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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Tue, 1 Oct 2019 23:45:07 +0900
Message-ID: <CAK7LNARRAOk4YxFxdCvjF_eQd84nted1rhsqGhX5-UK5WKaDvA@mail.gmail.com>
Subject: Re: [PATCH] scripts/setlocalversion: clear local varaible to make it
 work for sh
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Hi Geert,

On Tue, Oct 1, 2019 at 10:20 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Yamada-san,
>
> s/varaible/variable/ in subject.
>
> On Tue, Oct 1, 2019 at 2:17 PM Masahiro Yamada
> <yamada.masahiro@socionext.com> wrote:
> > Geert Uytterhoeven reports a strange side-effect of commit 858805b336be
> > ("kbuild: add $(BASH) to run scripts with bash-extension"), which
> > inserts the contents of a localversion file in the build directory twice.
> >
> > [Steps to Reproduce]
> >   $ echo bar > localversion
> >   $ mkdir build
> >   $ cd build/
> >   $ echo foo > localversion
> >   $ make -s -f ../Makefile defconfig include/config/kernel.release
> >   $ cat include/config/kernel.release
> >   5.4.0-rc1foofoobar
> >
> > This comes down to the behavior change of 'local' variables.
> >
> > The 'man sh' on my Ubuntu machine, where sh is an alias to dash,
> > explains as follows:
> >   When a variable is made local, it inherits the initial value and
> >   exported and readonly flags from the variable with the same name
> >   in the surrounding scope, if there is one. Otherwise, the variable
> >   is initially unset.
> >
> > [Test Code]
> >
> >   foo ()
> >   {
> >           local res
> >           echo "res: $res"
> >   }
> >
> >   res=1
> >   foo
> >
> > [Result]
> >
> >   $ sh test.sh
> >   res: 1
> >   $ bash test.sh
> >   res:
> >
> > So, scripts/setlocalversion correctly works only for bash in spite of
> > its hashbang being #!/bin/sh. Nobody had noticed it before because
> > CONFIG_SHELL was previously set to sh only when bash is missing, which
> > is very unlikely to happen.
> >
> > The benefit of commit 858805b336be is to make people write portable and
> > correct code. I gave it the Fixes tag since it uncovered the issue for
> > most of people.
> >
> > Clear the variable 'res' in collect_files() to make it work for sh
> > (and it also works on distributions where sh is an alias to bash).
> >
> > Fixes: commit 858805b336be ("kbuild: add $(BASH) to run scripts with bash-extension")
> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
> Can you please use
>
>     Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> instead?

OK, I will.

Thanks.


> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
>
> Thanks, that fixes the issue for me!
>
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds


-- 
Best Regards
Masahiro Yamada