From 2a6c04635f77e0eae1a9ac653339ab52fb8f7afc Mon Sep 17 00:00:00 2001
From: Mike McLean <mikem@redhat.com>
Date: Oct 05 2017 20:15:23 +0000
Subject: messagebus plugin: avoid duplicate context updates


---

diff --git a/plugins/hub/messagebus.py b/plugins/hub/messagebus.py
index 93a5b63..0fe8bb3 100644
--- a/plugins/hub/messagebus.py
+++ b/plugins/hub/messagebus.py
@@ -236,9 +236,11 @@ def prep_message(cbtype, *args, **kws):
     else:
         raise PluginError('unsupported exchange type: %s' % exchange_type)
 
-    messages = getattr(context, 'messagebus_plugin_messages', [])
+    messages = getattr(context, 'messagebus_plugin_messages', None)
+    if messages is None:
+        messages = []
+        context.messagebus_plugin_messages = messages
     messages.append(message)
-    context.messagebus_plugin_messages = messages
 
 
 @callback('postCommit')