### Problem to solve On projects that only accept FF merges and therefore generally require a rebase, receiving MRs that don't have the allow_collaboration flag set means that they can't be merged from GitLab itself without being manually rebased by committers and re-submitted in a new MR or pushed directly. ### Target audience Project maintainers who wants to rebase branches before merging them to avoid merge commits. ### Proposal Add a new configuration boolean to the project, something like "require_allow_collaboration_on_merge_requests". When it is set to true, when a developer wants to create a merge request, the "allow_collaboration" checkbox would be pre-ticked and greyed out with a message along the lines of "The maintainers of <project> require that branches submitted as a merge request allow modifications, by submitting this merge request, you give them access to modify your branch." ### What does success look like, and how can we measure that? Maintainers of FF-only projects no longer receive merge requests that they can't merge because they can't rebase them.