Comment 4 for bug 1827741

This is still a problem: I wanted to upgrade from eoan to focal and forgot about this bug, so the upgrade failed again (I think it actually crashed this time, the GUI window disappeared, but I accidentally dismissed the "send report" prompt, so I'm not sure how exactly).

It seems the pattern is still the same: The source.list is rewritten from eoan to focal, Default-Release is unchanged, so subsequent apt operations fail. If I then remove the Default-Release and retry to retry the upgrade with `update-manager -c`, that seems to block indefinitely at some step, even before it offers to upgrade to focal.

Reverting the sources.list changes from focal to eoan *and* removing Default-Release does allow the upgrade to be started again (like the last time).

I just noticed that when you have insufficient disk space, the upgrade procedure correctly reverts the changes made to sources.list. If this would also happen with a Default-Release-based failure, then at least recovery would be a lot easier (so this is actually a second, separate problem).