Show an error message when the user tries to set the commit flag or add trybots to a private issue.

gcl.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """\
 Wrapper script around Rietveld's upload.py that simplifies working with groups
 of files.
 """
 
@@ skipping 1349 matching lines @@
   # When the command is 'try' and --patchset is used, the patch to try
   # is on the Rietveld server.
   if not args:
     ErrorExit("You need to pass a change list name")
   if args[0].find(',') != -1:
     change_info = LoadChangelistInfoForMultiple(args[0], GetRepositoryRoot(),
                                                 True, True)
   else:
     change_info = ChangeInfo.Load(args[0], GetRepositoryRoot(),
                                   True, True)
+
+  props = change_info.RpcServer().get_issue_properties(
+    change_info.issue, False)
+  if props.get('private'):
+    ErrorExit('Cannot use trybots on a private issue')
+
   if change_info.GetFiles():
     args = args[1:]
   else:
     change_info = None
   return TryChange(change_info, args, swallow_exception=False)
 
 
 @attrs(usage='<old-name> <new-name>')
 def CMDrename(args):
   """Renames an existing change."""
@@ skipping 118 matching lines @@
       raise
     print >> sys.stderr, (
         'AppEngine is misbehaving and returned HTTP %d, again. Keep faith '
         'and retry or visit go/isgaeup.\n%s') % (e.code, str(e))
     return 1
 
 
 if __name__ == "__main__":
   fix_encoding.fix_encoding()
   sys.exit(main(sys.argv[1:]))