Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 25 Mar 2019 10:47:59 +0000
From:   Andre Przywara <andre.przywara@arm.com>
To:     Masahiro Yamada <yamada.masahiro@socionext.com>
Cc:     Vladimir Kondratiev <vladimir.kondratiev@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] kbuild: gitignore output directory
Message-ID: <20190325104759.079a18ec@donnerap.cambridge.arm.com>
In-Reply-To: <CAK7LNAT3Yf1_3L77VNjtcr5SP2eM0x19hid0J45PcHqf8Fwcwg@mail.gmail.com>
References: <20190203084840.6113-1-vladimir.kondratiev@intel.com>
        <20190322155212.133029-1-andre.przywara@arm.com>
        <CAK7LNAT3Yf1_3L77VNjtcr5SP2eM0x19hid0J45PcHqf8Fwcwg@mail.gmail.com>
Organization: ARM
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Sun, 24 Mar 2019 11:22:11 +0900
Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

Hi Masahiro,

> On Sat, Mar 23, 2019 at 12:53 AM Andre Przywara <andre.przywara@arm.com> wrote:
> >
> > Hi,
> >  
> > > When compiling into output directory using O=, many files
> > > created under KBUILD_OUTPUT that git considers
> > > as new ones; git clients, ex. "git gui" lists it, and it clutters
> > > file list making it difficult to see what was really changed
> > >
> > > Generate .gitignore in output directory that ignores all
> > > its content  
> >
> > just found this when testing -rc1.
> > Unfortunately this breaks my setup, because I keep a totally separate
> > git repository in my build directories to track (various versions of)
> > .config. So .gitignore there is carefully crafted to ignore most build
> > artefacts, but not .config, for instance.
> >
> > I am not sure how git would interact with the build directory for you?
> > Do you build into a subdirectory of the kernel tree?
> >
> > I was hoping that we would not overwrite unrelated files in directories
> > outside of the kernel tree. In case this is about a subdirectory of the
> > source tree, can we somehow check for this case?  
> 
> 
> I am not sure if it is worthwhile
> adjusting the upstream kernel to
> the workflow of an individual like this.

I would argue that we should not overwrite files in the build directory
which are unrelated to the actual kernel *build*.
Another point is that one could easily add the build (sub-)directory
to .git/info/exclude to make git ignore it, without touching any git
monitored file at all. But I couldn't find an easy way to keep
my .gitignore file in place.

> If it is, we could like this:
> 
> outputmakefile:
> ifneq ($(KBUILD_SRC),)
>         $(Q)ln -fsn $(srctree) source
>         $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree)
>         $(Q)test -e .gitignore || \
>         { echo "# this is build directory, ignore it"; echo "*"; } > .gitignore

Thanks, that looks good and fixes it for me!

Cheers,
Andre.

> endif
> 
> 
> > Cheers,
> > Andre.
> >  
> > >
> > > Signed-off-by: Vladimir Kondratiev <vladimir.kondratiev@linux.intel.com>
> > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> > > ---
> > >  Makefile | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/Makefile b/Makefile
> > > index 97ee0be24d52..d487fca342c4 100644
> > > --- a/Makefile
> > > +++ b/Makefile
> > > @@ -483,10 +483,13 @@ PHONY += outputmakefile
> > >  # outputmakefile generates a Makefile in the output directory, if using a
> > >  # separate output directory. This allows convenient use of make in the
> > >  # output directory.
> > > +# At the same time when output Makefile generated, generate .gitignore to
> > > +# ignore whole output directory
> > >  outputmakefile:
> > >  ifneq ($(KBUILD_SRC),)
> > >       $(Q)ln -fsn $(srctree) source
> > >       $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree)
> > > +     $(Q){ echo "# this is build directory, ignore it"; echo "*"; } > .gitignore
> > >  endif
> > >
> > >  ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
> > > --
> > > 2.17.1  
> >  
> 
>