[PATCH v3] checkpatch: add warning for lines starting with a '#' in commit log

[Dwaipayan Ray <dwaipayanray1@gmail.com>]

Commit log lines starting with '#' are dropped by git as comments.
Add a check to emit a warning for these lines.

Also add a --fix option to insert a space before the leading '#' in
such lines.

Suggested-by: Joe Perches <joe@perches.com>
Suggested-by: Peilin Ye <yepeilin.cs@gmail.com>
Tested-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
---
Changes in v3:
- Modify commit message for more clarity
- Modify warning message
- Modify --fix option to substitute single space instead of tab

Changes in v2:
- Modify warning message and type
- Style fixes

 scripts/checkpatch.pl | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e8c1ed0b1fad..7940889877ba 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2966,6 +2966,15 @@ sub process {
 			$commit_log_possible_stack_dump = 0;
 		}
 
+# Check for lines starting with a #
+		if ($in_commit_log && $line =~ /^#/) {
+			if (WARN("COMMIT_COMMENT_SYMBOL",
+				 "Commit log lines starting with '#' are dropped by git as comments\n" . $herecurr) &&
+			    $fix) {
+				$fixed[$fixlinenr] =~ s/^/ /;
+			}
+		}
+
 # Check for git id commit length and improperly formed commit descriptions
 		if ($in_commit_log && !$commit_log_possible_stack_dump &&
 		    $line !~ /^\s*(?:Link|Patchwork|http|https|BugLink|base-commit):/i &&
-- 
2.27.0