[PATCH v2] checkpatch: add warning for lines starting with a '#' in commit log

[Dwaipayan Ray]

Commit log lines starting with a '#' can be dropped by git if
the corresponding commit message is reworded by a maintainer.
This minor error can be easily avoided if checkpatch warns
for the same.

Add a new check which emits a warning on finding lines starting
with a '#'. Also add a quick fix by adding a tab in front of
such lines.

Suggested-by: Peilin Ye <yepeilin.cs@xxxxxxxxx>
Tested-by: Peilin Ye <yepeilin.cs@xxxxxxxxx>
Signed-off-by: Dwaipayan Ray <dwaipayanray1@xxxxxxxxx>
---
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..eb8b13cf3f40 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 a '#' will be dropped by git as a comment\n" . $herecurr) &&
+			    $fix) {
+				$fixed[$fixlinenr] =~ s/^#/\t#/;
+			}
+		}
+
 # 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