From 45dc54b6563e3d8eabdbcde7837307dbd1e2e44c 2012-08-19 00:57:28
From: Robert McGibbon <rmcgibbo@gmail.com>
Date: 2012-08-19 00:57:28
Subject: [PATCH] empty string should not be inserted

---

diff --git a/IPython/parallel/client/client.py b/IPython/parallel/client/client.py
index 0df5c7c..3803b2a 100644
--- a/IPython/parallel/client/client.py
+++ b/IPython/parallel/client/client.py
@@ -395,7 +395,7 @@ class Client(HasTraits):
         
         if self._cd is not None:
             if url_file is None:
-                if cluster_id is None:
+                if not cluster_id:
                     client_json = 'ipcontroller-client.json'
                 else:
                     client_json = 'ipcontroller-%s-client.json' % cluster_id