Pip 24.2 Cache Key Generation: Unexpected Cache Misses on Minor Version Bumps

Goal

Reduce bandwidth and storage costs for a low‑traffic Python deployment by reusing the same wheel files across repeated installs.

Unresolved Behavior

When a dependency’s minor version changes, pip’s internal cache key may change even if the wheel file is identical. This can trigger a cache miss and cause an unnecessary download from PyPI, negating the cost savings.

Key Constraints

• The cache directory is set via --cache-dir or PIP_CACHE_DIR.
• Cache hit rate depends on exact dependency tree hash.
• Current pip releases do not document a stable policy for key generation across version bumps.

Questions

1. Does pip 24.2 generate cache keys that include the full dependency version string, or does it use a more generic hash?
2. What is the documented behavior for cache key regeneration when a transitive dependency’s minor version changes but the wheel file remains the same?
3. Are there any flags or configuration options that can enforce a more stable cache key across minor version updates?