Ran into issue while tinkering around with a chaos monkey that did splits, merges and kills exclusively, which resulted in regions getting stuck in transition in merging new state indefinitely which i think happens when the rs is killed during the merge but before the ponr, in which case the new regions state in master is merging new. When the rs dies at this point the master executes RegionStates.serverOffline() for the rs which does
We donot handle merging new here and end up with "THIS SHOULD NOT HAPPEN: unexpected ...". Post this we have the new region which does not have any data stuck which leads to the balancer not running.
I think we should handle mergingnew the same way as splittingnew.