import contextlib import functools import logging from typing import ( TYPE_CHECKING, Dict, FrozenSet, Iterable, Iterator, List, Mapping, NamedTuple, Optional, Sequence, Set, Tuple, TypeVar, cast, ) from pip._vendor.packaging.requirements import InvalidRequirement from pip._vendor.packaging.specifiers import SpecifierSet from pip._vendor.packaging.utils import NormalizedName, canonicalize_name from pip._vendor.resolvelib import ResolutionImpossible from pip._internal.cache import CacheEntry, WheelCache from pip._internal.exceptions import ( DistributionNotFound, InstallationError, MetadataInconsistent, UnsupportedPythonVersion, UnsupportedWheel, ) from pip._internal.index.package_finder import PackageFinder from pip._internal.metadata import BaseDistribution, get_default_environment from pip._internal.models.link import Link from pip._internal.models.wheel import Wheel from pip._internal.operations.prepare import RequirementPreparer from pip._internal.req.constructors import install_req_from_link_and_ireq from pip._internal.req.req_install import ( InstallRequirement, check_invalid_constraint_type, ) from pip._internal.resolution.base import InstallRequirementProvider from pip._internal.utils.compatibility_tags import get_supported from pip._internal.utils.hashes import Hashes from pip._internal.utils.packaging import get_requirement from pip._internal.utils.virtualenv import running_under_virtualenv from .base import Candidate, CandidateVersion, Constraint, Requirement from .candidates import ( AlreadyInstalledCandidate, BaseCandidate, EditableCandidate, ExtrasCandidate, LinkCandidate, RequiresPythonCandidate, as_base_candidate, ) from .found_candidates import FoundCandidates, IndexCandidateInfo from .requirements import ( ExplicitRequirement, RequiresPythonRequirement, SpecifierRequirement, UnsatisfiableRequirement, ) if TYPE_CHECKING: from typing import Protocol class ConflictCause(Protocol): requirement: RequiresPythonRequirement parent: Candidate logger = logging.getLogger(__name__) C = TypeVar("C") Cache = Dict[Link, C] class CollectedRootRequirements(NamedTuple): requirements: List[Requirement] constraints: Dict[str, Constraint] user_requested: Dict[str, int] class Factory: def __init__( self, finder: PackageFinder, preparer: RequirementPreparer, make_install_req: InstallRequirementProvider, wheel_cache: Optional[WheelCache], use_user_site: bool, force_reinstall: bool, ignore_installed: bool, ignore_requires_python: bool, py_version_info: Optional[Tuple[int, ...]] = None, ) -> None: self._finder = finder self.preparer = preparer self._wheel_cache = wheel_cache self._python_candidate = RequiresPythonCandidate(py_version_info) self._make_install_req_from_spec = make_install_req self._use_user_site = use_user_site self._force_reinstall = force_reinstall self._ignore_requires_python = ignore_requires_python self._build_failures: Cache[InstallationError] = {} self._link_candidate_cache: Cache[LinkCandidate] = {} self._editable_candidate_cache: Cache[EditableCandidate] = {} self._installed_candidate_cache: Dict[str, AlreadyInstalledCandidate] = {} self._extras_candidate_cache: Dict[ Tuple[int, FrozenSet[str]], ExtrasCandidate ] = {} if not ignore_installed: env = get_default_environment() self._installed_dists = { dist.canonical_name: dist for dist in env.iter_installed_distributions(local_only=False) } else: self._installed_dists = {} @property def force_reinstall(self) -> bool: return self._force_reinstall def _fail_if_link_is_unsupported_wheel(self, link: Link) -> None: if not link.is_wheel: return wheel = Wheel(link.filename) if wheel.supported(self._finder.target_python.get_tags()): return msg = f"{link.filename} is not a supported wheel on this platform." raise UnsupportedWheel(msg) def _make_extras_candidate( self, base: BaseCandidate, extras: FrozenSet[str] ) -> ExtrasCandidate: cache_key = (id(base), extras) try: candidate = self._extras_candidate_cache[cache_key] except KeyError: candidate = ExtrasCandidate(base, extras) self._extras_candidate_cache[cache_key] = candidate return candidate def _make_candidate_from_dist( self, dist: BaseDistribution, extras: FrozenSet[str], template: InstallRequirement, ) -> Candidate: