Merge pull request #1244 from UN-OCHA/berliner/HPC-9954

HPC-9954: Prevent errors with mega menu block if menu link content entities disappear for some reason

html/modules/custom/ghi_menu/ghi_menu.deploy.php

@@ -143,3 +143,12 @@ function ghi_menu_deploy_add_pages_item_to_admin_menu(&$sandbox) {
   $menu_link->set('parent', 'system.admin_content');
   $menu_link->save();
 }
+
+/**
+ * Fix broken menu items.
+ */
+function ghi_menu_deploy_cleanup_broken_menu_items(&$sandbox) {
+  /** @var \Drupal\ghi_menu\GhiMenuStorageHelper $menu_tree_storage_helper */
+  $menu_tree_storage_helper = \Drupal::service('ghi_menu.menu_tree_storage_helper');
+  $menu_tree_storage_helper->cleanupMenuStorage();
+}

html/modules/custom/ghi_menu/ghi_menu.services.yml

@@ -2,7 +2,15 @@ services:
   ghi_menu.entity_operations_manager:
     class: Drupal\ghi_menu\GhiEntityOperationsManager
     arguments: ['@publishcontent.access', '@csrf_token', '@redirect.destination', '@current_user']
+  ghi_menu.menu_tree_storage_helper:
+    class: Drupal\ghi_menu\GhiMenuStorageHelper
+    arguments: ['@menu.link_tree', '@menu.tree_storage']
   ghi_menu.route_subscriber:
     class: Drupal\ghi_menu\EventSubscriber\RouteSubscriber
     tags:
       - { name: event_subscriber }
+  ghi_menu.menu_rebuild_subscriber:
+    class: Drupal\ghi_menu\EventSubscriber\MenuRouterRebuildSubscriber
+    arguments: ['@ghi_menu.menu_tree_storage_helper']
+    tags:
+      - { name: event_subscriber }

html/modules/custom/ghi_menu/src/EventSubscriber/MenuRouterRebuildSubscriber.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace Drupal\ghi_menu\EventSubscriber;
+
+use Drupal\Core\Routing\RoutingEvents;
+use Drupal\ghi_menu\GhiMenuStorageHelper;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Rebuilds the default menu links and runs menu-specific code if necessary.
+ */
+class MenuRouterRebuildSubscriber implements EventSubscriberInterface {
+
+  /**
+   * The menu storage helper service.
+   *
+   * @var \Drupal\ghi_menu\GhiMenuStorageHelper
+   */
+  protected $menuStorageHelper;
+
+  /**
+   * Constructs the MenuRouterRebuildSubscriber object.
+   *
+   * @param \Drupal\ghi_menu\GhiMenuStorageHelper $menu_storage_helper
+   *   The menu storage helper service.
+   */
+  public function __construct(GhiMenuStorageHelper $menu_storage_helper) {
+    $this->menuStorageHelper = $menu_storage_helper;
+  }
+
+  /**
+   * Cleanup the menu tree storage.
+   *
+   * @param \Drupal\Component\EventDispatcher\Event $event
+   *   The event object.
+   */
+  public function onRouterRebuild($event) {
+    $this->menuStorageHelper->cleanupMenuStorage();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents(): array {
+    // Run after CachedRouteRebuildSubscriber.
+    $events[RoutingEvents::FINISHED][] = ['onRouterRebuild', 120];
+    return $events;
+  }
+
+}

