Newbie question regarding 3way merge order.

Hi guys

I got a dumb question for you to wholeheartedly laugh at, and to which the answer seems to be so self evident. I'd still like a possibly authoritative statement though, just for the books.

The question is whether a (3way) merge is commutative, purely in terms of content (i.e. disregarding commit history for now). Iow if no matter in which order I merge A and B, i.e. A into B or B into A, I'd be guaranteed to arrive at the same content.

If yes, a followup question would be if the merge machinery sitting beneath rebase is exactly the same as that of a standard merge.

The reason I ask is obvious I guess. What basically interests me is if I gave a bunch of topic branches exposure on a test branch and, after resolving issues, applied them to stable, that I could be 100% sure to not introduce new issues content wise just by applying merges in a different order or form (rebase, patch set).

Thanks for feedback, Raimund.