Github user agresch commented on the issue:
https://github.com/apache/storm/pull/2816
@danny0405 - I'm not really knowledgable about any of this particular code,
but the LocalState API clearly allows returning null, rather than throwing any
exception. I'm just trying to cover the callstack I provided in the JIRA. If
we feel this shouldn't happen, maybe LocalState getApprovedWorkers() should
throw an exception if there are no approved workers?---
