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from __future__ import annotations
import collections
import copy
from abc import ABCMeta, abstractmethod
from functools import partial
from itertools import chain, count, groupby
from typing import Any, Container, DefaultDict, Iterable, Iterator
import click
from pip._internal.exceptions import DistributionNotFound
from pip._internal.operations.build.build_tracker import (
get_build_tracker,
update_env_context_manager,
)
from pip._internal.req import InstallRequirement
from pip._internal.req.constructors import install_req_from_line
from pip._internal.resolution.resolvelib.base import Candidate
from pip._internal.resolution.resolvelib.candidates import ExtrasCandidate
from pip._internal.resolution.resolvelib.resolver import Resolver
from pip._internal.utils.logging import indent_log
from pip._internal.utils.temp_dir import TempDirectory, global_tempdir_manager
from pip._vendor.packaging.specifiers import SpecifierSet
from pip._vendor.packaging.utils import canonicalize_name
from pip._vendor.resolvelib.resolvers import ResolutionImpossible, Result
from piptools.cache import DependencyCache
from piptools.repositories.base import BaseRepository
from ._compat import create_wheel_cache
from .exceptions import PipToolsError
from .logging import log
from .utils import (
UNSAFE_PACKAGES,
as_tuple,
copy_install_requirement,
format_requirement,
format_specifier,
is_pinned_requirement,
is_url_requirement,
key_from_ireq,
key_from_req,
omit_list_value,
strip_extras,
)
green = partial(click.style, fg="green")
magenta = partial(click.style, fg="magenta")
class RequirementSummary:
"""
Summary of a requirement's properties for comparison purposes.
"""
def __init__(self, ireq: InstallRequirement) -> None:
self.req = ireq.req
self.key = key_from_ireq(ireq)
self.extras = frozenset(ireq.extras)
self.specifier = ireq.specifier
def __eq__(self, other: object) -> bool:
if not isinstance(other, self.__class__):
return NotImplemented
return (
self.key == other.key
and self.specifier == other.specifier
and self.extras == other.extras
)
def __hash__(self) -> int:
return hash((self.key, self.specifier, self.extras))
def __str__(self) -> str:
return repr((self.key, str(self.specifier), sorted(self.extras)))
def combine_install_requirements(
ireqs: Iterable[InstallRequirement],
) -> InstallRequirement:
"""
Return a single install requirement that reflects a combination of
all the inputs.
"""
# We will store the source ireqs in a _source_ireqs attribute;
# if any of the inputs have this, then use those sources directly.
source_ireqs: list[InstallRequirement] = []
for ireq in ireqs:
source_ireqs.extend(getattr(ireq, "_source_ireqs", [ireq]))
# Optimization. Don't bother with combination logic.
if len(source_ireqs) == 1:
return source_ireqs[0]
link_attrs = {
attr: getattr(source_ireqs[0], attr) for attr in ("link", "original_link")
}
constraint = source_ireqs[0].constraint
extras = set(source_ireqs[0].extras)
# deepcopy the accumulator req so as to not modify the inputs
req = copy.deepcopy(source_ireqs[0].req)
for ireq in source_ireqs[1:]:
# NOTE we may be losing some info on dropped reqs here
if req is not None and ireq.req is not None:
req.specifier &= ireq.req.specifier
constraint &= ireq.constraint
extras |= ireq.extras
if req is not None:
req.extras = set(extras)
for attr_name, attr_val in link_attrs.items():
link_attrs[attr_name] = attr_val or getattr(ireq, attr_name)
# InstallRequirements objects are assumed to come from only one source, and
# so they support only a single comes_from entry. This function breaks this
# model. As a workaround, we deterministically choose a single source for
# the comes_from entry, and add an extra _source_ireqs attribute to keep
# track of multiple sources for use within pip-tools.
if any(ireq.comes_from is None for ireq in source_ireqs):
# None indicates package was directly specified.
comes_from = None
else:
