Bug#490169: apt: undesired autoremove behavior

[Daniel Burrows <dburrows@debian.org>]

On Thu, Jul 10, 2008 at 05:34:30AM -0700, Joshua Kwan <joshk@triplehelix.org> was heard to say:
> I recently installed the latest msttcorefonts, which is now a dummy
> package for the new name ttf-msttcorefonts-installer. I had previously
> installed msttcorefonts manually.
> 
> Since msttcorefonts is now a dummy package, I removed it from my system.
> But because ttf-msttcorefonts-installer was installed as a dependency of
> msttcorefonts, apt now suggests it for autoremoval. I think this
> behavior is highly misleading.
> 
> A potential solution would involve a package control field indicating
> the status of msttcorefonts as a dummy package for
> ttf-msttcorefonts-installer. That way, the "manually installed" state,
> true or false, could propagate to the new package.
> 
> Obviously, this will happen consistently in the very common case of
> all dummy packages being used in Debian.
> 
> Thoughts?

  Personally, I think the occasionally-discussed "Obsoletes" header would
be a better approach, if we wanted to add a new header.  This would
sort of function as a reverse dependency -- if A Obsoletes B and you have
B installed, an "upgrade" or "install" operation on B should install A
(and of course copy the automatic flag over).

  I don't remember why this hasn't been implemented -- was it just that
no-one got around to it or were there practical problems (other than the
fact that my summary above is underspecified)?  I don't think dpkg needs
to care about this header since it's something that's only interesting
for whole-system upgrades.

  Daniel