--- a/mozillatry.py	Tue Dec 04 11:16:14 2012 -0800
+++ b/mozillatry.py	Tue Dec 04 13:22:39 2012 -0800
@@ -66,6 +66,11 @@
         message += ['--post-to-bugzilla', 'Bug', str(bug)]
     return ' '.join(message)
 
+### configuration parsing
+
+class ConfigurationError(Exception):
+    """error when checking configuration"""
+
 class MozillaTryConfiguration(configuration.Configuration):
 
     usage = '%prog [options] patch <patch2> <...>'
@@ -87,14 +92,11 @@
     def __init__(self):
         configuration.Configuration.__init__(self, usage=self.usage, load='--config')
 
-    def check(self, parser, options, args):
+    def check(self, config):
         """check configuration"""
 
-        if not args:
-            parser.print_help()
-            parser.exit()
-        if (not options.opt) and (not options.debug):
-            parser.error("Must enable opt or debug builds")
+        if (not config.get('opt')) and (not config.get('debug')):
+            raise ConfigurationError("Must have opt or debug builds")
 
 
 def read_config(filename, options):
@@ -123,6 +125,9 @@
     # parse command line arguments
     parser = MozillaTryConfiguration()
     options, args = parser.parse_args()
+    if not args:
+        parser.print_usage()
+        parser.exit()
 
     # get mozilla-central repository directory
     try_directory = options.mozilla_central