dist-upgrad removed packages

[Bill Moseley <moseley@hank.org>]

Did a long-over-due dist-upgrade on a laptop today, and even after
using Debian for years I'm still wondering how to best deal with
packages "kept back" and packages that apt-get wants to remove.  I
kind of deal with them manually -- apt-get install them and fix what
gets removed.  What worries me is when packages are removed.

I'm running Sid, and I understand that there will be times with
dependencies are broken.  I also spent 45 minutes on google looking
at various posts about this (quite a few simply state running
dist-upgrade fixes everything.  Nope.)  Haven't found a good
description of how to clearly display the specific problems with the
packages -- so pointers to pages welcome.

For for example, looking at "alsamixergui", just to pick one:

apt-get says alsamixergui will be held back and aptitude wants to
remove it:

    # apt-get dist-upgrade
    Reading package lists... Done
    Building dependency tree... Done
    Calculating upgrade... Done
    The following packages have been kept back:
      alsamixergui caudium caudium-modules fgfs-base flightgear gksu grip id3v2
      libdiscover1 libdiscover2 libsdl-mixer1.2 simgear0
    0 upgraded, 0 newly installed, 0 to remove and 12 not upgraded.
    bumby:/home/moseley# apt-get dist-upgrade
    Reading package lists... Done
    Building dependency tree... Done
    Calculating upgrade... Done
    The following packages have been kept back:
      alsamixergui caudium caudium-modules fgfs-base flightgear gksu grip id3v2
      libdiscover1 libdiscover2 libsdl-mixer1.2 simgear0
    0 upgraded, 0 newly installed, 0 to remove and 12 not upgraded.

And aptitude wants to REMOVE the package:

    # aptitude dist-upgrade
    ...
    Reading task descriptions... Done  
    The following NEW packages will be automatically installed:
      libgksuui1.0-1 libid3-3.8.3c2 plib1.8.4c2 
    The following packages will be automatically REMOVED:
      alsamixergui easytag libdiscover1 libfltk1.1c102 libgksuui1.0-0 
      libid3-3.8.3 plib1c102 splay 
    The following packages have been kept back:
      caudium caudium-modules libsdl-mixer1.2 
    The following NEW packages will be installed:
      libgksuui1.0-1 libid3-3.8.3c2 plib1.8.4c2 
    The following packages will be REMOVED:
      alsamixergui easytag libdiscover1 libfltk1.1c102 libgksuui1.0-0 
      libid3-3.8.3 plib1c102 splay 
    The following packages will be upgraded:
      fgfs-base flightgear gksu grip id3v2 libdiscover2 simgear0 
    7 packages upgraded, 3 newly installed, 8 to remove and 3 not upgraded.


    # apt-cache policy alsamixergui
    alsamixergui:
      Installed: 0.9.0rc2-1-7
      Candidate: 0.9.0rc2-1-9


I'd like to keep that mixer, so is there a way to see why it's either
held back (apt-get) or removed (aptitude)?

How would you deal with these conflicts?

-- 
Bill Moseley
moseley@hank.org