517 yet,
    # and the user hasn't explicitly stated a preference,
    # we do so if the project has a pyproject.toml file.
    elif use_pep517 is None:
        use_pep517 = has_pyproject

    # At this point, we know whether we're going to use PEP 517.
    assert use_pep517 is not None

    # If we're using the legacy code path, there is nothing further
    # for us to do here.
    if not use_pep517:
        return None

    if build_system is None:
        # Either the user has a pyproject.toml with no build-system
        # section, or the user has no pyproject.toml, but has opted in
        # explicitly via --use-pep517.
        # In the absence of any explicit backend specification, we
        # assume the setuptools backend that most closely emulates the
        # traditional direct setup.py execution, and require wheel and
        # a version of setuptools that supports that backend.

        build_system = {
            "requires": ["setuptools>=40.8.0", "wheel"],
            "build-backend": "setuptools.build_meta:__legacy__",
        }

    # If we're using PEP 517, we have build system information (either
    # from pyproject.toml, or defaulted by the code above).
    # Note that at this point, we do not know if the user has actually
    # specified a backend, though.
    assert build_system is not None

    # Ensure that the build-system section in pyproject.toml conforms
    # to PEP 518.
    error_template = (
        "{package} has a pyproject.toml file that does not comply "
        "with PEP 518: {reason}"
    )

    # Specifying the build-system table but not the requires key is invalid
    if "requires" not in build_system:
        raise InstallationError(
            error_template.format(package=req_name, reason=(
                "it has a 'build-system' table but not "
                "'build-system.requires' which is mandatory in the table"
            ))
        )

    # Error out if requires is not a list of strings
    requires = build_system["requires"]
    if not _is_list_of_str(requires):
        raise InstallationError(error_template.format(
            package=req_name,
            reason="'build-system.requires' is not a list of strings.",
        ))

    # Each requirement must be valid as per PEP 508
    for requirement in requires:
        try:
            Requirement(requirement)
        except InvalidRequirement:
            raise InstallationError(
                error_template.format(
                    package=req_name,
                    reason=(
                        "'build-system.requires' contains an invalid "
                        "requirement: {!r}".format(requirement)
                    ),
                )
            )

    backend = build_system.get("build-backend")
    backend_path = build_system.get("backend-path", [])
    check = []  # type: List[str]
    if backend is None:
        # If the user didn't specify a backend, we assume they want to use
        # the setuptools backend. But we can't be sure they have included
        # a version of setuptools which supplies the backend, or wheel
        # (which is needed by the backend) in their requirements. So we
        # make a note to check that those requirements are present once
        # we have set up the environment.
        # This is quite a lot of work to check for a very specific case. But
        # the problem is, that case is potentially quite common - projects that
        # adopted PEP 518 early for the ability to specify requirements to
        # execute setup.py, but never considered needing to mention the build
        # tools themselves. The original PEP 518 code had a similar check (but
        # implemented in a different way).
        backend = "setuptools.build_meta:__legacy__"
        check = ["setuptools>=40.8.0", "wheel"]

    return BuildSystemDetails(requires, backend, check, backend_path)
Ejemplo n.º 21
0
def parse_req_from_line(name, line_source):
    # type: (str, Optional[str]) -> RequirementParts
    if is_url(name):
        marker_sep = '; '
    else:
        marker_sep = ';'
    if marker_sep in name:
        name, markers_as_string = name.split(marker_sep, 1)
        markers_as_string = markers_as_string.strip()
        if not markers_as_string:
            markers = None
        else:
            markers = Marker(markers_as_string)
    else:
        markers = None
    name = name.strip()
    req_as_string = None
    path = os.path.normpath(os.path.abspath(name))
    link = None
    extras_as_string = None

    if is_url(name):
        link = Link(name)
    else:
        p, extras_as_string = _strip_extras(path)
        url = _get_url_from_path(p, name)
        if url is not None:
            link = Link(url)

