If the uuid of a SceneObjectGroup (RootPart) is changed before adding to the scene, remove the old uuid reference from m_parts as well as adding the new one.

The separate remove and set operations is SOG.set_UUID() are both locked under m_parts.SyncRoot since they are logically atomic (though this isn't such an issue if the SOG isn't part of a scene)
Added unit test for this behaviour.
Also changed the second m_parts.AddOrReplace() to m_parts.Add().  As the old reference is now removed we never end up replacing an identical uuid.  And if we replace a uuid that's already there (from a child part) then this is an error.

1 files changed, 6 insertions, 2 deletions

diff --git a/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs b/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
index 994b9e3..b655f39 100644
--- a/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
@@ -330,8 +330,12 @@ namespace OpenSim.Region.Framework.Scenes
             get { return m_rootPart.UUID; }
             set 
             {
-                m_rootPart.UUID = value;
-                m_parts.AddOrReplace(value, m_rootPart);
+                lock (m_parts.SyncRoot)
+                {
+                    m_parts.Remove(m_rootPart.UUID);
+                    m_rootPart.UUID = value;
+                    m_parts.Add(value, m_rootPart);
+                }
             }
         }