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Date:   Wed, 7 Nov 2018 12:55:14 -0800
From:   Guenter Roeck <linux@roeck-us.net>
To:     Genki Sky <sky@genki.is>
Cc:     Brian Norris <briannorris@chromium.org>, lists@nerdbynature.de,
        yamada.masahiro@socionext.com,
        Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Revert "scripts/setlocalversion: git: Make -dirty check
 more robust"
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On Wed, Nov 07, 2018 at 12:43:58PM -0800, Genki Sky wrote:
> On Wed, 7 Nov 2018 10:44:37 -0800, Brian Norris <briannorris@chromium.org> wrote:
> > On Tue, Nov 06, 2018 at 08:00:36PM -0800, Brian Norris wrote:
> > > On a different tangent: how about the --no-optional-locks (see
> > > git(1))? Will this get you your "up-to-date" result without writing to
> > > the .git directory? I've only read the documentation, but not tested
> > > it.
> 
> This option definitely seems to be what we want, good find.
> 
> > Unfortunately, --no-optional-locks is new as of git 2.14. Dunno how new
> > of a git we expect people to use.
> 
> Hmm, I'm not sure who can speak to this.
> 
> Though if it's too recent, then based on earlier discussion, it sounds
> like something like this (hack) might work best:
> 
>   [ -w .git ] &&
>           touch .git/some-file-here 2>/dev/null &&
>           git update-index --refresh --unmerged >/dev/null
>   if git diff-index --name-only HEAD | ...

I do not think it is a good idea to create a random file in the .git directory
under any circumstance, and much less so if an output directory was specified,
no matter if the path is read-only or not. I also still think that it is a
bad idea to touch the source tree if an output directory was specified.
It defeats the purpose of specifying an output directory.

Ubuntu 16.04 ships with git version 2.7.4.

Guenter