Merge pull request #258 from rabbitmq/rabbitmq-dotnet-client-257

michaelklishin · web-flow · commit a0600dfcec3f · 2016-09-16T17:37:12.000+04:00
Handle potential NullReferenceException in HeartbeatReadTimerCallback
diff --git a/projects/client/RabbitMQ.Client/src/client/impl/Connection.cs b/projects/client/RabbitMQ.Client/src/client/impl/Connection.cs
@@ -1024,17 +1024,21 @@ public void HeartbeatReadTimerCallback(object state)
                     TerminateMainloop();
                     FinishClose();
                 }
-                else
+                else if(_heartbeatReadTimer != null)
                 {
                     _heartbeatReadTimer.Change(Heartbeat * 1000, Timeout.Infinite);
                 }
             }
             catch (ObjectDisposedException)
             {
-
                 // timer is already disposed,
                 // e.g. due to shutdown
             }
+            catch (NullReferenceException)
+            {
+                // timer has already been disposed from a different thread after null check
+                // this event should be rare
+            }
         }
 
         public void HeartbeatWriteTimerCallback(object state)

Original file line number	Diff line number	Diff line change
`@@ -1024,17 +1024,21 @@ public void HeartbeatReadTimerCallback(object state)`
`1024`	`1024`	`TerminateMainloop();`
`1025`	`1025`	`FinishClose();`
`1026`	`1026`	`}`
`1027`		`- else`
	`1027`	`+ else if(_heartbeatReadTimer != null)`
`1028`	`1028`	`{`
`1029`	`1029`	`_heartbeatReadTimer.Change(Heartbeat * 1000, Timeout.Infinite);`
`1030`	`1030`	`}`
`1031`	`1031`	`}`
`1032`	`1032`	`catch (ObjectDisposedException)`
`1033`	`1033`	`{`
`1034`		`-`
`1035`	`1034`	`// timer is already disposed,`
`1036`	`1035`	`// e.g. due to shutdown`
`1037`	`1036`	`}`
	`1037`	`+ catch (NullReferenceException)`
	`1038`	`+ {`
	`1039`	`+ // timer has already been disposed from a different thread after null check`
	`1040`	`+ // this event should be rare`
	`1041`	`+ }`
`1038`	`1042`	`}`
`1039`	`1043`
`1040`	`1044`	`public void HeartbeatWriteTimerCallback(object state)`