try: base = self._installed_candidate_cache[dist.canonical_name] except KeyError: base = AlreadyInstalledCandidate(dist, template, factory=self) self._installed_candidate_cache[dist.canonical_name] = base if not extras: return base return self._make_extras_candidate(base, extras) def _make_candidate_from_link( self, link: Link, extras: FrozenSet[str], template: InstallRequirement, name: Optional[NormalizedName], version: Optional[CandidateVersion], ) -> Optional[Candidate]: # TODO: Check already installed candidate, and use it if the link and # editable flag match. if link in self._build_failures: # We already tried this candidate before, and it does not build. # Don't bother trying again. return None if template.editable: if link not in self._editable_candidate_cache: try: self._editable_candidate_cache[link] = EditableCandidate( link, template, factory=self, name=name, version=version, ) except MetadataInconsistent as e: logger.info( "Discarding [blue underline]%s[/]: [yellow]%s[reset]", link, e, extra={"markup": True}, ) self._build_failures[link] = e return None base: BaseCandidate = self._editable_candidate_cache[link] else: if link not in self._link_candidate_cache: try: self._link_candidate_cache[link] = LinkCandidate( link, template, factory=self, name=name, version=version, ) except MetadataInconsistent as e: logger.info( "Discarding [blue underline]%s[/]: [yellow]%s[reset]", link, e, extra={"markup": True}, ) self._build_failures[link] = e return None base = self._link_candidate_cache[link] if not extras: return base return self._make_extras_candidate(base, extras) def _iter_found_candidates( self, ireqs: Sequence[InstallRequirement], specifier: SpecifierSet, hashes: Hashes, prefers_installed: bool, incompatible_ids: Set[int], ) -> Iterable[Candidate]: if not ireqs: return () # The InstallRequirement implementation requires us to give it a # "template". Here we just choose the first requirement to represent # all of them. # Hopefully the Project model can correct this mismatch in the future. template = ireqs[0] assert template.req, "Candidates found on index must be PEP 508" name = canonicalize_name(template.req.name) extras: FrozenSet[str] = frozenset() for ireq in ireqs: assert ireq.req, "Candidates found on index must be PEP 508" specifier &= ireq.req.specifier hashes &= ireq.hashes(trust_internet=False) extras |= frozenset(ireq.extras) def _get_installed_candidate() -> Optional[Candidate]: """Get the candidate for the currently-installed version.""" # If --force-reinstall is set, we want the version from the index # instead, so we "pretend" there is nothing installed. if self._force_reinstall: return None try: installed_dist = self._installed_dists[name] except KeyError: return None # Don't use the installed distribution if its version does not fit # the current dependency graph. if not specifier.contains(installed_dist.version, prereleases=True): return None candidate = self._make_candidate_from_dist( dist=installed_dist, extras=extras, template=template, ) # The candidate is a known incompatibility. Don't use it. if id(candidate) in incompatible_ids: return None return candidate def iter_index_candidate_infos() -> Iterator[IndexCandidateInfo]: result = self._finder.find_best_candidate( project_name=name, specifier=specifier, hashes=hashes, ) icans = list(result.iter_applicable()) # PEP 592: Yanked releases are ignored unless the specifier # explicitly pins a version (via '==' or '===') that can be # solely satisfied by a yanked release. all_yanked = all(ican.link.is_yanked for ican in icans) def is_pinned(specifier: SpecifierSet) -> bool: for sp in specifier: if sp.operator == "===": return True if sp.operator != "==": continue if sp.version.endswith(".