ubiquity fails to complete automated upgrade with python traceback in _restore_package_selection_in_cache

[Louis Bouchard]

While upgrading to 14.04, I got the following during the 'upgrade' phase of the installation :

WARNING:root:can't add zenity (E:Unable to correct problems, you have held broken packages.)
May 5 06:56:52 ubuntu ubiquity: WARNING:root:can't add zenity-common (E:Unable to correct problems, you have held broken packages.)
May 5 06:56:52 ubuntu ubiquity: WARNING:root:can't add zip (E:Unable to correct problems, you have held broken packages.)
May 5 06:56:52 ubuntu ubiquity: WARNING:root:can't add zlib1g (E:Unable to correct problems, you have held broken packages.)
May 5 06:56:52 ubuntu ubiquity: WARNING:root:can't add zlib1g-dev (E:Unable to correct problems, you have held broken packages.)
May 5 06:56:52 ubuntu ubiquity: WARNING:root:can't add zsync (E:Unable to correct problems, you have held broken packages.)
May 5 06:56:52 ubuntu ubiquity: Traceback (most recent call last):
May 5 06:56:52 ubuntu ubiquity: File "/usr/bin/apt-clone", line 131, in <module>
May 5 06:56:52 ubuntu ubiquity: args.source, args.destination, args.new_distro_codename, protect_installed)
May 5 06:56:52 ubuntu ubiquity: File "/usr/lib/python3/dist-packages/apt_clone.py", line 473, in restore_state
May 5 06:56:52 ubuntu ubiquity: self._restore_package_selection(statefile, targetdir, protect_installed)
May 5 06:56:52 ubuntu ubiquity: File "/usr/lib/python3/dist-packages/apt_clone.py", line 607, in _restore_package_selection
May 5 06:56:52 ubuntu ubiquity: self._restore_package_selection_in_cache(statefile, cache, protect_installed)
May 5 06:56:52 ubuntu ubiquity: File "/usr/lib/python3/dist-packages/apt_clone.py", line 584, in _restore_package_selection_in_cache
May 5 06:56:52 ubuntu ubiquity: resolver.resolve()

This was already reported in Bug #847475 but apparently never looked at.

I don't know if the "Unable to correct problems, you have held broken packages" have something to do with the issue, but the traceback does bring failure to the 'apt-clone' phase.

The system is installed and usable with one single user, but the rest of the environment has not been recovered

Since the problem happened during installation, running ubuntu-bug is mostly useless. I can have the logs in /var/log/installer available if needed

[Dimitri John Ledkov (xnox)]

Thanks the attached tarball does have all logs and the apt-clone tarball. In case of failure, apt-clone shouldn't crash/generated tracebacks. So it needs investigation, what's going on. Could be typical python3.4 porting issue of non-inherited FDs.