Upgrade resolvelib to 1.0.1 (#11879)

Co-authored-by: Pradyun Gedam <[email protected]>

Author: pradyunsg

news/resolvelib.vendor.rst

@@ -1 +1 @@
-Upgrade resolvelib to 0.9.0
+Upgrade resolvelib to 1.0.1

src/pip/_vendor/resolvelib/__init__.py

@@ -11,7 +11,7 @@
     "ResolutionTooDeep",
 ]
 
-__version__ = "0.9.0"
+__version__ = "1.0.1"
 
 
 from .providers import AbstractProvider, AbstractResolver

src/pip/_vendor/resolvelib/resolvers.py

@@ -1,4 +1,5 @@
 import collections
+import itertools
 import operator
 
 from .providers import AbstractResolver
@@ -191,8 +192,8 @@ def _remove_information_from_criteria(self, criteria, parents):
                     information
                     for information in criterion.information
                     if (
-                        information[1] is None
-                        or self._p.identify(information[1]) not in parents
+                        information.parent is None
+                        or self._p.identify(information.parent) not in parents
                     )
                 ],
                 criterion.incompatibilities,
@@ -266,8 +267,8 @@ def _attempt_to_pin_criterion(self, name):
         # end, signal for backtracking.
         return causes
 
-    def _backtrack(self):
-        """Perform backtracking.
+    def _backjump(self, causes):
+        """Perform backjumping.
 
         When we enter here, the stack is like this::
 
@@ -283,22 +284,46 @@ def _backtrack(self):
 
         Each iteration of the loop will:
 
-        1.  Discard Z.
-        2.  Discard Y but remember its incompatibility information gathered
+        1.  Identify Z. The incompatibility is not always caused by the latest
+            state. For example, given three requirements A, B and C, with
+            dependencies A1, B1 and C1, where A1 and B1 are incompatible: the
+            last state might be related to C, so we want to discard the
+            previous state.
+        2.  Discard Z.
+        3.  Discard Y but remember its incompatibility information gathered
             previously, and the failure we're dealing with right now.
-        3.  Push a new state Y' based on X, and apply the incompatibility
+        4.  Push a new state Y' based on X, and apply the incompatibility
             information from Y to Y'.
-        4a. If this causes Y' to conflict, we need to backtrack again. Make Y'
+        5a. If this causes Y' to conflict, we need to backtrack again. Make Y'
             the new Z and go back to step 2.
-        4b. If the incompatibilities apply cleanly, end backtracking.
+        5b. If the incompatibilities apply cleanly, end backtracking.
         """
+        incompatible_reqs = itertools.chain(
+            (c.parent for c in causes if c.parent is not None),
+            (c.requirement for c in causes),
+        )
+        incompatible_deps = {self._p.identify(r) for r in incompatible_reqs}
         while len(self._states) >= 3:
             # Remove the state that triggered backtracking.
             del self._states[-1]
 
-            # Retrieve the last candidate pin and known incompatibilities.
-            broken_state = self._states.pop()
-            name, candidate = broken_state.mapping.popitem()
+            # Ensure to backtrack to a state that caused the incompatibility
+            incompatible_state = False
+            while not incompatible_state:
+                # Retrieve the last candidate pin and known incompatibilities.
+                try:
+                    broken_state = self._states.pop()
+                    name, candidate = broken_state.mapping.popitem()
+                except (IndexError, KeyError):
+                    raise ResolutionImpossible(causes)
+                current_dependencies = {
+                    self._p.identify(d)
+                    for d in self._p.get_dependencies(candidate)
+                }
+                incompatible_state = not current_dependencies.isdisjoint(
+                    incompatible_deps
+                )
+
             incompatibilities_from_broken = [
                 (k, list(v.incompatibilities))
                 for k, v in broken_state.criteria.items()
@@ -403,10 +428,10 @@ def resolve(self, requirements, max_rounds):
 
             if failure_causes:
                 causes = [i for c in failure_causes for i in c.information]
-                # Backtrack if pinning fails. The backtrack process puts us in
+                # Backjump if pinning fails. The backjump process puts us in
                 # an unpinned state, so we can work on it in the next round.
                 self._r.resolving_conflicts(causes=causes)
-                success = self._backtrack()
+                success = self._backjump(causes)
                 self.state.backtrack_causes[:] = causes
 
                 # Dead ends everywhere. Give up.

src/pip/_vendor/vendor.txt

@@ -15,7 +15,7 @@ requests==2.28.2
 rich==12.6.0
     pygments==2.13.0
     typing_extensions==4.4.0
-resolvelib==0.9.0
+resolvelib==1.0.1
 setuptools==65.6.3
 six==1.16.0
 tenacity==8.1.0