[PATCH v2 0/3] clang-format: modify rules to reduce false-positives

This series is in response to an email thread [1] around the usage of '.clang-format' and its effectiveness.

The goal of the series is to improve the usage of 'clang-format' in the
repository. To do this we:
1. Reduce the number of false positives. Majority of which is due to
   line-wrapping. We remove the 'ColumnLimit' from 'clang-format'. This
   removes the responsibility of line-wrapping from 'clang-format' and puts
   it into the hands of the user.
2. Add a rule to 'meson' to run 'git clang-format' by running 'meson
   compile style'.
3. Make the 'RemoveBracesLLVM' permanent by moving it to
   '.clang-format'.

With this, running `git clang-format` for the last 25 commits in master, seems to produce much less false positives.

  diff --git a/builtin/diff.c b/builtin/diff.c
  index c6231edce4..246b81caa2 100644
  --- a/builtin/diff.c
  +++ b/builtin/diff.c
  @@ -30,14 +30,13 @@
   #define DIFF_NO_INDEX_IMPLICIT 2

   static const char builtin_diff_usage[] =
  -"git diff [<options>] [<commit>] [--] [<path>...]\n"
  -"   or: git diff [<options>] --cached [--merge-base] [<commit>] [--] [<path>...]\n"
  -"   or: git diff [<options>] [--merge-base] <commit> [<commit>...] <commit> [--] [<path>...]\n"
  -"   or: git diff [<options>] <commit>...<commit> [--] [<path>...]\n"
  -"   or: git diff [<options>] <blob> <blob>\n"
  -"   or: git diff [<options>] --no-index [--] <path> <path> [<pathspec>...]"
  -"\n"
  -COMMON_DIFF_OPTIONS_HELP;
  +	"git diff [<options>] [<commit>] [--] [<path>...]\n"
  +	"   or: git diff [<options>] --cached [--merge-base] [<commit>] [--] [<path>...]\n"
  +	"   or: git diff [<options>] [--merge-base] <commit> [<commit>...] <commit> [--] [<path>...]\n"
  +	"   or: git diff [<options>] <commit>...<commit> [--] [<path>...]\n"
  +	"   or: git diff [<options>] <blob> <blob>\n"
  +	"   or: git diff [<options>] --no-index [--] <path> <path> [<pathspec>...]"
  +	"\n" COMMON_DIFF_OPTIONS_HELP;

   static const char *blob_path(struct object_array_entry *entry)
   {
  diff --git a/builtin/stash.c b/builtin/stash.c
  index 7cd3ad8aa4..90e441a6e5 100644
  --- a/builtin/stash.c
  +++ b/builtin/stash.c
  @@ -1802,7 +1802,8 @@ static int push_stash(int argc, const char **argv, const char *prefix,

 		  argc = parse_options(argc, argv, prefix, options,
 				       push_assumed ? git_stash_usage :
  -				     git_stash_push_usage, flags);
  +						    git_stash_push_usage,
  +				     flags);
 		  force_assume |= patch_mode;
 	  }

  diff --git a/bundle-uri.c b/bundle-uri.c
  index c9d65aa0ce..89f59aafe8 100644
  --- a/bundle-uri.c
  +++ b/bundle-uri.c
  @@ -123,7 +123,7 @@ void print_bundle_list(FILE *fp, struct bundle_list *list)
 		  for (i = 0; i < BUNDLE_HEURISTIC__COUNT; i++) {
 			  if (heuristics[i].heuristic == list->heuristic) {
 				  fprintf(fp, "\theuristic = %s\n",
  -				       heuristics[list->heuristic].name);
  +					heuristics[list->heuristic].name);
 				  break;
 			  }
 		  }
  diff --git a/diff-no-index.c b/diff-no-index.c
  index 4aeeb98cfa..a3892a9ccc 100644
  --- a/diff-no-index.c
  +++ b/diff-no-index.c
  @@ -325,7 +325,7 @@ static int fixup_paths(const char **path, struct strbuf *replacement)
 	  return 0;
   }

  -static const char * const diff_no_index_usage[] = {
  +static const char *const diff_no_index_usage[] = {
 	  N_("git diff --no-index [<options>] <path> <path> [<pathspec>...]"),
 	  NULL
   };
  diff --git a/pathspec.h b/pathspec.h
  index 5e3a6f1fe7..601b9ca201 100644
  --- a/pathspec.h
  +++ b/pathspec.h
  @@ -80,7 +80,7 @@ struct pathspec {
    * For git diff --no-index, indicate that we are operating without
    * a repository or index.
    */
  -#define PATHSPEC_NO_REPOSITORY (1<<7)
  +#define PATHSPEC_NO_REPOSITORY (1 << 7)

   /**
    * Given command line arguments and a prefix, convert the input to

While now I'm tempted to mark the 'check-style' CI job as required. I think we should do that in the future.

[1]: https://lore.kernel.org/git/xmqqmsa3adpw.fsf@gitster.g/

---
Changes in v2:
- Drop the patch to add 120 column length to editorconfig. This way, we
  will continue to use the default of 80 columns. Adding a higher column
  length makes editorconfig combine smaller lines during block
  formatting. This is not desirable.
- Ensure that meson specifically checks for 'git-clang-format' and not
  just 'clang-format'.
- Link to v1: https://lore.kernel.org/r/20250625-525-make-clang-format-more-robust-v1-0-67a49ecc2fd5@gmail.com

---
 .clang-format         | 27 +++++++++++++++------------
 ci/run-style-check.sh | 18 +-----------------
 meson.build           | 12 ++++++++++++
 3 files changed, 28 insertions(+), 29 deletions(-)

Karthik Nayak (3):
      clang-format: set 'ColumnLimit' to 0
      clang-format: add 'RemoveBracesLLVM' to the main config
      meson: add rule to run 'git clang-format'

Range-diff versus v1:

1:  a62b4b7fe8 < -:  ---------- editorconfig: set maximum line length to 120 characters
2:  4b4d49273e = 1:  5479d22f80 clang-format: set 'ColumnLimit' to 0
3:  b9abb50adf = 2:  dacc7cc2b3 clang-format: add 'RemoveBracesLLVM' to the main config
4:  03cc722f8f ! 3:  b13832ed57 meson: add rule to run 'git clang-format'
    @@ meson.build: if headers_to_check.length() != 0 and compiler.get_argument_syntax(
        alias_target('check-headers', hdr_check)
      endif
      
    -+clang_format = find_program('clang-format', required: false)
    -+if clang_format.found()
    ++git_clang_format = find_program('git-clang-format', required: false)
    ++if git_clang_format.found()
     +  run_target('style',
     +    command: [
     +      'git', 'clang-format',

base-commit: f0135a9047ca37d4d117dcf21f7e3e89fad85d00 change-id: 20250625-525-make-clang-format-more-robust-968126c991b9

Thanks
- Karthik