I prefer to say, merges should only flow one way. (And always rebase before a merge.) If you are merging master into a feature branch that has ongoing work an

I prefer to say, merges should only flow one way. (And always rebase before a merge.) If you are merging master into a feature branch that has ongoing work and continues without merging back to master, that's the problem. If your feature branch is short-lived, it can be easily rebased. If your other branch is more like a release branch, with lots of work that can't be rebased easily, some times you can't really avoid a merge from master without communicating it first. If your team is large or distributed it might not be practical to say "release has moved to (rebased ref), please catch up" In that case you should treat merges to release the same as merges to master (they should be finished bits of work that are considered published) and any unmerged features for the release, are kept on feature branches that are based on the release. They can be rebased after the point where master is merged back into release to avoid the nasty merge conflicts.