On Sun, Feb 05, 2012 at 09:30:15PM -0800, Junio C Hamano wrote: > Jeff King <peff@xxxxxxxx> writes: > > > Sure, that's one way to do it. But I don't see any point in not allowing > > "git checkout -b" to be another way of doing it. Is there some other use > > case for "git checkout -b" from an unborn branch? Or is there some > > harmful outcome that can come from doing so that we need to be > > protecting against? Am I missing something? > > Mostly because it is wrong at the conceptual level to do so. > > git checkout -b foo > > is a short-hand for > > git checkout -b foo HEAD > > which is a short-hand for > > git branch foo HEAD && > git checkout foo > > But the last one has no chance of working if you think about it, because > "git branch foo $start" is a way to start a branch at $start and you need > to have something to point at with refs/heads/foo. > > So we are breaking the equivalence between these three only when HEAD > points at an unborn branch. I think it is only wrong at the conceptual level because you have specified the concepts in such a way that it is so. That is how git does it _now_, but the whole point of this is to change git's behavior to handle a potentially useful special case. I could also say this: "git checkout -b foo HEAD" does two things: 1. create a new branch "foo" pointing to the current sha1 of HEAD 2. point the HEAD symref at refs/heads/foo And then the proposed behavior might amend the first point to say: 1. if HEAD points to an existing ref, then create a new branch... which is perfectly consistent and simple. It does violate your "X is a short-hand for Y" above, but why is that a bad thing? It seems you are arguing against a special case _because_ it is a special case, not because it is not a reasonable thing to do or expect. Anyway. I am still not convinced that this is even a useful thing to want to do, so I am certainly not volunteering to write such a patch. So perhaps there is no point arguing about it. -Peff -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html