    # it's a local file, dir, or url
    if link:
        # Handle relative file URLs
        if link.scheme == 'file' and re.search(r'\.\./', link.url):
            link = Link(
                path_to_url(os.path.normpath(os.path.abspath(link.path))))
        # wheel file
        if link.is_wheel:
            wheel = Wheel(link.filename)  # can raise InvalidWheelFilename
            req_as_string = "{wheel.name}=={wheel.version}".format(**locals())
        else:
            # set the req to the egg fragment.  when it's not there, this
            # will become an 'unnamed' requirement
            req_as_string = link.egg_fragment

    # a requirement specifier
    else:
        req_as_string = name

    extras = convert_extras(extras_as_string)

    def with_source(text):
        # type: (str) -> str
        if not line_source:
            return text
        return '{} (from {})'.format(text, line_source)

    if req_as_string is not None:
        try:
            req = Requirement(req_as_string)
        except InvalidRequirement:
            if os.path.sep in req_as_string:
                add_msg = "It looks like a path."
                add_msg += deduce_helpful_msg(req_as_string)
            elif ('=' in req_as_string
                  and not any(op in req_as_string for op in operators)):
                add_msg = "= is not a valid operator. Did you mean == ?"
            else:
                add_msg = ''
            msg = with_source(
                'Invalid requirement: {!r}'.format(req_as_string))
            if add_msg:
                msg += '\nHint: {}'.format(add_msg)
            raise InstallationError(msg)
        else:
            # Deprecate extras after specifiers: "name>=1.0[extras]"
            # This currently works by accident because _strip_extras() parses
            # any extras in the end of the string and those are saved in
            # RequirementParts
            for spec in req.specifier:
                spec_str = str(spec)
                if spec_str.endswith(']'):
                    msg = "Extras after version '{}'.".format(spec_str)
                    replace = "moving the extras before version specifiers"
                    deprecated(msg, replacement=replace, gone_in="21.0")
    else:
        req = None

    return RequirementParts(req, link, markers, extras)
Ejemplo n.º 22
0
def install(
        install_options,  # type: List[str]
        global_options,  # type: Sequence[str]
        root,  # type: Optional[str]
        home,  # type: Optional[str]
        prefix,  # type: Optional[str]
        use_user_site,  # type: bool
        pycompile,  # type: bool
        scheme,  # type: Scheme
        setup_py_path,  # type: str
        isolated,  # type: bool
        req_name,  # type: str
        build_env,  # type: BuildEnvironment
        unpacked_source_directory,  # type: str
        req_description,  # type: str
):
    # type: (...) -> bool

    header_dir = scheme.headers

    with TempDirectory(kind="record") as temp_dir:
        try:
            record_filename = os.path.join(temp_dir.path, 'install-record.txt')
            install_args = make_setuptools_install_args(
                setup_py_path,
                global_options=global_options,
                install_options=install_options,
                record_filename=record_filename,
                root=root,
                prefix=prefix,
                header_dir=header_dir,
                home=home,
                use_user_site=use_user_site,
                no_user_config=isolated,
                pycompile=pycompile,
            )

            runner = runner_with_spinner_message(
                "Running setup.py install for {}".format(req_name))
            with indent_log(), build_env:
                runner(
                    cmd=install_args,
                    cwd=unpacked_source_directory,
                )

            if not os.path.exists(record_filename):
                logger.debug('Record file %s not found', record_filename)
                # Signal to the caller that we didn't install the new package
                return False

        except Exception:
            # Signal to the caller that we didn't install the new package
            raise LegacyInstallFailure

        # At this point, we have successfully installed the requirement.

        # We intentionally do not use any encoding to read the file because
        # setuptools writes the file using distutils.file_util.write_file,
        # which does not specify an encoding.
        with open(record_filename) as f:
            record_lines = f.read().splitlines()

    def prepend_root(path):
        # type: (str) -> str
        if root is None or not os.path.isabs(path):
            return path
        else:
            return change_root(root, path)

    for line in record_lines:
        directory = os.path.dirname(line)
        if directory.endswith('.egg-info'):
            egg_info_dir = prepend_root(directory)
            break
    else:
        message = ("{} did not indicate that it installed an "
                   ".egg-info directory. Only setup.py projects "
                   "generating .egg-info directories are supported."
                   ).format(req_description)
        raise InstallationError(message)