# Populate the comes_from field from one of the sources.
# Requirement input order is not stable, so we need to sort:
# We choose the shortest entry in order to keep the printed
# representation as concise as possible.
comes_from = min(
(ireq.comes_from for ireq in source_ireqs),
key=lambda x: (len(str(x)), str(x)),
)
combined_ireq = copy_install_requirement(
template=source_ireqs[0],
req=req,
comes_from=comes_from,
constraint=constraint,
extras=extras,
**link_attrs,
)
combined_ireq._source_ireqs = source_ireqs
return combined_ireq
class BaseResolver(metaclass=ABCMeta):
repository: BaseRepository
unsafe_constraints: set[InstallRequirement]
@abstractmethod
def resolve(self, max_rounds: int) -> set[InstallRequirement]:
"""
Find concrete package versions for all the given InstallRequirements
and their recursive dependencies and return a set of pinned
``InstallRequirement``'s.
"""
def resolve_hashes(
self, ireqs: set[InstallRequirement]
) -> dict[InstallRequirement, set[str]]:
"""Find acceptable hashes for all of the given ``InstallRequirement``s."""
log.debug("")
log.debug("Generating hashes:")
with self.repository.allow_all_wheels(), log.indentation():
return {ireq: self.repository.get_hashes(ireq) for ireq in ireqs}
def _filter_out_unsafe_constraints(
self,
ireqs: set[InstallRequirement],
unsafe_packages: Container[str],
) -> None:
"""
Remove from a given set of ``InstallRequirement``'s unsafe constraints.
"""
for req in ireqs.copy():
if req.name in unsafe_packages:
self.unsafe_constraints.add(req)
ireqs.remove(req)
class LegacyResolver(BaseResolver):
def __init__(
self,
constraints: Iterable[InstallRequirement],
existing_constraints: dict[str, InstallRequirement],
repository: BaseRepository,
cache: DependencyCache,
prereleases: bool | None = False,
clear_caches: bool = False,
allow_unsafe: bool = False,
unsafe_packages: set[str] | None = None,
) -> None:
"""
This class resolves a given set of constraints (a collection of
InstallRequirement objects) by consulting the given Repository and the
DependencyCache.
"""
self.our_constraints = set(constraints)
self.their_constraints: set[InstallRequirement] = set()
self.repository = repository
self.dependency_cache = cache
self.prereleases = prereleases
self.clear_caches = clear_caches
self.allow_unsafe = allow_unsafe
self.unsafe_constraints: set[InstallRequirement] = set()
self.unsafe_packages = unsafe_packages or UNSAFE_PACKAGES
options = self.repository.options
if "legacy-resolver" not in options.deprecated_features_enabled:
raise PipToolsError("Legacy resolver deprecated feature must be enabled.")
# Make sure there is no enabled 2020-resolver
options.features_enabled = omit_list_value(
options.features_enabled, "2020-resolver"
)
@property
def constraints(self) -> set[InstallRequirement]:
return set(
self._group_constraints(chain(self.our_constraints, self.their_constraints))
)
def resolve(self, max_rounds: int = 10) -> set[InstallRequirement]:
"""
Find concrete package versions for all the given InstallRequirements
and their recursive dependencies and return a set of pinned
``InstallRequirement``'s.
Resolves constraints one round at a time, until they don't change
anymore. Protects against infinite loops by breaking out after a max
number rounds.
"""
if self.clear_caches:
self.dependency_cache.clear()
self.repository.clear_caches()
# Ignore existing packages
with update_env_context_manager(PIP_EXISTS_ACTION="i"):
for current_round in count(start=1): # pragma: no branch
if current_round > max_rounds:
raise RuntimeError(
"No stable configuration of concrete packages "
"could be found for the given constraints after "
"{max_rounds} rounds of resolving.\n"
"This is likely a bug.".format(max_rounds=max_rounds)
)
log.debug("")
log.debug(magenta(f"{f'ROUND {current_round}':^60}"))
has_changed, best_matches = self._resolve_one_round()
log.debug("-" * 60)
log.debug(
"Result of round {}: {}".format(
current_round,
"not stable" if has_changed else "stable, done",
)
)
if not has_changed:
