Partial fix for issue #390. (#399)

* Partial fix for issue #390.

* Proper fix for issue #390.

Author: vinci6k

addons/source-python/packages/source-python/messages/hooks.py

@@ -182,7 +182,11 @@ def _pre_send_user_message(args):
         _recipients.update(*tuple(tmp_recipients), clear=True)
         args[1] = _recipients
 
-        buffer = make_object(ProtobufMessage, args[3])
+        try:
+            buffer = make_object(ProtobufMessage, args[3])
+        except RuntimeError:
+            # Patch for issue #390 - UserMessage was created by another plugin.
+            buffer = ProtobufMessage.from_abstract_pointer(args[3])
 
         protobuf_user_message_hooks.notify(_recipients, buffer)
 
@@ -270,4 +274,4 @@ def _pre_message_end(args):
         # Update buffer if data has been changed
         if data.has_been_changed():
             buffer_write.seek_to_bit(0)
-            impl.write(buffer_write, data)
+            impl.write(buffer_write, data)