On Sunday 28 January 2007 13:16:37 Duncan wrote:
> OK, either way you did it, you should now be clear of the old kde
> meta-packages, but you'll still have the actual packages merged.
> However, once the metapackage is unmerged, you can again run emerge
> --depclean --pretend, and portage should list all the dependencies of the
> slot leaf you just removed as stuff it'd now remove.

I didn't really have the patience to read all the way through your post but 
this part does appear to be incorrect.

The world file can only contain package names (neither slots nor versions) so 
removing kde-3.4 while keeping kde-3.5 is not going to change what's in the 
world file. If something in the world file depends on kdelibs-3.5 then 
`emerge --depclean` will not remove kdelibs-3.4 or any other old slots that 
really aren't needed anymore.

Only --prune or --unmerge will do that and both of those currently have the 
downside that they don't check whether it's still needed (as in the case of 
autoconf, automake etc.). Implementing a safer --prune reusing some of the 
code from --depclean (which was improved a lot in portage-2.1.1) has been 
discussed in the past but it isn't done yet.

Fortunately we do know that for any package in the kde categories pruning old 
slots is indeed safe.

-- 
Bo Andresen