throwing error while creating tags which have required field.

Closes #2987882

core/lib/Drupal/Core/Entity/Plugin/EntityReferenceSelection/DefaultSelection.php

@@ -22,6 +22,7 @@
 use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\user\EntityOwnerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\Entity\EntityStorageException;
 
 /**
  * Default plugin implementation of the Entity Reference Selection plugin.
@@ -416,7 +417,6 @@ public function validateReferenceableEntities(array $ids) {
    */
   public function createNewEntity($entity_type_id, $bundle, $label, $uid) {
     $entity_type = $this->entityTypeManager->getDefinition($entity_type_id);
-
     $values = [
       $entity_type->getKey('label') => $label,
     ];
@@ -431,6 +431,16 @@ public function createNewEntity($entity_type_id, $bundle, $label, $uid) {
       $entity->setOwnerId($uid);
     }
 
+    $violations = $entity->validate();
+    if ($violations->count() > 0) {
+      $messages = [];
+      foreach ($violations as $violation) {
+        $messages[] = $violation->getPropertyPath() . ': ' . $violation->getMessage();
+      }
+      $message = "Cannot auto-create entity due to validation errors: " . implode('; ', $messages);
+      throw new EntityStorageException($message);
+    }
+
     return $entity;
   }