From f2f49704de2e25a20d96a3701c2442829aaf2971 Mon Sep 17 00:00:00 2001
From: Mikhail Sobolev <mss@mawhrin.net>
Date: Sat, 17 Jan 2015 18:11:30 +0200
Subject: [PATCH] make default value for dialects safe

---
 master/buildbot/status/web/change_hook.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/master/buildbot/status/web/change_hook.py b/master/buildbot/status/web/change_hook.py
index 801d39fa50f..ea13e0a8ca6 100644
--- a/master/buildbot/status/web/change_hook.py
+++ b/master/buildbot/status/web/change_hook.py
@@ -32,13 +32,16 @@ class ChangeHookResource(resource.Resource):
     contentType = "text/html; charset=utf-8"
     children = {}
 
-    def __init__(self, dialects={}):
+    def __init__(self, dialects=None):
         """
         The keys of 'dialects' select a modules to load under
         master/buildbot/status/web/hooks/
         The value is passed to the module's getChanges function, providing
         configuration options to the dialect.
         """
+        if dialects is None:
+            dialects = {}
+
         self.dialects = dialects
         self.request_dialect = None