Add PRESUBMIT check for native API changes.

PRESUBMIT.py

 # Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import json
 import os
 import platform
 import re
 import subprocess
 import sys
 
 
+NATIVE_API_DIRS = (
+  'talk/app/webrtc',
+  'webrtc',
+  'webrtc/common_audio/include',  # DEPRECATED (will go away).
+  'webrtc/modules/audio_coding/include',
+  'webrtc/modules/audio_conference_mixer/include',  # DEPRECATED (will go away).
+  'webrtc/modules/audio_device/include',
+  'webrtc/modules/audio_processing/include',
+  'webrtc/modules/bitrate_controller/include',
+  'webrtc/modules/include',
+  'webrtc/modules/remote_bitrate_estimator/include',
+  'webrtc/modules/rtp_rtcp/include',
+  'webrtc/modules/rtp_rtcp/source',  # DEPRECATED (will go away).
+  'webrtc/modules/utility/include',
+  'webrtc/modules/video_coding/codecs/h264/include',
+  'webrtc/modules/video_coding/codecs/i420/include',
+  'webrtc/modules/video_coding/codecs/vp8/include',
+  'webrtc/modules/video_coding/codecs/vp9/include',
+  'webrtc/modules/video_coding/include',
+  'webrtc/system_wrappers/include',
+  'webrtc/voice_engine/include',
+)
+
+
+def _VerifyNativeApiHeadersListIsValid(input_api, output_api):
+  """Ensures the list of native API header directories is up to date."""
+  non_existing_paths = []
+  native_api_full_paths = [
+      input_api.os_path.join(input_api.PresubmitLocalPath(),
+                             *path.split('/')) for path in NATIVE_API_DIRS]
+  for path in native_api_full_paths:
+    if not os.path.isdir(path):
+      non_existing_paths.append(path)
+  if non_existing_paths:
+    return [output_api.PresubmitError(
+        'Directories to native API headers have changed which has made the '
+        'list in PRESUBMIT.py outdated.\nPlease update it to the current '
+        'location of our native APIs.',
+        non_existing_paths)]
+  return []
+
+
+def _CheckNativeApiHeaderChanges(input_api, output_api):
+  """Checks to remind proper changing of native APIs."""
+  files = []
+  for f in input_api.AffectedSourceFiles(input_api.FilterSourceFile):
+    if f.LocalPath().endswith('.h'):
+      for path in NATIVE_API_DIRS:
+        if os.path.dirname(f.LocalPath()) == path:
+          files.append(f)
+
+  if files:
+    return [output_api.PresubmitPromptWarning(
+        'You seem to be changing native API header files. Please make sure '
+        'you:\n'
+        '  1. Make compatible changes that doesn\'t break existing clients.\n'

[hlundin-webrtc, 2015/11/27 07:46:13]

doesn't -> don't
(Native English speakers: please correct me if I'm wrong.)

[kjellander_webrtc, 2015/11/27 08:40:32]

Thanks.

+        '  2. Mark the old APIs as deprecated.\n'
+        '  3. Create a timeline and plan for when the deprecated method will '
+        'be removed (preferably 3 months or so).\n'
+        '  4. Update/inform existing downstream code to update their code to '

[hlundin-webrtc, 2015/11/27 07:46:13]

Inform the code to update their code? Have we reached the singularity? :)

Suggest:
"Urge downstream code owners to stop using the deprecated APIs."

[kjellander_webrtc, 2015/11/27 08:40:32]

Oops :) thanks for correcting this.

+        'the new API: \n'
+        'announce to discuss-webrtc@googlegroups.com and '
+        'webrtc-users@google.com.\n'
+        '  5. (after ~3 months) remove the deprecated API.\n'
+        'Related files:',
+        files)]
+  return []
+
+
 def _CheckNoIOStreamInHeaders(input_api, output_api):
   """Checks to make sure no .h files include <iostream>."""
   files = []
   pattern = input_api.re.compile(r'^#include\s*<iostream>',
                                  input_api.re.MULTILINE)
   for f in input_api.AffectedSourceFiles(input_api.FilterSourceFile):
     if not f.LocalPath().endswith('.h'):
       continue
     contents = input_api.ReadFile(f)
     if pattern.search(contents):
@@ skipping 265 matching lines @@
       black_list=(r'.+\.gyp$', r'.+\.gypi$', r'.+\.gn$', r'.+\.gni$', 'DEPS'))
   results.extend(input_api.canned_checks.CheckLongLines(
       input_api, output_api, maxlen=80, source_file_filter=long_lines_sources))
   results.extend(input_api.canned_checks.CheckChangeHasNoTabs(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasNoStrayWhitespace(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeTodoHasOwner(
       input_api, output_api))
   results.extend(_CheckApprovedFilesLintClean(input_api, output_api))
+  results.extend(_CheckNativeApiHeaderChanges(input_api, output_api))
   results.extend(_CheckNoIOStreamInHeaders(input_api, output_api))
   results.extend(_CheckNoFRIEND_TEST(input_api, output_api))
   results.extend(_CheckGypChanges(input_api, output_api))
   results.extend(_CheckUnwantedDependencies(input_api, output_api))
   results.extend(_RunPythonTests(input_api, output_api))
   return results
 
 
 def CheckChangeOnUpload(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   results.extend(
       input_api.canned_checks.CheckGNFormatted(input_api, output_api))
   return results
 
 
 def CheckChangeOnCommit(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
+  results.extend(_VerifyNativeApiHeadersListIsValid(input_api, output_api))
   results.extend(input_api.canned_checks.CheckOwners(input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeWasUploaded(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasBugField(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasTestField(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckTreeIsOpen(
@@ skipping 18 matching lines @@
     for builder in masters[master]:
       if 'presubmit' in builder:
         # Do not trigger presubmit builders, since they're likely to fail
         # (e.g. OWNERS checks before finished code review), and we're running
         # local presubmit anyway.
         pass
       else:
         try_config[master][builder] = ['defaulttests']
 
   return try_config