From: Daniil Fedotov <dfedotov@pivotal.io>
Date: Mon, 14 Dec 2015 16:01:24 +0000
Subject: [PATCH] Ignore unknown channel acks in queue


diff --git a/src/rabbit_queue_consumers.erl b/src/rabbit_queue_consumers.erl
index 4b1f07d..7c5bbba 100644
--- a/src/rabbit_queue_consumers.erl
+++ b/src/rabbit_queue_consumers.erl
@@ -276,7 +276,9 @@ subtract_acks([T | TL] = AckTags, Prefix, CTagCounts, AckQ) ->
             subtract_acks(TL, Prefix,
                           orddict:update_counter(CTag, 1, CTagCounts), QTail);
         {{value, V}, QTail} ->
-            subtract_acks(AckTags, [V | Prefix], CTagCounts, QTail)
+            subtract_acks(AckTags, [V | Prefix], CTagCounts, QTail);
+        {empty, _} -> 
+            subtract_acks([], Prefix, CTagCounts, AckQ)
     end.
 
 possibly_unblock(Update, ChPid, State) ->