On Fri, 2009-07-31 at 20:30 +0200, Miroslav Lichvar wrote: > > Yes, but that's not what I'm talking about. I mean the explicit > conflicts between current versions of packages. I.e. the thing that > makes the complexity exponential. > > For example: > package A: depends on X > package B: conflicts with D > package C: provides X > package D: provides X > > yum install A B fails here as it tries to install A B D. The solution > is to install A B C. Right, yum doesn't do "backtracking", so it doesn't "solve" the above when the conflict is with C. However apart from things like running Sodoku in the depsovler (Michael, feel free to post a comment in the blog for zypper results :): http://illiterat.livejournal.com/6119.html ...this kind of thing is often best handled by eliminating the conflicts, rather than having a mini. version of prolog to write the depsolver in. IMO. There are also similar cases like: pkg-A: depends on X pkg-B: provides X pkg-ZOOM: provides X ..."yum install pkg-A pkg-ZOOM" will install all three packages, when it doesn't need to install pkg-B. Again this can often be solved much better by fixing the package metadata, rather than trying to make the solver more intelligent. Again, IMO. It's also worth noting that yum doesn't do removal on conflicts, so in your example if pkg-B was already installed then apt (and AIUI zypper) will remove pkg-B and install pkg-A and pkg-C ... where yum will not assume that was the intent. And, yes, in general I agree that's it's probably very hard to compare performance well because of the different design goals and features/etc. I'm not sure I'd say it's impossible though. -- James Antill - james@xxxxxxxxxxxxxxxxx "I'd just like to see a realistic approach to updates via packages." -- Les Mikesell -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
