diff -r 715b9eec6da9 -r 8666438778c7 server/serverctl.py
--- a/server/serverctl.py	Wed Apr 24 18:11:37 2013 +0200
+++ b/server/serverctl.py	Fri Apr 05 14:44:03 2013 +0200
@@ -39,7 +39,6 @@
 from cubicweb.server.serverconfig import (
     USER_OPTIONS, ServerConfiguration, SourceConfiguration,
     ask_source_config, generate_source_config)
-from yams.diff import schema_diff
 
 # utility functions ###########################################################
 
@@ -1077,6 +1076,7 @@
     min_args = max_args = 2
 
     def run(self, args):
+        from yams.diff import schema_diff
         appid = args.pop(0)
         diff_tool = args.pop(0)
         config = ServerConfiguration.config_for(appid)