Merge branch '2.4-develop' into AC-15107-Catalog

Author: manishranjan-adobe

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/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,