branchmap: check node against changelog instead of repo Testing 'node in repo' requires constructing a changectx, which is a little expensive. Testing 'repo.changelog.hasnode(node)' is notably faster. This saves 10-20ms off of every command, when testing a few thousand nodes from the branch cache. I considered changing the implementation of localrepository.__contains__ so every place would benefit from the change, but since localrepository.__contains__ uses changectx to check if the commit exists, it means it supports a wider range of possible inputs (like revs, hashes, '.', etc), so it seemed unnecessarily risky.