[clang-tidy] Fix check_clang_tidy.py trivially passing default CHECK

[zinovy.nis]

Summary

In https://reviews.llvm.org/D52971#1262200, @ymandel wrote:

Hi,

It looks like this change has disabled FileCheck for all clang-tidy lit tests that don't use check-prefixes. So, they all trivially pass even if their CHECK... lines are wrong. An easy repro is just to randomly modify any CHECK line in a lit file (e.g. llvm/tools/clang/tools/extra/test/clang-tidy/readability-avoid-const-params-in-decls.cpp) and run ninja check-clang-tools.

In check_clang_tidy.py, if you add back (slightly modified) lines 93-95 to the else branch (line 132), it seems to fix the problem. For example, add:

has_check_fixes = check_fixes_prefixes[0] in input_text
has_check_messages = check_messages_prefixes[0] in input_text
has_check_notes = check_notes_prefixes[0] in input_text

[JonasToth]

Did you verify it actually works?
Otherwise LGTM and because its a bug-fix you can commit and other concerns can be done post-commit.

test/clang-tidy/check_clang_tidy.py

129

Nit: Could you please move this assert three lines up? It looks that its actually checking the conditions established there.

test/clang-tidy/check_clang_tidy.py

def main():
   parser = argparse.ArgumentParser()
   parser.add_argument('-expect-clang-tidy-error', action='store_true')
   parser.add_argument('-resource-dir')
   parser.add_argument('-assume-filename')
   parser.add_argument('input_file_name')
   parser.add_argument('check_name')
   parser.add_argument('temp_file_name')
   parser.add_argument('-check-suffix', '-check-suffixes',
-                      default=[], type=csv,
+                      default=[''], type=csv,
                       help="comma-separated list of FileCheck suffixes")
 
   args, extra_args = parser.parse_known_args()
 
   resource_dir = args.resource_dir
   assume_file_name = args.assume_filename
   input_file_name = args.input_file_name
   check_name = args.check_name
def main():
   check_fixes_prefixes = []
   check_messages_prefixes = []
   check_notes_prefixes = []
 
   has_check_fixes = False
   has_check_messages = False
   has_check_notes = False
 
-  if any(args.check_suffix):
-    for check in args.check_suffix:
-      if not re.match('^[A-Z0-9\-]+$', check):
-        sys.exit('Only A..Z, 0..9 and "-" are ' +
-          'allowed in check suffixes list, but "%s" was given' % (check))
+    if check and not re.match('^[A-Z0-9\-]+$', check):
 
-      file_check_suffix = '-' + check
-      check_fixes_prefix = 'CHECK-FIXES' + file_check_suffix
-      check_messages_prefix = 'CHECK-MESSAGES' + file_check_suffix
-      check_notes_prefix = 'CHECK-NOTES' + file_check_suffix
+    file_check_suffix = ('-' + check) if check else ''
 
-      has_check_fix = check_fixes_prefix in input_text 
-      has_check_message = check_messages_prefix in input_text
-      has_check_note = check_notes_prefix in input_text 
+    has_check_fix = check_fixes_prefix in input_text
+    has_check_note = check_notes_prefix in input_text
 
-      if has_check_note and has_check_message:
-        sys.exit('Please use either %s or %s but not both' %
-          (check_notes_prefix, check_messages_prefix))
 
-      if not has_check_fix and not has_check_message and not has_check_note:
-        sys.exit('%s, %s or %s not found in the input' %
-          (check_fixes_prefix, check_messages_prefix, check_notes_prefix))
 
-      has_check_fixes = has_check_fixes or has_check_fix
-      has_check_messages = has_check_messages or has_check_message
-      has_check_notes = has_check_notes or has_check_note
 
-      check_fixes_prefixes.append(check_fixes_prefix)
-      check_messages_prefixes.append(check_messages_prefix)
-      check_notes_prefixes.append(check_notes_prefix)
-  else:
-    check_fixes_prefixes = ['CHECK-FIXES']
-    check_messages_prefixes = ['CHECK-MESSAGES']
-    check_notes_prefixes = ['CHECK-NOTES']
 
+  assert has_check_fixes or has_check_messages or has_check_notes
   # Remove the contents of the CHECK lines to avoid CHECKs matching on
   # themselves.  We need to keep the comments to preserve line numbers while
   # avoiding empty lines which could potentially trigger formatting-related
   # checks.
   cleaned_test = re.sub('// *CHECK-[A-Z0-9\-]*:[^\r\n]*', '//', input_text)
 
   write_file(temp_file_name, cleaned_test)