In our release meeting in Brussels, we talked about blocking back-merges, where a merge is based on a later release branch, but it gets merged to an earlier branch: https://trac.torproject.org/projects/tor/wiki/org/meetings/2019BrusselsNetworkTeam/Notes/StableMaintainer#ActionItems Our merge workflow is typically: * base the bugfix branch on the maint branch for the earliest possible backport release * merge the bugfix branch to master (or alpha and master) * test for a while * merge the bugfix branch to an earlier release, then merge forward to master * merge maint-* into release-* for each release series So I'm not sure exactly how we can limit ourselves to just these merges. Here are some ideas: * Count the commits, and put a limit on the number of commits * Keep an ordered list of releases, and check that: * maint: merged branches are based on this maint release, or an earlier maint release * release: merged branches are based on the same maint release * Is there some neat trick that I'm missing?