(this is a rewrite of the original question as suggested in the comments)
I'm running Ubuntu 22.04 and am using firefox from the mozillateam ppa. My setup has ppa-firefox at priority 1001 (as suggested here) and my snap-firefox at priority 500 (default). Today, unattended-upgrades silently replaced my ppa-firefox with snap-firefox and I have trouble figuring out why.
I managed to reinstall my ppa-firefox with a simple apt-get remove firefox; apt-get install firefox so I suspect the priorities are working, but unattended-upgrade somehow didn't respect them. The question is why?
Here's my ppa-firefox app-pin:
$ cat /etc/apt/preferences.d/mozilla-firefox
Package: *
Pin: release o=LP-PPA-mozillateam
Pin-Priority: 1001
Here's my current apt-cache policy after reinstalling firefox:
# apt-cache policy firefox
firefox:
Installed: 120.0+build1-0ubuntu0.22.04.1~mt1
Candidate: 120.0+build1-0ubuntu0.22.04.1~mt1
Version table:
1:1snap1-0ubuntu2 500
500 http://de.archive.ubuntu.com/ubuntu jammy/main amd64 Packages
*** 120.0+build1-0ubuntu0.22.04.1~mt1 1001
1001 https://ppa.launchpadcontent.net/mozillateam/ppa/ubuntu jammy/main amd64 Packages
100 /var/lib/dpkg/status
The unattended-upgrades-log admits it:
$ grep 'Unpacking firefox' /var/log/unattended-upgrades/unattended-upgrades-dpkg.log
Unpacking firefox (1:1snap1-0ubuntu2) over (119.0.1+build1-0ubuntu0.22.04.1~mt1)
EDIT: I have since given priority -1 to both snap and snap-firefox, as suggested in comments and answers to the questions above. So, I suppose this is fixed, but the question why unattended-upgrades replaced my ppa-firefox in spite of its higher priority (1001 > 500) remains open.