[PATCH v3 1/2] checkpatch: fix false positive for COMMIT_LOG_LONG_LINE with URLs

[Aditya Srivastava]

Currently checkpatch warns for long line in commit messages even for
URL lines.

An evaluation over v5.6..v5.8 found that out of 1703 warnings reported
by this class, 161 are due to the line containg URLs. Out of these 161,
53 are due to lines where URL is the first non-whitespace character of
the line.

E.g. running checkpatch on commit 3cde818cd02b ("ASoC: topology:
Consolidate how dtexts and dvalues are freed") reports this warning:

WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
https://mailman.alsa-project.org/pipermail/alsa-devel/2019-January/144761.html

Avoid giving users warning for character limit for such cases, instead
suggest them to prefix the URLs with "Link:"

Signed-off-by: Aditya Srivastava <yashsri421@xxxxxxxxx>
---
 scripts/checkpatch.pl | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e6857bdfcb2d..e8851ce73149 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3023,9 +3023,14 @@ sub process {
 		      $line =~ /^\s*(?:Fixes:|Link:|$signature_tags)/i ||
 					# A Fixes: or Link: line or signature tag line
 		      $commit_log_possible_stack_dump)) {
-			WARN("COMMIT_LOG_LONG_LINE",
-			     "Possible unwrapped commit description (prefer a maximum 75 chars per line)\n" . $herecurr);
-			$commit_log_long_line = 1;
+			if ($line =~ /^\s*[a-z][\w\.\+\-]*:\/\/\S+/i) {
+				WARN("COMMIT_LOG_LONG_LINE",
+				     "Consider prefixing the URL with 'Link:'\n" . $herecurr);
+			} else {
+				WARN("COMMIT_LOG_LONG_LINE",
+				     "Possible unwrapped commit description (prefer a maximum 75 chars per line)\n" . $herecurr);
+				$commit_log_long_line = 1;
+			}
 		}
 
 # Reset possible stack dump if a blank line is found
-- 
2.17.1