Re: [PATCH 4/4] core.abbrev: raise the default abbreviation to 12 hexdigits

From: Jeff King <peff@peff.net>
Date: Sep 30, 2016, 07:47 UTC
Message-ID: <20160930074708.pthqg4ttl5rtpy3i@sigill.intra.peff.net>
In-Reply-To: <xmqqbmz6cna5.fsf@gitster.mtv.corp.google.com>

On Thu, Sep 29, 2016 at 04:13:38PM -0700, Junio C Hamano wrote:

Show 16 quoted lines

> There are very early ones in the program startup sequence in the
> following functions, but I do not think of a reason why our new and
> early call to prepare_packed_git() might be problematic, given that
> all of them require us to have an access to the repository (i.e.
> this change cannot introduce a regression where a command used to
> work outside a repository but barf when prepare_packed_git() is
> called early):
> 
>  - builtin/describe.c
>  - builtin/rev-list.c
>  - builtin/rev-parse.c
> 
> I thought that the one in diff.c might be problematic when the "git
> diff" command is run outside a repository with the "--no-index"
> option, but it appears that init_default_abbrev() seems to be OK
> when run outside a repository.

Actually, "diff --no-index" is currently buggy in this regard. In the followup series to jk/setup-sequence-update (which I mentioned but haven't posted yet), I teach get_object_dir() not to blindly default to ".git", and found that "diff --no-index" is perfectly happy to look in ".git/objects" for find_unique_abbrev(), even when we know there's no repository (or it has an unknown vintage).

I fixed it there by just using the default abbrev value for out-of-repo diffs, and skip calling find_unique_abbrev() at all. That would here, too.

But if we add object-store initialization at other times, it's a potential conflict. IMHO this should stay inside find_unique_abbrev(), where we know we already must look at the object store.

-Peff