scripts/check-signed-off: check that commits do not have an empty body

Check that all new commits have a commit body besides the summary line
and git trailers.

Signed-off-by: Carlos López <carlos.lopez@suse.com>

scripts/check-signed-off.sh

@@ -4,6 +4,9 @@
 # Copyright (c) 2023 SUSE LLC
 #
 # Author: Carlos López <carlos.lopez@suse.com>
+#
+# Simple script to check that a commit has a Signed-off-by trailer and a
+# nonempty commit body.
 
 matches_any() {
 	needle=$1
@@ -18,6 +21,21 @@ matches_any() {
 	return 1
 }
 
+# Check that the body for the given commit is not empty
+nonempty_body() {
+	body=$(git show --no-patch --format="%b" "$1" | sed '/^ *$/d')
+	trailers=$(git show --no-patch --format="%(trailers:only)" "$1")
+
+	# Remove trailers
+	for trailer in "${trailers[@]}"; do
+		body=$(echo "$body" | grep -F -v "$trailer")
+	done
+
+	# Return 1 if there is no body
+	[ -z "$body" ] && return 1
+	return 0
+}
+
 if [ $# -lt 1 ]; then
 	echo "Usage: $0 <start_commit> [<end_commit>]"
 	exit 1
@@ -35,6 +53,12 @@ for c in ${commits[@]}; do
 	parents=$(git cat-file -p "$c" | grep -c parent)
 	[ "$parents" -gt "1" ] && continue
 
+	nonempty_body "$c"
+	if [ "$?" != "0" ]; then
+		echo "Message body is empty for commit $c"
+		exit 1
+	fi
+
 	commit_email=$(git show --no-patch --pretty="format:%ae" "$c" || exit 1)
 	commit_name=$(git show --no-patch --pretty="format:%an" "$c" || exit 1)
 	sign_names=$(git show --no-patch "$c" | sed -nr 's/^[[:space:]]*Signed-off-by: (.*) <(.*)>/\1/p' || exit 1)