check-patches: enforce prose on changelog entries

Check if the Changelog-*: trailers have proper English sentences
starting with a capital letter and ending in a period. Update
CONTRIBUTING with an explicit mention of this.

Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com>
Reviewed-by: Moritz Poldrack <moritz@poldrack.dev>
Acked-by: Robin Jarry <robin@jarry.cc>

2 files changed, 9 insertions, 1 deletions

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 1a4d0bd2..6c9df2c7 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -44,7 +44,9 @@ commits). Follow these general rules:
   trailer with the commit id and its title.
 - When in doubt, follow the format and layout of the recent existing commits.
 - If your commit brings visible changes for end-users, add one of the following
-  trailers with a short and concise description of the change.
+  trailers with a short and concise description of the change. The change
+  should be described in full sentences, starting with a capital letter and
+  ending in a period.
 
   * `Changelog-added:` for new features.
   * `Changelog-fixed:` for bug fixes.
diff --git a/contrib/check-patches b/contrib/check-patches
index 450eabae..cea65a1f 100755
--- a/contrib/check-patches
+++ b/contrib/check-patches
@@ -39,6 +39,12 @@ for rev in $revisions; do
 		err "'Signed-off-by: $author' trailer is missing"
 	fi
 
+	if git log --format="%(trailers:only,unfold)" -1 "$rev" | \
+			grep -v '^Changelog-[a-z]\+: [A-Z`\*_].\+\.$' | \
+			grep -q '^Changelog-[a-z]\+: '; then
+		err "Changelog-* trailers should start with a capital letter and end with a period"
+	fi
+
 	body=$(git log --format='%b' -1 "$rev")
 	body=${body%$(git log --format='%(trailers)' -1 "$rev")}
 	if [ "$(echo "$body" | wc -w)" -lt 3 ]; then