Fix RunPylint affected files regex issue

presubmit_canned_checks.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.
 
 """Generic presubmit checks that can be reused by other presubmit checks."""
 
 import os as _os
 _HERE = _os.path.dirname(_os.path.abspath(__file__))
 
 
@@ skipping 608 matching lines @@
       if Find(filepath, black_list):
         dirnames.remove(item)
     for item in filenames:
       filepath = input_api.os_path.join(dirpath, item)[path_len + 1:]
       if Find(filepath, white_list) and not Find(filepath, black_list):
         files.append(filepath)
   return files
 
 
 def RunPylint(input_api, output_api, white_list=None, black_list=None,
-              disabled_warnings=None):
+              disabled_warnings=None, extra_paths_list=None):
   """Run pylint on python files.
 
   The default white_list enforces looking only at *.py files.
   """
   white_list = tuple(white_list or ('.*\.py$',))
   black_list = tuple(black_list or input_api.DEFAULT_BLACK_LIST)
+  extra_paths_list = extra_paths_list or []
+
   if input_api.is_committing:
     error_type = output_api.PresubmitError
   else:
     error_type = output_api.PresubmitPromptWarning
 
   # Only trigger if there is at least one python file affected.
-  src_filter = lambda x: input_api.FilterSourceFile(x, white_list, black_list)
+  rel_path = lambda x : input_api.os_path.join(input_api.os_path.relpath(
+      input_api.PresubmitLocalPath(), input_api.change.RepositoryRoot()), x)
+  src_filter = lambda x: input_api.FilterSourceFile(
+      x, map(rel_path, white_list), map(rel_path, black_list))
   if not input_api.AffectedSourceFiles(src_filter):
+    input_api.logging.info('Skipping pylint: no matching changes.')
     return []
 
   extra_args = ['--rcfile=%s' % input_api.os_path.join(_HERE, 'pylintrc')]
   if disabled_warnings:
     extra_args.extend(['-d', ','.join(disabled_warnings)])
 
   files = _FetchAllFiles(input_api, white_list, black_list)
   if not files:
     return []
 
+  input_api.logging.info('Running pylint on: %s', files)
   # Copy the system path to the environment so pylint can find the right
   # imports.
   env = input_api.environ.copy()
   import sys
-  env['PYTHONPATH'] = input_api.os_path.pathsep.join(sys.path)
+  env['PYTHONPATH'] = input_api.os_path.pathsep.join(
+      extra_paths_list + sys.path)
 
   def run_lint(files):
     # We can't import pylint directly due to licensing issues, so we run
     # it in another process. Windows needs help running python files so we
     # explicitly specify the interpreter to use. It also has limitations on
     # the size of the command-line, so we pass arguments via a pipe.
     command = [input_api.python_executable,
                input_api.os_path.join(_HERE, 'third_party', 'pylint.py'),
                '--args-on-stdin']
     try:
@@ skipping 11 matching lines @@
       return child.returncode
     except OSError:
       return 'Pylint failed!'
 
   result = None
   # Always run pylint and pass it all the py files at once.
   # Passing py files one at time is slower and can produce
   # different results.  input_api.verbose used to be used
   # to enable this behaviour but differing behaviour in
   # verbose mode is not desirable.
+  # Leave this unreachable code in here so users can make
+  # a quick local edit to diagnose pylint issues more
+  # easily.
   if True:
+    print('Running pylint on %d files.' % len(files))
     result = run_lint(sorted(files))
   else:
     for filename in sorted(files):
       print('Running pylint on %s' % filename)
       result = run_lint([filename]) or result
   if isinstance(result, basestring):
     return [error_type(result)]
   elif result:
     return [error_type('Fix pylint errors first.')]
   return []
@@ skipping 280 matching lines @@
     snapshot("checking description")
     results.extend(input_api.canned_checks.CheckChangeHasDescription(
         input_api, output_api))
     results.extend(input_api.canned_checks.CheckDoNotSubmitInDescription(
         input_api, output_api))
     snapshot("checking do not submit in files")
     results.extend(input_api.canned_checks.CheckDoNotSubmitInFiles(
         input_api, output_api))
   snapshot("done")
   return results