diff env/lib/python3.9/site-packages/pip/_vendor/resolvelib/providers.py @ 0:4f3585e2f14b draft default tip

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/pip/_vendor/resolvelib/providers.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,119 @@
+class AbstractProvider(object):
+    """Delegate class to provide requirement interface for the resolver."""
+
+    def identify(self, requirement_or_candidate):
+        """Given a requirement or candidate, return an identifier for it.
+
+        This is used in many places to identify a requirement or candidate,
+        e.g. whether two requirements should have their specifier parts merged,
+        whether two candidates would conflict with each other (because they
+        have same name but different versions).
+        """
+        raise NotImplementedError
+
+    def get_preference(self, resolution, candidates, information):
+        """Produce a sort key for given requirement based on preference.
+
+        The preference is defined as "I think this requirement should be
+        resolved first". The lower the return value is, the more preferred
+        this group of arguments is.
+
+        :param resolution: Currently pinned candidate, or `None`.
+        :param candidates: An iterable of possible candidates.
+        :param information: A list of requirement information.
+
+        The `candidates` iterable's exact type depends on the return type of
+        `find_matches()`. A sequence is passed-in as-is if possible. If it
+        returns a callble, the iterator returned by that callable is passed
+        in here.
+
+        Each element in `information` is a named tuple with two entries:
+
+        * `requirement` specifies a requirement contributing to the current
+          candidate list.
+        * `parent` specifies the candidate that provides (dependend on) the
+          requirement, or `None` to indicate a root requirement.
+
+        The preference could depend on a various of issues, including (not
+        necessarily in this order):
+
+        * Is this package pinned in the current resolution result?
+        * How relaxed is the requirement? Stricter ones should probably be
+          worked on first? (I don't know, actually.)
+        * How many possibilities are there to satisfy this requirement? Those
+          with few left should likely be worked on first, I guess?
+        * Are there any known conflicts for this requirement? We should
+          probably work on those with the most known conflicts.
+
+        A sortable value should be returned (this will be used as the `key`
+        parameter of the built-in sorting function). The smaller the value is,
+        the more preferred this requirement is (i.e. the sorting function
+        is called with `reverse=False`).
+        """
+        raise NotImplementedError
+
+    def find_matches(self, requirements):
+        """Find all possible candidates that satisfy the given requirements.
+
+        This should try to get candidates based on the requirements' types.
+        For VCS, local, and archive requirements, the one-and-only match is
+        returned, and for a "named" requirement, the index(es) should be
+        consulted to find concrete candidates for this requirement.
+
+        The return value should produce candidates ordered by preference; the
+        most preferred candidate should come first. The return type may be one
+        of the following:
+
+        * A callable that returns an iterator that yields candidates.
+        * An collection of candidates.
+        * An iterable of candidates. This will be consumed immediately into a
+          list of candidates.
+
+        :param requirements: A collection of requirements which all of the
+            returned candidates must match. All requirements are guaranteed to
+            have the same identifier. The collection is never empty.
+        """
+        raise NotImplementedError
+
+    def is_satisfied_by(self, requirement, candidate):
+        """Whether the given requirement can be satisfied by a candidate.
+
+        The candidate is guarenteed to have been generated from the
+        requirement.
+
+        A boolean should be returned to indicate whether `candidate` is a
+        viable solution to the requirement.
+        """
+        raise NotImplementedError
+
+    def get_dependencies(self, candidate):
+        """Get dependencies of a candidate.
+
+        This should return a collection of requirements that `candidate`
+        specifies as its dependencies.
+        """
+        raise NotImplementedError
+
+
+class AbstractResolver(object):
+    """The thing that performs the actual resolution work."""
+
+    base_exception = Exception
+
+    def __init__(self, provider, reporter):
+        self.provider = provider
+        self.reporter = reporter
+
+    def resolve(self, requirements, **kwargs):
+        """Take a collection of constraints, spit out the resolution result.
+
+        This returns a representation of the final resolution state, with one
+        guarenteed attribute ``mapping`` that contains resolved candidates as
+        values. The keys are their respective identifiers.
+
+        :param requirements: A collection of constraints.
+        :param kwargs: Additional keyword arguments that subclasses may accept.
+
+        :raises: ``self.base_exception`` or its subclass.
+        """
+        raise NotImplementedError