Merge pull request #4187 from craftcms/fix/4185-undefined-array-key-name

[5.x] Fix error: undefined array key for gateway change

Author: nfourtythree

CHANGELOG.md

@@ -3,7 +3,8 @@
 ## Unreleased
 
 - Fixed a bug where newly created variants weren’t visible on Edit product screens. 
-- Fixed a SQL error that could occur when viewing product indexes. 
+- Fixed a SQL error that could occur when viewing product indexes.
+- Fixed a PHP error that occurred when applying project config changes after updating. ([#4185](https://github.com/craftcms/commerce/issues/4185))
 
 ## 5.5.0.1 - 2025-11-24
 

src/services/Gateways.php

@@ -295,6 +295,11 @@ public function handleChangedGateway(ConfigEvent $event): void
         $gatewayUid = $event->tokenMatches[0];
         $data = $event->newValue;
 
+        // Bail if the data is not a valid gateway config array
+        if (!is_array($data)) {
+            return;
+        }
+
         $transaction = Craft::$app->getDb()->beginTransaction();
         try {
             $gatewayRecord = $this->_getGatewayRecord($gatewayUid);