fix(doctrine): avoid deprecated ArrayAccess on FieldMapping in DoctrineORMListener (#506)

* Enhance DoctrineORMListener for compatibility with Doctrine ORM 3.x

- Updated field mapping logic to support both legacy array mapping and the new FieldMapping object introduced in Doctrine ORM 3.x.
- Ensured backward compatibility with existing implementations while preparing for future ORM 4.0 changes.

* Refactor field mapping logic in DoctrineORMListener for improved compatibility

- Adjusted the handling of field mappings to ensure proper support for the FieldMapping object in Doctrine ORM 3.x.
- Removed deprecated ArrayAccess usage to prepare for future ORM 4.0 changes, enhancing code maintainability.

Author: HecFranco

Storage/Listener/DoctrineORMListener.php

@@ -25,8 +25,19 @@ public function loadClassMetadata(LoadClassMetadataEventArgs $eventArgs)
         foreach ($metadata->getFieldNames() as $name) {
             $fieldMapping = $metadata->getFieldMapping($name);
 
-            if (isset($fieldMapping['type']) && 'string' === $fieldMapping['type']) {
-                $fieldMapping['length'] = 191;
+            if (\is_array($fieldMapping)) {
+                // Doctrine ORM 2.x / legacy array mapping
+                if (isset($fieldMapping['type']) && 'string' === $fieldMapping['type']) {
+                    $fieldMapping['length'] = 191;
+                    $metadata->fieldMappings[$name] = $fieldMapping;
+                }
+
+                continue;
+            }
+
+            // Doctrine ORM 3+: FieldMapping object — avoid deprecated ArrayAccess (removed in ORM 4.0)
+            if ('string' === $fieldMapping->type) {
+                $fieldMapping->length = 191;
                 $metadata->fieldMappings[$name] = $fieldMapping;
             }
         }