Bug#1034035: linux-image-6.1.0-7-amd64: linux image installation fails dkms step if headers are absent

[Russ Hamilton <brusshamilton@gmail.com>]

Package: linux-image-6.1.0-7-amd64
Version: linux-image-6.1.0-7-amd64
Severity: normal
X-Debbugs-Cc: brusshamilton@gmail.com

Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?
I was trying to install the linux-image-6.1.0-7-amd64 package on my bullseye
system (needed newer drivers).
   * What exactly did you do (or not do) that was effective (or
     ineffective)?
I enabled the debian unstable list in my apt sources, but pinned a preference
for bullseye packages.
Then I ran `sudo apt-get install linux-image-6.1.0-7-amd64`
   * What was the outcome of this action?
The installation appeared to have succeeded (apt returned succeess), but on
further examination kernel modules for necessary drivers were missing. A close
inspection of the installation log revealed the lines:
```
/etc/kernel/postinst.d/dkms:
dkms: running auto installation service for kernel 6.1.0-7-amd64:Error! Your
kernel headers for kernel 6.1.0-7-amd64 cannot be found.
Please install the linux-headers-6.1.0-7-amd64 package,
or use the --kernelsourcedir option to tell DKMS where it's located
.
```
   * What outcome did you expect instead?
I expected either the linux 6.1.0 kernel image to be installed and any dynamic
kernel modules built or for the installation to fail due to impossible
dependencies.


Comments:
1. If the kernel installation requires the headers to function properly, then
they should probably be a package dependency.
2. If dkms fails then we should probably consider the linux image installation
as having failed and revert to a consistent state instead of continuing.

-- System Information:
Debian Release: 11.6
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500,
'proposed-updates'), (500, 'stable'), (100, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.10.0-21-amd64 (SMP w/8 CPU threads)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.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 linux-image-6.1.0-7-amd64 depends on:
ii  initramfs-tools [linux-initramfs-tool]  0.140
ii  kmod                                    28-1
ii  linux-base                              4.6

Versions of packages linux-image-6.1.0-7-amd64 recommends:
ii  apparmor             2.13.6-10
ii  firmware-linux-free  20200122-1

Versions of packages linux-image-6.1.0-7-amd64 suggests:
pn  debian-kernel-handbook  <none>
ii  grub-efi-amd64          2.06-3~deb11u5