    new_lines = []
    for line in record_lines:
        filename = line.strip()
        if os.path.isdir(filename):
            filename += os.path.sep
        new_lines.append(os.path.relpath(prepend_root(filename), egg_info_dir))
    new_lines.sort()
    ensure_dir(egg_info_dir)
    inst_files_path = os.path.join(egg_info_dir, 'installed-files.txt')
    with open(inst_files_path, 'w') as f:
        f.write('\n'.join(new_lines) + '\n')

    return True
Ejemplo n.º 23
0
def untar_file(filename, location):
    # type: (str, str) -> None
    """
    Untar the file (with path `filename`) to the destination `location`.
    All files are written based on system defaults and umask (i.e. permissions
    are not preserved), except that regular file members with any execute
    permissions (user, group, or world) have "chmod +x" applied after being
    written.  Note that for windows, any execute changes using os.chmod are
    no-ops per the python docs.
    """
    ensure_dir(location)
    if filename.lower().endswith('.gz') or filename.lower().endswith('.tgz'):
        mode = 'r:gz'
    elif filename.lower().endswith(BZ2_EXTENSIONS):
        mode = 'r:bz2'
    elif filename.lower().endswith(XZ_EXTENSIONS):
        mode = 'r:xz'
    elif filename.lower().endswith('.tar'):
        mode = 'r'
    else:
        logger.warning(
            'Cannot determine compression type for file %s', filename,
        )
        mode = 'r:*'
    tar = tarfile.open(filename, mode)
    try:
        leading = has_leading_dir([
            member.name for member in tar.getmembers()
        ])
        for member in tar.getmembers():
            fn = member.name
            if leading:
                # https://github.com/python/mypy/issues/1174
                fn = split_leading_dir(fn)[1]  # type: ignore
            path = os.path.join(location, fn)
            if not is_within_directory(location, path):
                message = (
                    'The tar file ({}) has a file ({}) trying to install '
                    'outside target directory ({})'
                )
                raise InstallationError(
                    message.format(filename, path, location)
                )
            if member.isdir():
                ensure_dir(path)
            elif member.issym():
                try:
                    # https://github.com/python/typeshed/issues/2673
                    tar._extract_member(member, path)  # type: ignore
                except Exception as exc:
                    # Some corrupt tar files seem to produce this
                    # (specifically bad symlinks)
                    logger.warning(
                        'In the tar file %s the member %s is invalid: %s',
                        filename, member.name, exc,
                    )
                    continue
            else:
                try:
                    fp = tar.extractfile(member)
                except (KeyError, AttributeError) as exc:
                    # Some corrupt tar files seem to produce this
                    # (specifically bad symlinks)
                    logger.warning(
                        'In the tar file %s the member %s is invalid: %s',
                        filename, member.name, exc,
                    )
                    continue
                ensure_dir(os.path.dirname(path))
                assert fp is not None
                with open(path, 'wb') as destfp:
                    shutil.copyfileobj(fp, destfp)
                fp.close()
                # Update the timestamp (useful for cython compiled files)
                # https://github.com/python/typeshed/issues/2673
                tar.utime(member, path)  # type: ignore
                # member have any execute permissions for user/group/world?
                if member.mode & 0o111:
                    set_extracted_file_to_default_mode_plus_executable(path)
    finally:
        tar.close()
Ejemplo n.º 24
0
def call_subprocess(
    cmd,  # type: Union[List[str], CommandArgs]
    show_stdout=False,  # type: bool
    cwd=None,  # type: Optional[str]
    on_returncode='raise',  # type: str
    extra_ok_returncodes=None,  # type: Optional[Iterable[int]]
    command_desc=None,  # type: Optional[str]
    extra_environ=None,  # type: Optional[Mapping[str, Any]]
    unset_environ=None,  # type: Optional[Iterable[str]]
    spinner=None,  # type: Optional[SpinnerInterface]
    log_failed_cmd=True  # type: Optional[bool]
):
    # type: (...) -> Text
    """
    Args:
      show_stdout: if true, use INFO to log the subprocess's stderr and
        stdout streams.  Otherwise, use DEBUG.  Defaults to False.
      extra_ok_returncodes: an iterable of integer return codes that are
        acceptable, in addition to 0. Defaults to None, which means [].
      unset_environ: an iterable of environment variable names to unset
        prior to calling subprocess.Popen().
      log_failed_cmd: if false, failed commands are not logged, only raised.
    """
    if extra_ok_returncodes is None:
        extra_ok_returncodes = []
    if unset_environ is None:
        unset_environ = []
    # Most places in pip use show_stdout=False. What this means is--
    #
    # - We connect the child's output (combined stderr and stdout) to a
    #   single pipe, which we read.
    # - We log this output to stderr at DEBUG level as it is received.
    # - If DEBUG logging isn't enabled (e.g. if --verbose logging wasn't
    #   requested), then we show a spinner so the user can still see the
    #   subprocess is in progress.
    # - If the subprocess exits with an error, we log the output to stderr
    #   at ERROR level if it hasn't already been displayed to the console
    #   (e.g. if --verbose logging wasn't enabled).  This way we don't log
    #   the output to the console twice.
    #
    # If show_stdout=True, then the above is still done, but with DEBUG
    # replaced by INFO.
    if show_stdout:
        # Then log the subprocess output at INFO level.
        log_subprocess = subprocess_logger.info
        used_level = logging.INFO
    else:
        # Then log the subprocess output using DEBUG.  This also ensures
        # it will be logged to the log file (aka user_log), if enabled.
        log_subprocess = subprocess_logger.debug
        used_level = logging.DEBUG