*"): continue return True return False pinned = is_pinned(specifier) # PackageFinder returns earlier versions first, so we reverse. for ican in reversed(icans): if not (all_yanked and pinned) and ican.link.is_yanked: continue func = functools.partial( self._make_candidate_from_link, link=ican.link, extras=extras, template=template, name=name, version=ican.version, ) yield ican.version, func return FoundCandidates( iter_index_candidate_infos, _get_installed_candidate(), prefers_installed, incompatible_ids, ) def _iter_explicit_candidates_from_base( self, base_requirements: Iterable[Requirement], extras: FrozenSet[str], ) -> Iterator[Candidate]: """Produce explicit candidates from the base given an extra-ed package. :param base_requirements: Requirements known to the resolver. The requirements are guaranteed to not have extras. :param extras: The extras to inject into the explicit requirements' candidates. """ for req in base_requirements: lookup_cand, _ = req.get_candidate_lookup() if lookup_cand is None: # Not explicit. continue # We've stripped extras from the identifier, and should always # get a BaseCandidate here, unless there's a bug elsewhere. base_cand = as_base_candidate(lookup_cand) assert base_cand is not None, "no extras here" yield self._make_extras_candidate(base_cand, extras) def _iter_candidates_from_constraints( self, identifier: str, constraint: Constraint, template: InstallRequirement, ) -> Iterator[Candidate]: """Produce explicit candidates from constraints. This creates "fake" InstallRequirement objects that are basically clones of what "should" be the template, but with original_link set to link. """ for link in constraint.links: self._fail_if_link_is_unsupported_wheel(link) candidate = self._make_candidate_from_link( link, extras=frozenset(), template=install_req_from_link_and_ireq(link, template), name=canonicalize_name(identifier), version=None, ) if candidate: yield candidate def find_candidates( self, identifier: str, requirements: Mapping[str, Iterable[Requirement]], incompatibilities: Mapping[str, Iterator[Candidate]], constraint: Constraint, prefers_installed: bool, ) -> Iterable[Candidate]: # Collect basic lookup information from the requirements. explicit_candidates: Set[Candidate] = set() ireqs: List[InstallRequirement] = [] for req in requirements[identifier]: cand, ireq = req.get_candidate_lookup() if cand is not None: explicit_candidates.add(cand) if ireq is not None: ireqs.append(ireq) # If the current identifier contains extras, add explicit candidates # from entries from extra-less identifier. with contextlib.suppress(InvalidRequirement): parsed_requirement = get_requirement(identifier) explicit_candidates.update( self._iter_explicit_candidates_from_base( requirements.get(parsed_requirement.name, ()), frozenset(parsed_requirement.extras), ), ) # Add explicit candidates from constraints. We only do this if there are # known ireqs, which represent requirements not already explicit. If # there are no ireqs, we're constraining already-explicit requirements, # which is handled later when we return the explicit candidates. if ireqs: try: explicit_candidates.update( self._iter_candidates_from_constraints( identifier, constraint, template=ireqs[0], ), ) except UnsupportedWheel: # If we're constrained to install a wheel incompatible with the # target architecture, no candidates will ever be valid. return () # Since we cache all the candidates, incompatibility identification # can be made quicker by comparing only the id() values. incompat_ids = {id(c) for c in incompatibilities.get(identifier, ())} # If none of the requirements want an explicit candidate, we can ask # the finder for candidates. if not explicit_candidates: return self._iter_found_candidates( ireqs, constraint.specifier, constraint.hashes, prefers_installed, incompat_ids, ) return ( c for c in explicit_candidates if id(c) not in incompat_ids and constraint.is_satisfied_by(c) and all(req.is_satisfied_by(c) for req in requirements[identifier]) ) def _make_requirement_from_install_req( self, ireq: InstallRequirement, requested_extras: Iterable[str] ) -> Optional[Requirement]: if not ireq.match_markers(requested_extras): logger.info( "Ignoring %s: markers '%s' don't match your environment", ireq.name, ireq.markers, ) return None if not ireq.link: return SpecifierRequirement(ireq) self._fail_if_link_is_unsupported_wheel(ireq.link) cand = self._make_candidate_from_link( ireq.link, extras=frozenset(ireq.extras), template=ireq, name=canonicalize_name(ireq.name) if ireq.name else None, version=None, ) if cand is None: # There's no way we can satisfy a URL requirement if the