I strive to have every commit be meaningful/buildable/testable/etc. To that end, I use a lot of `git rebase -x` to massage the pull request into a reasonable sequence of commits that “tell a story”. Having a bunch of “fixing foo” commits is ugly to me and reduces my ability to bisect problems later on.

Sometimes I will actually create the fixup commits and push them separately to communicate with the submitter, but then squash them into the appropriate places in history before merging.

The only technical issue is when someone has signed their commits, as I obviously cannot re-sign them :-). In that case, I call it out to them and let them re-sign if they want before I merge.