Re: Git push failure with update hook success

From: Shawn O. Pearce <spearce@spearce.org>
Date: Mar 7, 2007, 17:38 UTC
Message-ID: <20070307173804.GC27922@spearce.org>
In-Reply-To: <17902.62836.920473.810183@lisa.zopyra.com>

Bill Lear <rael@zopyra.com> wrote:

> Ok, thank you for fixing this.  I guess the call run_update_hook()
> should not in fact come after the write_ref_sha1() block, and just
> before the 'return 0' line, because you don't want to run the
> write_ref_sha1() at all if the update hook complains.

Exactly.  :-)

Show 19 quoted lines

> >You probably want to use the post-update hook to send email.
> >This hook will always run if it exists and is executable, but it
> >won't be given a ref that failed to be updated.
> >
> >Of course an unfortunate downside to the post-update hook is it
> >does not receive the old SHA-1 of the ref; it just gets the ref name.
> 
> Hmm, I agree that this sounds like the better place, logically
> speaking, for the email report to be generated, but unfortunate since
> I'm lame with git, so writing a post-update hook from scratch will
> probably be beyond my abilities, but since I just watched "Touching
> the Void" last night, I might be inspired to brave it.
>
> Since it just gets the ref name, would one (of sufficient skill) be
> able to reconstruct the same sort of report that the "pre" update hook
> does?  That is, from the ref name can I get the old SHA-1?  If I try
> to write this, what I think I would like to do is just call the
> existing update hook from the post-update hook, with the post update
> hook figuring out the proper arguments to pass along.

If you have a reflog enabled you can use name@{1}..name to generate the list, but this is subject to a race condition as the ref could be updated by someone else before you get to look at it to generate the output.

I'm actually working on a patch right now to create a new hook
(hooks/post-receive ?) that takes the 3 arg form like hooks/update
does, avoiding the race condition entirely.

-- 
Shawn.