PRESUBMIT.py - v8/v8 - Git at Google

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
 #       with the distribution.
 #     * Neither the name of Google Inc. nor the names of its
 #       contributors may be used to endorse or promote products derived
 #       from this software without specific prior written permission.
 #
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 """Top-level presubmit script for V8.

 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """

 import ast
 import json
 import os
 import re
 import sys
 import traceback

 # This line is 'magic' in that git-cl looks for it to decide whether to
 # use Python3 instead of Python2 when running the code in this file.
 USE_PYTHON3 = True

 _EXCLUDED_PATHS = (
     r"^test[\\\/].*",
     r"^testing[\\\/].*",
     r"^third_party[\\\/].*",
     r"^tools[\\\/].*",
 )

 _LICENSE_FILE = (
     r"LICENSE"
 )

 # Regular expression that matches code which should not be run through cpplint.
 _NO_LINT_PATHS = (
     r'src[\\\/]base[\\\/]export-template\.h',
 )


 # Regular expression that matches code only used for test binaries
 # (best effort).
 _TEST_CODE_EXCLUDED_PATHS = (
     r'.+-unittest\.cc',
     # Has a method VisitForTest().
     r'src[\\\/]compiler[\\\/]ast-graph-builder\.cc',
     # Test extension.
     r'src[\\\/]extensions[\\\/]gc-extension\.cc',
     # Runtime functions used for testing.
     r'src[\\\/]runtime[\\\/]runtime-test\.cc',
     # Testing helpers.
     r'src[\\\/]heap[\\\/]cppgc[\\\/]testing\.cc',
 )


 _TEST_ONLY_WARNING = (
     'You might be calling functions intended only for testing from\n'
     'production code.  It is OK to ignore this warning if you know what\n'
     'you are doing, as the heuristics used to detect the situation are\n'
     'not perfect.  The commit queue will not block on this warning.')


 def _V8PresubmitChecks(input_api, output_api):
   """Runs the V8 presubmit checks."""
   import sys
   sys.path.append(input_api.os_path.join(
         input_api.PresubmitLocalPath(), 'tools'))
   from v8_presubmit import CppLintProcessor
   from v8_presubmit import GCMoleProcessor
   from v8_presubmit import JSLintProcessor
   from v8_presubmit import TorqueLintProcessor
   from v8_presubmit import SourceProcessor
   from v8_presubmit import StatusFilesProcessor

   def FilterFile(affected_file):
     return input_api.FilterSourceFile(
       affected_file,
       files_to_check=None,
       files_to_skip=_NO_LINT_PATHS)

   def FilterTorqueFile(affected_file):
     return input_api.FilterSourceFile(
       affected_file,
       files_to_check=(r'.+\.tq'))

   def FilterJSFile(affected_file):
     return input_api.FilterSourceFile(
       affected_file,
       files_to_check=(r'.+\.m?js'))

   results = []
   if not CppLintProcessor().RunOnFiles(
       input_api.AffectedFiles(file_filter=FilterFile, include_deletes=False)):
     results.append(output_api.PresubmitError("C++ lint check failed"))
   if not TorqueLintProcessor().RunOnFiles(
       input_api.AffectedFiles(file_filter=FilterTorqueFile,
                               include_deletes=False)):
     results.append(output_api.PresubmitError("Torque format check failed"))
   if not JSLintProcessor().RunOnFiles(
       input_api.AffectedFiles(file_filter=FilterJSFile,
                               include_deletes=False)):
     results.append(output_api.PresubmitError("JS format check failed"))
   if not SourceProcessor().RunOnFiles(
       input_api.AffectedFiles(include_deletes=False)):
     results.append(output_api.PresubmitError(
         "Copyright header, trailing whitespaces and two empty lines " \
         "between declarations check failed"))
   if not StatusFilesProcessor().RunOnFiles(
       input_api.AffectedFiles(include_deletes=True)):
     results.append(output_api.PresubmitError("Status file check failed"))
   if not GCMoleProcessor().RunOnFiles(
       input_api.AffectedFiles(include_deletes=False)):
     results.append(output_api.PresubmitError("GCMole pattern check failed"))
   results.extend(input_api.canned_checks.CheckAuthorizedAuthor(
       input_api, output_api, bot_allowlist=[
         'v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com',
         'v8-ci-test262-import-export@chops-service-accounts.iam.gserviceaccount.com',
         'chrome-cherry-picker@chops-service-accounts.iam.gserviceaccount.com',
       ]))
   return results


