Bug#1018878: live-build: dealing with firmware files provided by multiple packages

[Raphael Hertzog <raphael@offensive-security.com>]

Package: live-build
Version: 1:20220505
Severity: normal
User: devel@kali.org
Usertags: origin-kali

Looking closely at the issue that I reported in #1018873, I realize that
the Contents file have those entries:
lib/firmware/nvidia/470.141.03/gsp.bin      non-free/kernel/nvidia-kernel-support,non-free/kernel/nvidia-tesla-470-kernel-support
lib/firmware/nvidia/510.85.02/gsp.bin       non-free/kernel/nvidia-tesla-510-kernel-support,non-free/kernel/nvidia-tesla-kernel-support

But live-build only tries to install "nvidia-tesla-470-kernel-support" and
"nvidia-tesla-kernel-support" so the last packages mentionned on each
line. It completely ignores the first package...

But given that two packages providing the same file are conflicting, we
can't install both packages. But we have no hints on which package
is most appropriate either.

This sounds like sub-optimal packaging on the nvidia side.

But the problem is real and I believe that live-build should do something
when it detects it instead of randomly picking one or the other.

My suggestion is "skip the line entirely and put a warning in the log".

What do you think?

-- Package-specific info:

-- System Information:
Debian Release: bookworm/sid
  APT prefers stable-security
  APT policy: (500, 'stable-security'), (500, 'unstable'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 5.18.0-3-amd64 (SMP w/16 CPU threads; PREEMPT)
Kernel taint flags: TAINT_WARN
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages live-build depends on:
ii  debootstrap  1.0.127

Versions of packages live-build recommends:
ii  apt-utils                       2.5.2
ii  bzip2                           1.0.8-5
ii  cpio                            2.13+dfsg-7
ii  cryptsetup                      2:2.5.0-2
ii  file                            1:5.41-4
ii  live-boot-doc                   1:20220505
ii  live-config-doc                 11.0.3
ii  live-manual-html [live-manual]  2:20151217.2
ii  rsync                           3.2.5-1
ii  systemd-container               251.4-1
ii  wget                            1.21.3-1+b2
ii  xz-utils                        5.2.5-2.1

Versions of packages live-build suggests:
ii  e2fsprogs  1.46.5-2
ii  mtd-utils  1:2.1.4-1+b1
ii  parted     3.5-1

-- no debconf information

-- 
Raphaël Hertzog