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Diffstat (limited to 'venv/Lib/site-packages/pip-19.0.3-py3.7.egg/pip/_internal/resolve.py')
| -rw-r--r-- | venv/Lib/site-packages/pip-19.0.3-py3.7.egg/pip/_internal/resolve.py | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/venv/Lib/site-packages/pip-19.0.3-py3.7.egg/pip/_internal/resolve.py b/venv/Lib/site-packages/pip-19.0.3-py3.7.egg/pip/_internal/resolve.py new file mode 100644 index 0000000..33f572f --- /dev/null +++ b/venv/Lib/site-packages/pip-19.0.3-py3.7.egg/pip/_internal/resolve.py @@ -0,0 +1,393 @@ +"""Dependency Resolution + +The dependency resolution in pip is performed as follows: + +for top-level requirements: + a. only one spec allowed per project, regardless of conflicts or not. + otherwise a "double requirement" exception is raised + b. they override sub-dependency requirements. +for sub-dependencies + a. "first found, wins" (where the order is breadth first) +""" + +import logging +from collections import defaultdict +from itertools import chain + +from pip._internal.exceptions import ( + BestVersionAlreadyInstalled, DistributionNotFound, HashError, HashErrors, + UnsupportedPythonVersion, +) +from pip._internal.req.constructors import install_req_from_req_string +from pip._internal.utils.logging import indent_log +from pip._internal.utils.misc import dist_in_usersite, ensure_dir +from pip._internal.utils.packaging import check_dist_requires_python +from pip._internal.utils.typing import MYPY_CHECK_RUNNING + +if MYPY_CHECK_RUNNING: + from typing import Optional, DefaultDict, List, Set # noqa: F401 + from pip._internal.download import PipSession # noqa: F401 + from pip._internal.req.req_install import InstallRequirement # noqa: F401 + from pip._internal.index import PackageFinder # noqa: F401 + from pip._internal.req.req_set import RequirementSet # noqa: F401 + from pip._internal.operations.prepare import ( # noqa: F401 + DistAbstraction, RequirementPreparer + ) + from pip._internal.cache import WheelCache # noqa: F401 + +logger = logging.getLogger(__name__) + + +class Resolver(object): + """Resolves which packages need to be installed/uninstalled to perform \ + the requested operation without breaking the requirements of any package. + """ + + _allowed_strategies = {"eager", "only-if-needed", "to-satisfy-only"} + + def __init__( + self, + preparer, # type: RequirementPreparer + session, # type: PipSession + finder, # type: PackageFinder + wheel_cache, # type: Optional[WheelCache] + use_user_site, # type: bool + ignore_dependencies, # type: bool + ignore_installed, # type: bool + ignore_requires_python, # type: bool + force_reinstall, # type: bool + isolated, # type: bool + upgrade_strategy, # type: str + use_pep517=None # type: Optional[bool] + ): + # type: (...) -> None + super(Resolver, self).__init__() + assert upgrade_strategy in self._allowed_strategies + + self.preparer = preparer + self.finder = finder + self.session = session + + # NOTE: This would eventually be replaced with a cache that can give + # information about both sdist and wheels transparently. + self.wheel_cache = wheel_cache + + # This is set in resolve + self.require_hashes = None # type: Optional[bool] + + self.upgrade_strategy = upgrade_strategy + self.force_reinstall = force_reinstall + self.isolated = isolated + self.ignore_dependencies = ignore_dependencies + self.ignore_installed = ignore_installed + self.ignore_requires_python = ignore_requires_python + self.use_user_site = use_user_site + self.use_pep517 = use_pep517 + + self._discovered_dependencies = \ + defaultdict(list) # type: DefaultDict[str, List] + + def resolve(self, requirement_set): + # type: (RequirementSet) -> None + """Resolve what operations need to be done + + As a side-effect of this method, the packages (and their dependencies) + are downloaded, unpacked and prepared for installation. This + preparation is done by ``pip.operations.prepare``. + + Once PyPI has static dependency metadata available, it would be + possible to move the preparation to become a step separated from + dependency resolution. + """ + # make the wheelhouse + if self.preparer.wheel_download_dir: + ensure_dir(self.preparer.wheel_download_dir) + + # If any top-level requirement has a hash specified, enter + # hash-checking mode, which requires hashes from all. + root_reqs = ( + requirement_set.unnamed_requirements + + list(requirement_set.requirements.values()) + ) + self.require_hashes = ( + requirement_set.require_hashes or + any(req.has_hash_options for req in root_reqs) + ) + + # Display where finder is looking for packages + locations = self.finder.get_formatted_locations() + if locations: + logger.info(locations) + + # Actually prepare the files, and collect any exceptions. Most hash + # exceptions cannot be checked ahead of time, because + # req.populate_link() needs to be called before we can make decisions + # based on link type. + discovered_reqs = [] # type: List[InstallRequirement] + hash_errors = HashErrors() + for req in chain(root_reqs, discovered_reqs): + try: + discovered_reqs.extend( + self._resolve_one(requirement_set, req) + ) + except HashError as exc: + exc.req = req + hash_errors.append(exc) + + if hash_errors: + raise hash_errors + + def _is_upgrade_allowed(self, req): + # type: (InstallRequirement) -> bool + if self.upgrade_strategy == "to-satisfy-only": + return False + elif self.upgrade_strategy == "eager": + return True + else: + assert self.upgrade_strategy == "only-if-needed" + return req.is_direct + + def _set_req_to_reinstall(self, req): + # type: (InstallRequirement) -> None + """ + Set a requirement to be installed. + """ + # Don't uninstall the conflict if doing a user install and the + # conflict is not a user install. + if not self.use_user_site or dist_in_usersite(req.satisfied_by): + req.conflicts_with = req.satisfied_by + req.satisfied_by = None + + # XXX: Stop passing requirement_set for options + def _check_skip_installed(self, req_to_install): + # type: (InstallRequirement) -> Optional[str] + """Check if req_to_install should be skipped. + + This will check if the req is installed, and whether we should upgrade + or reinstall it, taking into account all the relevant user options. + + After calling this req_to_install will only have satisfied_by set to + None if the req_to_install is to be upgraded/reinstalled etc. Any + other value will be a dist recording the current thing installed that + satisfies the requirement. + + Note that for vcs urls and the like we can't assess skipping in this + routine - we simply identify that we need to pull the thing down, + then later on it is pulled down and introspected to assess upgrade/ + reinstalls etc. + + :return: A text reason for why it was skipped, or None. + """ + if self.ignore_installed: + return None + + req_to_install.check_if_exists(self.use_user_site) + if not req_to_install.satisfied_by: + return None + + if self.force_reinstall: + self._set_req_to_reinstall(req_to_install) + return None + + if not self._is_upgrade_allowed(req_to_install): + if self.upgrade_strategy == "only-if-needed": + return 'already satisfied, skipping upgrade' + return 'already satisfied' + + # Check for the possibility of an upgrade. For link-based + # requirements we have to pull the tree down and inspect to assess + # the version #, so it's handled way down. + if not req_to_install.link: + try: + self.finder.find_requirement(req_to_install, upgrade=True) + except BestVersionAlreadyInstalled: + # Then the best version is installed. + return 'already up-to-date' + except DistributionNotFound: + # No distribution found, so we squash the error. It will + # be raised later when we re-try later to do the install. + # Why don't we just raise here? + pass + + self._set_req_to_reinstall(req_to_install) + return None + + def _get_abstract_dist_for(self, req): + # type: (InstallRequirement) -> DistAbstraction + """Takes a InstallRequirement and returns a single AbstractDist \ + representing a prepared variant of the same. + """ + assert self.require_hashes is not None, ( + "require_hashes should have been set in Resolver.resolve()" + ) + + if req.editable: + return self.preparer.prepare_editable_requirement( + req, self.require_hashes, self.use_user_site, self.finder, + ) + + # satisfied_by is only evaluated by calling _check_skip_installed, + # so it must be None here. + assert req.satisfied_by is None + skip_reason = self._check_skip_installed(req) + + if req.satisfied_by: + return self.preparer.prepare_installed_requirement( + req, self.require_hashes, skip_reason + ) + + upgrade_allowed = self._is_upgrade_allowed(req) + abstract_dist = self.preparer.prepare_linked_requirement( + req, self.session, self.finder, upgrade_allowed, + self.require_hashes + ) + + # NOTE + # The following portion is