 def _CheckPythonLiterals(input_api, output_api):
   """Checks that all .pyl files are valid python literals."""
   affected_files = [
       af for af in input_api.AffectedFiles()
       if af.LocalPath().endswith('.pyl')
   ]

   results = []
   for af in affected_files:
     try:
       ast.literal_eval('\n'.join(af.NewContents()))
     except SyntaxError as e:
       results.append(output_api.PresubmitError(
           f'Failed to parse python literal {af.LocalPath()}:\n' +
           traceback.format_exc(0)
       ))

   return results


 def _CheckUnwantedDependencies(input_api, output_api):
   """Runs checkdeps on #include statements added in this
   change. Breaking - rules is an error, breaking ! rules is a
   warning.
   """
   # We need to wait until we have an input_api object and use this
   # roundabout construct to import checkdeps because this file is
   # eval-ed and thus doesn't have __file__.
   original_sys_path = sys.path
   try:
     root = input_api.PresubmitLocalPath()
     if not os.path.exists(os.path.join(root, 'buildtools')):
       root = os.path.dirname(root)
       if not os.path.exists(os.path.join(root, 'buildtools')):
         raise RuntimeError(
             "Failed to find //buildtools directory for checkdeps")
     sys.path = sys.path + [
         input_api.os_path.join(root, 'buildtools', 'checkdeps')
     ]
     import checkdeps
     from cpp_checker import CppChecker
     from rules import Rule
   finally:
     # Restore sys.path to what it was before.
     sys.path = original_sys_path

   def _FilesImpactedByDepsChange(files):
     all_files = [f.AbsoluteLocalPath() for f in files]
     deps_files = [p for p in all_files if IsDepsFile(p)]
     impacted_files = union([_CollectImpactedFiles(path) for path in deps_files])
     impacted_file_objs = [ImpactedFile(path) for path in impacted_files]
     return impacted_file_objs

   def IsDepsFile(p):
     return os.path.isfile(p) and os.path.basename(p) == 'DEPS'

   def union(list_of_lists):
     """Ensure no duplicates"""
     return set(sum(list_of_lists, []))

   def _CollectImpactedFiles(deps_file):
     # TODO(liviurau): Do not walk paths twice. Then we have no duplicates.
     # Higher level DEPS changes may dominate lower level DEPS changes.
     # TODO(liviurau): Check if DEPS changed in the right way.
     # 'include_rules' impact c++ files but 'vars' or 'deps' do not.
     # Maybe we just eval both old and new DEPS content and check
     # if the list are the same.
     result = []
     parent_dir = os.path.dirname(deps_file)
     for relative_f in input_api.change.AllFiles(parent_dir):
       abs_f = os.path.join(parent_dir, relative_f)
       if CppChecker.IsCppFile(abs_f):
         result.append(abs_f)
     return result

   class ImpactedFile(object):
     """Duck type version of AffectedFile needed to check files under directories
     where a DEPS file changed. Extend the interface along the line of
     AffectedFile if you need it for other checks."""

     def __init__(self, path):
       self._path = path

     def LocalPath(self):
       path = self._path.replace(os.sep, '/')
       return os.path.normpath(path)

     def ChangedContents(self):
       with open(self._path) as f:
         # TODO(liviurau): read only '#include' lines
         lines = f.readlines()
       return enumerate(lines, start=1)

   def _FilterDuplicates(impacted_files, affected_files):
     """"We include all impacted files but exclude affected files that are also
     impacted. Files impacted by DEPS changes take precedence before files
     affected by direct changes."""
     result = impacted_files[:]
     only_paths = set([imf.LocalPath() for imf in impacted_files])
     for af in affected_files:
       if not af.LocalPath() in only_paths:
         result.append(af)
     return result

