[Fedora-packaging] Overlapping/variant rpms - how to ensure correct resolution

[Scott Lawrence]

I'm the project coordinator of the sipXpbx project [1] and we're
distributing quite a number of RPMs (in the fullness of time we'd like
to get them into Extras, but that is a topic for another list and
another day) .  The project itself consists of several component RPMs
and there are some other open source projects on which we depend that we
build RPMs for, mostly because they don't.  The one exception to the
"mostly because they don't" is the difficulty I'm looking for advice on
from those who understand packaging.

Fedora Core inludes w3c-libwww.rpm, but that version does not include
compilation with openssl.  For lots of good reasons, we need the
openssl, so we build a version of the w3c-libwww.rpm that has it
enabled; that's the only difference.

Our first approach to dealing with the conflict was just to instruct our
users to configure yum to exclude the w3c-libwww package from all
repositories but ours, but that's a bit of a pain.

We tried adding a 'requires' line to our spec file that called for
'libwwwssl.so' (which is in our rpm but not the Core rpm for the same
package), but then yum seemed to want to load both...

In any event, this seems to me to raise a general issue of how to cope
with the fact that some packages can be built in (potentially
overlapping) variants.  How can we make all of the variants available
and express what each provides so that tools like yum can make the
correct choice?

[1] http://www.sipfoundry.org/sipXpbx/

-- 
Scott Lawrence
Consulting Engineer
Pingtel Corp.
http://www.pingtel.com/
+1.781.938.5306 x162