Missing depends on python3-apt in grub-common

[Simon Poirier]

/usr/lib/grub/grub-sort-version fails to run on buildd due to a missing dependency on python3-apt (providing the apt_pkg python module). This shows in buildd images and other systems which might not have python3-apt.

This doesn't make update-grub fail, but has the nasty side-effect of failing to generate kernel/initrd menu entries.

Reproducing (in a fresh minimal VM):

# apt-get remove python3-apt # unless you happen to have an image which already hasn't it.
# update-grub
root@tstn:~# update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/50-cloudimg-settings.cfg'
Generating grub configuration file ...
Traceback (most recent call last):
  File "/usr/lib/grub/grub-sort-version", line 4, in <module>
    import apt_pkg
ModuleNotFoundError: No module named 'apt_pkg'
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
Adding boot menu entry for UEFI Firmware Settings ...
done
# grep vmlinuz /boot/grub/grub.cfg
EOF

Expected:

# update-grub
# grep /boot/grub/grub.cfg
 linux /vmlinuz-6.6.0-14-generic root=UUID=09855eaa-8c6....

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Philip Roche (philroche)]

This appears to be a dup of https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/2048953