From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Mon, 15 Oct 2012 11:53:28 GMT
Subject: Re: push race
Message-ID: <CACsJy8Aw1iM9BTqv4jmoEK+a1gzKUL0rfVGFsnebofd67LxZew@mail.gmail.com>
In-Reply-To: <vpqd30k806o.fsf@grenoble-inp.fr>

On Mon, Oct 15, 2012 at 6:05 PM, Matthieu Moy
<Matthieu.Moy@grenoble-inp.fr> wrote:
> Angelo Borsotti <angelo.borsotti@gmail.com> writes:
>
>> the push command checks first if the tips of the branches match those
>> of the remote references, and if it does uploads the snapshot.
>
> The update does two things: upload objects to the database, and then
> update the reference. Adding objects to the database does not change the
> repository until the objects are reachable from a ref. Updating the ref
> is usually done giving the expected old sha1, and locks the ref, so it
> can't change in the meantime.
>
> I don't know this part of the code very well, but check refs.c for the C
> part, and "git update-ref" for the plumbing interface.

I think it's lock_any_ref_for_update(), which is called inside
refs.c:update_ref().
-- 
Duy