Bug#970011: linux: missing build dependency on kernel-wedge in stage1 build

[Helmut Grohne <helmut@subdivi.de>]

Source: linux
Version: 5.8.7-1
Severity: important
User: helmutg@debian.org
Usertags: rebootstrap

Hi,

I'm run into a bootstrap failure caused by linux:
https://jenkins.debian.net/job/rebootstrap_hppa_gcc10/9/
| dh_prep
| dh_prep: warning: All requested packages have been excluded (e.g. via a Build-Profile or due to architecture restrictions).
| kernel-wedge install-files 5.8.0-1
| bash: kernel-wedge: command not found
| make[2]: Leaving directory '/tmp/buildd/linux/linux-5.8.7'
| make[2]: *** [debian/rules.real:573: install-udeb_hppa] Error 127
| make[1]: Leaving directory '/tmp/buildd/linux/linux-5.8.7'
| make[1]: *** [debian/rules.gen:89: binary-arch_hppa] Error 2
| make: *** [debian/rules:43: binary-arch] Error 2
| dpkg-buildpackage: error: debian/rules binary-arch subprocess returned exit status 2

What we see here is that kernel-wedge is not found while cross building
linux with the stage1 profile for hppa. This seems to be a recent thing.
It used to work earlier. I'm not sure yet, how many other architectures
are affected.

A kernel-wedge dependency is there, but it is tagged <!stage1>. That
used to be true.

Do note that the failing target is install-udeb_hppa and that in a
stage1 build, we don't produce any udebs. So in reality it seems more
likely that the whole target should be skipped, but isn't. The target
seems to be pulled in by debian/rules.gen, but that's about where I
stopped understanding the logic. Can I ask you to look into this?

In the mean time, I guess installing kernel-wedge is a viable
workaround.

While looking into linux' build profiles I was wondering whether we
still need stage1. linux gained a number of functional profiles
including pkg.linux.nokernel, pkg.linux.notools and pkg.linux.nosource.
Their combination does not exactly reproduce stage1, but it is close.
I'm wondering whether we can simply switch any stage1 user to using the
combination of these three and be done. I haven't tried whether this
actually works yet, but I believe it is feasible and you get the idea.

Helmut