Revert of Add PRESUBMIT.py warning for contradictory NOTREACHED() use. (

https://codereview.chromium.org/344563003/)

Reason for revert:
It seems to be checking code that is not part of the diff. 

I also think there are some legitimate cases for not reached in the middle of a block but that is something that can be discussed on the bug.

Filed https://code.google.com/p/chromium/issues/detail?id=388731 to track.

Original issue's description:
> Add PRESUBMIT.py warning for contradictory NOTREACHED() use.
> 
> As recently discussed on chromium-dev [1] and subsequently incorporated into the
> Chromium Coding Style [2], NOTREACHED() followed by code is an anti-pattern.
> This CL lets PRESUBMIT.py detect most of these cases and print a warning to the
> developer.
> [1] https://groups.google.com/a/chromium.org/d/msg/chromium-dev/c2X0D1Z6X2o/ddkFLqQP0P0J
> [2] http://www.chromium.org/developers/coding-style#TOC-CHECK-DCHECK-and-NOTREACHED-
> 
> BUG=none
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=279681

TBR=maruel@chromium.org,tnagel@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=none

Review URL: https://codereview.chromium.org/357693004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@279710 0039d316-1c4b-4281-b951-d872f2087c98

PRESUBMIT.py

@@ -1229,94 +1229,6 @@ def _CheckNoDeprecatedCSS(input_api, output_api):
               (fpath.LocalPath(), line_num, deprecated_value, value)))
   return results
 
-
-def _StripCommentsAndStrings(input_api, s):
-  """Remove comments, replace string literals by a single token.  Requires that
-  input data is formatted with unix-style line ends."""
-
-  s = input_api.re.sub(r'\\\n', r'', s)    # Continue lines ending in backslash.
-
-  out = ''
-  i = 0
-  while i < len(s):
-    c = s[i]
-
-    if c == '/':
-      mo = input_api.re.match(r'//.*', s[i:])
-      if mo:
-        i += len(mo.group(0))
-        continue
-      mo = input_api.re.match(r'/\*.*?\*/', s[i:], input_api.re.DOTALL)
-      if mo:
-        i += len(mo.group(0))
-        continue
-
-    if c == "'":
-      mo = input_api.re.match(r"'((\\\\)|(\\')|[^']+?)'", s[i:])
-      if not mo:
-        raise Exception('bad char: ' + s[i:])
-      i += len(mo.group(0))
-      out += ' CHAR_LITERAL '
-      continue
-
-    if c == '"':
-      mo = input_api.re.match(r'".*?(?<!\\)(\\\\)*"', s[i:])
-      if not mo:
-        raise Exception('bad string: ' + s[i:])
-      i += len(mo.group(0))
-      out += ' STRING_LITERAL '
-      continue
-
-    out += c
-    i += 1
-
-  return out
-
-
-def _CheckContradictoryNotreachedUse(input_api, output_api):
-  file_inclusion_pattern = (
-      r".+\.c$", r".+\.cc$", r".+\.cpp$", r".+\.h$", r".+\.hpp$", r".+\.inl$",
-      r".+\.m$", r".+\.mm$" )
-  black_list = (_EXCLUDED_PATHS + input_api.DEFAULT_BLACK_LIST)
-  file_filter = lambda f: input_api.FilterSourceFile(
-      f, white_list=file_inclusion_pattern, black_list=black_list)
-  results = []
-  for fpath in input_api.AffectedFiles(file_filter=file_filter):
-    results.extend(_CheckContradictoryNotreachedUseInFile(input_api, fpath))
-  return [output_api.PresubmitPromptWarning(r) for r in results]
-
-
-def _CheckContradictoryNotreachedUseInFile(input_api, f):
-  style_url = (
-      'http://chromium.org/developers/coding-style'
-      '#TOC-CHECK-DCHECK-and-NOTREACHED-')
-  contents = f.NewContents()
-  text = ''.join(line + '\n' for line in f.NewContents())
-  text = _StripCommentsAndStrings(input_api, text)
-
-  results = []
-  while True:
-    # Capture text between NOTREACHED(); and the next closing brace or "break".
-    mo = input_api.re.search(
-        r'[ \t]*NOTREACHED\(\s*\).*?;(?P<between>.*?)((\bbreak\b)|})',
-        text, input_api.re.DOTALL)
-    # TODO(tnagel): Catch loops inside which NOTREACHED() is followed by break.
-    if not mo:
-      break
-    text = text[mo.end():]
-    if input_api.re.match(r'[\s;]*$', mo.group('between'), input_api.re.DOTALL):
-      continue
-    excerpt = mo.group(0).rstrip()
-    if len(excerpt) > 100:
-      excerpt = excerpt[:100] + ' \u2026'  # ellipsis
-    results.append(
-        '%s:  NOTREACHED() may only be used at end-of-block '
-        'but is followed by code.\n%s\n'
-        'Offending section (comments/strings possibly stripped):\n%s'
-        % (f, style_url, excerpt))
-  return results
-
-
 def _CommonChecks(input_api, output_api):
   """Checks common to both upload and commit."""
   results = []
@@ -1354,7 +1266,6 @@ def _CommonChecks(input_api, output_api):
   results.extend(_CheckUserActionUpdate(input_api, output_api))
   results.extend(_CheckNoDeprecatedCSS(input_api, output_api))
   results.extend(_CheckParseErrors(input_api, output_api))
-  results.extend(_CheckContradictoryNotreachedUse(input_api, output_api))
 
   if any('PRESUBMIT.py' == f.LocalPath() for f in input_api.AffectedFiles()):
     results.extend(input_api.canned_checks.RunUnitTestsInDirectory(

PRESUBMIT_test.py

@@ -413,52 +413,6 @@ def testValidOSMacroNames(self):
     self.assertEqual(0, len(errors))
 
 
-class CheckContradictoryNotreachedUseTest(unittest.TestCase):
-  def testValid(self):
-    lines = ['{',
-             '  // NOTREACHED();',
-             '  /* NOTREACHED(); */',
-             "  char a = '\\\\', b = '\\0', c = '\\'';",
-             '  char d[] = "NOTREACHED();";',
-             '  NOTREACHED(); // blah',
-             '  /* comment */',
-             '  // line continuation \\',
-             '  still inside comment',
-             '  // comment followed by empty line',
-             '',
-             '  ;; ; ;;;',
-             '}',
-             'switch (i) {',
-             '  case 7: NOTREACHED(); break;',
-             '}']
-    output = PRESUBMIT._CheckContradictoryNotreachedUseInFile(
-        MockInputApi(), MockFile('some/path/foo_platform.cc', lines))
-    self.assertEqual(0, len(output))
-
-  def testInvalid(self):
-    lines = ['{',
-             '  NOTREACHED();',
-             '  return;',
-             '}',
-             '{',
-             '  NOTREACHED();',
-             '  /* */',
-             '  return;',
-             '  /* */',
-             '}',
-             '{',
-             '  NOTREACHED();',
-             '  // trailing space, not a line continuation \\ ',
-             '  return;',
-             '}',
-             'switch (i) {',
-             '  case 7: NOTREACHED(); some_thing(); break;',
-             '}']
-    output = PRESUBMIT._CheckContradictoryNotreachedUseInFile(
-        MockInputApi(), MockFile('some/path/foo_platform.cc', lines))
-    self.assertEqual(4, len(output))
-
-
 class CheckAddedDepsHaveTetsApprovalsTest(unittest.TestCase):
   def testFilesToCheckForIncomingDeps(self):
     changed_lines = [