Debian: Update for trixie-backports

[rlaager]

This needs to be tested.

The change from 500 to 990 may be incorrect. Looking at the apt_preferences docs again, actually 990 is used if a “target release” is set. So I’d have to test that some more. If you don’t have a “target release”, then 500 is the default and 500 here would be fine. But if your target release is trixie or stable, then the backport might lose. It depends on which field that is matching and how that field is set in backports.

[wommy]

Re: Pin-Priority for trixie-backports

Hey @rlaager - You're right to question 990. I agree 500 should be used, and here's why.

Why Not 990

From apt_preferences(5), priority 990 overrides target release settings. Priority 500 is the standard default where version numbers decide between equal-priority repos.

The Behavior

With default APT config, backports has higher versions (2.2.6 vs 2.2.3), so it wins at priority 500. Security updates go to backports first with bumped versions.

$ apt policy zfs-dkms
  500 http://deb.debian.org/debian trixie/main           (2.2.3)
  500 http://deb.debian.org/debian trixie-backports/main (2.2.6)
  Candidate: 2.2.6~rc1-1~bpo12+1

The APT::Default-Release Edge Case

The Debian Wiki discourages setting APT::Default-Release because it breaks security updates.

If someone sets it anyway, stable gets priority 990. With pin 500, stable wins (990 > 500). With pin 990, they tie unpredictably. Normal users won't hit this - it's a larger configuration issue outside the scope of pin priority.

The Recommendation

 Package: src:zfs-linux
 Pin: release n=trixie-backports
-Pin-Priority: 990
+Pin-Priority: 500

There's ongoing discussion about best practices, but this is a sensible default. Users who need different behavior can override locally.

References

• apt_preferences(5) - APT priority specification
• Debian Wiki: APT::Default-Release - Why it's discouraged