fix fatal error when using an object as default value in ChoiceType

Author: Cristoforo Cervino

src/Bridge/Transformer/ChoiceTransformer.php

@@ -4,6 +4,7 @@
 
 use Matthias\SymfonyConsoleForm\Console\Helper\Question\AlwaysReturnKeyOfChoiceQuestion;
 use Symfony\Component\Console\Question\Question;
+use Symfony\Component\Form\ChoiceList\View\ChoiceView;
 use Symfony\Component\Form\FormInterface;
 
 final class ChoiceTransformer extends AbstractTransformer
@@ -20,4 +21,21 @@ public function transform(FormInterface $form): Question
 
         return $question;
     }
+
+    protected function defaultValueFrom(FormInterface $form)
+    {
+        $defaultValue = parent::defaultValueFrom($form);
+
+        // $defaultValue could be an object
+        // Let's find out what form computed to be its view representation
+        $formView = $form->createView();
+        $defaultValueFromChoiceView = \array_reduce(
+            $formView->vars['choices'],
+            static fn(
+                ?string $carry,
+                ChoiceView $choiceView
+            ): ?string => (null === $carry && $choiceView->data === $defaultValue) ? $choiceView->value : $carry
+        );
+        return $defaultValueFromChoiceView ?? $defaultValue;
+    }
 }