Fix type hint errors due to new resolvelib

src/pip/_internal/resolution/resolvelib/factory.py

@@ -748,7 +748,7 @@ def get_installation_error(
         # The simplest case is when we have *one* cause that can't be
         # satisfied. We just report that case.
         if len(e.causes) == 1:
-            req, parent = e.causes[0]
+            req, parent = next(iter(e.causes))
             if req.name not in constraints:
                 return self._report_single_requirement_conflict(req, parent)
 

src/pip/_internal/resolution/resolvelib/reporter.py

@@ -1,15 +1,16 @@
 from collections import defaultdict
 from logging import getLogger
-from typing import Any, DefaultDict
+from typing import Any, DefaultDict, Optional
 
 from pip._vendor.resolvelib.reporters import BaseReporter
+from pip._vendor.resolvelib.resolvers import Criterion
 
 from .base import Candidate, Requirement
 
 logger = getLogger(__name__)
 
 
-class PipReporter(BaseReporter):
+class PipReporter(BaseReporter[Requirement, Candidate, str]):
     def __init__(self) -> None:
         self.reject_count_by_package: DefaultDict[str, int] = defaultdict(int)
 
@@ -32,7 +33,9 @@ def __init__(self) -> None:
             ),
         }
 
-    def rejecting_candidate(self, criterion: Any, candidate: Candidate) -> None:
+    def rejecting_candidate(
+        self, criterion: Criterion[Requirement, Candidate], candidate: Candidate
+    ) -> None:
         self.reject_count_by_package[candidate.name] += 1
 
         count = self.reject_count_by_package[candidate.name]
@@ -55,7 +58,7 @@ def rejecting_candidate(self, criterion: Any, candidate: Candidate) -> None:
         logger.debug(msg)
 
 
-class PipDebuggingReporter(BaseReporter):
+class PipDebuggingReporter(BaseReporter[Requirement, Candidate, str]):
     """A reporter that does an info log for every event it sees."""
 
     def starting(self) -> None:
@@ -71,7 +74,9 @@ def ending_round(self, index: int, state: Any) -> None:
     def ending(self, state: Any) -> None:
         logger.info("Reporter.ending(%r)", state)
 
-    def adding_requirement(self, requirement: Requirement, parent: Candidate) -> None:
+    def adding_requirement(
+        self, requirement: Requirement, parent: Optional[Candidate]
+    ) -> None:
         logger.info("Reporter.adding_requirement(%r, %r)", requirement, parent)
 
     def rejecting_candidate(self, criterion: Any, candidate: Candidate) -> None:

src/pip/_internal/resolution/resolvelib/resolver.py

@@ -82,7 +82,7 @@ def resolve(
             user_requested=collected.user_requested,
         )
         if "PIP_RESOLVER_DEBUG" in os.environ:
-            reporter: BaseReporter = PipDebuggingReporter()
+            reporter: BaseReporter[Requirement, Candidate, str] = PipDebuggingReporter()
         else:
             reporter = PipReporter()
         resolver: RLResolver[Requirement, Candidate, str] = RLResolver(

tests/unit/resolution_resolvelib/test_provider.py

@@ -5,6 +5,7 @@
 from pip._internal.models.candidate import InstallationCandidate
 from pip._internal.models.link import Link
 from pip._internal.req.constructors import install_req_from_req_string
+from pip._internal.resolution.resolvelib.base import Candidate
 from pip._internal.resolution.resolvelib.factory import Factory
 from pip._internal.resolution.resolvelib.provider import PipProvider
 from pip._internal.resolution.resolvelib.requirements import SpecifierRequirement
@@ -14,13 +15,13 @@
 
 
 def build_requirement_information(
-    name: str, parent: Optional[InstallationCandidate]
+    name: str, parent: Optional[Candidate]
 ) -> List["PreferenceInformation"]:
     install_requirement = install_req_from_req_string(name)
     # RequirementInformation is typed as a tuple, but it is a namedtupled.
     # https://github.com/sarugaku/resolvelib/blob/7bc025aa2a4e979597c438ad7b17d2e8a08a364e/src/resolvelib/resolvers.pyi#L20-L22
     requirement_information: PreferenceInformation = RequirementInformation(
-        requirement=SpecifierRequirement(install_requirement),  # type: ignore[call-arg]
+        requirement=SpecifierRequirement(install_requirement),
         parent=parent,
     )
     return [requirement_information]
@@ -29,7 +30,7 @@ def build_requirement_information(
 def test_provider_known_depths(factory: Factory) -> None:
     # Root requirement is specified by the user
     # therefore has an inferred depth of 1
-    root_requirement_name = "my-package"
+    root_requirement_name: str = "my-package"
     provider = PipProvider(
         factory=factory,
         constraints={},
@@ -60,7 +61,8 @@ def test_provider_known_depths(factory: Factory) -> None:
     transitive_requirement_name = "my-transitive-package"
 
     transitive_package_information = build_requirement_information(
-        name=transitive_requirement_name, parent=root_package_candidate
+        name=transitive_requirement_name,
+        parent=root_package_candidate,  # type: ignore
     )
     provider.get_preference(
         identifier=transitive_requirement_name,