Debian dependencies

[Lennart Sorensen]

On Tue, Nov 22, 2005 at 10:25:03AM -0500, phil wrote:
> Some time ago I put a spare 6GB drive in my Intel box to try out 
> Debian.  Mostly, I like it...enough so that I'm filling up the disk.
> 
> Before scratching my main SuSE installation, though, I thought I'd 
> clean up some of the packages I'm not using and see what that did to my 
> disk space.  Since I don't use sound on this system at all, I figured 
> getting rid of sound items that were marked "optional" made sense.  
> That idea, however, caused KPackage to recommend the removal of all (or 
> most) of KDE, which seemed a little extreme!
> 
> How does one better control dependencies so that uninstalling things 
> doesn't unravel the universe?

Well I have never used kpackage really being in my opinion one of the
worst gui package managers I have ever encountered.  synaptic is a lot
better and actually maintained by debian people.

aptitude is better yet in my opinion (being curses, not graphical) and I
tend to just use apt-get and dpkg myself.  The command line tools will
clearly list what they are going to do so I can decide if it is correct.

The problem with some of the "friendly" tools is that they will try
uninstalling anything automatically installed as a dependancy when the
thing causing the installation in the first place is removed.  For
example if you install the package 'kde' it depeds on all things kde.
If you later uninstall something from kde, it will of course have to
remove the 'kde' meta package since you are removing one of the things
it depends on.  Some "clever" package managers then go: You are removing
'kde' which was the reason I installed all this other stuff, so I will
be "helpful" and remove all those for you.  This was not what you wanted
in this case, but often for library dependancies of a package, it would
be what you want.  After all if you install foo and it depends on
libbar, it would be handy that removing foo will remove bar if nothing
else depends on it.  Since package 'kde' was the only thing installed
causing everything else to be installed, nothing else depends on the kde
components so the same rule says you must want to uninstall all or most
of kde.  Sometimes helpful isn't.  Sometimes friendly isn't.

Doing apt-get remove kdesoundthingy will only remove the things that it
must remove to make the dependancy tree valid.  The friendly tool may
still offer to clean up later unless you go tell it you actually want
those other things to stay installed by flagging them as such.

Lennart Sorensen
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