ACP2E-42: [Magento Cloud] Null response under items list in shopping cart with out of stock product

Author: victor-v-rad

app/code/Magento/QuoteGraphQl/Model/Resolver/CartItemErrors.php

@@ -0,0 +1,86 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\QuoteGraphQl\Model\Resolver;
+
+use Magento\Framework\Exception\LocalizedException;
+use Magento\Framework\Exception\RuntimeException;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+use Magento\Framework\GraphQl\Query\EnumLookup;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+use Magento\Quote\Model\Quote\Item;
+
+/**
+ * @inheritdoc
+ */
+class CartItemErrors implements ResolverInterface
+{
+    /**
+     * Error code
+     */
+    private const ERROR_UNDEFINED = 0;
+
+    /**
+     * @var EnumLookup
+     */
+    private $enumLookup;
+
+    /**
+     * @param EnumLookup $enumLookup
+     */
+    public function __construct(
+        EnumLookup $enumLookup
+    ) {
+        $this->enumLookup = $enumLookup;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
+    {
+        if (!isset($value['model'])) {
+            throw new LocalizedException(__('"model" value should be specified'));
+        }
+        /** @var Item $cartItem */
+        $cartItem = $value['model'];
+
+        return $this->getItemErrors($cartItem);
+    }
+
+    /**
+     * Get error messages for cart item
+     *
+     * @param Item $cartItem
+     * @return string[]|null
+     * @throws RuntimeException
+     */
+    private function getItemErrors(Item $cartItem): ?array
+    {
+        $hasError = (bool) $cartItem->getData('has_error');
+        if (!$hasError) {
+            return null;
+        }
+
+        $errors = [];
+        foreach ($cartItem->getErrorInfos() as $error) {
+            $errorType = $error['code'] ?? self::ERROR_UNDEFINED;
+            $message = $error['message'] ?? $cartItem->getMessage();
+            $errorEnumCode = $this->enumLookup->getEnumValueFromField(
+                'CartItemErrorType',
+                (string)$errorType
+            );
+            $errors[] = [
+                'code' => $errorEnumCode,
+                'message' => $message
+            ];
+        }
+
+        return $errors;
+    }
+}

app/code/Magento/QuoteGraphQl/Model/Resolver/CartItems.php

@@ -54,13 +54,6 @@ public function resolve(Field $field, $context, ResolveInfo $info, array $value
         $cart = $value['model'];
 
         $itemsData = [];
-        if ($cart->getData('has_error')) {
-            $errors = $cart->getErrors();
-            foreach ($errors as $error) {
-                $itemsData[] = new GraphQlInputException(__($error->getText()));
-            }
-        }
-
         $cartProductsData = $this->getCartProductsData($cart);
         $cartItems = $cart->getAllVisibleItems();
         /** @var QuoteItem $cartItem */

app/code/Magento/QuoteGraphQl/etc/graphql/di.xml

@@ -31,4 +31,15 @@
             <argument name="quoteTotalsCollector" xsi:type="object">Magento\Quote\Model\Quote\TotalsCollector\Proxy</argument>
         </arguments>
     </type>
+    <type name="Magento\Framework\GraphQl\Schema\Type\Enum\DefaultDataMapper">
+        <arguments>
+            <argument name="map" xsi:type="array">
+                <item name="CartItemErrorType" xsi:type="array">
+                    <item name="undefined" xsi:type="string">0</item>
+                    <item name="item_qty" xsi:type="string">1</item>
+                    <item name="item_increment" xsi:type="string">2</item>
+                </item>
+            </argument>
+        </arguments>
+    </type>
 </config>

app/code/Magento/QuoteGraphQl/etc/schema.graphqls

@@ -339,6 +339,18 @@ interface CartItemInterface @typeResolver(class: "Magento\\QuoteGraphQl\\Model\\
     quantity: Float! @doc(description: "The quantity of this item in the cart.")
     prices: CartItemPrices @resolver(class: "\\Magento\\QuoteGraphQl\\Model\\Resolver\\CartItemPrices") @doc(description: "Contains details about the price of the item, including taxes and discounts.")
     product: ProductInterface! @doc(description: "Details about an item in the cart.")
+    errors: [CartItemError!] @resolver(class: "\\Magento\\QuoteGraphQl\\Model\\Resolver\\CartItemErrors") @doc(description: "An array of errors encountered while loading the cart item")
+}
+
+type CartItemError {
+    code: CartItemErrorType! @doc(description: "An error code that describes the error encountered")
+    message: String! @doc(description: "A localized error message")
+}
+
+enum CartItemErrorType {
+    UNDEFINED
+    ITEM_QTY
+    ITEM_INCREMENTS
 }
 
 type Discount @doc(description:"Defines an individual discount. A discount can be applied to the cart as a whole or to an item.") {