As we've now hit at least a couple of different significant/interesting issues caused by DNF's handling of ambiguous provides: situations, I'm filing a tracker bug.
For clarity, by 'ambiguous provides' I mean this sort of case:
dog requires ball
greenball provides ball
redball provides ball
The package manager has to decide whether to install greenball or redball when the user asks for dog; how does it decide which to go with?
yum has a relatively sophisticated heuristic for handling these cases - YumBase._compare_providers() - while DNF has nothing comparable and tends to handle such cases in a way that can reasonably be described as 'worse'.
Hi Adam, can you reevaluate the provide selection bugs with libsolv-0.6.8-3 and eventually close them, please?
I'll try and find some time to re-test, yup. Thanks for the build.
This bug appears to have been reported against 'rawhide' during the Fedora 23 development cycle.
Changing version to '23'.
(As we did not run this process for some time, it could affect also pre-Fedora 23 development
cycle bugs. We are very sorry. It will help us with cleanup during Fedora 23 End Of Life. Thank you.)
More information and reason for this action is here:
The algorithm of libsolv has been improved in version 0.6.14 by trying to find the smallest set of dependencies available along with other heuristics. Moreover there is a guideline  where you can prefer one package over another. I am closing this, feel free to reopen and report other issues you encounter.