Ticket #44923: 44923.2.patch

wp-includes/class-walker-comment.php

@@ -55 +55 @@
         public function start_lvl( &$output, $depth = 0, $args = array() ) {
                 $GLOBALS['comment_depth'] = $depth + 1;
 
+                // Default class.
+                $classes = array( 'children' );
+
+                /**
+                 * Filters the CSS class(es) applied to a comments element.
+                 *
+                 * @since 4.9.9
+                 *
+                 * @param array    $classes The CSS classes that are applied to the comment  element.
+                 * @param stdClass $args    Uses 'style' argument for type of HTML list. Default empty array.
+                 * @param int      $depth   Depth of the current comment. Default 0.
+                 */
+                $class_names = join( ' ', apply_filters( 'comment_list_sublist_class', $classes, $args, $depth ) );
+                $class_names = $class_names ? sprintf( ' class="%s"', esc_attr( $class_names ) ) : '';
+
                 switch ( $args['style'] ) {
                         case 'div':
                                 break;
                         case 'ol':
-                                $output .= '<ol class="children">' . "\n";
+                                $output .= '<ol' . $class_names . '>' . "\n";
                                 break;
                         case 'ul':
                         default:
-                                $output .= '<ul class="children">' . "\n";
+                                $output .= '<ul' . $class_names . '>' . "\n";
                                 break;
                 }
         }