* Catch the occasional resolution exception that comes out of SceneCommunicationService.EnableChildAgents so we can see what hostname is failing

OpenSim/Framework/Communications/IGridServices.cs

@@ -41,7 +41,15 @@ namespace OpenSim.Framework.Communications
         RegionCommsListener RegisterRegion(RegionInfo regionInfos);
         
         bool DeregisterRegion(RegionInfo regionInfo);
+
+        /// <summary>
+        /// Get information about the regions neighbouring the given co-ordinates.
+        /// </summary>
+        /// <param name="x"></param>
+        /// <param name="y"></param>
+        /// <returns></returns>
         List<SimpleRegionInfo> RequestNeighbours(uint x, uint y);
+        
         RegionInfo RequestNeighbourInfo(ulong regionHandle);
         RegionInfo RequestClosestRegion(string regionName);
         Dictionary<string, string> GetGridSettings();

OpenSim/Framework/RegionInfo.cs

@@ -38,6 +38,9 @@ namespace OpenSim.Framework
     [Serializable]
     public class SimpleRegionInfo
     {
+//        private static readonly log4net.ILog m_log 
+//            = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
+        
         public SimpleRegionInfo()
         {
         }
@@ -100,6 +103,11 @@ namespace OpenSim.Framework
 
         public string RemotingAddress;
 
+        /// <value>
+        /// This accessor can throw all the exceptions that Dns.GetHostAddresses can throw.
+        /// 
+        /// XXX Isn't this really doing too much to be a simple getter, rather than an explict method?
+        /// </value>
         public IPEndPoint ExternalEndPoint
         {
             get
@@ -115,7 +123,6 @@ namespace OpenSim.Framework
                 // Reset for next check
                 ia = null;
                                                          
-                // New method favors IPv4
                 foreach (IPAddress Adr in Dns.GetHostAddresses(m_externalHostName))
                 {
                     if (ia == null)

OpenSim/Region/Communications/OGS1/OGS1GridServices.cs

@@ -206,11 +206,7 @@ namespace OpenSim.Region.Communications.OGS1
             return returnGridSettings;
         }
 
-        /// <summary>
+        // see IGridServices
-        /// 
-        /// </summary>
-        /// <param name="regionInfo"></param>
-        /// <returns></returns>
         public List<SimpleRegionInfo> RequestNeighbours(uint x, uint y)
         {
             Hashtable respData = MapBlockQuery((int) x - 1, (int) y - 1, (int) x + 1, (int) y + 1);

OpenSim/Region/Environment/Scenes/SceneCommunicationService.cs

@@ -278,10 +278,27 @@ namespace OpenSim.Region.Environment.Scenes
                     agent.child = true;
 
                     InformClientOfNeighbourDelegate d = InformClientOfNeighbourAsync;
+                    
+                    try
+                    {
                         d.BeginInvoke(avatar, agent, neighbours[i].RegionHandle, neighbours[i].ExternalEndPoint,
                                       InformClientOfNeighbourCompleted,
                                       d);
                     }
+                    catch (Exception e)
+                    {
+                        m_log.ErrorFormat(
+                            "[REGIONINFO]: Could not resolve external hostname {0} for region {1} ({2}, {3})", 
+                            neighbours[i].ExternalHostName, 
+                            neighbours[i].RegionHandle, 
+                            neighbours[i].RegionLocX, 
+                            neighbours[i].RegionLocY);
+                                                
+                        // FIXME: Okay, even though we've failed, we're still going to throw the exception on,
+                        // since I don't know what will happen if we just let the client continue
+                        throw e;                        
+                    }                    
+                }
             }
         }