    # Whether the subprocess will be visible in the console.
    showing_subprocess = subprocess_logger.getEffectiveLevel() <= used_level

    # Only use the spinner if we're not showing the subprocess output
    # and we have a spinner.
    use_spinner = not showing_subprocess and spinner is not None

    if command_desc is None:
        command_desc = format_command_args(cmd)

    log_subprocess("Running command %s", command_desc)
    env = os.environ.copy()
    if extra_environ:
        env.update(extra_environ)
    for name in unset_environ:
        env.pop(name, None)
    try:
        proc = subprocess.Popen(
            # Convert HiddenText objects to the underlying str.
            reveal_command_args(cmd),
            stderr=subprocess.STDOUT,
            stdin=subprocess.PIPE,
            stdout=subprocess.PIPE,
            cwd=cwd,
            env=env,
        )
        assert proc.stdin
        assert proc.stdout
        proc.stdin.close()
    except Exception as exc:
        if log_failed_cmd:
            subprocess_logger.critical(
                "Error %s while executing command %s",
                exc,
                command_desc,
            )
        raise
    all_output = []
    while True:
        # The "line" value is a unicode string in Python 2.
        line = console_to_str(proc.stdout.readline())
        if not line:
            break
        line = line.rstrip()
        all_output.append(line + '\n')

        # Show the line immediately.
        log_subprocess(line)
        # Update the spinner.
        if use_spinner:
            assert spinner
            spinner.spin()
    try:
        proc.wait()
    finally:
        if proc.stdout:
            proc.stdout.close()
    proc_had_error = (proc.returncode
                      and proc.returncode not in extra_ok_returncodes)
    if use_spinner:
        assert spinner
        if proc_had_error:
            spinner.finish("error")
        else:
            spinner.finish("done")
    if proc_had_error:
        if on_returncode == 'raise':
            if not showing_subprocess and log_failed_cmd:
                # Then the subprocess streams haven't been logged to the
                # console yet.
                msg = make_subprocess_output_error(
                    cmd_args=cmd,
                    cwd=cwd,
                    lines=all_output,
                    exit_status=proc.returncode,
                )
                subprocess_logger.error(msg)
            exc_msg = ('Command errored out with exit status {}: {} '
                       'Check the logs for full command output.').format(
                           proc.returncode, command_desc)
            raise InstallationError(exc_msg)
        elif on_returncode == 'warn':
            subprocess_logger.warning(
                'Command "%s" had error code %s in %s',
                command_desc,
                proc.returncode,
                cwd,
            )
        elif on_returncode == 'ignore':
            pass
        else:
            raise ValueError(
                'Invalid value: on_returncode={!r}'.format(on_returncode))
    return ''.join(all_output)
Ejemplo n.º 25
0
    def resolve(self, root_reqs, check_supported_wheels):
        # type: (List[InstallRequirement], bool) -> RequirementSet