for determining if a certain package is + # going to be re-installed/upgraded or not and reporting to the user. + # This should probably get cleaned up in a future refactor. + + # req.req is only avail after unpack for URL + # pkgs repeat check_if_exists to uninstall-on-upgrade + # (#14) + if not self.ignore_installed: + req.check_if_exists(self.use_user_site) + + if req.satisfied_by: + should_modify = ( + self.upgrade_strategy != "to-satisfy-only" or + self.force_reinstall or + self.ignore_installed or + req.link.scheme == 'file' + ) + if should_modify: + self._set_req_to_reinstall(req) + else: + logger.info( + 'Requirement already satisfied (use --upgrade to upgrade):' + ' %s', req, + ) + + return abstract_dist + + def _resolve_one( + self, + requirement_set, # type: RequirementSet + req_to_install # type: InstallRequirement + ): + # type: (...) -> List[InstallRequirement] + """Prepare a single requirements file. + + :return: A list of additional InstallRequirements to also install. + """ + # Tell user what we are doing for this requirement: + # obtain (editable), skipping, processing (local url), collecting + # (remote url or package name) + if req_to_install.constraint or req_to_install.prepared: + return [] + + req_to_install.prepared = True + + # register tmp src for cleanup in case something goes wrong + requirement_set.reqs_to_cleanup.append(req_to_install) + + abstract_dist = self._get_abstract_dist_for(req_to_install) + + # Parse and return dependencies + dist = abstract_dist.dist() + try: + check_dist_requires_python(dist) + except UnsupportedPythonVersion as err: + if self.ignore_requires_python: + logger.warning(err.args[0]) + else: + raise + + more_reqs = [] # type: List[InstallRequirement] + + def add_req(subreq, extras_requested): + sub_install_req = install_req_from_req_string( + str(subreq), + req_to_install, + isolated=self.isolated, + wheel_cache=self.wheel_cache, + use_pep517=self.use_pep517 + ) + parent_req_name = req_to_install.name + to_scan_again, add_to_parent = requirement_set.add_requirement( + sub_install_req, + parent_req_name=parent_req_name, + extras_requested=extras_requested, + ) + if parent_req_name and add_to_parent: + self._discovered_dependencies[parent_req_name].append( + add_to_parent + ) + more_reqs.extend(to_scan_again) + + with indent_log(): + # We add req_to_install before its dependencies, so that we + # can refer to it when adding dependencies. + if not requirement_set.has_requirement(req_to_install.name): + # 'unnamed' requirements will get added here + req_to_install.is_direct = True + requirement_set.add_requirement( + req_to_install, parent_req_name=None, + ) + + if not self.ignore_dependencies: + if req_to_install.extras: + logger.debug( + "Installing extra requirements: %r", + ','.join(req_to_install.extras), + ) + missing_requested = sorted( + set(req_to_install.extras) - set(dist.extras) + ) + for missing in missing_requested: + logger.warning( + '%s does not provide the extra \'%s\'', + dist, missing + ) + + available_requested = sorted( + set(dist.extras) & set(req_to_install.extras) + ) + for subreq in dist.requires(available_requested): + add_req(subreq, extras_requested=available_requested) + + if not req_to_install.editable and not req_to_install.satisfied_by: + # XXX: --no-install leads this to report 'Successfully + # downloaded' for only non-editable reqs, even though we took + # action on them. + requirement_set.successfully_downloaded.append(req_to_install) + + return more_reqs + + def get_installation_order(self, req_set): + # type: (RequirementSet) -> List[InstallRequirement] + """Create the installation order. + + The installation order is topological - requirements are installed + before the requiring thing. We break cycles at an arbitrary point, + and make no other guarantees. + """ + # The current implementation, which we may change at any point + # installs the user specified things in the order given, except when + # dependencies must come earlier to achieve topological order. + order = [] + ordered_reqs = set() # type: Set[InstallRequirement] + + def schedule(req): + if req.satisfied_by or req in ordered_reqs: + return + if req.constraint: + return + ordered_reqs.add(req) + for dep in self._discovered_dependencies[req.name]: + schedule(dep) + order.append(req) + + for install_req in req_set.requirements.values(): + schedule(install_req) + return order |