at the end of the day, it was inevitable

src/AppBundle/Form/Transformer/OnlyReverseTransformer.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace AppBundle\Form\Transformer;
+
+use Symfony\Component\Form\CallbackTransformer;
+
+/**
+ * Class OnlyReverseTransformer
+ * @package AppBundle\Form\Transformer
+ */
+class OnlyReverseTransformer extends CallbackTransformer
+{
+
+    /**
+     * OnlyReverseTransformer constructor.
+     *
+     * @param callable $reverseTransform The reverse transform callback.
+     */
+    public function __construct(callable $reverseTransform)
+    {
+        parent::__construct(function ($value) {
+            return $value;
+        }, $reverseTransform);
+    }
+}