Split from #4223
In #4223, Fedora is having trouble because they want buildSRPMFromSCM tasks to be limited to one set of arches, but for noarch buildArch tasks to be limited differently (for the same tag).
In #4013, we introduced the noarch_arches config for tags, but unfortunately this is not granular enough for what Fedora needs.
I don't think we can really fix this without implementing the new scheduler, which is on hold for now. However, perhaps there is some smaller piece we could do that might help.
This issue has been migrated to Fedora Forge: https://forge.fedoraproject.org/koji/koji/issues/4235
Please continue any further discussion there.