Create one "CommitIsAncestorFinder" per Rails request
Problem to solve
This was one of the hot spots identified in https://gitlab.com/gitlab-org/gitlab-ce/issues/57317
Further details
For users using Gitaly on top of NFS, accessing the Git data directly via Rugged may be faster than going through than Gitaly. A feature flag rugged_commit_is_ancestor was added in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25702 to activate the Rugged method to mitigate performance problems for some customers.
Proposal
Add a "CommitIsAncestorFinder" or similar.