#36431: Undefined index in TierPriceValidator.php

- fixed issue with undefined index customer group for changing tier price

Author: quterorta

app/code/Magento/Catalog/Model/Product/Price/Validation/TierPriceValidator.php

@@ -475,13 +475,15 @@ private function retrieveGroupValue(string $code)
             $item = array_shift($items);
 
             if (!$item) {
+                $this->customerGroupsByCode[$code] = false;
                 return false;
             }
 
             $itemCode = $item->getCode();
             $itemId = $item->getId();
 
             if ($itemCode !== $code) {
+                $this->customerGroupsByCode[$code] = false;
                 return false;
             }
 

app/code/Magento/Customer/Controller/Adminhtml/Group/Save.php

@@ -91,7 +91,8 @@ public function execute()
                 ? [] : $this->getRequest()->getParam('customer_group_excluded_websites');
             $resultRedirect = $this->resultRedirectFactory->create();
             try {
-                $customerGroupCode = trim((string)$this->getRequest()->getParam('code'));
+                $requestCode = $this->getRequest()->getParam('code');
+                $customerGroupCode = is_string($requestCode) ? trim($requestCode) : $requestCode;
 
                 if ($id !== null) {
                     $customerGroup = $this->groupRepository->getById((int)$id);