Oops

2 files changed, 3 insertions, 1 deletions

diff --git a/src/priority_queue.erl b/src/priority_queue.erl
index 572bca95ee..8ded389b7a 100644
--- a/src/priority_queue.erl
+++ b/src/priority_queue.erl
@@ -212,6 +212,7 @@ fold(Fun, Init, Q) -> case out_p(Q) of
                           {{value, V, P}, Q1} -> fold(Fun, Fun(V, P, Init), Q1)
                       end.
 
+highest({queue, [], [], 0})     -> exit(highest_priority_of_empty_queue);
 highest({queue, _, _, _})       -> 0;
 highest({pqueue, [{P, _} | _]}) -> maybe_negate_priority(P).
 
diff --git a/src/rabbit_amqqueue_process.erl b/src/rabbit_amqqueue_process.erl
index 60b56aeb07..dc2a7a3f17 100644
--- a/src/rabbit_amqqueue_process.erl
+++ b/src/rabbit_amqqueue_process.erl
@@ -550,7 +550,8 @@ notify_federation(#q{q                   = Q,
         false -> rabbit_federation_queue:stop(Q)
     end.
 
-active_unfederated(Cs) -> priority_queue:highest(Cs) >= 0.
+active_unfederated(Cs) ->
+    not priority_queue:is_empty(Cs) andalso priority_queue:highest(Cs) >= 0.
 
 consumer_priority({_ChPid, #consumer{args = Args}}) ->
     case rabbit_misc:table_lookup(Args, <<"x-priority">>) of