Fix linting issues and update news file

- Fix line length issues in _envs.py docstrings
- Fix mypy return type error for _iter_meta_path_distributions
- Remove debug print statements from factory.py
- Update news file to include meta_path finder support
- All linting checks now pass

Author: killerdevildog

news/optimize-dependency-cache.feature.rst

@@ -1 +1 @@
-Optimize dependency resolution performance by caching parsed dependencies and extras to avoid redundant parsing operations during candidate evaluation.
+Optimize dependency resolution performance by caching parsed dependencies and extras to avoid redundant parsing operations during candidate evaluation. Also add support for discovering distributions from sys.meta_path finders to enable in-memory package installations.

src/pip/_internal/metadata/importlib/_envs.py

@@ -77,7 +77,7 @@ def _find_impl(self, location: str) -> Iterator[FoundResult]:
             yield dist, info_location
 
     def find_meta_path_distributions(self) -> Iterator[FoundResult]:
-        """Find distributions from sys.meta_path finders (e.g., in-memory distributions)."""
+        """Find distributions from sys.meta_path finders."""
         try:
             # Get all distributions without specifying a path, which includes
             # distributions from sys.meta_path finders
@@ -154,13 +154,15 @@ def _iter_distributions(self) -> Iterator[BaseDistribution]:
         for location in self._paths:
             yield from finder.find(location)
             yield from finder.find_legacy_editables(location)
-        
-        # Also check for distributions from sys.meta_path finders (e.g., in-memory distributions)
+
+        # Also check for distributions from sys.meta_path finders
         # This is backwards compatible - if no custom finders exist, this does nothing
         yield from self._iter_meta_path_distributions(finder)
 
-    def _iter_meta_path_distributions(self, finder: _DistributionFinder) -> None:
-        """Yield distributions from sys.meta_path finders (e.g., in-memory distributions)."""
+    def _iter_meta_path_distributions(
+        self, finder: _DistributionFinder
+    ) -> Iterator[Distribution]:
+        """Yield distributions from sys.meta_path finders."""
         for dist, info_location in finder.find_meta_path_distributions():
             if info_location is None:
                 installed_location: BasePath | None = None

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

@@ -281,26 +281,22 @@ def _get_installed_candidate() -> Candidate | None:
             try:
                 # Don't use the installed distribution if its version
                 # does not fit the current dependency graph.
-                version_check = specifier.contains(installed_dist.version, prereleases=True)
-                print(f"DEBUG: specifier {specifier} contains {installed_dist.version} = {version_check}")
+                version_check = specifier.contains(
+                    installed_dist.version, prereleases=True
+                )
                 if not version_check:
-                    print(f"DEBUG: Returning None due to version specifier mismatch")
                     return None
             except InvalidVersion as e:
-                print(f"DEBUG: InvalidVersion error: {e}")
                 raise InvalidInstalledPackage(dist=installed_dist, invalid_exc=e)
 
             candidate = self._make_candidate_from_dist(
                 dist=installed_dist,
                 extras=extras,
                 template=template,
             )
-            print(f"DEBUG: Created candidate = {candidate}")
             # The candidate is a known incompatibility. Don't use it.
             if id(candidate) in incompatible_ids:
-                print(f"DEBUG: Returning None due to incompatible candidate")
                 return None
-            print(f"DEBUG: Returning candidate = {candidate}")
             return candidate
 
         def iter_index_candidate_infos() -> Iterator[IndexCandidateInfo]:

tests/functional/test_install.py

@@ -2586,7 +2586,7 @@ def find_distributions(self, context=None):
     custom_module_path = script.site_packages_path / "setup_custom_finder.py"
     with open(custom_module_path, "w") as f:
         f.write(sitecustomize_text)
-    
+
     # Create a .pth file that imports our module
     pth_content = "import setup_custom_finder"
     pth_file = script.site_packages_path / "setup_custom_finder.pth"