Display the actual tree status when the tree is closed. Much more helpful....

PRESUBMIT.py

 #!/usr/bin/python
 # Copyright (c) 2009 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.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
 details on the presubmit API built into gcl.
 """
@@ skipping 29 matching lines @@
 def CheckChangeOnCommit(input_api, output_api):
   results = []
   # TODO(maruel): max_cols is temporarily disabled. Reenable once the source
   # tree is in better shape.
   results.extend(LocalChecks(input_api, output_api, max_cols=0))
   results.extend(input_api.canned_checks.CheckChangeHasBugField(input_api,
                                                                 output_api))
   results.extend(input_api.canned_checks.CheckChangeHasTestField(input_api,
                                                                  output_api))
   # Make sure the tree is 'open'.
-  results.extend(input_api.canned_checks.CheckTreeIsOpen(
-      input_api, output_api,
-      'http://chromium-status.appspot.com/status', '0'
-  ))
+  results.extend(CheckTreeIsOpen(input_api, output_api,
+                                 'http://chromium-status.appspot.com/status',
+                                 '0',
+                                 'http://chromium-status.appspot.com/current'))
   results.extend(CheckTryJobExecution(input_api, output_api))
   return results
 
 
 def LocalChecks(input_api, output_api, max_cols=80):
   """Reports an error if for any source file in SOURCE_FILE_EXTENSIONS:
      - uses CR (or CRLF)
      - contains a TAB
      - has a line that ends with whitespace
      - contains a line >|max_cols| cols unless |max_cols| is 0.
@@ skipping 108 matching lines @@
       # stable enough and it seems to work fine.
       outputs.append(output_api.PresubmitNotifyResult(
           'You should try the patch first.'))
     else:
       # Another HTTP error happened, warn the user.
       # TODO(maruel): Change to a PresubmitPromptWarning once it deemed to work
       # fine.
       outputs.append(output_api.PresubmitNotifyResult(
           'Got %s while looking for try job status.' % str(e)))
   return outputs
+
+
+def CheckTreeIsOpen(input_api, output_api, url, closed, url_text):
+  """Similar to the one in presubmit_canned_checks except it shows an helpful
+  status text instead.
+  """
+  assert(input_api.is_committing)
+  try:
+    connection = input_api.urllib2.urlopen(url)
+    status = connection.read()
+    connection.close()
+    if input_api.re.match(closed, status):
+      long_text = status + '\n' + url
+      try:
+        connection = input_api.urllib2.urlopen(url_text)
+        text = connection.read()
+        connection.close()
+        match = input_api.re.search(r"\<div class\=\"Notice\"\>(.*)\<\/div\>",
+                                    text)
+        if match:
+          long_text = match.group(1).strip()
+      except IOError:
+        pass
+      return [output_api.PresubmitPromptWarning("The tree is closed.",
+                                                long_text=long_text)]
+  except IOError:
+    pass
+  return []