Software updater snuck in a package that is unwanted

[Paul Smith]

On Tue, 2017-10-17 at 15:33 -0600, compdoc wrote:
> Several times over the years, I have wanted to remove a package only
> to be told that I'd also be stripping out most of Mate as well.

Just to be clear, it's not the case that removing a package like
"ubuntu-mate", as scary as that sounds, necessarily removes "most of
Mate" or really, any of Mate.

As per my other email, ubuntu-mate is most likely a meta-package and as
such it doesn't actually even have any important files in it.  All that
removing it means is that you don't have all the packages that are
defined by the authors to represent that meta-package.

I don't use Mate so I can't be positive ubuntu-mate is a pure meta-
package so please don't assume I'm correct about this.

However, take as an example the "ubuntu-gnome-desktop" meta-package on
my system:

  $ apt show ubuntu-gnome-desktop
  Package: ubuntu-gnome-desktop
    ...
  Installed-Size: 12.3 kB
  Depends: <<...a metric ton of stuff...>>
    ...
  Download-Size: 3,722 B

If you look at this package it's very small and dpkg shows it has
hardly any files:

  $ dpkg -L ubuntu-gnome-desktop
  /.
  /usr
  /usr/share
  /usr/share/doc
  /usr/share/doc/ubuntu-gnome-desktop
  /usr/share/doc/ubuntu-gnome-desktop/changelog.gz
  /usr/share/doc/ubuntu-gnome-desktop/copyright

But yet, if I remove any package that it depends on then it will also
be removed:

  $ sudo apt remove evince
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  The following packages will be REMOVED:
    evince ubuntu-gnome-desktop
  0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded.
  After this operation, 818 kB disk space will be freed.
  Do you want to continue? [Y/n]

This won't actually remove any other parts of GNOME, but my system is
no longer considered to have the actual ubuntu-gnome-desktop installed
because I've removed one aspect of it.

That's not to say it's always completely harmless to remove it.  Other
packages may depend on the ubuntu-mate package, as a quick and simple
way to say they need Mate available, and if you don't have it installed
then they won't be able to be installed either.