From: Stefan Beller <sbeller@google.com>
Date: Wed, 17 May 2017 17:57:34 GMT
Subject: Re: [PATCH 17/23] get_packed_ref_cache(): assume "packed-refs" won't change while locked
Message-ID: <CAGZ79kb65sv8g6XUQMcGTkZ0ubpY2LYpj7g2wv15knXuv7oKhw@mail.gmail.com>
In-Reply-To: <eedc8f85c8237515bc66584649b1e3f3d547049c.1495014840.git.mhagger@alum.mit.edu>

On Wed, May 17, 2017 at 5:05 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> If we've got the "packed-refs" file locked, then it can't change;
> there's no need to keep calling `stat_validity_check()` on it.

This change will work in a world where all Git implementations
obey a lock. If there is at least one implementation that doesn't
care about the existence of lock files we may introduce a race
here.

I am not sure if it is worth to be extra careful in the common case
though. But I could imagine some people using a git repo on an
NFS concurrently with different implementations and one of them
is an old / careless lock-ignoring implementation.

My opinion is not strong enough that I'd veto such a patch
just food for thought.

Thanks,
Stefan