Fix for more child agent mismanagement (like #2846). On enqueueing events, we should not be creating new queues; if the queue doesn't exist -- too bad, event is dropped. That tends to happen just after the client is closed, and the EQ also closed. If someone places an event in that queue after that, that event should be dropped instead of creating a new, erroneous queue.

OpenSim/Region/Environment/Modules/Framework/EventQueueGetModule.cs

@@ -136,7 +136,12 @@ namespace OpenSim.Region.Environment.Modules.Framework
         }
         #endregion
 
-        private BlockingLLSDQueue GetQueue(UUID agentId)
+        /// <summary>
+        ///  Always returns a valid queue
+        /// </summary>
+        /// <param name="agentId"></param>
+        /// <returns></returns>
+        private BlockingLLSDQueue TryGetQueue(UUID agentId)
         {
             lock (queues)
             {
@@ -150,15 +155,34 @@ namespace OpenSim.Region.Environment.Modules.Framework
             }
         }
 
+        /// <summary>
+        /// May return a null queue
+        /// </summary>
+        /// <param name="agentId"></param>
+        /// <returns></returns>
+        private BlockingLLSDQueue GetQueue(UUID agentId)
+        {
+            lock (queues)
+            {
+                if (queues.ContainsKey(agentId))
+                {
+                    return queues[agentId];
+                }
+                else
+                    return null;
+            }
+        }
 
         #region IEventQueue Members
+
         public bool Enqueue(OSD ev, UUID avatarID)
         {
             m_log.DebugFormat("[EVENTQUEUE]: Enqueuing event for {0} in region {1}", avatarID, m_scene.RegionInfo.RegionName);
             try
             {
                 BlockingLLSDQueue queue = GetQueue(avatarID);
-                queue.Enqueue(ev);
+                if (queue != null)
+                    queue.Enqueue(ev);
             } catch(NullReferenceException e)
             {
                 m_log.Debug("[EVENTQUEUE] Caught exception: " + e);
@@ -166,11 +190,26 @@ namespace OpenSim.Region.Environment.Modules.Framework
             }
             return true;
         }
+
         #endregion
 
         private void OnNewClient(IClientAPI client)
         {
-            m_log.DebugFormat("[EVENTQUEUE]: New client {0} detected in region {1}", client.AgentId, m_scene.RegionInfo.RegionName);
+            //m_log.DebugFormat("[EVENTQUEUE]: New client {0} detected in region {1}", client.AgentId, m_scene.RegionInfo.RegionName);
+            //lock (queues)
+            //{
+            //    if (queues.ContainsKey(client.AgentId))
+            //    {
+            //        m_log.DebugFormat("[EVENTQUEUE]: Removing old queue for agent {0} in region {1}", client.AgentId,
+            //                          m_scene.RegionInfo.RegionName);
+            //        queues.Remove(client.AgentId);
+            //    }
+
+            //    m_log.DebugFormat("[EVENTQUEUE]: Adding new queue for agent {0} in region {1}", client.AgentId,
+            //                          m_scene.RegionInfo.RegionName);
+            //    queues[client.AgentId] = new BlockingLLSDQueue();
+            //}
+
             client.OnLogout += ClientClosed;
         }
 
@@ -317,7 +356,7 @@ namespace OpenSim.Region.Environment.Modules.Framework
 //                m_log.DebugFormat(debug + "  ]", agentID, m_scene.RegionInfo.RegionName, System.Threading.Thread.CurrentThread.Name);
 //            }
 
-            BlockingLLSDQueue queue = GetQueue(agentID);
+            BlockingLLSDQueue queue = TryGetQueue(agentID);
             OSD element = queue.Dequeue(15000); // 15s timeout
 
             Hashtable responsedata = new Hashtable();