Add a presubmit check to check that a certain set of Android specific files only have deletions.

PRESUBMIT.py

 # 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.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
 
@@ skipping 175 matching lines @@
       'RunAllPending()',
       (
        'This function is deprecated and we\'re working on removing it. Rename',
        'to RunUntilIdle',
       ),
       True,
     ),
 )
 
 
+_DELETIONS_ONLY_FILES = (
+    'build/android/findbugs_filter/findbugs_known_bugs.txt'

[Isaac (away), 2013/01/09 05:40:10]

if you keep this, you need a trailing comma on 197 or _DELETIONS_ONLY_FILES will
be a string, not a tuple.

[Siva Chandra, 2013/01/11 01:24:04]

Done.

+)
+
+
 
 def _CheckNoProductionCodeUsingTestOnlyFunctions(input_api, output_api):
   """Attempts to prevent use of functions intended only for testing in
   non-testing code. For now this is just a best-effort implementation
   that ignores header files and may have some false positives. A
   better implementation would probably need a proper C++ parser.
   """
   # We only scan .cc files and the like, as the declaration of
   # for-testing functions in header files are hard to distinguish from
   # calls to such functions without a proper C++ parser.
@@ skipping 415 matching lines @@
       warnings = _CheckIncludeOrderInFile(input_api, output_api, f, False,
                                           changed_linenums)
 
   results = []
   if warnings:
     results.append(output_api.PresubmitPromptWarning(_INCLUDE_ORDER_WARNING,
                                                      warnings))
   return results
 
 
+def _CheckDeletionsOnlyFiles(input_api, output_api):
+  """Check that a certain listed files only have deletions.

[Isaac (away), 2013/01/12 02:42:30]

nit: end triple quote on line 637 (delete line 638).

+  """
+  errors = []
+  for f in input_api.AffectedFiles():
+    if f.LocalPath() in _DELETIONS_ONLY_FILES:

[Isaac (away), 2013/01/09 05:40:10]

how about just:

if f.LocalPath() = 'build/android/...'

I don't think we're going to need this function for other files.

[Siva Chandra, 2013/01/11 01:24:04]

Unless you feel generality is bad here, I would prefer to keep it general. In an
other comment, you suggested that I move these changes to build/android. I have
same concern about generality for that as well.

[Isaac (away), 2013/01/12 02:42:30]

SGTM.  It's fine to keep the DELETION_ONLY_FILES as a list, but the style in
this file is to define the list in the narrowest possible scope.  i.e. if the
list is only used in this function, define the list inside the function.

+      if f.ChangedContents():
+        errors.append(f.LocalPath())
+  results = []
+  if errors:
+    results.append(output_api.PresubmitError(
+        'Following files should only contain deletions.', errors))
+  return results
+
+
 def _CommonChecks(input_api, output_api):
   """Checks common to both upload and commit."""
   results = []
   results.extend(input_api.canned_checks.PanProjectChecks(
       input_api, output_api, excluded_paths=_EXCLUDED_PATHS))
   results.extend(_CheckAuthorizedAuthor(input_api, output_api))
   results.extend(
     _CheckNoProductionCodeUsingTestOnlyFunctions(input_api, output_api))
   results.extend(_CheckNoIOStreamInHeaders(input_api, output_api))
   results.extend(_CheckNoUNIT_TESTInSourceFiles(input_api, output_api))
   results.extend(_CheckNoNewWStrings(input_api, output_api))
   results.extend(_CheckNoDEPSGIT(input_api, output_api))
   results.extend(_CheckNoBannedFunctions(input_api, output_api))
   results.extend(_CheckNoPragmaOnce(input_api, output_api))
   results.extend(_CheckNoTrinaryTrueFalse(input_api, output_api))
   results.extend(_CheckUnwantedDependencies(input_api, output_api))
   results.extend(_CheckFilePermissions(input_api, output_api))
   results.extend(_CheckNoAuraWindowPropertyHInHeaders(input_api, output_api))
   results.extend(_CheckIncludeOrder(input_api, output_api))
+  results.extend(_CheckDeletionsOnlyFiles(input_api, output_api))
   return results
 
 
 def _CheckSubversionConfig(input_api, output_api):
   """Verifies the subversion config file is correctly setup.
 
   Checks that autoprops are enabled, returns an error otherwise.
   """
   join = input_api.os_path.join
   if input_api.platform == 'win32':
@@ skipping 127 matching lines @@
 
   # Match things like path/aura/file.cc and path/file_aura.cc.
   # Same for ash and chromeos.
   if any(re.search('[/_](ash|aura)', f) for f in files):
     trybots += ['linux_chromeos_clang:compile', 'win_aura',
                 'linux_chromeos_asan']
   elif any(re.search('[/_]chromeos', f) for f in files):
     trybots += ['linux_chromeos_clang:compile', 'linux_chromeos_asan']
 
   return trybots