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From:   Alexander Kapshuk <alexander.kapshuk@gmail.com>
Date:   Tue, 13 Nov 2018 21:15:26 +0200
Message-ID: <CAJ1xhMW-zStA0yrxn6nWGE2CAhjky9-obOCz6=dqf-M0vr4OPQ@mail.gmail.com>
Subject: Re: [PATCH] scripts/setlocalversion: Improve -dirty check with
 git-status --no-optional-locks
To:     Brian Norris <briannorris@chromium.org>
Cc:     sky@genki.is, schwab@linux-m68k.org,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Douglas Anderson <dianders@chromium.org>,
        Guenter Roeck <linux@roeck-us.net>, lists@nerdbynature.de,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Tue, Nov 13, 2018 at 8:32 PM Brian Norris <briannorris@chromium.org> wrote:
>
> Hi Alexander,
>
> On Tue, Nov 13, 2018 at 12:36 AM Alexander Kapshuk
> <alexander.kapshuk@gmail.com> wrote:
> >
> > On Tue, Nov 13, 2018 at 2:09 AM Brian Norris <briannorris@chromium.org> wrote:
> > >
> > > On Mon, Nov 12, 2018 at 10:42:26AM +0200, Alexander Kapshuk wrote:
> > > > An even simpler approach would be:
> > > >
> > > > {
> > > >         git --no-optional-locks status -uno --porcelain 2>/dev/null ||
> > > >         git diff-index --name-only HEAD
> > > > } | grep -qv scripts/package &&
> > > >         printf '%s' -dirty
> > > >
> > > > Sample run:
> > > > cmd
> > > > sh: cmd: command not found
> > > >
> > > > {
> > > >         cmd 2>/dev/null ||
> > > >         date
> > > > } | grep -q 2018 &&
> > > >         printf '%s' ok
> > > > ok
> > >
> > > You lose accuracy here, because now you're skipping any line that
> > > contains 'scripts/package', which would include, e.g., paths like
> > >
> > >   tools/some/other-scripts/package
> > >
> > > Maybe if the grep expression were more like this?
> > >
> > >   grep -qv '^\(.. \)\?scripts/package'
> > >
> > > I think it'd be safe enough to ignore paths that start with two
> > > characters and a space, like:
> > >
> > > xy scripts/package
> > > x/ scripts/package
> > >
> > > Brian
> >
> > Thanks for your input.
> > I've found the following grep command, that uses extended regular
> > expressions, to work as required:
>
> Is there any good reason you switched to extended? It looks like my
> (basic regex) grep was equivalent.
>
> > {
> >         echo hello
> >         echo scripts/package
> >         echo '.. scripts/package'
> >         echo tools/some/other-scripts/package
> > } | grep -Ev '^(.. )?scripts/package'
> >
> > [Output]
> > hello
> > tools/some/other-scripts/package
> >
> > If the participants of this email exchange consider the proposed
> > implementation as fitting the bill,
> >
> > {
> >         git --no-optional-locks status -uno --porcelain 2>/dev/null ||
> >         git diff-index --name-only HEAD
> > } | grep -Eqv '^(.. )?scripts/package' &&
> >         printf '%s' -dirty
> >
> > Was the original committer of the patch proposed here,
> > https://lkml.org/lkml/2018/11/10/55, going to take it in, and resend it
> > as v2 of the patch, or did you want me to submit the patch instead?
> > I would be happy with either way.
>
> I can submit it. I expect Masahiro-san would prefer a proper v2 patch
> for review, given how much would change from my v1.
>
> And this time, I'll actually test it with a non-dirty tree! (Of
> course, my tree is naturally dirty when developing the patch, but I
> missed testing post-commit...)
>
> Brian

Hi Brian,

Thanks for taking my proposed patch in and submitting it.

I went with the ERE because, in my opinion, the pattern looks
'cleaner' without having the metacharacters like '()?' escaped.
EREs are POSIX-compatible, so should be supported by any POSIX-compliant shell.

Your non-ERE version does generate the same output as my ERE one. So
it just boils down to one's personal preference.

Thanks.