Merge pull request #13656 from notatallshaw/pre-compute-Python-Requirement-speicifier

Precompute Python Requirements Candidate Lookup

Author: notatallshaw

news/13656.bugfix.rst

@@ -0,0 +1 @@
+Precompute Python Requirements on each candidate, reducing time of long resolutions.

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

@@ -164,6 +164,12 @@ def __init__(self, specifier: SpecifierSet, match: Candidate) -> None:
         self._hash: int | None = None
         self._candidate = match
 
+        # Pre-compute candidate lookup to avoid repeated specifier checks
+        if specifier.contains(match.version, prereleases=True):
+            self._candidate_lookup: CandidateLookup = (match, None)
+        else:
+            self._candidate_lookup = (None, None)
+
     def __str__(self) -> str:
         return f"Python {self.specifier}"
 
@@ -197,9 +203,7 @@ def format_for_error(self) -> str:
         return str(self)
 
     def get_candidate_lookup(self) -> CandidateLookup:
-        if self.specifier.contains(self._candidate.version, prereleases=True):
-            return self._candidate, None
-        return None, None
+        return self._candidate_lookup
 
     def is_satisfied_by(self, candidate: Candidate) -> bool:
         assert candidate.name == self._candidate.name, "Not Python candidate"