        constraints = {}  # type: Dict[str, SpecifierSet]
        user_requested = set()  # type: Set[str]
        requirements = []
        for req in root_reqs:
            if req.constraint:
                # Ensure we only accept valid constraints
                problem = check_invalid_constraint_type(req)
                if problem:
                    raise InstallationError(problem)
                if not req.match_markers():
                    continue
                name = canonicalize_name(req.name)
                if name in constraints:
                    constraints[name] = constraints[name] & req.specifier
                else:
                    constraints[name] = req.specifier
            else:
                if req.user_supplied and req.name:
                    user_requested.add(canonicalize_name(req.name))
                r = self.factory.make_requirement_from_install_req(
                    req,
                    requested_extras=(),
                )
                if r is not None:
                    requirements.append(r)

        provider = PipProvider(
            factory=self.factory,
            constraints=constraints,
            ignore_dependencies=self.ignore_dependencies,
            upgrade_strategy=self.upgrade_strategy,
            user_requested=user_requested,
        )
        reporter = BaseReporter()
        resolver = RLResolver(provider, reporter)

        try:
            try_to_avoid_resolution_too_deep = 2000000
            self._result = resolver.resolve(
                requirements,
                max_rounds=try_to_avoid_resolution_too_deep,
            )

        except ResolutionImpossible as e:
            error = self.factory.get_installation_error(e)
            six.raise_from(error, e)

        req_set = RequirementSet(check_supported_wheels=check_supported_wheels)
        for candidate in self._result.mapping.values():
            ireq = candidate.get_install_requirement()
            if ireq is None:
                continue

            # Check if there is already an installation under the same name,
            # and set a flag for later stages to uninstall it, if needed.
            # * There isn't, good -- no uninstalltion needed.
            # * The --force-reinstall flag is set. Always reinstall.
            # * The installation is different in version or editable-ness, so
            #   we need to uninstall it to install the new distribution.
            # * The installed version is the same as the pending distribution.
            #   Skip this distrubiton altogether to save work.
            installed_dist = self.factory.get_dist_to_uninstall(candidate)
            if installed_dist is None:
                ireq.should_reinstall = False
            elif self.factory.force_reinstall:
                ireq.should_reinstall = True
            elif installed_dist.parsed_version != candidate.version:
                ireq.should_reinstall = True
            elif dist_is_editable(installed_dist) != candidate.is_editable:
                ireq.should_reinstall = True
            else:
                continue

            link = candidate.source_link
            if link and link.is_yanked:
                # The reason can contain non-ASCII characters, Unicode
                # is required for Python 2.
                msg = (
                    u'The candidate selected for download or install is a '
                    u'yanked version: {name!r} candidate (version {version} '
                    u'at {link})\nReason for being yanked: {reason}').format(
                        name=candidate.name,
                        version=candidate.version,
                        link=link,
                        reason=link.yanked_reason or u'<none given>',
                    )
                logger.warning(msg)

            req_set.add_named_requirement(ireq)

        reqs = req_set.all_requirements
        self.factory.preparer.prepare_linked_requirements_more(reqs)
        return req_set
Ejemplo n.º 26
0
    def run(self, options, args):
        # type: (Values, List[str]) -> int
        if options.use_user_site and options.target_dir is not None:
            raise CommandError("Can not combine '--user' and '--target'")

        cmdoptions.check_install_build_global(options)
        upgrade_strategy = "to-satisfy-only"
        if options.upgrade:
            upgrade_strategy = options.upgrade_strategy

        cmdoptions.check_dist_restriction(options, check_target=True)

        install_options = options.install_options or []

