The question is how the merge should be enforced. Should the developer have to rebase their feature branch or not? The advantage of rebasing is that you can run

The question is how the merge should be enforced. Should the developer have to rebase their feature branch or not? The advantage of rebasing is that you can run CI on the rebased branch, and if it passes, it's guaranteed to pass post-merge. Not so for non-rebased merges. The downside of rebasing is that you need some kind of queuing mechanism for pull requests so that developers aren't constantly rebasing and racing each other to get changes in.