Is that even necessary? I would have thought that simply making the branch and pushing it while it's on the same commit as the branch you're branching from would be enough.

You can't merge a branch that is even with another.

Well, sites like GitHub could be designed so the PR appears as merged from the beginning and then enabling the "merge" button, once more commits are available. Doing it this way also allows to naturally support merging a PR/MR more than once, which I don't know if it's undesirable, but it more closely aligns with what git supports.

I thought Github looked for an actual code difference in the PR creation process, but it seems you're correct! Thanks for the tip.