Set Attribute for lists

Closes #3354683

core/lib/Drupal/Core/Template/TwigExtension.php

@@ -763,6 +763,18 @@ public function checkDeprecations(array $context, array $used_variables): void {
    *   The element with the given class(es) in attributes.
    */
   public function addClass(array $element, ...$classes): array {
+    if (!\is_array($element)) {
+      return $element;
+    }
+    if (\array_is_list($element)) {
+      foreach ($element as $index => $item) {
+        if (!\is_array($item)) {
+          continue;
+        }
+        $element[$index] = $this->addClass($item, ...$classes);
+      }
+      return $element;
+    }
     $attributes = new Attribute($element['#attributes'] ?? []);
     $attributes->addClass(...$classes);
     $element['#attributes'] = $attributes->toArray();
@@ -789,6 +801,18 @@ public function addClass(array $element, ...$classes): array {
    *   The element with the given sanitized attribute's value.
    */
   public function setAttribute(array $element, string $name, mixed $value = NULL): array {
+    if (!\is_array($element)) {
+      return $element;
+    }
+    if (\array_is_list($element)) {
+      foreach ($element as $index => $item) {
+        if (!\is_array($item)) {
+          continue;
+        }
+        $element[$index] = $this->setAttribute($item, $name, $value);
+      }
+      return $element;
+    }
     $element['#attributes'] = AttributeHelper::mergeCollections(
       $element['#attributes'] ?? [],
       new Attribute([$name => $value])
@@ -796,7 +820,6 @@ public function setAttribute(array $element, string $name, mixed $value = NULL):
 
     // Make sure element gets rendered again.
     unset($element['#printed']);
-
     return $element;
   }