Issue #2569465 by penyaskito: CommentItem must override mainPropertyName()

core/modules/comment/src/Plugin/Field/FieldType/CommentItem.php

@@ -156,6 +156,13 @@ public function fieldSettingsForm(array $form, FormStateInterface $form_state) {
     return $element;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public static function mainPropertyName() {
+    return 'status';
+  }
+
   /**
    * {@inheritdoc}
    */

core/modules/comment/src/Tests/CommentItemTest.php

@@ -60,6 +60,9 @@ public function testCommentItem() {
       CommentItemInterface::CLOSED,
       CommentItemInterface::OPEN,
     ]), 'Comment status value in defined range');
+
+    $mainProperty = $entity->comment[0]->mainPropertyName();
+    $this->assertEqual('status', $mainProperty);
   }
 
 }