break
# Only include hard requirements and not pip constraints
results = {req for req in best_matches if not req.constraint}
# Filter out unsafe requirements.
if not self.allow_unsafe:
self._filter_out_unsafe_constraints(
ireqs=results,
unsafe_packages=self.unsafe_packages,
)
return results
def _group_constraints(
self, constraints: Iterable[InstallRequirement]
) -> Iterator[InstallRequirement]:
"""
Groups constraints (remember, InstallRequirements!) by their key name,
and combining their SpecifierSets into a single InstallRequirement per
package. For example, given the following constraints:
Django<1.9,>=1.4.2
django~=1.5
Flask~=0.7
This will be combined into a single entry per package:
django~=1.5,<1.9,>=1.4.2
flask~=0.7
"""
constraints = list(constraints)
for ireq in constraints:
if ireq.name is None:
# get_dependencies has side-effect of assigning name to ireq
# (so we can group by the name below).
self.repository.get_dependencies(ireq)
# Sort first by name, i.e. the groupby key. Then within each group,
# sort editables first.
# This way, we don't bother with combining editables, since the first
# ireq will be editable, if one exists.
for _, ireqs in groupby(
sorted(constraints, key=(lambda x: (key_from_ireq(x), not x.editable))),
key=key_from_ireq,
):
yield combine_install_requirements(ireqs)
def _resolve_one_round(self) -> tuple[bool, set[InstallRequirement]]:
"""
Resolves one level of the current constraints, by finding the best
match for each package in the repository and adding all requirements
for those best package versions. Some of these constraints may be new
or updated.
Returns whether new constraints appeared in this round. If no
constraints were added or changed, this indicates a stable
configuration.
"""
# Sort this list for readability of terminal output
constraints = sorted(self.constraints, key=key_from_ireq)
log.debug("Current constraints:")
with log.indentation():
for constraint in constraints:
log.debug(str(constraint))
log.debug("")
log.debug("Finding the best candidates:")
with log.indentation():
best_matches = {self.get_best_match(ireq) for ireq in constraints}
# Find the new set of secondary dependencies
log.debug("")
log.debug("Finding secondary dependencies:")
their_constraints: list[InstallRequirement] = []
with log.indentation():
for best_match in best_matches:
their_constraints.extend(self._iter_dependencies(best_match))
# Grouping constraints to make clean diff between rounds
theirs = set(self._group_constraints(their_constraints))
# NOTE: We need to compare RequirementSummary objects, since
# InstallRequirement does not define equality
diff = {RequirementSummary(t) for t in theirs} - {
RequirementSummary(t) for t in self.their_constraints
}
removed = {RequirementSummary(t) for t in self.their_constraints} - {
RequirementSummary(t) for t in theirs
}
has_changed = len(diff) > 0 or len(removed) > 0
if has_changed:
log.debug("")
log.debug("New dependencies found in this round:")
with log.indentation():
for new_dependency in sorted(diff, key=key_from_ireq):
log.debug(f"adding {new_dependency}")
log.debug("Removed dependencies in this round:")
with log.indentation():
for removed_dependency in sorted(removed, key=key_from_ireq):
log.debug(f"removing {removed_dependency}")
# Store the last round's results in the their_constraints
self.their_constraints = theirs
return has_changed, best_matches
def get_best_match(self, ireq: InstallRequirement) -> InstallRequirement:
"""
Returns a (pinned or editable) InstallRequirement, indicating the best
match to use for the given InstallRequirement (in the form of an
InstallRequirement).
Example:
Given the constraint Flask>=0.10, may return Flask==0.10.1 at
a certain moment in time.
Pinned requirements will always return themselves, i.e.
