Re: [PATCH] push: Correctly initialize nonfastforward in do_push.

From: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Date: Sep 16, 2009, 17:26 UTC
Message-ID: <vpqfxamby33.fsf@bauges.imag.fr>
In-Reply-To: <7vpr9q24oa.fsf@alter.siamese.dyndns.org>

Junio C Hamano <gitster@pobox.com> writes:

Show 9 quoted lines

> Matthieu Moy <Matthieu.Moy@imag.fr> writes:
>
>> The variable is assigned unconditionally in print_push_status, but
>> print_push_status is not reached by all codepaths. In particular, this
>> fixes a bug where "git push ... nonexisting-branch" was complaining about
>> non-fast forward.
>
> Hmm, the patch looks correct but I am scratching my head to see how this
> is triggered.  "git push ... nonexisting-branch" seems to get:

Short answer: trust me, without the patch, you get the non-fast forward (and valgrind tells you about conditional jump on uninitialized value), with, you don't ;-).

Longer one:

int transport_push(struct transport *transport,
		   int refspec_nr, const char **refspec, int flags,
		   int * nonfastforward)
{
[...]
		if (match_refs(local_refs, &remote_refs,
			       refspec_nr, refspec, match_flags)) {
			return -1; /* <------------------------------ you stop here */
		}
[...]
		if (!quiet || push_had_errors(remote_refs))
			print_push_status(transport->url, remote_refs,
					verbose | porcelain, porcelain,
					nonfastforward); /* <----- you would have updated nonfastforward there */
[...]
}

Actually, my initial version probably had the condition of the second if too. And with the first "return" statement in transport_push. Writting this, I'm wondering if it wouldn't be a better coding style to initialize nonfastforward to 0 within transport_push (in case other callers to transport_push appear one day, they won't get the the same bug). Second version of the patch is comming.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/