Upgrade from 20.04 to 22.04 failed: Unhandled exception: AttributeError: 'DistUpgradeController' object has no attribute 'tasks'

[Hessel Keegstra]

Hi,

One of my older machines experienced an error when upgrading from Xubuntu 20.04.5 to 22.04.1

In the tail of /var/log/dist-upgrade/main.log I see:

2022-12-15 18:20:59,402 ERROR not handled exception:
Traceback (most recent call last):

  File "/tmp/ubuntu-release-upgrader-5gqd3nds/jammy", line 8, in <module>
    sys.exit(main())

  File "/tmp/ubuntu-release-upgrader-5gqd3nds/DistUpgrade/DistUpgradeMain.py", line 241, in main
    if app.run():

  File "/tmp/ubuntu-release-upgrader-5gqd3nds/DistUpgrade/DistUpgradeController.py", line 2042, in run
    return self.fullUpgrade()

  File "/tmp/ubuntu-release-upgrader-5gqd3nds/DistUpgrade/DistUpgradeController.py", line 1991, in fullUpgrade
    if not self.calcDistUpgrade():

  File "/tmp/ubuntu-release-upgrader-5gqd3nds/DistUpgrade/DistUpgradeController.py", line 1100, in calcDistUpgrade
    if not self.cache.installTasks(self.tasks):

AttributeError: 'DistUpgradeController' object has no attribute 'tasks'

2022-12-15 18:20:59,402 DEBUG running apport_crash()

I believe this error has been reported before and was said to be fixed in bug report: 1969786

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:22.04.15
ProcVersionSignature: Ubuntu 5.4.0-135.152-generic 5.4.212
Uname: Linux 5.4.0-135-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.25
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
CrashReports:
 640:0:127:2150710:2022-12-15 18:21:05.586576824 +0100:2022-12-15 18:36:17.623828781 +0100:/var/crash/_usr_bin_do-release-upgrade.0.crash
 644:0:127:0:2022-12-15 18:21:05.586576824 +0100:2022-12-15 18:35:52.023460264 +0100:/var/crash/_usr_bin_do-release-upgrade.0.upload
CurrentDesktop: XFCE
Date: Thu Dec 15 18:59:00 2022
InstallationDate: Installed on 2020-05-02 (957 days ago)
InstallationMedia: Xubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to focal on 2022-12-15 (0 days ago)
VarLogDistupgradeTermlog:

[Nick Rosbrook (enr0n)]

Marking as a duplicate of 1969786. This still has not been fixed in Jammy, because we need a reproducer for an SRU. Maybe these logs can help with that.