underlying # candidate fails to build. An unnamed URL must be user-supplied, so # we fail eagerly. If the URL is named, an unsatisfiable requirement # can make the resolver do the right thing, either backtrack (and # maybe find some other requirement that's buildable) or raise a # ResolutionImpossible eventually. if not ireq.name: raise self._build_failures[ireq.link] return UnsatisfiableRequirement(canonicalize_name(ireq.name)) return self.make_requirement_from_candidate(cand) def collect_root_requirements( self, root_ireqs: List[InstallRequirement] ) -> CollectedRootRequirements: collected = CollectedRootRequirements([], {}, {}) for i, ireq in enumerate(root_ireqs): if ireq.constraint: # Ensure we only accept valid constraints problem = check_invalid_constraint_type(ireq) if problem: raise InstallationError(problem) if not ireq.match_markers(): continue assert ireq.name, "Constraint must be named" name = canonicalize_name(ireq.name) if name in collected.constraints: collected.constraints[name] &= ireq else: collected.constraints[name] = Constraint.from_ireq(ireq) else: req = self._make_requirement_from_install_req( ireq, requested_extras=(), ) if req is None: continue if ireq.user_supplied and req.name not in collected.user_requested: collected.user_requested[req.name] = i collected.requirements.append(req) return collected def make_requirement_from_candidate( self, candidate: Candidate ) -> ExplicitRequirement: return ExplicitRequirement(candidate) def make_requirement_from_spec( self, specifier: str, comes_from: Optional[InstallRequirement], requested_extras: Iterable[str] = (), ) -> Optional[Requirement]: ireq = self._make_install_req_from_spec(specifier, comes_from) return self._make_requirement_from_install_req(ireq, requested_extras) def make_requires_python_requirement( self, specifier: SpecifierSet, ) -> Optional[Requirement]: if self._ignore_requires_python: return None # Don't bother creating a dependency for an empty Requires-Python. if not str(specifier): return None return RequiresPythonRequirement(specifier, self._python_candidate) def get_wheel_cache_entry( self, link: Link, name: Optional[str] ) -> Optional[CacheEntry]: """Look up the link in the wheel cache. If ``preparer.require_hashes`` is True, don't use the wheel cache, because cached wheels, always built locally, have different hashes than the files downloaded from the index server and thus throw false hash mismatches. Furthermore, cached wheels at present have nondeterministic contents due to file modification times. """ if self._wheel_cache is None: return None return self._wheel_cache.get_cache_entry( link=link, package_name=name, supported_tags=get_supported(), ) def get_dist_to_uninstall(self, candidate: Candidate) -> Optional[BaseDistribution]: # TODO: Are there more cases this needs to return True? Editable? dist = self._installed_dists.get(candidate.project_name) if dist is None: # Not installed, no uninstallation required. return None # We're installing into global site. The current installation must # be uninstalled, no matter it's in global or user site, because the # user site installation has precedence over global. if not self._use_user_site: return dist # We're installing into user site. Remove the user site installation. if dist.in_usersite: return dist # We're installing into user site, but the installed incompatible # package is in global site. We can't uninstall that, and would let # the new user installation to "shadow" it. But shadowing won't work # in virtual environments, so we error out. if running_under_virtualenv() and dist.in_site_packages: message = ( f"Will not install to the user site because it will lack " f"sys.path precedence to {dist.raw_name} in {dist.location}" ) raise InstallationError(message) return None def _report_requires_python_error( self, causes: Sequence["ConflictCause"] ) -> UnsupportedPythonVersion: assert causes, "Requires-Python error reported with no cause" version = self._python_candidate.version if len(causes) == 1: specifier = str(causes[0].requirement.specifier) message = ( f"Package {causes[0].parent.name!r} requires a different " f"Python: {version} not in {specifier!r}" ) return