html/modules/custom/ghi_menu/src/GhiMenuStorageHelper.php

@@ -0,0 +1,87 @@
+<?php
+
+namespace Drupal\ghi_menu;
+
+use Drupal\Component\Plugin\Exception\PluginException;
+use Drupal\Core\Menu\MenuLinkTreeInterface;
+use Drupal\Core\Menu\MenuTreeParameters;
+use Drupal\Core\Menu\MenuTreeStorageInterface;
+use Drupal\menu_link_content\Plugin\Menu\MenuLinkContent;
+
+/**
+ * Helper service for menu storage.
+ */
+class GhiMenuStorageHelper {
+
+  /**
+   * The menu tree service.
+   *
+   * @var \Drupal\Core\Menu\MenuLinkTreeInterface
+   */
+  protected $menuTree;
+
+  /**
+   * The menu link tree storage.
+   *
+   * @var \Drupal\Core\Menu\MenuTreeStorageInterface
+   */
+  protected $treeStorage;
+
+  /**
+   * Constructs a \Drupal\Core\Menu\MenuLinkManager object.
+   *
+   * @param \Drupal\Core\Menu\MenuLinkTreeInterface $menu_tree
+   *   The menu tree service.
+   * @param \Drupal\Core\Menu\MenuTreeStorageInterface $tree_storage
+   *   The menu link tree storage.
+   */
+  public function __construct(MenuLinkTreeInterface $menu_tree, MenuTreeStorageInterface $tree_storage) {
+    $this->menuTree = $menu_tree;
+    $this->treeStorage = $tree_storage;
+  }
+
+  /**
+   * Cleanup the menu storage.
+   *
+   * While it seems like an edge case, we had situations where an item in the
+   * menu storage referenced a menu content link that was already deleted,
+   * resulting in a WSOD due to an unhandled PluginException. This logic here
+   * removes those broken items in the menu tree storage.
+   */
+  public function cleanupMenuStorage() {
+    $parameters = new MenuTreeParameters();
+    $menu_names = $this->treeStorage->getMenuNames();
+    foreach ($menu_names as $menu_name) {
+      $menu_tree = $this->menuTree->load($menu_name, $parameters);
+      $this->purgeBrokenItems($menu_tree);
+    }
+  }
+
+  /**
+   * Purge broken menu links from the tree.
+   *
+   * @param \Drupal\Core\Menu\MenuLinkTreeElement[] $menu_tree
+   *   The menu tree to filter.
+   */
+  private function purgeBrokenItems(array $menu_tree) {
+    foreach ($menu_tree as $id => $item) {
+      if (!empty($item->subtree)) {
+        $this->purgeBrokenItems($item->subtree);
+      }
+      $link = $item->link;
+      if (!$link instanceof MenuLinkContent) {
+        continue;
+      }
+      try {
+        // Just try to get the entity. If this throws an exception, this menu
+        // item is broken.
+        $link->getEntity();
+      }
+      catch (PluginException $e) {
+        $this->treeStorage->delete($id);
+      }
+
+    }
+  }
+
+}

html/modules/custom/ghi_menu/src/Plugin/Block/MegaMenuBlock.php

@@ -2,6 +2,7 @@
 
 namespace Drupal\ghi_menu\Plugin\Block;
 
+use Drupal\Component\Plugin\Exception\PluginException;
 use Drupal\Component\Utility\Html;
 use Drupal\Core\Block\BlockBase;
 use Drupal\Core\Cache\Cache;
@@ -13,6 +14,7 @@
 use Drupal\Core\Render\Element\RenderElement;
 use Drupal\Core\Render\Element\VerticalTabs;
 use Drupal\ghi_blocks\Traits\VerticalTabsTrait;
+use Drupal\menu_link_content\Plugin\Menu\MenuLinkContent;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -56,6 +58,13 @@ class MegaMenuBlock extends BlockBase implements ContainerFactoryPluginInterface
    */
   protected $menuTree;
 
+  /**
+   * The menu tree manipulators.
+   *
+   * @var \Drupal\Core\Menu\DefaultMenuLinkTreeManipulators
+   */
+  protected $menuTreeManipulators;
+
   /**
    * {@inheritdoc}
    */
@@ -66,6 +75,7 @@ public static function create(ContainerInterface $container, array $configuratio
     $instance->entityFieldManager = $container->get('entity_field.manager');
     $instance->moduleHandler = $container->get('module_handler');
     $instance->menuTree = $container->get('menu.link_tree');
+    $instance->menuTreeManipulators = $container->get('menu.default_tree_manipulators');
     return $instance;
   }
 
@@ -206,6 +216,8 @@ public function getMenuItems() {
     $parameters = $this->menuTree->getCurrentRouteMenuTreeParameters('main');
     $parameters->expandedParents = [];
     $menu_tree = $this->menuTree->load($menu->id(), $parameters);
+    $this->filterBrokenItems($menu_tree);
+
     // Transform the tree using the manipulators you want.
     $manipulators = [
       // Only show links that are accessible for the current user.
@@ -217,6 +229,31 @@ public function getMenuItems() {
     return $menu_tree;
   }
 
+  /**
+   * Filter broken menu links from the tree.
+   *
+   * @param \Drupal\Core\Menu\MenuLinkTreeElement[] $menu_tree
+   *   The menu tree to filter.
+   */
+  private function filterBrokenItems(array &$menu_tree) {
+    foreach ($menu_tree as $key => &$item) {
+      $link = $item->link;
+      if (!$link instanceof MenuLinkContent) {
+        continue;
+      }
+      try {
+        $this->menuTreeManipulators->checkAccess([$item]);
+      }
+      catch (PluginException $e) {
+        unset($menu_tree[$key]);
+        continue;
+      }
+      if ($item->hasChildren) {
+        $this->filterBrokenItems($item->subtree);
+      }
+    }
+  }
+
   /**
    * {@inheritdoc}
    */