Return explicit `null` in UserFormField::getSaveValue()

diff --git a/wcfsetup/install/files/lib/system/form/builder/field/user/UserFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/user/UserFormField.class.php
index 973807601c596b960c91d27480272d358d2496fa..4b365da45f9290b173a70fb6c43ef6ef2d576efe 100644 (file)
--- a/wcfsetup/install/files/lib/system/form/builder/field/user/UserFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/user/UserFormField.class.php
@@ -74,7 +74,7 @@ class UserFormField extends AbstractFormField implements
     {
         if (empty($this->getUsers())) {
             if ($this->isNullable()) {
-                return;
+                return null;
             }
 
             return 0;