Created attachment 1061828 [details]
Reproducer

When running the attached script as of now, DNF crashes like so:

[  153.993020] firstboot.sh[409]: + dnf -y upgrade
[  232.837579] firstboot.sh[409]: Last metadata expiration check performed 0:00:20 ago on Wed Aug 12 03:26:26 2015.
[  237.533123] firstboot.sh[409]: Dependencies resolved.
[  237.568847] firstboot.sh[409]: Traceback (most recent call last):
[  237.570133] firstboot.sh[409]: File "/usr/bin/dnf", line 35, in <module>
[  237.571053] firstboot.sh[409]: main.user_main(sys.argv[1:], exit_code=True)
[  237.571943] firstboot.sh[409]: File "/usr/lib/python3.4/site-packages/dnf/cli/main.py", line 193, in user_main
[  237.576142] firstboot.sh[409]: errcode = main(args)
[  237.576929] firstboot.sh[409]: File "/usr/lib/python3.4/site-packages/dnf/cli/main.py", line 84, in main
[  237.578025] firstboot.sh[409]: return _main(base, args)
[  237.578794] firstboot.sh[409]: File "/usr/lib/python3.4/site-packages/dnf/cli/main.py", line 146, in _main
[  237.582947] firstboot.sh[409]: ret = resolving(cli, base)
[  237.583736] firstboot.sh[409]: File "/usr/lib/python3.4/site-packages/dnf/cli/main.py", line 168, in resolving
[  237.584847] firstboot.sh[409]: base.do_transaction(display=displays)
[  237.588776] firstboot.sh[409]: File "/usr/lib/python3.4/site-packages/dnf/cli/cli.py", line 165, in do_transaction
[  237.590015] firstboot.sh[409]: pkg_str = self.output.list_transaction(trans)
[  237.590905] firstboot.sh[409]: File "/usr/lib/python3.4/site-packages/dnf/cli/output.py", line 1024, in list_transaction
[  237.592104] firstboot.sh[409]: for pkg in self._skipped_broken_deps(skipped_conflicts):
[  237.593068] firstboot.sh[409]: File "/usr/lib/python3.4/site-packages/dnf/cli/output.py", line 947, in _skipped_broken_deps
[  237.597528] firstboot.sh[409]: goal_diff -= skipped_conflicts
[  237.598655] firstboot.sh[409]: TypeError: unsupported operand type(s) for -=: 'set' and 'map'