[Bug 1896810] Re: Cannot upgrade Kubuntu from 18.04 to 20.04

[Andy Pienkowski]

Reading the main.log and apt.log files, it turns out my Ubuntu 20.04
upgrade was prevented because of a redundant Python 2 installation.
Since Python 3.7+ is now the Python installation of choice for the
latest Linux systems, it's possible to remove Python 2 without any
impact to the Ubuntu installation.

The removal of Python 2 followed from my Ubuntu 18.04 installation only
by using the following command:

sudo apt remove python-minimal

Hope this solves your Ubuntu 20.04 installation problems like it solved
mine.

If you want to reinstall Python 2 after upgrading to Ubuntu 20.04 for
any reason, you can do this with:

sudo apt install python-minimal

or

sudo apt install python2

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https://bugs.launchpad.net/bugs/1896810

Title:
  Cannot upgrade Kubuntu from 18.04 to 20.04

Status in ubuntu-release-upgrader package in Ubuntu:
  Confirmed

Bug description:
  I am trying to update from Kubuntu 18.04 to 20.04. This is the
  command:

  `sudo do-release-upgrade -dm desktop`

  My system is:

  ```
  Description:    Ubuntu 18.04.5 LTS
  Release:        18.04
  ```

  Unfortunately I keep getting this error:

  ```
  An unresolvable problem occurred while calculating the upgrade. 

  This was likely caused by: 
  * Unofficial software packages not provided by Ubuntu 
  Please use the tool 'ppa-purge' from the ppa-purge 
  package to remove software from a Launchpad PPA and 
  try the upgrade again. 

  If none of this applies, then please report this bug using the 
  command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If 
  you want to investigate this yourself the log files in 
  '/var/log/dist-upgrade' will contain details about the upgrade. 
  Specifically, look at 'main.log' and 'apt.log'.
  ```

  Reading the main.log file I keep getting problems about kubuntu-
  desktop package:

  ```
  2020-09-23 19:38:30,750 ERROR NvidiaDetection returned a error: invalid literal for int() with base 10: 'server'
  2020-09-23 19:38:30,754 DEBUG Installing 'baloo-kf5' (kubuntu-desktop PostUpgradeInstall rule)
  2020-09-23 19:38:30,754 DEBUG Removing 'powermanagement-interface' (kubuntu-desktop PostUpgradeRemove rule)
  2020-09-23 19:38:30,754 DEBUG Removing 'guidance-power-manager' (kubuntu-desktop PostUpgradeRemove rule)
  2020-09-23 19:38:30,754 DEBUG Removing 'kde-guidance-powermanager' (kubuntu-desktop PostUpgradeRemove rule)
  2020-09-23 19:38:30,755 DEBUG Removing 'kmix' (kubuntu-desktop PostUpgradeRemove rule)
  2020-09-23 19:38:30,755 DEBUG quirks: running PostDistUpgradeCache
  2020-09-23 19:38:30,755 DEBUG running Quirks.PostDistUpgradeCache
  2020-09-23 19:38:30,986 DEBUG Comparing 5.4.0-42 with
  2020-09-23 19:38:30,986 DEBUG Comparing 5.4.0-48 with 5.4.0-42
  2020-09-23 19:38:31,099 INFO installing linux metapackage: linux-generic
  2020-09-23 19:38:31,099 DEBUG Installing 'linux-generic' (linux metapackage may have been accidentally uninstalled)
  2020-09-23 19:38:31,135 DEBUG Marking 'kubuntu-desktop' for upgrade
  2020-09-23 19:38:31,323 WARNING Can't mark 'kubuntu-desktop' for upgrade (E:Unable to correct problems, you have held broken packages.)
  2020-09-23 19:38:31,747 ERROR Dist-upgrade failed: 'Broken packages after upgrade: kubuntu-desktop'
  ```

  I have already tried to:

  - uninstall the package before upgrade
  - reinstall the package before upgrade
  - update the package before upgrade

  What can I do?

  Thanks!

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: ubuntu-release-upgrader-core 1:18.04.38
  ProcVersionSignature: Ubuntu 5.4.0-48.52~18.04.1-generic 5.4.60
  Uname: Linux 5.4.0-48-generic x86_64
  NonfreeKernelModules: nvidia_modeset nvidia
  ApportVersion: 2.20.9-0ubuntu7.17
  Architecture: amd64
  CrashDB: ubuntu
  CurrentDesktop: KDE
  Date: Wed Sep 23 19:38:46 2020
  InstallationDate: Installed on 2019-11-23 (305 days ago)
  InstallationMedia: Kubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to bionic on 2020-09-23 (0 days ago)

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