Bug#362313: xserver-xorg dependency hell

[Bill Allombert <allomber@math.u-bordeaux.fr>]

On Thu, Apr 20, 2006 at 07:50:21PM +0200, Michel Dänzer wrote:
> On Thu, 2006-04-20 at 18:57 +0200, allomber@math.u-bordeaux.fr wrote:
> > 
> > xserver-xorg-core -> xserver-xorg-video-all -> xserver-xorg-video-apm -> xserver-xorg-core
> > 
> > and 
> > 
> > xserver-xorg-core -> xserver-xorg-input-all -> xserver-xorg-input-evdev -> xserver-xorg-core
> 
> Note that the -all links are really redundant, as every individual
> driver can satisfy the xserver-xorg-core dependency on its own.
> 
> Do you have a better suggestion, given that the server requires at least
> one video and input driver and that the drivers aren't useful without
> the server?

I might be mistaken, but as I see it the server require exactly 
the video drivers for the cards configured in the xorg.conf file.
If you have a ATI card, installing xserver-xorg-video-nv will fulfill
the xserver-xorg-core dependency but will do no good for the server.
Similarly installing xserver-xorg-input-synaptics will fulfill the 
dependency but will do nothing if you d not have a synaptics device.

So this is a case where a dependency cannot be expressed by the system.
In that case, we usually make them "recommends" and document them
in the packages description.

Secondly, since xserver-xorg is more or less mandatory and already
depends on xserver-xorg-video-all | xserver-xorg-video,
xserver-xorg-input-all | xserver-xorg-input, I think xserver-xorg-core
can get away with this dependency.

Thirdly, I don't think users can reasonnably expect the drivers packages
to depend on the server. They should only expect the dependencies to 
avoid an incompatible set of servers and drivers to be installable and
cause crashes.

Cheers,
-- 
Bill. <ballombe@debian.org>

Imagine a large red swirl here.