fixed return type of client_id callback when creating a case

modules/opencase_defaults/opencase_defaults.module

@@ -11,6 +11,11 @@ use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\user\Entity\Role;
 use Drupal\user\RoleInterface;
 
+
+
+function opencase_defaults_client_callback():array  {
+  return [\Drupal::request()->query->get('client_id')];
+}
 /**
  * Implements hook_help().
  */
@@ -55,6 +60,21 @@ function opencase_defaults_entity_base_field_info($entity_type) {
         'weight' => -6,
       ));
   }
+  if ($entity_type->id() === 'oc_case') {
+    $fields['client'] = BaseFieldDefinition::create('entity_reference')
+      ->setLabel('Client')
+      ->setSetting('target_type', 'oc_actor')
+      ->setSetting('handler', 'default')
+      ->setTranslatable(TRUE)
+      ->setCardinality(1)
+      ->setSetting('handler_settings', [
+        ['target_bundles' => ['client' => 'client'] ]         
+      ])
+      ->setDisplayConfigurable('form', true)
+      ->setDisplayConfigurable('view', true)
+      ->setDefaultValueCallback('opencase_defaults_client_callback')
+      ->setRequired(TRUE);
+  }
   return $fields;
 }