kdm not working after upgrade from KDE 3.5 to 4.3.4

[Rémi Moyen <rmoyen@gmail.com>]

Hi all,

(this is my first post on this list, please excuse me if I make any mistakes...)

I have a Debian testing system on which for a long time I kept old KDE
3.5 packages because I didn't want KDE 4 (I tried it around 4.0,
didn't like), I figured it was time I gave it another try. So after an
aptitude update, I did an aptitude dist-upgrade (something I hadn't
done since at least 6-12 months -- I did a number of updates of
specific packages in the mean time, though).

aptitude offered me a solution which required removing a lot of
packages (old KDE 3.5 ones), installing a lot of new ones, and
updating some. The install went fine, without any error messages. I
now have a bunch of KDE 4.3.1 packages (version 4:4.3.4-1, the latest
in squeeze).

I rebooted, got to the kdm welcome screen, obviously in KDE 4 style,
and logged in... only to see kdm pop again! No error message. I'm not
on this computer right now, but there wasn't any error message (nor
anything that looked even remotely related) in /var/log/kdm.log. In
the console, though, I can see when launching kdm some messages (sorry
for not having copied down the exact formulation) along the line of
"cannot copy file /etc/kde4/kdm/Xsession".

Now, I looked at the kdm package. dpkg -L told me that it provides a
number of files in /etc/kde4/kdm/ (including kdmrc, but also Xsession
and others). However, my /etc/kde4/kdm/ only contains kdmrc, no other
files. I tried aptitude reinstall kdm, deleting the .deb file in
/var/cache/apt/archives first to force a new download, I got the same
result. The .deb file apparently contains these files (at least I see
these files with a dpkg-deb -x), but for some reason they are not
extracted (and my disk is far from full)!

Just to try, I manually copied these files from the dpk-deb -x result
to /etc/kde4/kdm, but I still got exactly the same behaviour, so I
guess there is something more. Nonetheless, it shows that these files
really exist in the .deb, so why are they not extracted?

I also tried removing all packages in my system that seemed related to
KDE and re-installing kde-full (which dragged along all KDE, including
kdm), because it seemed I had a lot of old KDE 3 stuff hanging around
(and a lot of other junk I hadn't used for a long time, like compiz,
so a bit of house-cleaning was not useless...), but I still get the
same behaviour.

Does anybody have an idea of what's going on with this package, or of
any tests I could run to find the problem?

Thanks!
-- 
Rémi Moyen