   added_includes = []
   affected_files = input_api.AffectedFiles()
   impacted_by_deps = _FilesImpactedByDepsChange(affected_files)
   for f in _FilterDuplicates(impacted_by_deps, affected_files):
     if not CppChecker.IsCppFile(f.LocalPath()):
       continue

     changed_lines = [line for line_num, line in f.ChangedContents()]
     added_includes.append([f.LocalPath(), changed_lines])

   deps_checker = checkdeps.DepsChecker(input_api.PresubmitLocalPath())

   error_descriptions = []
   warning_descriptions = []
   for path, rule_type, rule_description in deps_checker.CheckAddedCppIncludes(
       added_includes):
     description_with_path = '{}\n    {}'.format(path, rule_description)
     if rule_type == Rule.DISALLOW:
       error_descriptions.append(description_with_path)
     else:
       warning_descriptions.append(description_with_path)

   results = []
   if error_descriptions:
     results.append(output_api.PresubmitError(
         'You added one or more #includes that violate checkdeps rules.',
         error_descriptions))
   if warning_descriptions:
     results.append(output_api.PresubmitPromptOrNotify(
         'You added one or more #includes of files that are temporarily\n'
         'allowed but being removed. Can you avoid introducing the\n'
         '#include? See relevant DEPS file(s) for details and contacts.',
         warning_descriptions))
   return results


 def _CheckHeadersHaveIncludeGuards(input_api, output_api):
   """Ensures that all header files have include guards."""
   file_inclusion_pattern = r'src/.+\.h'

   def FilterFile(affected_file):
     files_to_skip = _EXCLUDED_PATHS + input_api.DEFAULT_FILES_TO_SKIP
     return input_api.FilterSourceFile(
       affected_file,
       files_to_check=(file_inclusion_pattern, ),
       files_to_skip=files_to_skip)

   leading_src_pattern = input_api.re.compile(r'^src[\\\/]')
   dash_dot_slash_pattern = input_api.re.compile(r'[-.\\\/]')

   def PathToGuardMacro(path):
     """Guards should be of the form V8_PATH_TO_FILE_WITHOUT_SRC_H_."""
     x = input_api.re.sub(leading_src_pattern, 'v8_', path)
     x = input_api.re.sub(dash_dot_slash_pattern, '_', x)
     x = x.upper() + "_"
     return x

   problems = []
   for f in input_api.AffectedSourceFiles(FilterFile):
     local_path = f.LocalPath()
     guard_macro = PathToGuardMacro(local_path)
     guard_patterns = [
             input_api.re.compile(r'^#ifndef ' + guard_macro + '$'),
             input_api.re.compile(r'^#define ' + guard_macro + '$'),
             input_api.re.compile(r'^#endif  // ' + guard_macro + '$')]
     skip_check_pattern = input_api.re.compile(
             r'^// PRESUBMIT_INTENTIONALLY_MISSING_INCLUDE_GUARD')
     found_patterns = [ False, False, False ]
     file_omitted = False

     for line in f.NewContents():
       for i in range(len(guard_patterns)):
         if guard_patterns[i].match(line):
           found_patterns[i] = True
       if skip_check_pattern.match(line):
         file_omitted = True
         break

     if not file_omitted and not all(found_patterns):
       problems.append('{}: Missing include guard \'{}\''.format(
           local_path, guard_macro))

   if problems:
     return [output_api.PresubmitError(
         'You added one or more header files without an appropriate\n'
         'include guard. Add the include guard {#ifndef,#define,#endif}\n'
         'triplet or omit the check entirely through the magic comment:\n'
         '"// PRESUBMIT_INTENTIONALLY_MISSING_INCLUDE_GUARD".', problems)]
   else:
     return []


 def _CheckNoInlineHeaderIncludesInNormalHeaders(input_api, output_api):
   """Attempts to prevent inclusion of inline headers into normal header
   files. This tries to establish a layering where inline headers can be
   included by other inline headers or compilation units only."""
   file_inclusion_pattern = r'(?!.+-inl\.h).+\.h'
   include_directive_pattern = input_api.re.compile(r'#include ".+-inl.h"')
   include_error = (
     'You are including an inline header (e.g. foo-inl.h) within a normal\n'
     'header (e.g. bar.h) file.  This violates layering of dependencies.')

