Merge branch 'piccit-master'

StackExchange.Redis/StackExchange/Redis/Message.cs

@@ -6,6 +6,7 @@
 using System.Runtime.Serialization;
 #endif
 using System.Text;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace StackExchange.Redis
@@ -493,15 +494,19 @@ public void SetResponseReceived()
             performance?.SetResponseReceived();
         }
 
-        public bool TryComplete(bool isAsync)
-        {
-            if (resultBox != null)
-            {
-                var ret = resultBox.TryComplete(isAsync);
+        public bool TryComplete(bool isAsync)
+        {
+            //Ensure we can never call TryComplete on the same resultBox from two threads by grabbing it now
+            var currBox = Interlocked.Exchange(ref resultBox, null);
+            if (currBox != null)
+            {
+                var ret = currBox.TryComplete(isAsync);
 
-                if (ret && isAsync)
+                //in async mode TryComplete will have unwrapped and recycled resultBox
+                if (!(ret && isAsync))
                 {
-                    resultBox = null; // in async mode TryComplete will have unwrapped and recycled resultBox; ensure we no longer reference it via this message
+                    //put result box back if it was not already recycled
+                    Interlocked.Exchange(ref resultBox, currBox);
                 }
 
                 performance?.SetCompleted();

StackExchange.Redis/StackExchange/Redis/MessageQueue.cs

@@ -35,11 +35,13 @@ public Message PeekPing(out int queueLength)
                 queueLength = high.Count + regular.Count;
                 if (high.Count != 0 && (peeked = high.Peek()).Command == RedisCommand.PING)
                 {
-                    return peeked;
+                    //In a disconnect scenario, we don't want to complete the Ping message twice,
+                    //dequeue it now so it wont get dequeued in AbortUnsent (if we're going down that code path)
+                    return high.Dequeue();
                 }
                 if (regular.Count != 0 && (peeked = regular.Peek()).Command == RedisCommand.PING)
                 {
-                    return peeked;
+                    return regular.Dequeue();
                 }
             }
             return null;

StackExchange.Redis/StackExchange/Redis/PhysicalBridge.cs

@@ -315,7 +315,6 @@ internal void OnDisconnected(ConnectionFailureType failureType, PhysicalConnecti
             Trace("OnDisconnected");
 
             // if the next thing in the pipe is a PING, we can tell it that we failed (this really helps spot doomed connects)
-            // note that for simplicity we haven't removed it from the queue; that's OK
             int count;
             var ping = queue.PeekPing(out count);
             if (ping != null)