Flask==0.10.1 => Flask==0.10.1
"""
if ireq.editable or is_url_requirement(ireq):
# NOTE: it's much quicker to immediately return instead of
# hitting the index server
best_match = ireq
elif is_pinned_requirement(ireq):
# NOTE: it's much quicker to immediately return instead of
# hitting the index server
best_match = ireq
elif ireq.constraint:
# NOTE: This is not a requirement (yet) and does not need
# to be resolved
best_match = ireq
else:
best_match = self.repository.find_best_match(
ireq, prereleases=self.prereleases
)
# Format the best match
log.debug(
"found candidate {} (constraint was {})".format(
format_requirement(best_match), format_specifier(ireq)
)
)
best_match.comes_from = ireq.comes_from
if hasattr(ireq, "_source_ireqs"):
best_match._source_ireqs = ireq._source_ireqs
return best_match
def _iter_dependencies(
self, ireq: InstallRequirement
) -> Iterator[InstallRequirement]:
"""
Given a pinned, url, or editable InstallRequirement, collects all the
secondary dependencies for them, either by looking them up in a local
cache, or by reaching out to the repository.
Editable requirements will never be looked up, as they may have
changed at any time.
"""
# Pip does not resolve dependencies of constraints. We skip handling
# constraints here as well to prevent the cache from being polluted.
# Constraints that are later determined to be dependencies will be
# marked as non-constraints in later rounds by
# `combine_install_requirements`, and will be properly resolved.
# blob/6896dfcd831330c13e076a74624d95fa55ff53f4/src/pip/_internal/
# legacy_resolve.py#L325
if ireq.constraint:
return
if ireq.editable or is_url_requirement(ireq):
dependencies = self.repository.get_dependencies(ireq)
# Don't just yield from above. Instead, use the same `markers`-stripping
# behavior as we have for cached dependencies below.
dependency_strings = sorted(str(ireq.req) for ireq in dependencies)
yield from self._ireqs_of_dependencies(ireq, dependency_strings)
return
elif not is_pinned_requirement(ireq):
raise TypeError(f"Expected pinned or editable requirement, got {ireq}")
# Now, either get the dependencies from the dependency cache (for
# speed), or reach out to the external repository to
# download and inspect the package version and get dependencies
# from there
if ireq not in self.dependency_cache:
log.debug(
f"{format_requirement(ireq)} not in cache, need to check index",
fg="yellow",
)
dependencies = self.repository.get_dependencies(ireq)
self.dependency_cache[ireq] = sorted(str(ireq.req) for ireq in dependencies)
# Example: ['Werkzeug>=0.9', 'Jinja2>=2.4']
dependency_strings = self.dependency_cache[ireq]
yield from self._ireqs_of_dependencies(ireq, dependency_strings)
def _ireqs_of_dependencies(
self, ireq: InstallRequirement, dependency_strings: list[str]
) -> Iterator[InstallRequirement]:
log.debug(
"{:25} requires {}".format(
format_requirement(ireq),
", ".join(sorted(dependency_strings, key=lambda s: s.lower())) or "-",
)
)
# This yields new InstallRequirements that are similar to those that
# produced the dependency_strings, but they lack `markers` on their
# underlying Requirements:
for dependency_string in dependency_strings:
yield install_req_from_line(
dependency_string, constraint=ireq.constraint, comes_from=ireq
)
class BacktrackingResolver(BaseResolver):
"""A wrapper for backtracking resolver."""
def __init__(
self,
constraints: Iterable[InstallRequirement],
existing_constraints: dict[str, InstallRequirement],
repository: BaseRepository,
allow_unsafe: bool = False,
unsafe_packages: set[str] | None = None,
**kwargs: Any,
) -> None:
self.constraints = list(constraints)
self.repository = repository
self.allow_unsafe = allow_unsafe
self.unsafe_packages = unsafe_packages or UNSAFE_PACKAGES
options = self.options = self.repository.options
self.session = self.repository.session
self.finder = self.repository.finder
self.command = self.repository.command
self.unsafe_constraints: set[InstallRequirement] = set()
self.existing_constraints = existing_constraints
# Categorize InstallRequirements into sets by key
constraints_sets: DefaultDict[str, set[InstallRequirement]] = (
collections.defaultdict(set)
)
for ireq in constraints:
constraints_sets[key_from_ireq(ireq)].add(ireq)
# Collapse each set of InstallRequirements using combine_install_requirements
self._constraints_map = {
ireq_key: combine_install_requirements(ireqs)
for ireq_key, ireqs in constraints_sets.items()
}
# Make sure there is no enabled legacy resolver
options.deprecated_features_enabled = omit_list_value(
options.deprecated_features_enabled, "legacy-resolver"
)
def resolve(self, max_rounds: int = 10) -> set[InstallRequirement]:
"""
Find concrete package versions for all the given InstallRequirements
and their recursive dependencies and return a set of pinned
``InstallRequirement``'s.
