[clang-tidy] correct clang-tidy-diff.py help message

[sugak]

Summary

Looks like the original code was copied from clang-format-diff.py.
Update help message to make it clang-tidy specific.

[Eugene.Zelenko]

clang-tidy/tool/clang-tidy-diff.py

42

Shouldn't -p be used to specify compile database as in run-clang-tidy.py?

[sugak]

clang-tidy/tool/clang-tidy-diff.py

42

From the test plan it looks like this script doesn't support compilation database input:

git diff -U0 HEAD^ | clang-tidy-diff.py -checks=-*,misc-use-override -p1 -- -std=gnu++14

It is similar to patch-like tools that process unified diff input -- uses -p to adjust file path. I can fix it in a separate diff, just need a better name for the current function of -p.

[alexfh]

Looks good. Thank you for fixing the copy-paste failures!

Do you need me to commit the patch for you?

clang-tidy/tool/clang-tidy-diff.py

42

The -p flag (compilation database path) to clang-tidy can be specified after the --:

git diff -U0 HEAD^ | clang-tidy-diff.py -checks=-*,misc-use-override -p1 -- -p path/to/compile_commands.json

It might be slightly confusing to have two -p flags, but both make sense.

[sugak]

Thank you for the review! I need someone to commit this for me :)

clang-tidy/tool/clang-tidy-diff.py

 import json
 import re
 import subprocess
 import sys
 
 
 def main():
   parser = argparse.ArgumentParser(description=
-                                   'Reformat changed lines in diff. Without -i '
-                                   'option just output the diff that would be '
-                                   'introduced.')
+                                   'Run clang-tidy against changed files, and '
+                                   'output diagnostics only for modified '
+                                   'lines.')
   parser.add_argument('-clang-tidy-binary', metavar='PATH',
                       default='clang-tidy',
                       help='path to clang-tidy binary')
   parser.add_argument('-p', metavar='NUM', default=0,
                       help='strip the smallest prefix containing P slashes')
   parser.add_argument('-regex', metavar='PATTERN', default=None,
-                      help='custom pattern selecting file paths to reformat '
+                      help='custom pattern selecting file paths to check '
                       '(case sensitive, overrides -iregex)')
   parser.add_argument('-iregex', metavar='PATTERN', default=
                       r'.*\.(cpp|cc|c\+\+|cxx|c|cl|h|hpp|m|mm|inc)',
-                      help='custom pattern selecting file paths to reformat '
+                      help='custom pattern selecting file paths to check '
                       '(case insensitive, overridden by -regex)')
 
   parser.add_argument('-fix', action='store_true', default=False,
                       help='apply suggested fixes')
   parser.add_argument('-checks',
                       help='checks filter, when not specified, use clang-tidy '
                       'default',
                       default='')