Grouped product frontend quantity validation added and code refactor

app/code/Magento/CatalogInventory/Block/Plugin/ProductView.php

@@ -1,26 +1,29 @@
 <?php
 /**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
+ * Copyright 2015 Adobe
+ * All Rights Reserved.
  */
 namespace Magento\CatalogInventory\Block\Plugin;
 
-use Magento\CatalogInventory\Api\StockRegistryInterface;
+use Magento\CatalogInventory\Model\Product\QuantityValidator;
+use Magento\Framework\App\ObjectManager;
 
 class ProductView
 {
     /**
-     * @var StockRegistryInterface
+     * @var QuantityValidator
      */
-    private $stockRegistry;
+    private $productQuantityValidator;
 
     /**
-     * @param StockRegistryInterface $stockRegistry
+     * @param QuantityValidator|null $productQuantityValidator
      */
     public function __construct(
-        StockRegistryInterface $stockRegistry
+        QuantityValidator $productQuantityValidator = null
     ) {
-        $this->stockRegistry = $stockRegistry;
+        $this->productQuantityValidator = $productQuantityValidator ?: ObjectManager::getInstance()->get(
+            QuantityValidator::class
+        );
     }
 
     /**
@@ -34,20 +37,12 @@ public function afterGetQuantityValidators(
         \Magento\Catalog\Block\Product\View $block,
         array $validators
     ) {
-        $stockItem = $this->stockRegistry->getStockItem(
-            $block->getProduct()->getId(),
-            $block->getProduct()->getStore()->getWebsiteId()
+        return array_merge(
+            $validators,
+            $this->productQuantityValidator->getData(
+                $block->getProduct()->getSku(),
+                $block->getProduct()->getStore()->getWebsiteId()
+            )
         );
-
-        $params = [];
-        if ($stockItem->getMaxSaleQty()) {
-            $params['maxAllowed'] = (float)$stockItem->getMaxSaleQty();
-        }
-        if ($stockItem->getQtyIncrements() > 0) {
-            $params['qtyIncrements'] = (float)$stockItem->getQtyIncrements();
-        }
-        $validators['validate-item-quantity'] = $params;
-
-        return $validators;
     }
 }

app/code/Magento/CatalogInventory/Model/Product/QuantityValidator.php

@@ -0,0 +1,85 @@
+<?php
+/**
+ * Copyright 2024 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\CatalogInventory\Model\Product;
+
+use Magento\Framework\Exception\LocalizedException;
+use Magento\InventoryConfigurationApi\Api\GetStockItemConfigurationInterface;
+use Magento\InventorySalesApi\Api\StockResolverInterface;
+use Magento\InventorySalesApi\Api\Data\SalesChannelInterface;
+use Magento\Store\Model\StoreManagerInterface;
+
+class QuantityValidator
+{
+    /**
+     * @param GetStockItemConfigurationInterface $getStockItemConfiguration
+     * @param StoreManagerInterface $storeManager
+     * @param StockResolverInterface $stockResolver
+     */
+    public function __construct(
+        private readonly GetStockItemConfigurationInterface $getStockItemConfiguration,
+        private readonly StoreManagerInterface $storeManager,
+        private readonly StockResolverInterface $stockResolver
+    ) {
+    }
+
+    /**
+     * To get quantity validators
+     *
+     * @param string $sku
+     * @param int|null $websiteId
+     *
+     * @return array
+     */
+    public function getData(string $sku, int|null $websiteId): array
+    {
+        try {
+            $stockItemConfig = $this->getStockItemConfiguration->execute(
+                $sku,
+                $this->getStockId($websiteId)
+            );
+
+            $params = [];
+            $validators = [];
+            $params['minAllowed'] = $stockItemConfig->getMinSaleQty();
+
+            if ($stockItemConfig->getMaxSaleQty()) {
+                $params['maxAllowed'] = $stockItemConfig->getMaxSaleQty();
+            }
+            if ($stockItemConfig->getQtyIncrements() > 0) {
+                $params['qtyIncrements'] = $stockItemConfig->getQtyIncrements();
+            }
+            $validators['validate-item-quantity'] = $params;
+
+            return $validators;
+        } catch (\Exception $e) {
+            return [];
+        }
+    }
+
+    /**
+     * Get Stock ID by Website ID
+     *
+     * @param int|null $websiteId
+     * @return int
+     * @throws LocalizedException
+     */
+    private function getStockId(?int $websiteId): int
+    {
+        if ($websiteId === null) {
+            $websiteId = $this->storeManager->getWebsite()->getId();
+        }
+
+        $websiteCode = $this->storeManager->getWebsite($websiteId)->getCode();
+        $stock = $this->stockResolver->execute(
+            SalesChannelInterface::TYPE_WEBSITE,
+            $websiteCode
+        );
+
+        return (int) $stock->getStockId();
+    }
+}

app/code/Magento/CatalogInventory/Test/Unit/Model/Product/QuantityValidatorTest.php

@@ -0,0 +1,104 @@
+<?php
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\CatalogInventory\Test\Unit\Model\Product;
+
+use Magento\CatalogInventory\Model\Product\QuantityValidator;
+use Magento\InventoryConfigurationApi\Api\GetStockItemConfigurationInterface;
+use Magento\InventoryConfigurationApi\Api\Data\StockItemConfigurationInterface;
+use Magento\InventorySalesApi\Api\Data\SalesChannelInterface;
+use Magento\InventoryApi\Api\Data\StockInterface;
+use Magento\InventorySalesApi\Api\StockResolverInterface;
+use Magento\Store\Api\Data\WebsiteInterface;
+use Magento\Store\Model\StoreManagerInterface;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \Magento\CatalogInventory\Model\Product\QuantityValidator
+ */
+class QuantityValidatorTest extends TestCase
+{
+    private const WEBSITE_ID = 1;
+    private const WEBSITE_CODE = 'base';
+    private const STOCK_ID = 1;
+    private const TEST_SKU = 'TEST-SKU';
+
+    /**
+     * @var QuantityValidator
+     */
+    private $quantityValidator;
+
+    /**
+     * @var GetStockItemConfigurationInterface|MockObject
+     */
+    private $getStockItemConfiguration;
+
+    /**
+     * @var StoreManagerInterface|MockObject
+     */
+    private $storeManager;
+
+    /**
+     * @var StockResolverInterface|MockObject
+     */
+    private $stockResolver;
+
+    protected function setUp(): void
+    {
+        $this->getStockItemConfiguration = $this->createMock(GetStockItemConfigurationInterface::class);
+        $this->storeManager = $this->createMock(StoreManagerInterface::class);
+        $this->stockResolver = $this->createMock(StockResolverInterface::class);
+
+        $this->quantityValidator = new QuantityValidator(
+            $this->getStockItemConfiguration,
+            $this->storeManager,
+            $this->stockResolver
+        );
+    }
+
+    public function testGetDataWithValidators(): void
+    {
+        $website = $this->createMock(WebsiteInterface::class);
+        $website->method('getCode')->willReturn(self::WEBSITE_CODE);
+
+        $stock = $this->createMock(StockInterface::class);
+        $stock->method('getStockId')->willReturn(self::STOCK_ID);
+
+        $stockItemConfiguration = $this->createMock(StockItemConfigurationInterface::class);
+        $stockItemConfiguration->method('getMinSaleQty')->willReturn(2.0);
+        $stockItemConfiguration->method('getMaxSaleQty')->willReturn(10.0);
+        $stockItemConfiguration->method('getQtyIncrements')->willReturn(2.0);
+
+        // Set expectations
+        $this->storeManager->expects($this->once())
+            ->method('getWebsite')
+            ->with(self::WEBSITE_ID)
+            ->willReturn($website);
+
+        $this->stockResolver->expects($this->once())
+            ->method('execute')
+            ->with(SalesChannelInterface::TYPE_WEBSITE, self::WEBSITE_CODE)
+            ->willReturn($stock);
+
+        $this->getStockItemConfiguration->expects($this->once())
+            ->method('execute')
+            ->with(self::TEST_SKU, self::STOCK_ID)
+            ->willReturn($stockItemConfiguration);
+
+        $expected = [
+            'validate-item-quantity' => [
+                'minAllowed' => 2,
+                'maxAllowed' => 10,
+                'qtyIncrements' => 2.0
+            ]
+        ];
+
+        $result = $this->quantityValidator->getData(self::TEST_SKU, self::WEBSITE_ID);
+        $this->assertEquals($expected, $result);
+    }
+}

app/code/Magento/CatalogInventory/composer.json

@@ -8,6 +8,8 @@
         "php": "~8.2.0||~8.3.0||~8.4.0",
         "magento/framework": "*",
         "magento/module-catalog": "*",
+        "magento/module-inventory-configuration-api": "*",
+        "magento/module-inventory-sales-api": "*",
         "magento/module-config": "*",
         "magento/module-customer": "*",
         "magento/module-eav": "*",

app/code/Magento/CatalogInventory/etc/module.xml

@@ -1,14 +1,16 @@
 <?xml version="1.0"?>
 <!--
 /**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
+ * Copyright 2011 Adobe
+ * All Rights Reserved.
  */
 -->
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
     <module name="Magento_CatalogInventory" >
         <sequence>
             <module name="Magento_Catalog"/>
+            <module name="Magento_InventoryConfigurationApi"/>
+            <module name="Magento_InventorySalesApi"/>
         </sequence>
     </module>
 </config>