Re: Bug: 'git am --abort' can silently reset the wrong branch

[Jeff King <peff@peff.net>]

On Fri, May 08, 2009 at 02:01:16AM -0700, Junio C Hamano wrote:

> > Switching branches and clobbering some other branch
> > with --abort is just _one_ thing you can do to screw yourself. You could
> > also have been doing useful work on the _same_ branch, and that would
> > get clobbered by --abort.  However, I'm not sure if we have a good way
> > of telling the difference between "work which I did to try to get these
> > patches to apply, but which should be thrown away when I abort" and
> > "work which I did because I forgot I had an active git-am".
> 
> I think I've said this already, but honestly speaking, I think --abort
> should not do --reset at all, but just remove the $dotest directory.  Or
> perhaps introduce a --clear option to do so.

I assumed that people actually liked the current "reset" behavior, so I
didn't want to propose getting rid of it.  Personally, I hate it. So I
would be very happy to see it ripped out entirely, and then that neatly
solves the problem (i.e., it now errs on the side of not throwing away
work).

> What I sometimes see to my users happen is to try applying to the oldest
> integration branch the patch (the users think) ought to apply, see it fail
> to apply, switch to a bit newer branch and run "am" again (trusting that
> it will pick up the material from $dotest), repeat the above and then give
> up with "git am --abort".  I do not think anybody can offhand explain to
> which branch and to what state the command takes the user back to in such
> a situation without looking at what the code actually does X-<; even
> though I think it should take the user back to the original branch, I do
> not think that is what the code does.

No, the current code clobbers whatever is in the current HEAD with
ORIG_HEAD. So not only might you set another random branch back to the
originally am'd branch, but if you did a pull in between you can pick up
some random commit.

-Peff