[Bug 1888575] Re: Split motd-news config into a new package

Tue Aug 25 20:40:22 UTC 2020

Bionic verification

This verification is quite long, given the amount of tests involved.

TL;DR All tests from (a) to (j) passed as required.

bionic verification succeeded.

Latest updates from bionic:
base-files:
 *** 10.1ubuntu2.9 500
        500 http://br.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
and
ubuntu-server:
 *** 1.417.4 500
        500 http://br.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages

a) base-files installed, ubuntu-server installed, unmodified /e/d/motd-news
apt install base-files
- upgrades ubuntu-server
- installs motd-news-config
- /e/d/motd-news remains, motd-news remains enabled

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.9 amd64        Debian base system miscellaneous files
ii  ubuntu-server  1.417.4       amd64        The Ubuntu Server system

Unmodified config:
$ dpkg -s base-files | grep /etc/default/motd-news; echo -n ' '; md5sum /etc/default/motd-news | awk '{print $2,$1}'
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c

Installing base-files pulls in motd-news-config and upgrades base-files and ubuntu-server:
ubuntu at bionic-motd-news-split:~$ sudo apt install base-files
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  motd-news-config ubuntu-server
Recommended packages:
  grub-legacy-ec2
The following NEW packages will be installed:
  motd-news-config
The following packages will be upgraded:
  base-files ubuntu-server
2 upgraded, 1 newly installed, 0 to remove and 14 not upgraded

motd-news remains enabled:
ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force

 * Are you ready for Kubernetes 1.19? It's nearly here! Try RC3 with
   sudo snap install microk8s --channel=1.19/candidate --classic

   https://microk8s.io/ has docs and details.

config is now part of motd-news-config package:
ubuntu at bionic-motd-news-split:~$ dpkg -s motd-news-config | grep /etc/default/motd-news; echo -n ' '; md5sum /etc/default/motd-news | awk '{print $2,$1}'
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c

b) base-files installed, ubuntu-server installed, modified /e/d/motd-news
apt install base-files
- upgrades ubuntu-server
- installs motd-news-config
- /e/d/motd-news remains with the original modification

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.9 amd64        Debian base system miscellaneous files
ii  ubuntu-server  1.417.4       amd64        The Ubuntu Server system

Modified config:
ubuntu at bionic-motd-news-split:~$ sudo sed -i "s,^ENABLED=.*,ENABLED=0," /etc/default/motd-news
ubuntu at bionic-motd-news-split:~$ dpkg -s base-files | grep /etc/default/motd-news; echo -n ' '; md5sum /etc/default/motd-news | awk '{print $2,$1}'
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c
 /etc/default/motd-news e2d38a5c7454c64a967d6a2fe033558f

motd-news disabled with that modification:
ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at bionic-motd-news-split:~$ echo $?
0

Running apt install base-files also pulls in motd-news-config and upgrades ubuntu-server:
ubuntu at bionic-motd-news-split:~$ sudo apt install base-files
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  motd-news-config ubuntu-server
Recommended packages:
  grub-legacy-ec2
The following NEW packages will be installed:
  motd-news-config
The following packages will be upgraded:
  base-files ubuntu-server
2 upgraded, 1 newly installed, 0 to remove and 14 not upgraded.

Config file now belongs to motd-news-config, and is still flagged as modified:
ubuntu at bionic-motd-news-split:~$ dpkg -s motd-news-config | grep /etc/default/motd-news; echo -n ' '; md5sum /etc/default/motd-news | awk '{print $2,$1}'
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c
 /etc/default/motd-news e2d38a5c7454c64a967d6a2fe033558f

And motd-news remains disabled because of the modification:
ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at bionic-motd-news-split:~$ echo $?
0

And no other config file is in /e/d:
ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 682 Aug 25 19:26 /etc/default/motd-news

c) base-files installed, ubuntu-server not installed, unmodified /e/d/motd-news
apt install base-files
- upgrades base-files
- removes /e/d/motd-news
- motd-news is disabled

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching ubuntu-server
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.9 amd64        Debian base system miscellaneous files

Unmodified config:
ubuntu at bionic-motd-news-split:~$ dpkg -s base-files | grep /etc/default/motd-news; echo -n ' '; md5sum /etc/default/motd-news | awk '{print $2,$1}'
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c

apt install base-files upgrades base-files and only that:
ubuntu at bionic-motd-news-split:~$ sudo apt install base-files
...
The following packages will be upgraded:
  base-files
1 upgraded, 0 newly installed, 0 to remove and 14 not upgraded.

