Update to Drupal 8.1.8. For more information, see https://www.drupal.org/project/drupal/releases/8.1.8

core/modules/menu_link_content/src/Plugin/migrate/process/d6/InternalUri.php

@@ -1,30 +0,0 @@
-<?php
-
-namespace Drupal\menu_link_content\Plugin\migrate\process\d6;
-
-use Drupal\migrate\MigrateExecutableInterface;
-use Drupal\migrate\ProcessPluginBase;
-use Drupal\migrate\Row;
-
-/**
- * Process a path into an 'internal:' URI.
- *
- * @MigrateProcessPlugin(
- *   id = "internal_uri"
- * )
- */
-class InternalUri extends ProcessPluginBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
-    list($path) = $value;
-
-    if (parse_url($path, PHP_URL_SCHEME) === NULL) {
-      return 'internal:/' . $path;
-    }
-    return $path;
-  }
-
-}

core/modules/menu_link_content/src/Plugin/migrate/process/d6/LinkUri.php

@@ -0,0 +1,84 @@
+<?php
+
+namespace Drupal\menu_link_content\Plugin\migrate\process\d6;
+
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Url;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drupal\migrate\ProcessPluginBase;
+use Drupal\migrate\Row;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Processes a link path into an 'internal:' or 'entity:' URI.
+ *
+ * @MigrateProcessPlugin(
+ *   id = "link_uri"
+ * )
+ */
+class LinkUri extends ProcessPluginBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The entity type manager, used to fetch entity link templates.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * Constructs a LinkUri object.
+   *
+   * @param array $configuration
+   *   A configuration array containing information about the plugin instance.
+   * @param string $plugin_id
+   *   The plugin_id for the plugin instance.
+   * @param mixed $plugin_definition
+   *   The plugin implementation definition.
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   The entity type manager, used to fetch entity link templates.
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityTypeManagerInterface $entity_type_manager) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition);
+    $this->entityTypeManager = $entity_type_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $container->get('entity_type.manager')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    list($path) = $value;
+    $path = ltrim($path, '/');
+
+    if (parse_url($path, PHP_URL_SCHEME) === NULL) {
+      $path = 'internal:/' . $path;
+
+      // Convert entity URIs to the entity scheme, if the path matches a route
+      // of the form "entity.$entity_type_id.canonical".
+      // @see \Drupal\Core\Url::fromEntityUri()
+      $url = Url::fromUri($path);
+      if ($url->isRouted()) {
+        $route_name = $url->getRouteName();
+        foreach (array_keys($this->entityTypeManager->getDefinitions()) as $entity_type_id) {
+          if ($route_name == "entity.$entity_type_id.canonical" && isset($url->getRouteParameters()[$entity_type_id])) {
+            return "entity:$entity_type_id/" . $url->getRouteParameters()[$entity_type_id];
+          }
+        }
+      }
+    }
+    return $path;
+  }
+
+}