reproducible crash in jammy: Uncaught exception: ../../src/ui.cc:1549: void auto_fix_broken(): Assertion "resman->resolver_exists()" failed.

[Rolf Leggewie]

When updating from focal to jammy I found the following reproducible way to crash aptitude.

$ apt policy python3-chardet
python3-chardet:
  Installed: 3.0.4-4build1
  Candidate: 4.0.0-1
  Version table:
     4.0.0-1 500
        500 http://de.archive.ubuntu.com/ubuntu jammy/main amd64 Packages
        500 http://de.archive.ubuntu.com/ubuntu jammy/main i386 Packages
 *** 3.0.4-4build1 500
        500 http://de.archive.ubuntu.com/ubuntu focal/main amd64 Packages
        500 http://de.archive.ubuntu.com/ubuntu focal/main i386 Packages
        100 /var/lib/dpkg/status

python3-chardet and python3-six cannot currently upgrade on my machine due to bug 1958720. Updated packages come in all the time for jammy at the moment. When I hit + on the section of "Upgradable Packages" in aptitude I am thus currently always breaking packages. Aptitude calculates a way for me to resolve the problem, usually holding a couple of packages at their current version. I accept and then aptitude still shows 2 broken packages (this is a bug in itself, I guess). I can verify with b that the broken packages are python3-chardet and python3-six. I can hold both packages with : and move on and nothing bad happens. But if I don't do that and instead rely on aptitude resolving conflicts before installing by hitting g, then aptitude will reliably crash.

$ sudo aptitude
Uncaught exception: ../../src/ui.cc:1549: void auto_fix_broken(): Assertion "resman->resolver_exists()" failed.

[Axel Beckert (xtaran)]

If you can still reproduce this, can you run "aptitude-create-state-bundle lp-1959485-crash-dist-upgrade.tbz2" and send me the resulting tar ball?

(You probably need to upload the tar-ball somewhere as these can have a size around several hundred megabytes. Not sure if Launchpad can host such big files as attachement to bug reports.)

[Rolf Leggewie (r0lf)]

Thank you Axel, for having a look.

I am in the process of creating the requested information and will make it available to you privately. Not sure if that's necessary, though as it should be fairly easy to reproduce this problem.

1) create jammy chroot/VM
2) add focal to sources.list
3) install autoradio, python-is-python2 and python3-six from focal
4) sudo aptitude and try to update autoradio but make sure python-is-python2 is kept (I assume this will trigger the resolver, let it choose to upgrade autoradio to jammy and keep the other focal packages around)
5) I was surprised to find that despite choosing a resolution from aptitude resolver, aptitude shows broken packages at this point
6) hit g and witness the crash

[Rolf Leggewie (r0lf)]

I don't currently have access to the machine that exhibited the problem but I was indeed able to reproduce the issue without any problem from a jammy pbuilder chroot this way.