evolve: evolve --divergent failed when merge had nothing to do (issue4950) Before this patch, if the divergence resolution lead to an empty commit, the transaction would be rolled back and the divergence not resolved. This patch allows empty commits in that case. It is legitimate to end up with an empty commit in that case, for example when divergent commits differ over their commit messages.

inhibit: use dirty revset trick to speedup the inhibit search space. See documentation for details. I'm a bit sad about this changesets.

inhibit: use 'repo.revs' instead of 'repo.set' This skip the creation of a changectx object.