Issue #3089842 by xavier.masson: Drag to re-order doesn't work withou…

js/select2.js

@@ -43,7 +43,7 @@
         $(this).select2(config);
 
         // Copied from https://github.com/woocommerce/woocommerce/blob/master/assets/js/admin/wc-enhanced-select.js#L118
-        if (Object.prototype.hasOwnProperty.call(config, 'ajax') && config.multiple) {
+        if (config.multiple) {
           var $select = $(this);
           var $list = $select.next('.select2-container').find('ul.select2-selection__rendered');
           Sortable.create($list[0], {

src/Element/Select2.php

@@ -203,6 +203,17 @@ public static function processSelect(&$element, FormStateInterface $form_state,
       $element['#options'] = $empty_option + $element['#options'];
     }
 
+    if ($element['#multiple']) {
+      $values = isset($element['#value']) ? $element['#value'] : $element['#default_value'];
+      $values = is_array($values) ? $values : [$values];
+
+      // Apply field values order on the options.
+      if (!empty($values)) {
+        $flipped_keys = array_intersect_key(array_flip($values), $element['#options']);
+        $element['#options'] = array_replace($flipped_keys, $element['#options']);
+      }
+    }
+
     // Set the type from select2 to select to get proper form validation.
     $element['#type'] = 'select';
 
@@ -305,18 +316,6 @@ public static function preRenderAutocomplete($element) {
     }
     $element = call_user_func_array($value_callable, [&$element]);
 
-    // Reduce options to the preselected ones and bring them in the correct
-    // order.
-    $options = OptGroup::flattenOptions($element['#options']);
-    $values = isset($element['#value']) ? $element['#value'] : $element['#default_value'];
-    $values = is_array($values) ? $values : [$values];
-    $element['#options'] = [];
-    foreach ($values as $value) {
-      if (isset($options[$value])) {
-        $element['#options'][$value] = $options[$value];
-      }
-    }
-
     /** @var \Drupal\Core\Access\AccessManagerInterface $access_manager */
     $access_manager = \Drupal::service('access_manager');
     $access = $access_manager->checkNamedRoute($element['#autocomplete_route_name'], $element['#autocomplete_route_parameters'], \Drupal::currentUser(), TRUE);

src/Plugin/EntityReferenceSelection/ViewsWithAutoCreation.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace Drupal\select2\Plugin\EntityReferenceSelection;
+
+use Drupal\Core\Entity\EntityReferenceSelection\SelectionWithAutocreateInterface;
+use Drupal\user\EntityOwnerInterface;
+use Drupal\views\Plugin\EntityReferenceSelection\ViewsSelection;
+
+/**
+ * Plugin implementation of the 'selection' entity_reference with autocreation.
+ *
+ * @EntityReferenceSelection(
+ *   id = "views_with_autocreation",
+ *   label = @Translation("Views: Filter by an entity reference view and allow autocreation"),
+ *   group = "views",
+ *   weight = 0
+ * )
+ */
+class ViewsWithAutoCreation extends ViewsSelection implements SelectionWithAutocreateInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function createNewEntity($entity_type_id, $bundle, $label, $uid) {
+    $entity_type = $this->entityTypeManager->getDefinition($entity_type_id);
+    $bundle_key = $entity_type->getKey('bundle');
+    $label_key = $entity_type->getKey('label');
+    $entity = $this->entityTypeManager->getStorage($entity_type_id)->create([
+      $bundle_key => $bundle,
+      $label_key => $label,
+    ]);
+    if ($entity instanceof EntityOwnerInterface) {
+      $entity->setOwnerId($uid);
+    }
+    return $entity;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateReferenceableNewEntities(array $entities) {
+    return array_filter($entities, function ($entity) {
+      if (isset($this->configuration['handler_settings']['auto_create_bundle'])) {
+        return ($entity->bundle() === $this->configuration['handler_settings']['auto_create_bundle']);
+      }
+      return TRUE;
+    });
+  }
+
+}

src/Plugin/Field/FieldWidget/Select2EntityReferenceWidget.php

@@ -170,7 +170,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
     // with 'autocreate' or 'autocomplete' we want to ignore that.
     $element['#multiple'] = $this->multiple && (count($this->options) > 1 || isset($element['#autocreate']) || $element['#autocomplete']);
 
-    if ($element['#autocomplete'] && $element['#multiple']) {
+    if ($element['#multiple']) {
       $entity_definition = $this->entityTypeManager->getDefinition($element['#target_type']);
       $message = $this->t("Drag to re-order @entity_types.", ['@entity_types' => $entity_definition->getPluralLabel()]);
       if (!empty($element['#description'])) {