--- /dev/null
+<?php
+
+namespace Drupal\menu_ui\Form;
+
+use Drupal\Core\Database\Connection;
+use Drupal\Core\Entity\EntityDeleteForm;
+use Drupal\Core\Menu\MenuLinkManagerInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Defines a confirmation form for deletion of a custom menu.
+ */
+class MenuDeleteForm extends EntityDeleteForm {
+
+ /**
+ * The menu link manager.
+ *
+ * @var \Drupal\Core\Menu\MenuLinkManagerInterface
+ */
+ protected $menuLinkManager;
+
+ /**
+ * The database connection.
+ *
+ * @var \Drupal\Core\Database\Connection
+ */
+ protected $connection;
+
+ /**
+ * Constructs a new MenuDeleteForm.
+ *
+ * @param \Drupal\Core\Menu\MenuLinkManagerInterface $menu_link_manager
+ * The menu link manager.
+ * @param \Drupal\Core\Database\Connection $connection
+ * The database connection.
+ */
+ public function __construct(MenuLinkManagerInterface $menu_link_manager, Connection $connection) {
+ $this->menuLinkManager = $menu_link_manager;
+ $this->connection = $connection;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function create(ContainerInterface $container) {
+ return new static(
+ $container->get('plugin.manager.menu.link'),
+ $container->get('database')
+ );
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getDescription() {
+ $caption = '';
+ $num_links = $this->menuLinkManager->countMenuLinks($this->entity->id());
+ if ($num_links) {
+ $caption .= '<p>' . $this->formatPlural($num_links, '<strong>Warning:</strong> There is currently 1 menu link in %title. It will be deleted (system-defined items will be reset).', '<strong>Warning:</strong> There are currently @count menu links in %title. They will be deleted (system-defined links will be reset).', ['%title' => $this->entity->label()]) . '</p>';
+ }
+ $caption .= '<p>' . t('This action cannot be undone.') . '</p>';
+ return $caption;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function logDeletionMessage() {
+ $this->logger('menu')->notice('Deleted custom menu %title and all its menu links.', ['%title' => $this->entity->label()]);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function submitForm(array &$form, FormStateInterface $form_state) {
+ // Locked menus may not be deleted.
+ if ($this->entity->isLocked()) {
+ return;
+ }
+
+ // Delete all links to the overview page for this menu.
+ // @todo Add a more generic helper function to the menu link plugin
+ // manager to remove links to a entity or other ID used as a route
+ // parameter that is being removed. Also, consider moving this to
+ // menu_ui.module as part of a generic response to entity deletion.
+ // https://www.drupal.org/node/2310329
+ $menu_links = $this->menuLinkManager->loadLinksByRoute('entity.menu.edit_form', ['menu' => $this->entity->id()], TRUE);
+ foreach ($menu_links as $id => $link) {
+ $this->menuLinkManager->removeDefinition($id);
+ }
+
+ parent::submitForm($form, $form_state);
+ }
+
+}