   def FilterFile(affected_file):
     files_to_skip = _EXCLUDED_PATHS + input_api.DEFAULT_FILES_TO_SKIP
     return input_api.FilterSourceFile(
       affected_file,
       files_to_check=(file_inclusion_pattern, ),
       files_to_skip=files_to_skip)

   problems = []
   for f in input_api.AffectedSourceFiles(FilterFile):
     local_path = f.LocalPath()
     for line_number, line in f.ChangedContents():
       if (include_directive_pattern.search(line)):
         problems.append('{}:{}\n    {}'.format(local_path, line_number,
                                                line.strip()))

   if problems:
     return [output_api.PresubmitError(include_error, problems)]
   else:
     return []


 def _CheckInlineHeadersIncludeNonInlineHeadersFirst(input_api, output_api):
   """Checks that the first include in each inline header ("*-inl.h") is the
   non-inl counterpart of that header, if that file exists."""
   file_inclusion_pattern = r'.+-inl\.h'
   include_error = (
       'The first include of an -inl.h header should be the non-inl counterpart.'
   )

   def FilterFile(affected_file):
     files_to_skip = _EXCLUDED_PATHS + input_api.DEFAULT_FILES_TO_SKIP + (
         # Exclude macro-assembler-<ARCH>-inl.h headers because they have special
         # include rules (arch-specific macro assembler headers must be included
         # via the general macro-assembler.h).
         r'src[\\\/]codegen[\\\/].*[\\\/]macro-assembler-.*-inl\.h',)
     return input_api.FilterSourceFile(
         affected_file,
         files_to_check=(file_inclusion_pattern,),
         files_to_skip=files_to_skip)

   to_non_inl = lambda filename: filename[:-len("-inl.h")] + ".h"
   problems = []
   for f in input_api.AffectedSourceFiles(FilterFile):
     if not os.path.isfile(to_non_inl(f.AbsoluteLocalPath())):
       continue
     non_inl_header = to_non_inl(f.LocalPath()).replace(os.sep, '/')
     first_include = None
     for line in f.NewContents():
       if line.startswith('#include '):
         first_include = line
         break
     expected_include = f'#include "{non_inl_header}"'
     if first_include is None:
       problems.append(f'{f.LocalPath()}: should include {non_inl_header}\n'
                       '    found no includes in the file.')
     elif not first_include.startswith(expected_include):
       problems.append(
           f'{f.LocalPath()}: should include {non_inl_header} first\n'
           f'    found: {first_include}')

   if problems:
     return [output_api.PresubmitError(include_error, problems)]
   else:
     return []


 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, as the declaration of for-testing functions in
   # header files are hard to distinguish from calls to such functions without a
   # proper C++ parser.
   file_inclusion_pattern = r'.+\.cc'

   base_function_pattern = r'[ :]test::[^\s]+|ForTest(ing)?|for_test(ing)?'
   inclusion_pattern = input_api.re.compile(
       r'({})\s*\('.format(base_function_pattern))
   comment_pattern = input_api.re.compile(
       r'//.*({})'.format(base_function_pattern))
   exclusion_pattern = input_api.re.compile(
       r'::[A-Za-z0-9_]+({})|({})[^;]+'.format(base_function_pattern,
                                               base_function_pattern) + '\{')

   def FilterFile(affected_file):
     files_to_skip = (_EXCLUDED_PATHS +
                      _TEST_CODE_EXCLUDED_PATHS +
                      input_api.DEFAULT_FILES_TO_SKIP)
     return input_api.FilterSourceFile(
       affected_file,
       files_to_check=(file_inclusion_pattern, ),
       files_to_skip=files_to_skip)

   problems = []
   for f in input_api.AffectedSourceFiles(FilterFile):
     local_path = f.LocalPath()
     for line_number, line in f.ChangedContents():
       if (inclusion_pattern.search(line) and
           not comment_pattern.search(line) and
           not exclusion_pattern.search(line)):
         problems.append('{}:{}\n    {}'.format(local_path, line_number,
                                                line.strip()))

