acpi-override-initramfs makes update-initramfs fail when /var/lib/acpi-override/ is empty

[Manfred Hampl]

Ubuntu 20.04, but the same version is also in 20.10

user@system:~$ sudo apt install acpi-override-initramfs
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  acpi-override-initramfs
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/2.640 B of archives.
After this operation, 17,4 kB of additional disk space will be used.
Selecting previously unselected package acpi-override-initramfs.
(Reading database ... 206064 files and directories currently installed.)
Preparing to unpack .../acpi-override-initramfs_0.1+nmu1_all.deb ...
Unpacking acpi-override-initramfs (0.1+nmu1) ...
Setting up acpi-override-initramfs (0.1+nmu1) ...
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools (0.136ubuntu6.2) ...
update-initramfs: Generating /boot/initrd.img-5.4.0-42-generic
cp: cannot stat '/var/lib/acpi-override/*': No such file or directory
E: /usr/share/initramfs-tools/hooks/acpi-override failed with return 1.
update-initramfs: failed for /boot/initrd.img-5.4.0-42-generic with 1.
dpkg: error processing package initramfs-tools (--configure):
 installed initramfs-tools package post-installation script subprocess returned
error exit status 1
Errors were encountered while processing:
 initramfs-tools
E: Sub-process /usr/bin/dpkg returned an error code (1)

I assume the problematic statement is in line 18 in /usr/share/initramfs-tools/hooks/acpi-override
cp -a /var/lib/acpi-override/* "$ACPI/kernel/firmware/acpi/" || exit 1

If there is no file in /var/lib/acpi-override/ (which is to be expected at initial installation of that package) the cp command gives return code 1 and dpkg ends with an error.

In my opinion the cp command should only be executed when files exist, so it probably has to be put into some kind of "if" clause (or needs an "ignore-if-empty" option).

[Launchpad Janitor (janitor)]

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