176 lines
7.5 KiB
Python
176 lines
7.5 KiB
Python
from typing import TYPE_CHECKING, Dict, Iterable, Iterator, Mapping, Sequence, Union
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from pip._vendor.resolvelib.providers import AbstractProvider
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from .base import Candidate, Constraint, Requirement
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from .factory import Factory
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if TYPE_CHECKING:
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from pip._vendor.resolvelib.providers import Preference
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from pip._vendor.resolvelib.resolvers import RequirementInformation
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PreferenceInformation = RequirementInformation[Requirement, Candidate]
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_ProviderBase = AbstractProvider[Requirement, Candidate, str]
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else:
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_ProviderBase = AbstractProvider
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# Notes on the relationship between the provider, the factory, and the
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# candidate and requirement classes.
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#
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# The provider is a direct implementation of the resolvelib class. Its role
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# is to deliver the API that resolvelib expects.
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#
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# Rather than work with completely abstract "requirement" and "candidate"
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# concepts as resolvelib does, pip has concrete classes implementing these two
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# ideas. The API of Requirement and Candidate objects are defined in the base
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# classes, but essentially map fairly directly to the equivalent provider
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# methods. In particular, `find_matches` and `is_satisfied_by` are
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# requirement methods, and `get_dependencies` is a candidate method.
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#
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# The factory is the interface to pip's internal mechanisms. It is stateless,
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# and is created by the resolver and held as a property of the provider. It is
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# responsible for creating Requirement and Candidate objects, and provides
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# services to those objects (access to pip's finder and preparer).
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class PipProvider(_ProviderBase):
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"""Pip's provider implementation for resolvelib.
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:params constraints: A mapping of constraints specified by the user. Keys
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are canonicalized project names.
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:params ignore_dependencies: Whether the user specified ``--no-deps``.
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:params upgrade_strategy: The user-specified upgrade strategy.
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:params user_requested: A set of canonicalized package names that the user
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supplied for pip to install/upgrade.
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"""
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def __init__(
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self,
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factory, # type: Factory
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constraints, # type: Dict[str, Constraint]
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ignore_dependencies, # type: bool
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upgrade_strategy, # type: str
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user_requested, # type: Dict[str, int]
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):
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# type: (...) -> None
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self._factory = factory
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self._constraints = constraints
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self._ignore_dependencies = ignore_dependencies
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self._upgrade_strategy = upgrade_strategy
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self._user_requested = user_requested
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def identify(self, requirement_or_candidate):
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# type: (Union[Requirement, Candidate]) -> str
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return requirement_or_candidate.name
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def get_preference(
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self,
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identifier: str,
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resolutions: Mapping[str, Candidate],
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candidates: Mapping[str, Iterator[Candidate]],
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information: Mapping[str, Iterator["PreferenceInformation"]],
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) -> "Preference":
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"""Produce a sort key for given requirement based on preference.
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The lower the return value is, the more preferred this group of
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arguments is.
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Currently pip considers the followings in order:
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* Prefer if any of the known requirements points to an explicit URL.
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* If equal, prefer if any requirements contain ``===`` and ``==``.
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* If equal, prefer if requirements include version constraints, e.g.
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``>=`` and ``<``.
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* If equal, prefer user-specified (non-transitive) requirements, and
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order user-specified requirements by the order they are specified.
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* If equal, order alphabetically for consistency (helps debuggability).
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"""
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def _get_restrictive_rating(requirements):
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# type: (Iterable[Requirement]) -> int
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"""Rate how restrictive a set of requirements are.
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``Requirement.get_candidate_lookup()`` returns a 2-tuple for
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lookup. The first element is ``Optional[Candidate]`` and the
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second ``Optional[InstallRequirement]``.
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* If the requirement is an explicit one, the explicitly-required
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candidate is returned as the first element.
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* If the requirement is based on a PEP 508 specifier, the backing
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``InstallRequirement`` is returned as the second element.
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We use the first element to check whether there is an explicit
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requirement, and the second for equality operator.
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"""
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lookups = (r.get_candidate_lookup() for r in requirements)
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cands, ireqs = zip(*lookups)
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if any(cand is not None for cand in cands):
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return 0
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spec_sets = (ireq.specifier for ireq in ireqs if ireq)
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operators = [
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specifier.operator for spec_set in spec_sets for specifier in spec_set
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]
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if any(op in ("==", "===") for op in operators):
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return 1
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if operators:
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return 2
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# A "bare" requirement without any version requirements.
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return 3
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rating = _get_restrictive_rating(r for r, _ in information[identifier])
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order = self._user_requested.get(identifier, float("inf"))
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# HACK: Setuptools have a very long and solid backward compatibility
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# track record, and extremely few projects would request a narrow,
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# non-recent version range of it since that would break a lot things.
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# (Most projects specify it only to request for an installer feature,
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# which does not work, but that's another topic.) Intentionally
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# delaying Setuptools helps reduce branches the resolver has to check.
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# This serves as a temporary fix for issues like "apache-airlfow[all]"
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# while we work on "proper" branch pruning techniques.
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delay_this = identifier == "setuptools"
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return (delay_this, rating, order, identifier)
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def find_matches(
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self,
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identifier: str,
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requirements: Mapping[str, Iterator[Requirement]],
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incompatibilities: Mapping[str, Iterator[Candidate]],
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) -> Iterable[Candidate]:
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def _eligible_for_upgrade(name):
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# type: (str) -> bool
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"""Are upgrades allowed for this project?
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This checks the upgrade strategy, and whether the project was one
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that the user specified in the command line, in order to decide
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whether we should upgrade if there's a newer version available.
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(Note that we don't need access to the `--upgrade` flag, because
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an upgrade strategy of "to-satisfy-only" means that `--upgrade`
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was not specified).
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"""
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if self._upgrade_strategy == "eager":
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return True
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elif self._upgrade_strategy == "only-if-needed":
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return name in self._user_requested
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return False
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return self._factory.find_candidates(
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identifier=identifier,
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requirements=requirements,
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constraint=self._constraints.get(identifier, Constraint.empty()),
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prefers_installed=(not _eligible_for_upgrade(identifier)),
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incompatibilities=incompatibilities,
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)
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def is_satisfied_by(self, requirement, candidate):
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# type: (Requirement, Candidate) -> bool
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return requirement.is_satisfied_by(candidate)
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def get_dependencies(self, candidate):
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# type: (Candidate) -> Sequence[Requirement]
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with_requires = not self._ignore_dependencies
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return [r for r in candidate.iter_dependencies(with_requires) if r is not None]
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