        logger.debug("Using %s", get_pip_version())
        options.use_user_site = decide_user_install(
            options.use_user_site,
            prefix_path=options.prefix_path,
            target_dir=options.target_dir,
            root_path=options.root_path,
            isolated_mode=options.isolated_mode,
        )

        target_temp_dir = None  # type: Optional[TempDirectory]
        target_temp_dir_path = None  # type: Optional[str]
        if options.target_dir:
            options.ignore_installed = True
            options.target_dir = os.path.abspath(options.target_dir)
            if (os.path.exists(options.target_dir) and not
                    os.path.isdir(options.target_dir)):
                raise CommandError(
                    "Target path exists but is not a directory, will not "
                    "continue."
                )

            # Create a target directory for using with the target option
            target_temp_dir = TempDirectory(kind="target")
            target_temp_dir_path = target_temp_dir.path
            self.enter_context(target_temp_dir)

        global_options = options.global_options or []

        session = self.get_default_session(options)

        target_python = make_target_python(options)
        finder = self._build_package_finder(
            options=options,
            session=session,
            target_python=target_python,
            ignore_requires_python=options.ignore_requires_python,
        )
        build_delete = (not (options.no_clean or options.build_dir))
        wheel_cache = WheelCache(options.cache_dir, options.format_control)

        req_tracker = self.enter_context(get_requirement_tracker())

        directory = TempDirectory(
            options.build_dir,
            delete=build_delete,
            kind="install",
            globally_managed=True,
        )

        try:
            reqs = self.get_requirements(args, options, finder, session)

            reject_location_related_install_options(
                reqs, options.install_options
            )

            preparer = self.make_requirement_preparer(
                temp_build_dir=directory,
                options=options,
                req_tracker=req_tracker,
                session=session,
                finder=finder,
                use_user_site=options.use_user_site,
            )
            resolver = self.make_resolver(
                preparer=preparer,
                finder=finder,
                options=options,
                wheel_cache=wheel_cache,
                use_user_site=options.use_user_site,
                ignore_installed=options.ignore_installed,
                ignore_requires_python=options.ignore_requires_python,
                force_reinstall=options.force_reinstall,
                upgrade_strategy=upgrade_strategy,
                use_pep517=options.use_pep517,
            )

            self.trace_basic_info(finder)

            requirement_set = resolver.resolve(
                reqs, check_supported_wheels=not options.target_dir
            )

            try:
                pip_req = requirement_set.get_requirement("pip")
            except KeyError:
                modifying_pip = False
            else:
                # If we're not replacing an already installed pip,
                # we're not modifying it.
                modifying_pip = pip_req.satisfied_by is None
            protect_pip_from_modification_on_windows(
                modifying_pip=modifying_pip
            )

            check_binary_allowed = get_check_binary_allowed(
                finder.format_control
            )

            reqs_to_build = [
                r for r in requirement_set.requirements.values()
                if should_build_for_install_command(
                    r, check_binary_allowed
                )
            ]

            _, build_failures = build(
                reqs_to_build,
                wheel_cache=wheel_cache,
                build_options=[],
                global_options=[],
            )

            # If we're using PEP 517, we cannot do a direct install
            # so we fail here.
            pep517_build_failure_names = [
                r.name   # type: ignore
                for r in build_failures if r.use_pep517
            ]  # type: List[str]
            if pep517_build_failure_names:
                raise InstallationError(
                    "Could not build wheels for {} which use"
                    " PEP 517 and cannot be installed directly".format(
                        ", ".join(pep517_build_failure_names)
                    )
                )

            # For now, we just warn about failures building legacy
            # requirements, as we'll fall through to a direct
            # install for those.
            for r in build_failures:
                if not r.use_pep517:
                    r.legacy_install_reason = 8368

            to_install = resolver.get_installation_order(
                requirement_set
            )

            # Check for conflicts in the package set we're installing.
            conflicts = None  # type: Optional[ConflictDetails]
            should_warn_about_conflicts = (
                not options.ignore_dependencies and
                options.warn_about_conflicts
            )
            if should_warn_about_conflicts:
                conflicts = self._determine_conflicts(to_install)