Config file is gone, motd-news is disabled:
ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory

ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at bionic-motd-news-split:~$ echo $?
0

d) base-files installed, ubuntu-server not installed, modified /e/d/motd-news
apt install base-files
- upgrades base-files
- /e/d/motd-news gets renamed to backup
- motd-news is disabled

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching ubuntu-server
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.9 amd64        Debian base system miscellaneous files

Modified config:
ubuntu at bionic-motd-news-split:~$ sudo sed -i "s,^ENABLED=.*,ENABLED=0," /etc/default/motd-news 
ubuntu at bionic-motd-news-split:~$ dpkg -s base-files | grep /etc/default/motd-news; echo -n ' '; md5sum /etc/default/motd-news | awk '{print $2,$1}'
 /etc/default/motd-news c08a329a603b640095da5ffe4e73491c
 /etc/default/motd-news e2d38a5c7454c64a967d6a2fe033558f

Due to the modification, motd-news is disabled:
ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at bionic-motd-news-split:~$ echo $?
0

apt install base-files upgrades just base-files, and leaves a backup config around:
ubuntu at bionic-motd-news-split:~$ sudo apt install base-files
...
The following packages will be upgraded:
  base-files
1 upgraded, 0 newly installed, 0 to remove and 14 not upgraded.

motd-news remains disabled, since there is just the renamed config file around now:
ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at bionic-motd-news-split:~$ echo $?
0
ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 682 Aug 25 19:31 /etc/default/motd-news.dpkg-bak
ubuntu at bionic-motd-news-split:~$

e) removing motd-news-config will also remove ubuntu-server (since it's a depends, and not a recommends)

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
ii  base-files       10.1ubuntu2.10 amd64        Debian base system miscellaneous files
ii  motd-news-config 10.1ubuntu2.10 all          Configuration for motd-news shipped in base-files
ii  ubuntu-server    1.417.5        amd64        The Ubuntu Server system

ubuntu at bionic-motd-news-split:~$ sudo apt remove motd-news-config
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  motd-news-config ubuntu-server
0 upgraded, 0 newly installed, 2 to remove and 14 not upgraded.

f) upgrading just ubuntu-server should pull motd-news-config in, and force-upgrade base-files

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.9 amd64        Debian base system miscellaneous files
ii  ubuntu-server  1.417.4       amd64        The Ubuntu Server system

ubuntu-server pulls in motd-news-config and also upgrades base-files:
ubuntu at bionic-motd-news-split:~$ sudo apt install ubuntu-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  base-files motd-news-config
The following NEW packages will be installed:
  motd-news-config
The following packages will be upgraded:
  base-files ubuntu-server
2 upgraded, 1 newly installed, 0 to remove and 14 not upgraded.

g) Removing motd-news-server leaves /e/d/motd-news around; purging motd-news-server removes the /e/d/motd-news config file

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
ii  base-files       10.1ubuntu2.10 amd64        Debian base system miscellaneous files
ii  motd-news-config 10.1ubuntu2.10 all          Configuration for motd-news shipped in base-files
ii  ubuntu-server    1.417.5        amd64        The Ubuntu Server system
ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 682 Aug  7 20:02 /etc/default/motd-news

Removing:
ubuntu at bionic-motd-news-split:~$ sudo apt remove motd-news-config
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  motd-news-config ubuntu-server
0 upgraded, 0 newly installed, 2 to remove and 14 not upgraded.
(...)
Removing motd-news-config (10.1ubuntu2.10) ...

ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 682 Aug  7 20:02 /etc/default/motd-news

Purging (same starting point, not shown for brevity):
ubuntu at bionic-motd-news-split:~$ sudo apt purge motd-news-config
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  motd-news-config* ubuntu-server*
0 upgraded, 0 newly installed, 2 to remove and 14 not upgraded.
(...)
Purging configuration files for motd-news-config (10.1ubuntu2.10) ...

ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory
ubuntu at bionic-motd-news-split:~$

h) base-files installed, ubuntu-server installed, removed /e/d/motd-news
- apt install base-files
- upgrades base-files, upgrades ubuntu-server, installs motd-news-config
- /e/d/motd-news is installed with ENABLED=0

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.9 amd64        Debian base system miscellaneous files
ii  ubuntu-server  1.417.4       amd64        The Ubuntu Server system
ubuntu at bionic-motd-news-split:~$ sudo rm /etc/default/motd-news
ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory

ubuntu at bionic-motd-news-split:~$ head -n 7 /etc/default/motd-news 
# Enable/disable the dynamic MOTD news service
# This is a useful way to provide dynamic, informative
# information pertinent to the users and administrators
# of the local system
# Changed by motd-news-config.postinst:
# config file was manually removed - disable the service
ENABLED=0

i) base-files installed, ubuntu-server NOT installed, removed e/d/motd-news
- apt install base-files
- base-files is upgraded
- no /e/d/motd-news is installed, motd-news remains disabled

Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching ubuntu-server
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.9 amd64        Debian base system miscellaneous files
ubuntu at bionic-motd-news-split:~$ sudo rm /etc/default/motd-news
ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory

ubuntu at bionic-motd-news-split:~$ sudo apt install base-files
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be upgraded:
  base-files
1 upgraded, 0 newly installed, 0 to remove and 14 not upgraded.

motd-news remains disabled, but the zero-sized ".wasremoved" file remains:
ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
-rw-r--r-- 1 root root 0 Aug 25 19:43 /etc/default/motd-news.wasremoved
ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at bionic-motd-news-split:~$ echo $?
0

j) Perform a release upgrade from the previous ubuntu release to the one being tested while having ubuntu-server NOT installed (or use a desktop install). At the end, motd-news should be disabled. Verify with:

$ sudo /etc/update-motd.d/50-motd-news --force
$ (no output)

j1) Without applying the bionic proposed update, i.e., no bionic-proposed packages installed (unlikely scenario, as the release upgrader wants the current release to be up-to-date):
Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching ubuntu-server
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.9 amd64        Debian base system miscellaneous files

I did something a bit risky and added a sources.list line for focal-proposed, so the release upgrade used focal-proposed which might break for unrelated reasons.
But during the confirmation step I, the details page already showed just base-files being upgraded and no motd-news-config package being installed.

Status after the release upgrade finished:
ubuntu at bionic-motd-news-split:~$ apt-cache policy base-files
base-files:
  Installed: 11ubuntu5.2
  Candidate: 11ubuntu5.2
  Version table:
 *** 11ubuntu5.2 500
        500 http://br.archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages

motd-news disabled:
ubuntu at bionic-motd-news-split:~$ ls -la /etc/default/motd-news*
ls: cannot access '/etc/default/motd-news*': No such file or directory
ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at bionic-motd-news-split:~$ echo $?
0

j2) With the bionic proposed update applied to a non-server system:
Starting point:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching motd-news-config
ii  base-files     10.1ubuntu2.10 amd64        Debian base system miscellaneous files

motd-news is already disabled, because there is no /etc/default/motd-news config file.
To make sure the focal-proposed base-files is used, I added a focal-proposed sources.list line like in the previous (j1) case, and just prior to running do-release-upgrade, removed the bionic-proposed one.
The page showing what would be upgraded and installed only listed base-files and not motd-news-config, as expected.

Status at the end:
base-files from focal-proposed installed as expected:
ubuntu at bionic-motd-news-split:~$ apt-cache policy base-files
base-files:
  Installed: 11ubuntu5.2
  Candidate: 11ubuntu5.2
  Version table:
 *** 11ubuntu5.2 500
        500 http://br.archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages

No motd-news-config installed:
ubuntu at bionic-motd-news-split:~$ dpkg -l base-files ubuntu-server motd-news-config | grep ^ii
dpkg-query: no packages found matching motd-news-config
ii  base-files     11ubuntu5.2  amd64        Debian base system miscellaneous files

motd-news disabled:
ubuntu at bionic-motd-news-split:~$ sudo /etc/update-motd.d/50-motd-news --force
ubuntu at bionic-motd-news-split:~$ echo $?
0

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to ubuntu-meta in Ubuntu.
https://bugs.launchpad.net/bugs/1888575

Title:
  Split motd-news config into a new package

Status in base-files package in Ubuntu:
  Fix Released
Status in ubuntu-meta package in Ubuntu:
  Fix Released
Status in base-files source package in Xenial:
  Fix Committed
Status in ubuntu-meta source package in Xenial:
  Fix Committed
Status in base-files source package in Bionic:
  Fix Committed
Status in ubuntu-meta source package in Bionic:
  Fix Committed
Status in base-files source package in Focal:
  Fix Committed
Status in ubuntu-meta source package in Focal:
  Fix Committed
Status in base-files source package in Groovy:
  Fix Released
Status in ubuntu-meta source package in Groovy:
  Fix Released

Bug description:
  [Impact]
  The motd-news script is largely useless for desktop users, as they rarely login via a text console. It makes more sense for server users.