"""
with update_env_context_manager(
PIP_EXISTS_ACTION="i"
), get_build_tracker() as build_tracker, global_tempdir_manager(), indent_log():
# Mark direct/primary/user_supplied packages
for ireq in self.constraints:
if ireq.constraint:
ireq.extras = set() # pip does not support extras in constraints
ireq.user_supplied = True
# Pass compiled requirements from `requirements.txt`
# as constraints to resolver
compatible_existing_constraints: dict[str, InstallRequirement] = {}
for ireq in self.existing_constraints.values():
# Skip if the compiled install requirement conflicts with
# the primary install requirement.
primary_ireq = self._constraints_map.get(key_from_ireq(ireq))
if primary_ireq is not None:
_, version, _ = as_tuple(ireq)
prereleases = ireq.specifier.prereleases
if not primary_ireq.specifier.contains(version, prereleases):
continue
ireq.extras = set()
ireq.constraint = True
ireq.user_supplied = False
compatible_existing_constraints[key_from_ireq(ireq)] = ireq
wheel_cache = create_wheel_cache(
cache_dir=self.options.cache_dir,
format_control=self.options.format_control,
)
temp_dir = TempDirectory(
delete=not self.options.no_clean,
kind="resolve",
globally_managed=True,
)
preparer_kwargs = {
"temp_build_dir": temp_dir,
"options": self.options,
"session": self.session,
"finder": self.finder,
"use_user_site": False,
"build_tracker": build_tracker,
}
preparer = self.command.make_requirement_preparer(**preparer_kwargs)
resolver = self.command.make_resolver(
preparer=preparer,
finder=self.finder,
options=self.options,
wheel_cache=wheel_cache,
use_user_site=False,
ignore_installed=True,
ignore_requires_python=False,
force_reinstall=False,
use_pep517=self.options.use_pep517,
upgrade_strategy="to-satisfy-only",
)
self.command.trace_basic_info(self.finder)
for current_round in count(start=1): # pragma: no branch
if current_round > max_rounds:
raise RuntimeError(
"No stable configuration of concrete packages "
"could be found for the given constraints after "
f"{max_rounds} rounds of resolving.\n"
"This is likely a bug."
)
log.debug("")
log.debug(magenta(f"{f'ROUND {current_round}':^60}"))
is_resolved = self._do_resolve(
resolver=resolver,
compatible_existing_constraints=compatible_existing_constraints,
)
if is_resolved:
break
resolver_result = resolver._result
assert isinstance(resolver_result, Result)
# Prepare set of install requirements from resolver result.
result_ireqs = self._get_install_requirements(resolver_result=resolver_result)
# Filter out unsafe requirements.
if not self.allow_unsafe:
self._filter_out_unsafe_constraints(
ireqs=result_ireqs,
unsafe_packages=self.unsafe_packages,
)
return result_ireqs
def _do_resolve(
self,
resolver: Resolver,
compatible_existing_constraints: dict[str, InstallRequirement],
) -> bool:
"""
Return true on successful resolution, otherwise remove problematic
requirements from existing constraints and return false.
