[patchback]

This is a backport of PR #8247 as merged into main (55e78bb).

Closes #8246

Repository.new_version() cleared the content cache of the distributions serving the repository when the new version was started. Until the version is complete, those distributions still serve the previous one. A request in that window therefore put the previous answer back into the cache, and it was served until it expired (ten minutes by default). Details and a reproducer are in #8246.

What changes

• The call to invalidate_cache() moves from new_version() to RepositoryVersion.__exit__. It runs through transaction.on_commit after the version is complete, so no request can see the previous version after the cache is cleared.
• A version that changes nothing is discarded and no longer clears the cache.
• Publications already invalidate after complete=True is saved. They are not touched.

Why version deletion needs no change
RepositoryVersion.delete() also clears the cache before its own transaction commits. But a version that any distribution serves cannot be deleted:

• protected_versions() covers versions set on a distribution, versions behind distributed publications and checkpoints, and the version a repository distribution serves;
• the API, cleanup_old_versions and a model hook all refuse to delete them.

Tests

• pulpcore/tests/unit/models/test_repository_cache.py:

  • the cache is cleared while the new version is already complete;
  • a version without changes leaves the cache alone.

  Both fail without the change.

• The pulpcore and pulp_file unit suites pass.

Checklist

• Commits are cleanly separated with meaningful messages (simple features and bug fixes should be squashed to one commit)
• A changelog entry or entries has been added for any significant changes
• Follows the Pulp policy on AI Usage
• (For new features) - User documentation and test coverage has been added