            # Don't warn about script install locations if
            # --target has been specified
            warn_script_location = options.warn_script_location
            if options.target_dir:
                warn_script_location = False

            installed = install_given_reqs(
                to_install,
                install_options,
                global_options,
                root=options.root_path,
                home=target_temp_dir_path,
                prefix=options.prefix_path,
                warn_script_location=warn_script_location,
                use_user_site=options.use_user_site,
                pycompile=options.compile,
            )

            lib_locations = get_lib_location_guesses(
                user=options.use_user_site,
                home=target_temp_dir_path,
                root=options.root_path,
                prefix=options.prefix_path,
                isolated=options.isolated_mode,
            )
            working_set = pkg_resources.WorkingSet(lib_locations)

            installed.sort(key=operator.attrgetter('name'))
            items = []
            for result in installed:
                item = result.name
                try:
                    installed_version = get_installed_version(
                        result.name, working_set=working_set
                    )
                    if installed_version:
                        item += '-' + installed_version
                except Exception:
                    pass
                items.append(item)

            if conflicts is not None:
                self._warn_about_conflicts(
                    conflicts,
                    new_resolver='2020-resolver' in options.features_enabled,
                )

            installed_desc = ' '.join(items)
            if installed_desc:
                write_output(
                    'Successfully installed %s', installed_desc,
                )
        except EnvironmentError as error:
            show_traceback = (self.verbosity >= 1)

            message = create_env_error_message(
                error, show_traceback, options.use_user_site,
            )
            logger.error(message, exc_info=show_traceback)  # noqa

            return ERROR

        if options.target_dir:
            assert target_temp_dir
            self._handle_target_dir(
                options.target_dir, target_temp_dir, options.upgrade
            )

        return SUCCESS
Ejemplo n.º 27
0
    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 = compatibility_tags.get_supported()
            if (self.check_supported_wheels and not wheel.supported(tags)):
                raise InstallationError(
                    "{} is not a supported wheel on this platform.".format(
                        wheel.filename))

        # This next bit is really a sanity check.
        assert not install_req.user_supplied or parent_req_name is None, (
            "a user supplied req shouldn't have a parent")

        # Unnamed requirements are scanned again and the requirement won't be
        # added as a dependency until after scanning.
        if not install_req.name:
            self.add_unnamed_requirement(install_req)
            return [install_req], None

        try:
            existing_req = self.get_requirement(
                install_req.name)  # type: Optional[InstallRequirement]
        except KeyError:
            existing_req = None

        has_conflicting_requirement = (
            parent_req_name is None and existing_req
            and not existing_req.constraint
            and existing_req.extras == install_req.extras
            and existing_req.req.specifier != install_req.req.specifier)
        if has_conflicting_requirement:
            raise InstallationError(
                "Double requirement given: {} (already in {}, name={!r})".
                format(install_req, existing_req, install_req.name))

        # When no existing requirement exists, add the requirement as a
        # dependency and it will be scanned again after.
        if not existing_req:
            self.add_named_requirement(install_req)
            # We'd want to rescan this requirement later
            return [install_req], install_req

        # Assume there's no need to scan, and that we've already
        # encountered this for scanning.
        if install_req.constraint or not existing_req.constraint:
            return [], existing_req

        does_not_satisfy_constraint = (
            install_req.link
            and not (existing_req.link
                     and install_req.link.path == existing_req.link.path))
        if does_not_satisfy_constraint:
            raise InstallationError("Could not satisfy constraints for '{}': "
                                    "installation from path or url cannot be "
                                    "constrained to a version".format(
                                        install_req.name))
        # If we're now installing a constraint, mark the existing
        # object for real installation.
        existing_req.constraint = False
        # If we're now installing a user supplied requirement,
        # mark the existing object as such.
        if install_req.user_supplied:
            existing_req.user_supplied = True
        existing_req.extras = tuple(
            sorted(set(existing_req.extras) | set(install_req.extras)))
        logger.debug(
            "Setting %s extras to: %s",
            existing_req,
            existing_req.extras,
        )
        # Return the existing requirement for addition to the parent and
        # scanning again.
        return [existing_req], existing_req