Merge branch '2.4-develop' of github.com:magento-commerce/magento2ce into ACP2E-4019

Author: alzota

app/code/Magento/Catalog/Model/ProductLink/Repository.php

@@ -139,7 +139,7 @@ public function save(\Magento\Catalog\Api\Data\ProductLinkInterface $entity)
                 . 'Please ensure the parent product SKU is provided and try again.'
             ));
         }
-        if (!$entity->getLinkedProductSku()) {
+        if ($entity->getLinkedProductSku() === null || $entity->getLinkedProductSku() === '') {
             throw new CouldNotSaveException(__('The linked product SKU is invalid. Verify the data and try again.'));
         }
         $linkedProduct = $this->productRepository->get($entity->getLinkedProductSku());

app/code/Magento/Catalog/Test/Mftf/ActionGroup/AddToCartFromStorefrontProductPageActionGroup.xml

@@ -18,7 +18,15 @@
         </arguments>
         <waitForElementNotVisible selector="{{StorefrontProductActionSection.addToCartDisabled}}" stepKey="waitForAddToCartButtonToRemoveDisabledState"/>
         <!-- Scroll to button to prevent overlapping elements from intercepting click -->
-        <scrollToTopOfPage stepKey="scrollToAddToCartButton"/>
+        <scrollTo selector="{{StorefrontProductActionSection.addToCart}}" stepKey="scrollToAddToCartButton"/>
+        <wait time="1" stepKey="waitForScrollToComplete"/>
+        <!-- Additional scroll with JS to ensure element is in viewport and not intercepted -->
+        <executeJS function="
+            var element = document.querySelector('#product-addtocart-button');
+            if (element) {
+                element.scrollIntoView({behavior: 'smooth', block: 'center'});
+            }
+        " stepKey="scrollToAddToCartButtonWithJS"/>
         <waitForElementClickable selector="{{StorefrontProductActionSection.addToCart}}" stepKey="waitForAddToCartButton"/>
         <click selector="{{StorefrontProductActionSection.addToCart}}" stepKey="addToCart"/>
         <waitForPageLoad stepKey="waitForAddToCart"/>

app/code/Magento/Catalog/Test/Unit/Model/ProductLink/RepositoryTest.php

@@ -298,4 +298,16 @@ public function testDeleteWithNoSuchEntityException()
 
         $this->model->delete($entityMock);
     }
+
+    public function testSaveWithNullLinkedProductSku()
+    {
+        $this->expectException('Magento\Framework\Exception\CouldNotSaveException');
+        $this->expectExceptionMessage('The linked product SKU is invalid. Verify the data and try again.');
+
+        $entityMock = $this->createMock(\Magento\Catalog\Model\ProductLink\Link::class);
+        $entityMock->expects($this->any())->method('getSku')->willReturn('sku1');
+        $entityMock->expects($this->any())->method('getLinkedProductSku')->willReturn(null);
+
+        $this->model->save($entityMock);
+    }
 }

app/code/Magento/CatalogGraphQl/Model/Resolver/Product/ProductCustomAttributes.php

@@ -108,7 +108,9 @@ function (AttributeInterface $customAttribute) {
             }
             $attributeValue = $productData[$attributeCode] ?? "";
             if (is_array($attributeValue)) {
-                $attributeValue = implode(',', $attributeValue);
+                $attributeValue = (count($attributeValue) != count($attributeValue, COUNT_RECURSIVE))
+                    ? json_encode($attributeValue)
+                    : implode(',', $attributeValue);
             }
             $customAttributes[] = [
                 'attribute_code' => $attributeCode,