diff options
Diffstat (limited to 'third_party/python/pip-tools/piptools/resolver.py')
| -rw-r--r-- | third_party/python/pip-tools/piptools/resolver.py | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/third_party/python/pip-tools/piptools/resolver.py b/third_party/python/pip-tools/piptools/resolver.py new file mode 100644 index 0000000000..954f751ab9 --- /dev/null +++ b/third_party/python/pip-tools/piptools/resolver.py @@ -0,0 +1,408 @@ +# coding: utf-8 +from __future__ import absolute_import, division, print_function, unicode_literals + +import copy +import os +from functools import partial +from itertools import chain, count, groupby + +from pip._internal.req.constructors import install_req_from_line + +from . import click +from .logging import log +from .utils import ( + UNSAFE_PACKAGES, + format_requirement, + format_specifier, + is_pinned_requirement, + is_url_requirement, + key_from_ireq, +) + +green = partial(click.style, fg="green") +magenta = partial(click.style, fg="magenta") + + +class RequirementSummary(object): + """ + Summary of a requirement's properties for comparison purposes. + """ + + def __init__(self, ireq): + self.req = ireq.req + self.key = key_from_ireq(ireq) + self.extras = frozenset(ireq.extras) + self.specifier = ireq.specifier + + def __eq__(self, other): + return ( + self.key == other.key + and self.specifier == other.specifier + and self.extras == other.extras + ) + + def __hash__(self): + return hash((self.key, self.specifier, self.extras)) + + def __str__(self): + return repr((self.key, str(self.specifier), sorted(self.extras))) + + +def combine_install_requirements(repository, ireqs): + """ + 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 = [] + 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] + + # deepcopy the accumulator so as to not modify the inputs + combined_ireq = copy.deepcopy(source_ireqs[0]) + repository.copy_ireq_dependencies(source_ireqs[0], combined_ireq) + + for ireq in source_ireqs[1:]: + # NOTE we may be losing some info on dropped reqs here + combined_ireq.req.specifier &= ireq.req.specifier + if combined_ireq.constraint: + # We don't find dependencies for constraint ireqs, so copy them + # from non-constraints: + repository.copy_ireq_dependencies(ireq, combined_ireq) + combined_ireq.constraint &= ireq.constraint + # Return a sorted, de-duped tuple of extras + combined_ireq.extras = tuple( + sorted(set(tuple(combined_ireq.extras) + tuple(ireq.extras))) + ) + + # 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 len(source_ireqs) > 1: + if any(ireq.comes_from is None for ireq in source_ireqs): + # None indicates package was directly specified. + combined_ireq.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. + combined_ireq.comes_from = min( + (ireq.comes_from for ireq in source_ireqs), + key=lambda x: (len(str(x)), str(x)), + ) + combined_ireq._source_ireqs = source_ireqs + return combined_ireq + + +class Resolver(object): + def __init__( + self, + constraints, + repository, + cache, + prereleases=False, + clear_caches=False, + allow_unsafe=False, + ): + """ + 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() + self.repository = repository + self.dependency_cache = cache + self.prereleases = prereleases + self.clear_caches = clear_caches + self.allow_unsafe = allow_unsafe + self.unsafe_constraints = set() + + @property + def constraints(self): + return set( + self._group_constraints(chain(self.our_constraints, self.their_constraints)) + ) + + def resolve_hashes(self, ireqs): + """ + Finds acceptable hashes for all of the given InstallRequirements. + """ + 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 resolve(self, max_rounds=10): + """ + Finds concrete package versions for all the given InstallRequirements + and their recursive dependencies. The end result is a flat list of + (name, version) tuples. (Or an editable package.) + + 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 + os.environ[str("PIP_EXISTS_ACTION")] = str( + "i" + ) # NOTE: str() wrapping necessary for Python 2/3 compat + 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("{:^60}".format("ROUND {}".format(current_round)))) + 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 + + # If a package version (foo==2.0) was built in a previous round, + # and in this round a different version of foo needs to be built + # (i.e. foo==1.0), the directory will exist already, which will + # cause a pip build failure. The trick is to start with a new + # build cache dir for every round, so this can never happen. + self.repository.freshen_build_caches() + + del os.environ["PIP_EXISTS_ACTION"] + + # Only include hard requirements and not pip constraints + results = {req for req in best_matches if not req.constraint} + + # Filter out unsafe requirements. + self.unsafe_constraints = set() + if not self.allow_unsafe: + # reverse_dependencies is used to filter out packages that are only + # required by unsafe packages. This logic is incomplete, as it would + # fail to filter sub-sub-dependencies of unsafe packages. None of the + # UNSAFE_PACKAGES currently have any dependencies at all (which makes + # sense for installation tools) so this seems sufficient. + reverse_dependencies = self.reverse_dependencies(results) + for req in results.copy(): + required_by = reverse_dependencies.get(req.name.lower(), []) + if req.name in UNSAFE_PACKAGES or ( + required_by and all(name in UNSAFE_PACKAGES for name in required_by) + ): + self.unsafe_constraints.add(req) + results.remove(req) + + return results + + def _group_constraints(self, constraints): + """ + 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(self.repository, ireqs) + + def _resolve_one_round(self): + """ + 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 = [] + 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("adding {}".format(new_dependency)) + log.debug("Removed dependencies in this round:") + with log.indentation(): + for removed_dependency in sorted(removed, key=key_from_ireq): + log.debug("removing {}".format(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): + """ + 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): + """ + 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. + # See https://github.com/pypa/pip/ + # blob/6896dfcd831330c13e076a74624d95fa55ff53f4/src/pip/_internal/ + # legacy_resolve.py#L325 + if ireq.constraint: + return + + if ireq.editable or is_url_requirement(ireq): + for dependency in self.repository.get_dependencies(ireq): + yield dependency + return + elif not is_pinned_requirement(ireq): + raise TypeError( + "Expected pinned or editable requirement, got {}".format(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( + "{} not in cache, need to check index".format(format_requirement(ireq)), + 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] + log.debug( + "{:25} requires {}".format( + format_requirement(ireq), + ", ".join(sorted(dependency_strings, key=lambda s: s.lower())) or "-", + ) + ) + for dependency_string in dependency_strings: + yield install_req_from_line( + dependency_string, constraint=ireq.constraint, comes_from=ireq + ) + + def reverse_dependencies(self, ireqs): + non_editable = [ + ireq for ireq in ireqs if not (ireq.editable or is_url_requirement(ireq)) + ] + return self.dependency_cache.reverse_dependencies(non_editable) |