  We can use package dependencies to have the motd-news script enabled on servers, but disabled on desktops, and still handle upgrades. This is the plan:
  - move /etc/default/motd-news from base-files into a new binary package (motd-news-config, produced by src:base-files)
  - have ubuntu-server depend on motd-news-config
  - have base-files break current ubuntu-server, so that if base-files if upgraded and ubuntu-server is installed, ubuntu-server will also be upgraded to the new version which has the depends on motd-news-config

  Care must be taken to preserve a changed /etc/default/motd-news when
  the upgrade installs the new motd-news-config package. For example, on
  a server that has set ENABLED=0 in /etc/default/motd-news and upgrades
  to the new base-files and ubuntu-server, and gets the new motd-config-
  news package, ENABLED=0 must remain set.

  [Test Case]
  a) base-files installed, ubuntu-server installed, unmodified /e/d/motd-news
  apt install base-files
  - upgrades ubuntu-server
  - installs motd-news-config
  - /e/d/motd-news remains, motd-news remains enabled

  b) base-files installed, ubuntu-server installed, modified /e/d/motd-news
  apt install base-files
  - upgrades ubuntu-server
  - installs motd-news-config
  - /e/d/motd-news remains with the original modification

  c) base-files installed, ubuntu-server not installed, unmodified /e/d/motd-news
  apt install base-files
  - upgrades base-files
  - removes /e/d/motd-news
  - motd-news is disabled

  d) base-files installed, ubuntu-server not installed, modified /e/d/motd-news
  apt install base-files
  - upgrades base-files
  - /e/d/motd-news gets renamed to backup
  - motd-news is disabled

  e) removing motd-news-config will also remove ubuntu-server (since
  it's a depends, and not a recommends)

  f) upgrading just ubuntu-server should pull motd-news-config in, and
  force-upgrade base-files

  g) Removing motd-news-server leaves /e/d/motd-news around; purging
  motd-news-server removes the /e/d/motd-news config file

  h) base-files installed, ubuntu-server installed, removed /e/d/motd-news
  - apt install base-files
  - upgrades base-files, upgrades ubuntu-server, installs motd-news-config
  - /e/d/motd-news is installed with ENABLED=0

  i) base-files installed, ubuntu-server NOT installed, removed e/d/motd-news
  - apt install base-files
  - base-files is upgraded
  - no /e/d/motd-news is installed, motd-news remains disabled

  j) Perform a release upgrade from the previous ubuntu release to the
  one being tested while having ubuntu-server NOT installed (or use a
  desktop install). At the end, motd-news should be disabled. Verify
  with:

  $ sudo /etc/update-motd.d/50-motd-news --force
  $ (no output)

  [Regression Potential]
  This update is about config file ownership transfer: /e/d/motd-news belonged to base-files, now it belongs to motd-news-config. We tried to handle two important cases here:
  a) /e/d/motd-news config was changed while it belonged to base-files. For example, an user could have set ENABLED=0. We need to transfer that change to the motd-news-config package when it is installed, otherwise this SRU would jsut re-enabled motd-news. This is handled in d/motd-news-config.postinst's configure case.

  b) /e/d/motd-news config file was *removed* while it belonged to base-files. In such a case, a normal upgrade of the package (base-files in this example) would not reinstate the file. Much less this upgrade here, which has an explicit rm_conffile maintscript-helper for it. But the motd-news-config package that could be installed in the transaction would place the default config file back, and the default is ENABLED=1. Thus, a system that had motd-news disabled via removing the config file would now have it re-enabled after the upgrade.
  This was trickier to handle, and we do it in base-files's postinst and motd-news-config's  postinst. The drawback is that in one scenario, where just base-files is upgraded and /e/d/motd-news was manually removed by the user, there will be a /e/d/motd-news.wasremoved leftover empty file (see "other info" below for details).

