ci(commitlint): check PR number presence in merge commits (reanahub#592)

Author: mdonadoni

run-tests.sh

@@ -59,20 +59,23 @@ check_commitlint () {
         commit_hash=$(echo "$line" | cut -d ' ' -f 1)
         commit_title=$(echo "$line" | cut -d ' ' -f 2-)
         commit_number_of_parents=$(git rev-list --parents "$commit_hash" -n1 | awk '{print NF-1}')
+        # (i) skip checking release commits generated by Release Please
+        if [ "$commit_number_of_parents" -le 1 ] && echo "$commit_title" | grep -qP "^chore\(.*\): release"; then
+            continue
+        fi
+        # (ii) check presence of PR number
+        if ! echo "$commit_title" | grep -qP "\(\#$pr\)$"; then
+            echo "✖   Headline does not end by '(#$pr)' PR number: $commit_title"
+            found=1
+        fi
+        # (iii) check absence of merge commits in feature branches
         if [ "$commit_number_of_parents" -gt 1 ]; then
             if echo "$commit_title" | grep -qP "^chore\(.*\): merge "; then
-                break
+                break  # skip checking maint-to-master merge commits
             else
                 echo "✖   Merge commits are not allowed in feature branches: $commit_title"
                 found=1
             fi
-        elif echo "$commit_title" | grep -qP "^chore\(.*\): release"; then
-            true
-        elif echo "$commit_title" | grep -qP "\(\#$pr\)$"; then
-            true
-        else
-            echo "✖   Headline does not end by '(#$pr)' PR number: $commit_title"
-            found=1
         fi
     done < <(git log "$from..$to" --format="%H %s")
     if [ $found -gt 0 ]; then