ubuntu-release-upgrader failed to calculate upgrade

You have plenty of broken packages: clean your system and downgrade to genuine versions (via ppa-purge)

https://launchpadlibrarian.net/369105806/VarLogDistupgradeAptlog.txt

@dino99, your reply is not helpful, which packages from which PPAs are you talking about?

At first glance, these 2 'extra' sources could have introduced some conflicts:

examining: 'deb http://repository.spotify.com stable non-free # Spotify'
DEBUG entry '# deb http://repository.spotify.com stable non-free # Spotify désactivé pour la mise à niveau vers bionic' was disabled (unknown mirror)
DEBUG examining: 'deb http://files.eid.belgium.be/debian artful main'
DEBUG entry '# deb http://files.eid.belgium.be/debian bionic main # désactivé pour la mise à niveau vers bionic' was disabled (unknown mirror)
DEBUG examining: 'deb http://files2.eid.belgium.be/debian artful main'
DEBUG entry '# deb http://files2.eid.belgium.be/debian bionic main # désactivé pour la mise à niveau vers bionic' was disabled (unknown mirror)
DEBUG running doUpdate() (showErrors=True)
DEBUG openCache()
DEBUG failed to SystemUnLock() (E:Non verrouillé)
DEBUG /openCache(), new cache size 90789
DEBUG need_server_mode(): run in 'desktop' mode, (because of pkg 'ubuntu-desktop')
ERROR Dist-upgrade failed: 'E:Erreur, pkgProblem::Resolve a généré des ruptures, ce qui a pu être causé par les paquets devant être gardés en l'état.'
DEBUG abort called
DEBUG openCache()
DEBUG failed to SystemUnLock() (E:Non verrouillé)

I cannot reproduce the issue with the clone. But from the look of it I am wondering if some leftover from xenial could be causing this problem.

The problem was solved by removing some conflicting packages:
- libavfilter6,
- libopencv-highgui3.1,

and then "apt autoremove".

Right but they are both official versions and shouldn't block the upgrade.

Looking closely at the Aptclonesystemstate file we can see that the installed version of libavfilter6 was actually the bionic version installed on artful.

 686 libavcodec57 7:3.3.4-2 1
 687 libavfilter6 7:3.3.4-2 1
 688 libavformat57 7:3.3.4-2 1
 689 libavresample3 7:3.3.4-2 1
 690 libavutil55 7:3.3.4-2 1

This certainly caused the failure to calculate the upgrade and is not something we can fix.

Sorry I misread the version numbers. This is actually the version from 17.10.

I installed libavfilter6 and libopencv-highgui3.1 and was not able to recreate the bug so there must be some more packages involved.