UnsupportedPythonVersion(message) message = f"Packages require a different Python. {version} not in:" for cause in causes: package = cause.parent.format_for_error() specifier = str(cause.requirement.specifier) message += f"\n{specifier!r} (required by {package})" return UnsupportedPythonVersion(message) def _report_single_requirement_conflict( self, req: Requirement, parent: Optional[Candidate] ) -> DistributionNotFound: if parent is None: req_disp = str(req) else: req_disp = f"{req} (from {parent.name})" cands = self._finder.find_all_candidates(req.project_name) skipped_by_requires_python = self._finder.requires_python_skipped_reasons() versions = [str(v) for v in sorted({c.version for c in cands})] if skipped_by_requires_python: logger.critical( "Ignored the following versions that require a different python " "version: %s", "; ".join(skipped_by_requires_python) or "none", ) logger.critical( "Could not find a version that satisfies the requirement %s " "(from versions: %s)", req_disp, ", ".join(versions) or "none", ) if str(req) == "requirements.txt": logger.info( "HINT: You are attempting to install a package literally " 'named "requirements.txt" (which cannot exist). Consider ' "using the '-r' flag to install the packages listed in " "requirements.txt" ) return DistributionNotFound(f"No matching distribution found for {req}") def get_installation_error( self, e: "ResolutionImpossible[Requirement, Candidate]", constraints: Dict[str, Constraint], ) -> InstallationError: assert e.causes, "Installation error reported with no cause" # If one of the things we can't solve is "we need Python X.Y", # that is what we report. requires_python_causes = [ cause for cause in e.causes if isinstance(cause.requirement, RequiresPythonRequirement) and not cause.requirement.is_satisfied_by(self._python_candidate) ] if requires_python_causes: # The comprehension above makes sure all Requirement instances are # RequiresPythonRequirement, so let's cast for convenience. return self._report_requires_python_error( cast("Sequence[ConflictCause]", requires_python_causes), ) # Otherwise, we have a set of causes which can't all be satisfied # at once. # The simplest case is when we have *one* cause that can't be # satisfied. We just report that case. if len(e.causes) == 1: req, parent = e.causes[0] if req.name not in constraints: return self._report_single_requirement_conflict(req, parent) # OK, we now have a list of requirements that can't all be # satisfied at once. # A couple of formatting helpers def text_join(parts: List[str]) -> str: if len(parts) == 1: return parts[0] return ", ".join(parts[:-1]) + " and " + parts[-1] def describe_trigger(parent: Candidate) -> str: ireq = parent.get_install_requirement() if not ireq or not ireq.comes_from: return f"{parent.name}=={parent.version}" if isinstance(ireq.comes_from, InstallRequirement): return str(ireq.comes_from.name) return str(ireq.comes_from) triggers = set() for req, parent in e.causes: if parent is None: # This is a root requirement, so we can report it directly trigger = req.format_for_error() else: trigger = describe_trigger(parent) triggers.add(trigger) if triggers: info = text_join(sorted(triggers)) else: info = "the requested packages" msg = ( "Cannot install {} because these package versions " "have conflicting dependencies.".format(info) ) logger.critical(msg) msg = "\nThe conflict is caused by:" relevant_constraints = set() for req, parent in e.causes: if req.name in constraints: relevant_constraints.add(req.name) msg = msg + "\n " if parent: msg = msg + f"{parent.name} {parent.version} depends on " else: msg = msg + "The user requested " msg = msg + req.format_for_error() for key in relevant_constraints: spec = constraints[key].specifier msg += f"\n The user requested (constraint) {key}{spec}" msg = ( msg + "\n\n" + "To fix this you could try to:\n" + "1. loosen the range of package versions you've specified\n" + "2. remove package versions to allow pip attempt to solve " + "the dependency conflict\n" ) logger.info(msg) return DistributionNotFound( "ResolutionImpossible: for help visit " "https://pip.pypa.io/en/latest/topics/dependency-resolution/" "#dealing-with-dependency-conflicts" )