fix(symfony): add default item provider (#5039)

Author: soyuka

CreateProvider.php

@@ -58,7 +58,8 @@ public function provide(Operation $operation, array $uriVariables = [], array $c
         }
 
         $relation = $this->decorated->provide(new Get(uriVariables: $relationUriVariables, class: $relationClass), $uriVariables);
-        $resource = new ($operation->getClass());
+        $refl = new \ReflectionClass($operation->getClass());
+        $resource = $refl->newInstanceWithoutConstructor();
         $this->propertyAccessor->setValue($resource, $key, $relation);
 
         return $resource;

ObjectProvider.php

@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\State;
+
+use ApiPlatform\Metadata\Operation;
+
+/**
+ * An ItemProvider that just create a new object.
+ *
+ * @author Antoine Bluchet <[email protected]>
+ *
+ * @experimental
+ */
+final class ObjectProvider implements ProviderInterface
+{
+    public function provide(Operation $operation, array $uriVariables = [], array $context = []): ?object
+    {
+        $refl = new \ReflectionClass($operation->getClass());
+
+        return $refl->newInstanceWithoutConstructor();
+    }
+}