[PATCH v3 4/4] checkpatch: check for misuse of the link tags

[Matthieu Baerts <matthieu.baerts@tessares.net>]

"Link:" and "Closes:" tags have to be used with public URLs.

It is difficult to make sure the link is public but at least we can
verify the tag is followed by 'http(s):'.

With that, we avoid such a tag that is not allowed [1]:

  Closes: <number>

Link: https://lore.kernel.org/linux-doc/CAHk-=wh0v1EeDV3v8TzK81nDC40=XuTdY2MCr0xy3m3FiBV3+Q@mail.gmail.com/ [1]
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---
v3:
- new patch addressing Linus' concerns.
---
 scripts/checkpatch.pl | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index ca58c734ff22..e3cafd2cb77a 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3292,6 +3292,17 @@ sub process {
 			}
 		}
 
+# Check for misuse of the link tags
+		if ($in_commit_log &&
+		    $line =~ /^\s*(\w+:)\s*(\S+)/) {
+			my $tag = $1;
+			my $value = $2;
+			if ($tag =~ /^$link_tags_search$/ && $value !~ /^https?:/) {
+				WARN("COMMIT_LOG_WRONG_LINK",
+				     "'$tag' should be followed by a public http(s) link\n" . $herecurr);
+			}
+		}
+
 # Check for lines starting with a #
 		if ($in_commit_log && $line =~ /^#/) {
 			if (WARN("COMMIT_COMMENT_SYMBOL",

-- 
2.39.2