Comment 4 for bug 1780841

Tested an upgrade from Ubuntu 16.04 to Ubuntu 18.04:

bdmurray@clean-xenial-amd64:/tmp/u-r-u$ head /var/log/dist-upgrade/main.log
2018-07-11 15:30:56,243 INFO Using config files '['./DistUpgrade.cfg.xenial']'
2018-07-11 15:30:56,243 INFO uname information: 'Linux clean-xenial-amd64 4.4.0-121-generic #145-Ubuntu SMP Fri Apr 13 13:47:23 UTC 2018 x86_64'
2018-07-11 15:30:56,530 INFO apt version: '1.2.26'
2018-07-11 15:30:56,531 INFO python version: '3.5.2 (default, Nov 23 2017, 16:37:01)
[GCC 5.4.0 20160609]'
2018-07-11 15:30:56,534 INFO release-upgrader version '18.04.20' started
2018-07-11 15:30:56,537 INFO locale: 'en_US' 'UTF-8'
2018-07-11 15:30:56,756 DEBUG Using 'DistUpgradeViewText' view
2018-07-11 15:30:56,801 DEBUG enable dpkg --force-overwrite
2018-07-11 15:30:56,834 DEBUG creating statefile: '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'
bdmurray@clean-xenial-amd64:/tmp/u-r-u$ snap list
Name Version Rev Tracking Developer Notes
core 16-2.33.1 4917 stable canonical core
gnome-3-26-1604 3.26.0 70 stable canonical -
gnome-calculator 3.28.2 180 stable/… canonical -
gnome-characters 3.28.2 103 stable/… canonical -
gnome-logs 3.28.2 37 stable/… canonical -
gnome-system-monitor 3.28.2 51 stable/… canonical -
gtk-common-themes 0.1 319 stable/… canonical -
bdmurray@clean-xenial-amd64:/tmp/u-r-u$ for p in gnome-calculator gnome-characters gnome-logs gnome-system-monitor; do apt-cache policy $p; done
gnome-calculator:
  Installed: 1:3.28.1-1ubuntu1
  Candidate: 1:3.28.1-1ubuntu1
  Version table:
 *** 1:3.28.1-1ubuntu1 500
        500 http://192.168.10.7/ubuntu bionic/main amd64 Packages
        100 /var/lib/dpkg/status
gnome-characters:
  Installed: (none)
  Candidate: 3.28.2-0ubuntu1
  Version table:
     3.28.2-0ubuntu1 500
        500 http://192.168.10.7/ubuntu bionic-updates/main amd64 Packages
     3.28.0-3 500
        500 http://192.168.10.7/ubuntu bionic/main amd64 Packages
gnome-logs:
  Installed: (none)
  Candidate: 3.28.0-1
  Version table:
     3.28.0-1 500
        500 http://192.168.10.7/ubuntu bionic/main amd64 Packages
gnome-system-monitor:
  Installed: (none)
  Candidate: 3.28.2-0ubuntu1
  Version table:
     3.28.2-0ubuntu1 500
        500 http://192.168.10.7/ubuntu bionic-updates/main amd64 Packages
     3.28.1-1 500
        500 http://192.168.10.7/ubuntu bionic/main amd64 Packages

The fact that gnome-calculator was not removed was expected because unity-scope-calculator depends on it. From /var/log/dist-upgrade/main.log:

2018-07-11 16:55:42,517 DEBUG Start checking for obsolete pkgs
2018-07-11 16:56:07,402 DEBUG package 'gnome-calculator' has unwanted removals, skipping
2018-07-11 16:56:11,692 DEBUG 'gnome-calculator' scheduled for remove but not safe to remove, skipping
2018-07-11 16:56:26,776 DEBUG Finish checking for obsolete pkgs

This completes the main verification of the SRU there is still some additional testing needed though.