how to have yum prefer one dependency over others

[Richard W.M. Jones]

On Mon, Sep 19, 2011 at 11:05:47AM -0500, Matyas Selmeci wrote:
> Matthew Garrett wrote on Mon, Sep 19, 2011 at 05:00:28PM +0100:
> > On Mon, Sep 19, 2011 at 10:51:26AM -0500, Matyas Selmeci wrote:
> > > Kevin Kofler wrote on Mon, Sep 19, 2011 at 01:02:26PM +0200:
> > > > Michael Schroeder wrote:
> > > > > Sounds like you want weak dependencies (i.e. "Suggests" et al).
> > > > 
> > > > In this case, I think disjunctive dependencies (default | virtual), as 
> > > > Matthew Garrett pointed out, are the right solution, not soft dependencies 
> > > > (though those would also be nice).
> > > > 
> > > >         Kevin Kofler
> > > Functionally speaking, what is the difference between a soft dependency
> > > and a disjunctive dependency? How can you satisfy a soft dependency if
> > > you don't know what virtual dependency it is being used to provide?
> > 
> > If we have:
> > 
> > Requires: phonon-backend
> > Suggests: phonon-backend-gstreamer
> > 
> > What would you expect the outcome to be on a system that has 
> > phonon-backend-xine? I'd have thought that phonon-backend-gstreamer 
> > would get installed, even if you can later remove it. That's not the 
> > desired outcome.
> 
> I see. So 'Suggests' means it gets automatically installed (unless it
> explicitly conflicts with something already install I presume?), but
> can be removed without breaking the package it was brought in for
> (unless no other package provides the phonon-backend dependency).
> Do I have that right?

In Debian, 'Suggests', 'Recommends' etc have very specific meanings.
See in particular section 7.2 here:

http://www.debian.org/doc/debian-policy/ch-relationships.html

RPM of course doesn't have anything except hard requirements.

Rich.

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