  In general, the regression risks here are:
  - have motd-news enabled again on a system where it was previously disabled. We tried to envision two ways it would have been disabled (set ENABLED=0, and remove the config file). There are probably others
  - differences in dpkg and/or debhelper behavior in older ubuntu releases leading to unexpected results (should be covered by the test cases from this SRU)
  - xenial in particular is trickier, because src:base-files there does NOT use debhelper, so many of the things we take for granted have to be done by hand
  - have some sort of dpkg postinst or dependency error because of unpredicted scenarios. Certain assumptions are being made, like the renames that dpkg-maintscript-helper does, and that the filename /etc/default/motd-news.wasremoved that I'm touching and verifying is really mine and not something that was there already.
  - the versions I'm breaking/replacing on, and using rm_conffiles on, must be exact. These are the versions today in the archive (2020-08-12):

  base-files:
  x: 9.4ubuntu4.12
  b: 10.1ubuntu2.9
  f: 11ubuntu5.1
  g: 11ubuntu12 (was 11ubuntu10)

  ubuntu-meta:
  x: 1.361.4
  b: 1.417.4
  f: 1.450.1
  g: 1.452

  Which reflect in these relationships in the updated packages:
  Groovy:
  ubuntu-server 1.453:
    Depends: motd-news-config
  base-files 11ubuntu11:
    Breaks: ubuntu-server (<< 1.453)
    rm_conffile /etc/default/motd-news 11ubuntu11~ base-files
  motd-news-config 11ubuntu11:
    Breaks/Replaces: base-files (<< 11ubuntu11)

  Focal:
  ubuntu-server 1.450.2:
    Depends: motd-news-config
  base-files 11ubuntu5.2:
    Breaks: ubuntu-server (<< 1.450.2)
    rm_conffile /etc/default/motd-news 11ubuntu5.2~ base-files
  motd-news-config 11ubuntu5.2:
    Breaks/Replaces: base-files (<< 11ubuntu5.2)

  Bionic:
  ubuntu-server 1.417.5:
    Depends: motd-news-config
  base-files 10.1ubuntu2.10:
    Breaks: ubuntu-server (<< 1.417.5)
    rm_conffile /etc/default/motd-news 10.1ubuntu2.10~ base-files
  motd-news-config 10.1ubuntu2.10:
    Breaks/Replaces: base-files (<< 10.1ubuntu2.10)

  Xenial:
  ubuntu-server 1.361.5:
    Depends: motd-news-config
  base-files 9.4ubuntu4.13:
    Breaks: ubuntu-server (<< 1.361.5)
    rm_conffile /etc/default/motd-news 9.4ubuntu4.13~ base-files
  motd-news-config 9.4ubuntu4.13:
    Breaks/Replaces: base-files (<< 9.4ubuntu4.13)

  [Other Info]
  a) Testcase (i) will leave around an empty /etc/default/motd-news.wasremoved file, created by the base-files postinst. This file is removed by the motd-news-config postinst, but since that package doesn't get installed in that particular scenario, the file remains. I toyed with the idea of adding an extra check to base-file's postinst, like this:
  --- a/debian/postinst.in
  +++ b/debian/postinst.in
  @@ -133,7 +133,11 @@ motd_news_config="/etc/default/motd-news"
   if [ ! -e ${motd_news_config} ]; then
     if [ ! -e ${motd_news_config}.dpkg-remove ]; then
       if [ ! -e ${motd_news_config}.dpkg-backup ]; then
  -      touch ${motd_news_config}.wasremoved
  +      # The .wasremoved file only matters if ubuntu-server is installed,
  +      # because that's what will pull in motd-news-config
  +      if dpkg -l ubuntu-server 2>/dev/null | grep -q ^i; then
  +        touch ${motd_news_config}.wasremoved
  +      fi
       fi
     fi
   fi

  But deemed it too risky, and not worth further potential regressions.
  It seemed to work, though, at least for groovy.

  b) Currently the xenial cloud images, with the exception of the AWS
  one, do not have ubuntu-server installed. This means that this SRU
  will disable motd-news on them, unless ubuntu-server was manually
  installed for some reason. This includes LXD xenial images as well.

  c) The new motd-news-config package has its d/control priority set to
  "optional", so a release upgrade won't pick it up (presumably the same
  applies to the installer). I've been told there are archive overrides
  that might need updating as well: dear SRU team member, please check,
  or ask an archive admin to check.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/base-files/+bug/1888575/+subscriptions