   if problems:
     return [output_api.PresubmitPromptOrNotify(_TEST_ONLY_WARNING, problems)]
   else:
     return []


 def _CheckGenderNeutralInLicenses(input_api, output_api):
   # License files are taken as is, even if they include gendered pronouns.
   def LicenseFilter(path):
     input_api.FilterSourceFile(path, files_to_skip=_LICENSE_FILE)

   return input_api.canned_checks.CheckGenderNeutral(
     input_api, output_api, source_file_filter=LicenseFilter)


 def _RunTestsWithVPythonSpec(input_api, output_api):
   return input_api.RunTests(
     input_api.canned_checks.CheckVPythonSpec(input_api, output_api))


 def _CommonChecks(input_api, output_api):
   """Checks common to both upload and commit."""
   # TODO(machenbach): Replace some of those checks, e.g. owners and copyright,
   # with the canned PanProjectChecks. Need to make sure that the checks all
   # pass on all existing files.
   checks = [
       input_api.canned_checks.CheckOwnersFormat,
       input_api.canned_checks.CheckOwners,
       _CheckCommitMessageBugEntry,
       input_api.canned_checks.CheckPatchFormatted,
       _CheckGenderNeutralInLicenses,
       _V8PresubmitChecks,
       _CheckUnwantedDependencies,
       _CheckNoProductionCodeUsingTestOnlyFunctions,
       _CheckHeadersHaveIncludeGuards,
       _CheckNoInlineHeaderIncludesInNormalHeaders,
       _CheckInlineHeadersIncludeNonInlineHeadersFirst,
       _CheckJSONFiles,
       _CheckNoexceptAnnotations,
       _CheckBannedCpp,
       _RunTestsWithVPythonSpec,
       _CheckPythonLiterals,
   ]

   return sum([check(input_api, output_api) for check in checks], [])


 def _SkipTreeCheck(input_api, output_api):
   """Check the env var whether we want to skip tree check.
      Only skip if include/v8-version.h has been updated."""
   src_version = 'include/v8-version.h'
   if not input_api.AffectedSourceFiles(
       lambda file: file.LocalPath() == src_version):
     return False
   return input_api.environ.get('PRESUBMIT_TREE_CHECK') == 'skip'


 def _CheckCommitMessageBugEntry(input_api, output_api):
   """Check that bug entries are well-formed in commit message."""
   bogus_bug_msg = (
       'Bogus BUG entry: {}. Please specify prefix:number for v8 or chromium '
       '(e.g. chromium:12345) or b/number for buganizer.')
   results = []
   for bug in (input_api.change.BUG or '').split(','):
     bug = bug.strip()
     if 'none'.startswith(bug.lower()):
       continue
     if ':' not in bug and not bug.startswith('b/'):
       try:
         if int(bug) < 10000000:
           if int(bug) > 200000:
             prefix_guess = 'chromium'
           else:
             prefix_guess = 'v8'
           results.append(
               'BUG entry requires issue tracker prefix, e.g. {}:{}'.format(
                   prefix_guess, bug))
       except ValueError:
         results.append(bogus_bug_msg.format(bug))
     elif not re.match(r'\w+[:\/]\d+', bug):
       results.append(bogus_bug_msg.format(bug))
   return [output_api.PresubmitError(r) for r in results]


 def _CheckJSONFiles(input_api, output_api):
   def FilterFile(affected_file):
     return input_api.FilterSourceFile(
         affected_file,
         files_to_check=(r'.+\.json',))

   results = []
   for f in input_api.AffectedFiles(
       file_filter=FilterFile, include_deletes=False):
     with open(f.LocalPath()) as j:
       try:
         json.load(j)
       except Exception as e:
         results.append('JSON validation failed for {}. Error:\n{}'.format(
             f.LocalPath(), e))

   return [output_api.PresubmitError(r) for r in results]


 def _CheckNoexceptAnnotations(input_api, output_api):
   """
   Checks that all user-defined constructors and assignment operators are marked
   V8_NOEXCEPT.

