Issue #3347677 by douggreen: Bubble up cache contexts & tags from the rendered menu

src/Plugin/Block/SmartMenusBlock.php

@@ -3,6 +3,7 @@
 namespace Drupal\smartmenus\Plugin\Block;
 
 use Drupal\Core\Block\BlockBase;
+use Drupal\Core\Cache\Cache;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -253,8 +254,8 @@ class SmartMenusBlock extends BlockBase implements ContainerFactoryPluginInterfa
 
     $build['#menu_tree'] = $this->renderer->renderPlain($rendered_menu);
     $build['#cache'] = [
-      'contexts' => ['url.path'],
-      'tags' => $tree['#cache']['tags'],
+      'contexts' => Cache::mergeContexts(['url.path'], $rendered_menu['#cache']['contexts'] ?? []),
+      'tags' => Cache::mergeTags($tree['#cache']['tags'], $rendered_menu['#cache']['tags'] ?? []),
     ];
 
     return $build;