sync_spawn_command hangs for infinity if the vnode crashes or replies {stop, _, _} [JIRA: RIAK-2370] #807
Description
When sending a sync_spawn_command I notice in riak_core_vnode.erl:345 that the {stop, Reason, NewModState} case doesn't reply to the sender. Given that riak_core_vnode_master:148 issues a sync_spawn_command with a timeout of infinity, the caller will hang forever.
A similar thing happens when the vnode crashes during a handle_command. Any other command being handled at the time of the crash will hang forever. I think the vnode_master ought to trap_exits to catch vnode crashes and reply({vnode_error, _} to the sender.
To reproduce:
handle_command(ping, _Sender, State) ->
timer:sleep(5000),
exit(crashing_the_vnode),
{reply, ok, State};
ping() ->
riak_core_vnode_master:sync_spawn_command(Idx, ping, ).
1> spawn(fun() -> :ping() end).
2> :ping().
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CRASH REPORT ...
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