Return a meaningful error message when no arg is given to gclient recurse.

gclient.py

 #!/usr/bin/python
 # Copyright (c) 2010 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Meta checkout manager supporting both Subversion and GIT.
 
 Files
   .gclient      : Current client configuration, written by 'config' command.
                   Format is a Python script defining 'solutions', a list whose
@@ skipping 860 matching lines @@
 def CMDrecurse(parser, args):
   """Operates on all the entries.
 
   Runs a shell command on all entries.
   """
   # Stop parsing at the first non-arg so that these go through to the command
   parser.disable_interspersed_args()
   parser.add_option('-s', '--scm', action='append', default=[],
                     help='choose scm types to operate upon')
   options, args = parser.parse_args(args)
+  if not args:
+    print >> sys.stderr, 'Need to supply a command!'
+    return 1
   root_and_entries = gclient_utils.GetGClientRootAndEntries()
   if not root_and_entries:
     print >> sys.stderr, (
         'You need to run gclient sync at least once to use \'recurse\'.\n'
         'This is because .gclient_entries needs to exist and be up to date.')
     return 1
   root, entries = root_and_entries
   scm_set = set()
   for scm in options.scm:
     scm_set.update(scm.split(','))
@@ skipping 355 matching lines @@
     return CMDhelp(parser, argv)
   except gclient_utils.Error, e:
     print >> sys.stderr, 'Error: %s' % str(e)
     return 1
 
 
 if '__main__' == __name__:
   sys.exit(Main(sys.argv[1:]))
 
 # vim: ts=2:sw=2:tw=80:et: