LYNX-703 Bundle product does not return the correct discount percentage and amount

Author: cod40403

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

@@ -0,0 +1,51 @@
+<?php
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\QuoteGraphQl\Model\Resolver;
+
+use Magento\Framework\Exception\LocalizedException;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+use Magento\CatalogGraphQl\Model\Resolver\Product\Price\Discount;
+use Magento\Quote\Api\Data\CartItemInterface;
+
+class CatalogDiscount implements ResolverInterface
+{
+    /**
+     * CatalogDiscount constructor
+     *
+     * @param Discount $discount
+     */
+    public function __construct(
+        private readonly Discount $discount
+    ) {
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function resolve(
+        Field $field,
+        $context,
+        ResolveInfo $info,
+        ?array $value = null,
+        ?array $args = null
+    ):array {
+        if (!(($value['model'] ?? null) instanceof CartItemInterface) ||
+            empty($value['original_item_price']) ||
+            empty($value['price'])
+        ) {
+            throw new LocalizedException(__('The "model" value or pricing details are missing or invalid.'));
+        }
+
+        return $this->discount->getDiscountByDifference(
+            $value['original_item_price']['value'],
+            $value['price']['value']
+        );
+    }
+}

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

@@ -0,0 +1,54 @@
+<?php
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\QuoteGraphQl\Model\Resolver;
+
+use Magento\Framework\Exception\LocalizedException;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+use Magento\CatalogGraphQl\Model\Resolver\Product\Price\Discount;
+use Magento\Quote\Api\Data\CartItemInterface;
+
+class RowCatalogDiscount implements ResolverInterface
+{
+    /**
+     * RowCatalogDiscount constructor
+     *
+     * @param Discount $discount
+     */
+    public function __construct(
+        private readonly Discount $discount
+    ) {
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function resolve(
+        Field $field,
+        $context,
+        ResolveInfo $info,
+        ?array $value = null,
+        ?array $args = null
+    ):array {
+        if (!(($value['model'] ?? null) instanceof CartItemInterface) ||
+            empty($value['original_item_price']) ||
+            empty($value['price'])
+        ) {
+            throw new LocalizedException(__('The "model" value or pricing details are missing or invalid.'));
+        }
+
+        /** @var CartItemInterface $item */
+        $item = $value['model'];
+
+        return $this->discount->getDiscountByDifference(
+            $value['original_item_price']['value'] * $item->getTotalQty(),
+            $value['price']['value'] * $item->getTotalQty()
+        );
+    }
+}

app/code/Magento/QuoteGraphQl/composer.json

@@ -19,7 +19,8 @@
         "magento/module-gift-message-graph-ql": "*",
         "magento/module-catalog-inventory": "*",
         "magento/module-eav-graph-ql": "*",
-        "magento/module-downloadable": "*"
+        "magento/module-downloadable": "*",
+        "magento/module-catalog-graph-ql": "*"
     },
     "suggest": {
         "magento/module-graph-ql-cache": "*",

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

@@ -458,6 +458,8 @@ type CartItemPrices @doc(description: "Contains details about the price of the i
     total_item_discount: Money @doc(description: "The total of all discounts applied to the item.")
     original_item_price: Money! @doc(description: "The value of the original unit price for the item, including discounts.")
     original_row_total: Money! @doc(description: "The value of the original price multiplied by the quantity of the item.")
+    catalog_discount: ProductDiscount @doc(description: "The price discount for the unit price of the item represents the difference between its regular price and final price.") @resolver(class: "Magento\\QuoteGraphQl\\Model\\Resolver\\CatalogDiscount")
+    row_catalog_discount: ProductDiscount @doc(description: "The price discount multiplied by the item quantity represents the total difference between the regular price and the final price for the entire quote item.") @resolver(class: "Magento\\QuoteGraphQl\\Model\\Resolver\\RowCatalogDiscount")
 }
 
 type SelectedCustomizableOption @doc(description: "Identifies a customized product that has been placed in a cart.") {