   This is required for standard containers to pick the right constructors. Our
   macros (like MOVE_ONLY_WITH_DEFAULT_CONSTRUCTORS) add this automatically.
   Omitting it at some places can result in weird compiler errors if this is
   mixed with other classes that have the annotation.

   TODO(clemensb): This check should eventually be enabled for all files via
   tools/presubmit.py (https://crbug.com/v8/8616).
   """

   def FilterFile(affected_file):
     files_to_skip = _EXCLUDED_PATHS + (
         # Skip api.cc since we cannot easily add the 'noexcept' annotation to
         # public methods.
         r'src[\\\/]api[\\\/]api\.cc',
         # Skip src/bigint/ because it's meant to be V8-independent.
         r'src[\\\/]bigint[\\\/].*',
     )
     return input_api.FilterSourceFile(
         affected_file,
         files_to_check=(r'src[\\\/].*\.cc', r'src[\\\/].*\.h',
                         r'test[\\\/].*\.cc', r'test[\\\/].*\.h'),
         files_to_skip=files_to_skip)

   # matches any class name.
   class_name = r'\b([A-Z][A-Za-z0-9_:]*)(?:::\1)?'
   # initial class name is potentially followed by this to declare an assignment
   # operator.
   potential_assignment = r'(?:&\s+(?:\1::)?operator=)?\s*'
   # matches an argument list that contains only a reference to a class named
   # like the first capture group, potentially const.
   single_class_ref_arg = r'\(\s*(?:const\s+)?\1(?:::\1)?&&?[^,;)]*\)'
   # matches anything but a sequence of whitespaces followed by either
   # V8_NOEXCEPT or "= delete".
   not_followed_by_noexcept = r'(?!\s+(?:V8_NOEXCEPT|=\s+delete)\b)'
   full_pattern = r'^.*?' + class_name + potential_assignment + \
       single_class_ref_arg + not_followed_by_noexcept + '.*?$'
   regexp = input_api.re.compile(full_pattern, re.MULTILINE)

   errors = []
   for f in input_api.AffectedFiles(file_filter=FilterFile,
                                    include_deletes=False):
     with open(f.LocalPath()) as fh:
       for match in re.finditer(regexp, fh.read()):
         errors.append(f'in {f.LocalPath()}: {match.group().strip()}')

   if errors:
     return [output_api.PresubmitPromptOrNotify(
         'Copy constructors, move constructors, copy assignment operators and '
         'move assignment operators should be marked V8_NOEXCEPT.\n'
         'Please report false positives on https://crbug.com/v8/8616.',
         errors)]
   return []


 def _CheckBannedCpp(input_api, output_api):
   # We only check for a single pattern right now; feel free to add more, but
   # potentially change the logic for files_to_skip then (and skip individual
   # checks for individual files instead).
   bad_cpp = [
       ('std::bit_cast',
        'Use base::bit_cast instead, which has additional checks'),
   ]

   def file_filter(x):
     return input_api.FilterSourceFile(
         x,
         files_to_skip=[
             # The implementation of base::bit_cast uses std::bit_cast.
             r'src/base/macros\.h',
             # src/base/numerics is a dependency-free header-only library, hence
             # uses std::bit_cast directly.
             r'src/base/numerics/.*'
         ],
         files_to_check=[r'.*\.h$', r'.*\.cc$'])

   errors = []
   for f in input_api.AffectedSourceFiles(file_filter):
     for line_number, line in f.ChangedContents():
       for pattern, message in bad_cpp:
         if not pattern in line:
           continue
         # Skip if part of a comment.
         if '//' in line and line.index('//') < line.index(pattern):
           continue

         # Make sure there are word separators around the pattern.
         regex = r'\b%s\b' % pattern
         if not input_api.re.search(regex, line):
           continue

         errors.append(
             output_api.PresubmitError('Banned pattern ({}):\n  {}:{} {}'.format(
                 regex, f.LocalPath(), line_number, message)))
   return errors


 def CheckChangeOnUpload(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   return results


 def CheckChangeOnCommit(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   if not _SkipTreeCheck(input_api, output_api):
     results.extend(input_api.canned_checks.CheckTreeIsOpen(
         input_api, output_api,
         json_url='http://v8-status.appspot.com/current?format=json'))
   return results