Re: [PATCH] kbuild: Restore .version auto-increment behaviour for Debian packages

Masahiro Yamada
2022-11-16T21:00:29Z

On Wed, Nov 16, 2022 at 9:28 PM Marc Zyngier <maz@kernel.org> wrote:
>
> On Wed, 16 Nov 2022 06:09:31 +0000,
> Masahiro Yamada <masahiroy@kernel.org> wrote:
> >
> > On Wed, Nov 16, 2022 at 7:05 AM Marc Zyngier <maz@kernel.org> wrote:
> > >
> > > Since 2df8220cc511 ("kbuild: build init/built-in.a just once"),
> > > generating Debian packages using 'make bindeb-pkg' results in
> > > packages that are stuck to the same .version, leading to unexpected
> > > behaviours (multiple packages with the same version).
> > >
> > > That's because the mkdebian script samples the build version
> > > before building the kernel, and forces the use of that version
> > > number for the actual build.
> > >
> > > Restore the previous behaviour by calling init/build-version
> > > instead of reading the .version file. This is likely to result
> > > in too many .version bumps, but this is what was happening before
> > > (although the bump was affecting builds made after the current one).
> >
> >
> > What do you mean by "too many .version bumps"?
> >
> > Every "make bindeb-pkg" increments the version by one.
>
> And isn't that a problem? We increase the build number pointlessly,
> even if there is *nothing* to change.

I think "make *-pkg" should increment the version every time.

The .version is incremented only when vmlinux is updated.

When you change module code, only *.ko is relinked.
The .version stays because it is embedded in vmlinux.

Even if you build the kernel first, and .version has no change,
the package contents may have some changes.

> >
> > Is there any case where it increases more?
>
> No, but that's bad enough IMHO.
>
> > > Eventually, this script should be turned into something that
> > > is a bit less counter-intuitive (building the kernel first
> > > and only then generating the packaging artefacts).
> >
> >
> > How to achieve this?
>
>
> By building the kernel *before* sampling the version number, just like
> RPM does.
>
> >
> > The version is recorded in debian/chanegelog.
> > Without it, dpkg-buildpackage fails.
>
> And again, nothing forces us to do it in that order.
>
> > In my understanding, the version must be fixed before building the kernel.
>
> Can't immediately see what mandates it, but I'm sure you know better.
>
> Anyway, the current situation needs fixing. If you're unhappy with the
> patch, feel free to replace it with something that you consider more
> appropriate.
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.