"""
try:
resolver.resolve(
root_reqs=self.constraints
+ list(compatible_existing_constraints.values()),
check_supported_wheels=not self.options.target_dir,
)
except DistributionNotFound as e:
cause_exc = e.__cause__
if cause_exc is None:
raise
if not isinstance(cause_exc, ResolutionImpossible):
raise
# Collect all incompatible install requirement names
cause_ireq_names = {
strip_extras(key_from_req(cause.requirement))
for cause in cause_exc.causes
}
# Looks like resolution is impossible, try to fix
for cause_ireq_name in cause_ireq_names:
# Find the cause requirement in existing requirements,
# otherwise raise error
cause_existing_ireq = compatible_existing_constraints.get(
cause_ireq_name
)
if cause_existing_ireq is None:
raise
# Remove existing incompatible constraint that causes error
log.warning(
f"Discarding {cause_existing_ireq} to proceed the resolution"
)
del compatible_existing_constraints[cause_ireq_name]
return False
return True
def _get_install_requirements(
self, resolver_result: Result
) -> set[InstallRequirement]:
"""Return a set of install requirements from resolver results."""
result_ireqs: dict[str, InstallRequirement] = {}
# Get reverse requirements from the resolver result graph.
reverse_dependencies = self._get_reverse_dependencies(resolver_result)
# Transform candidates to install requirements
resolved_candidates = tuple(resolver_result.mapping.values())
for candidate in resolved_candidates:
ireq = self._get_install_requirement_from_candidate(
candidate=candidate,
reverse_dependencies=reverse_dependencies,
)
if ireq is None:
continue
project_name = canonicalize_name(candidate.project_name)
result_ireqs[project_name] = ireq
# Merge extras to install requirements
extras_candidates = (
candidate
for candidate in resolved_candidates
if isinstance(candidate, ExtrasCandidate)
)
for extras_candidate in extras_candidates:
project_name = canonicalize_name(extras_candidate.project_name)
ireq = result_ireqs[project_name]
ireq.extras |= extras_candidate.extras
ireq.req.extras |= extras_candidate.extras
return set(result_ireqs.values())
@staticmethod
def _get_reverse_dependencies(
resolver_result: Result,
) -> dict[str, set[str]]:
reverse_dependencies: DefaultDict[str, set[str]] = collections.defaultdict(set)
for candidate in resolver_result.mapping.values():
stripped_name = strip_extras(canonicalize_name(candidate.name))
for parent_name in resolver_result.graph.iter_parents(candidate.name):
# Skip root dependency which is always None
if parent_name is None:
continue
# Skip a dependency that equals to the candidate. This could be
# the dependency with extras.
stripped_parent_name = strip_extras(canonicalize_name(parent_name))
if stripped_name == stripped_parent_name:
continue
reverse_dependencies[stripped_name].add(stripped_parent_name)
return dict(reverse_dependencies)
def _get_install_requirement_from_candidate(
self, candidate: Candidate, reverse_dependencies: dict[str, set[str]]
) -> InstallRequirement | None:
ireq = candidate.get_install_requirement()
if ireq is None:
return None
# Determine a pin operator
version_pin_operator = "=="
version_as_str = str(candidate.version)
for specifier in ireq.specifier:
if specifier.operator == "===" and specifier.version == version_as_str:
version_pin_operator = "==="
break
# Prepare pinned install requirement. Copy it from candidate's install
# requirement so that it could be mutated later.
pinned_ireq = copy_install_requirement(
template=ireq,
# The link this candidate "originates" from. This is different
# from ``ireq.link`` when the link is found in the wheel cache.
# ``ireq.link`` would point to the wheel cache, while this points
# to the found remote link (e.g. from pypi.org).
link=candidate.source_link,
)
# Canonicalize name
assert ireq.name is not None
pinned_ireq.req.name = canonicalize_name(ireq.name)
# Pin requirement to a resolved version
pinned_ireq.req.specifier = SpecifierSet(
f"{version_pin_operator}{candidate.version}"
)
# Save reverse dependencies for annotation
ireq_key = key_from_ireq(ireq)
pinned_ireq._required_by = reverse_dependencies.get(ireq_key, set())
# Save sources for annotation
constraint_ireq = self._constraints_map.get(ireq_key)
if constraint_ireq is not None:
if hasattr(constraint_ireq, "_source_ireqs"):
# If the constraint is combined (has _source_ireqs), use those
pinned_ireq._source_ireqs = constraint_ireq._source_ireqs
else:
# Otherwise (the constraint is not combined) it is the source
pinned_ireq._source_ireqs = [constraint_ireq]
return pinned_ireq