Fixed PHP error that could occur if someone hada. custom shipping method implmenting the ShippingMethodInterface

Author: nfourtythree

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Release Notes for Craft Commerce
 
+## Unreleased
+
+- Fixed a PHP error that could occur when registering a custom shipping method.
+
 ## 4.8.2 - 2025-03-12
 
 - Fixed a bug where line items’ sale prices could be calculated incorrectly. ([#3928](https://github.com/craftcms/commerce/issues/3928))

src/elements/Order.php

@@ -1995,7 +1995,7 @@ public function getAvailableShippingMethodOptions(): array
     {
         // Matching will contain the core shipping methods and any plugin dynamically returned shipping methods.
         $methods = Plugin::getInstance()->getShippingMethods()->getMatchingShippingMethods($this);
-        $matchingMethodHandles = ArrayHelper::getColumn($methods, 'handle');
+        $matchingMethodHandles = ArrayHelper::getColumn($methods, fn(ShippingMethodInterface $sm) => $sm->getHandle());
 
         // Get all regular methods and add them to the list, for use only when the order is complete.
         if ($this->isCompleted) {