Issue #2084081 by amateescu: Fixed ER autocomplete doesn't work.

core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/field/widget/AutocompleteTagsWidget.php

@@ -24,7 +24,7 @@
  *   settings = {
  *     "match_operator" = "CONTAINS",
  *     "size" = 60,
- *     "autocomplete_path" = "entity_reference/autocomplete/tags",
+ *     "autocomplete_type" = "tags",
  *     "placeholder" = ""
  *   },
  *   multiple_values = TRUE

core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/field/widget/AutocompleteWidget.php

@@ -30,7 +30,7 @@
  *   settings = {
  *     "match_operator" = "CONTAINS",
  *     "size" = 60,
- *     "autocomplete_path" = "entity_reference/autocomplete/single",
+ *     "autocomplete_type" = "single",
  *     "placeholder" = ""
  *   }
  * )

core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/field/widget/AutocompleteWidgetBase.php

@@ -75,23 +75,24 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
 
     $entity = $items->getEntity();
 
-    // Prepare the autocomplete path.
-    $autocomplete_path = $this->getSetting('autocomplete_path');
-    $autocomplete_path .= '/' . $this->fieldDefinition->getFieldName() . '/' . $entity->entityType() . '/' . $entity->bundle() . '/';
-
-    // Use <NULL> as a placeholder in the URL when we don't have an entity.
-    // Most web servers collapse two consecutive slashes.
-    $id = 'NULL';
-    if ($entity && $entity_id = $entity->id()) {
-      $id = $entity_id;
+    // Prepare the autocomplete route parameters.
+    $autocomplete_route_parameters = array(
+      'type' => $this->getSetting('autocomplete_type'),
+      'field_name' => $this->fieldDefinition->getFieldName(),
+      'entity_type' => $entity->entityType(),
+      'bundle_name' => $entity->bundle(),
+    );
+
+    if ($entity_id = $entity->id()) {
+      $autocomplete_route_parameters['entity_id'] = $entity_id;
     }
-    $autocomplete_path .= $id;
 
     $element += array(
       '#type' => 'textfield',
       '#maxlength' => 1024,
       '#default_value' => implode(', ', $this->getLabels($items)),
-      '#autocomplete_path' => $autocomplete_path,
+      '#autocomplete_route_name' => 'entity_reference.autocomplete',
+      '#autocomplete_route_parameters' => $autocomplete_route_parameters,
       '#size' => $this->getSetting('size'),
       '#placeholder' => $this->getSetting('placeholder'),
       '#element_validate' => array(array($this, 'elementValidate')),

core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceAutoCreateTest.php

@@ -17,7 +17,7 @@ class EntityReferenceAutoCreateTest extends WebTestBase {
 
   public static function getInfo() {
     return array(
-      'name' => 'Entity Reference auto-create',
+      'name' => 'Entity Reference auto-create and autocomplete UI',
       'description' => 'Tests creating new entity (e.g. taxonomy-term) from an autocomplete widget.',
       'group' => 'Entity Reference',
     );
@@ -76,12 +76,16 @@ function setUp() {
   }
 
   /**
-   * Assert creation on a new entity.
+   * Tests that the autocomplete input element appears and the creation of a new
+   * entity.
    */
   public function testAutoCreate() {
     $user1 = $this->drupalCreateUser(array('access content', "create $this->referencing_type content"));
     $this->drupalLogin($user1);
 
+    $this->drupalGet('node/add/' . $this->referencing_type);
+    $this->assertFieldByXPath('//input[@id="edit-test-field-0-target-id" and contains(@class, "form-autocomplete")]', NULL, 'The autocomplete input element appears.');
+
     $new_title = $this->randomName();
 
     // Assert referenced node does not exist.