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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Fri, 9 Nov 2018 11:55:10 +0900
Message-ID: <CAK7LNATr-PgQn8OmPX835zS_mJdMnAw4odRX-+UdWJimgs++Rw@mail.gmail.com>
Subject: Re: [PATCH] Revert "scripts/setlocalversion: git: Make -dirty check
 more robust"
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Genki Sky <sky@genki.is>, Brian Norris <briannorris@chromium.org>,
        Christian Kujau <lists@nerdbynature.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, Nov 8, 2018 at 5:58 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> 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.


I agree.
We should avoid any write attempt to the source tree for any reason.


> Ubuntu 16.04 ships with git version 2.7.4.
>
> Guenter


-- 
Best Regards
Masahiro Yamada