--- /dev/null
+<?php
+
+namespace Drupal\user;
+
+/**
+ * Thrown by SharedTempStore and PrivateTempStore if they cannot acquire a lock.
+ *
+ * @see \Drupal\user\SharedTempStore
+ * @see \Drupal\user\PrivateTempStore
+ */
+class TempStoreException extends \Exception {}