Fix: allow null when using symfony/serializer

CHANGELOG

@@ -1,5 +1,6 @@
 3.10.1 (unreleased):
     * Fix: autoincrement fields are now properly registered when using attributes
+    * Fix: allow null when using symfony/serializer
 
 3.10.0 (2025-03-14):
     * Feature: Allow complex types to be handled by symfony/serializer if available

src/TingBundle/Serializer/SymfonySerializer.php

@@ -16,6 +16,9 @@ public function serialize($toSerialize, array $options = [])
 
     public function unserialize($serialized, array $options = [])
     {
+        if ($serialized === null) {
+            return null;
+        }
         $this->throwOnNullSerializer();
         if (!isset($options['type'])) {
             throw new \RuntimeException('SymfonySerializer requires type option to be set');