Fix the configurable stock index child status join and drop the isSalable N+1 on listings

InventoryConfigurableProduct/Plugin/Model/Product/Type/Configurable/IsSalablePlugin.php

@@ -0,0 +1,78 @@
+<?php
+/**
+ * Copyright 2026 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\InventoryConfigurableProduct\Plugin\Model\Product\Type\Configurable;
+
+use Magento\Catalog\Api\Data\ProductInterface;
+use Magento\Catalog\Model\Product\Attribute\Source\Status;
+use Magento\ConfigurableProduct\Model\Product\Type\Configurable;
+use Magento\Store\Model\Store;
+use Magento\Store\Model\StoreManagerInterface;
+
+/**
+ * Resolve configurable salability from the stock index instead of counting salable children per product.
+ */
+class IsSalablePlugin
+{
+    /**
+     * @param StoreManagerInterface $storeManager
+     */
+    public function __construct(private readonly StoreManagerInterface $storeManager)
+    {
+    }
+
+    /**
+     * Replace the per-product salable children count with the aggregate the stock index already holds.
+     *
+     * @param Configurable $subject
+     * @param callable $proceed
+     * @param ProductInterface $product
+     * @return bool
+     */
+    public function aroundIsSalable(Configurable $subject, callable $proceed, $product): bool
+    {
+        try {
+            if (!$product->hasData('is_salable') || !$this->isCurrentStoreScope($subject, $product)) {
+                return (bool)$proceed($product);
+            }
+        } catch (\Throwable $exception) {
+            return (bool)$proceed($product);
+        }
+
+        $salable = $product->getStatus() == Status::STATUS_ENABLED;
+        if ($salable) {
+            $salable = $product->getData('is_salable');
+        }
+
+        return (bool)(int)$salable;
+    }
+
+    /**
+     * Whether the salability being asked for is the one of the current store.
+     *
+     * @param Configurable $subject
+     * @param ProductInterface $product
+     * @return bool
+     */
+    private function isCurrentStoreScope(Configurable $subject, $product): bool
+    {
+        $storeFilter = $subject->getStoreFilter($product);
+        if ($storeFilter instanceof Store) {
+            $scopeStoreId = $storeFilter->getId();
+        } elseif ($storeFilter !== null) {
+            $scopeStoreId = $storeFilter;
+        } else {
+            $scopeStoreId = $product->getStoreId();
+        }
+
+        if ($scopeStoreId === null || $scopeStoreId === '') {
+            return false;
+        }
+
+        return (int)$scopeStoreId === (int)$this->storeManager->getStore()->getId();
+    }
+}

InventoryConfigurableProduct/Test/Unit/Plugin/Model/Product/Type/Configurable/IsSalablePluginTest.php

@@ -0,0 +1,176 @@
+<?php
+/**
+ * Copyright 2026 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\InventoryConfigurableProduct\Test\Unit\Plugin\Model\Product\Type\Configurable;
+
+use Magento\Catalog\Model\Product;
+use Magento\Catalog\Model\Product\Attribute\Source\Status;
+use Magento\ConfigurableProduct\Model\Product\Type\Configurable;
+use Magento\Framework\Exception\NoSuchEntityException;
+use Magento\InventoryConfigurableProduct\Plugin\Model\Product\Type\Configurable\IsSalablePlugin;
+use Magento\Store\Api\Data\StoreInterface;
+use Magento\Store\Model\Store;
+use Magento\Store\Model\StoreManagerInterface;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+class IsSalablePluginTest extends TestCase
+{
+    private const CURRENT_STORE_ID = 1;
+
+    /**
+     * @var IsSalablePlugin
+     */
+    private IsSalablePlugin $plugin;
+
+    /**
+     * @var StoreManagerInterface|MockObject
+     */
+    private $storeManagerMock;
+
+    /**
+     * @var Configurable|MockObject
+     */
+    private $configurableMock;
+
+    /**
+     * @inheritdoc
+     */
+    protected function setUp(): void
+    {
+        $this->storeManagerMock = $this->createMock(StoreManagerInterface::class);
+        $this->configurableMock = $this->createMock(Configurable::class);
+
+        $storeMock = $this->createMock(StoreInterface::class);
+        $storeMock->method('getId')->willReturn(self::CURRENT_STORE_ID);
+        $this->storeManagerMock->method('getStore')->willReturn($storeMock);
+
+        $this->plugin = new IsSalablePlugin($this->storeManagerMock);
+    }
+
+    public function testLoadedIsSalableIsUsedWithoutTouchingTheCore(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED, 'is_salable' => '1']);
+
+        $this->assertTrue($this->plugin->aroundIsSalable($this->configurableMock, $this->failingProceed(), $product));
+    }
+
+    public function testLoadedIsSalableZeroMakesProductNotSalable(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED, 'is_salable' => '0']);
+
+        $this->assertFalse($this->plugin->aroundIsSalable($this->configurableMock, $this->failingProceed(), $product));
+    }
+
+    public function testLoadedIsSalableNullMakesProductNotSalable(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED, 'is_salable' => null]);
+
+        $this->assertFalse($this->plugin->aroundIsSalable($this->configurableMock, $this->failingProceed(), $product));
+    }
+
+    public function testDisabledProductIsNotSalable(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_DISABLED, 'is_salable' => '1']);
+
+        $this->assertFalse($this->plugin->aroundIsSalable($this->configurableMock, $this->failingProceed(), $product));
+    }
+
+    public function testProductWithoutLoadedIsSalableIsDelegated(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED]);
+
+        $this->assertTrue(
+            $this->plugin->aroundIsSalable($this->configurableMock, static fn () => true, $product)
+        );
+    }
+
+    public function testStoreFilterOfAnotherStoreIsDelegated(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED, 'is_salable' => '1']);
+        $otherStore = $this->createMock(Store::class);
+        $otherStore->method('getId')->willReturn(7);
+        $this->configurableMock->method('getStoreFilter')->willReturn($otherStore);
+
+        $this->assertFalse(
+            $this->plugin->aroundIsSalable($this->configurableMock, static fn () => false, $product)
+        );
+    }
+
+    public function testStoreFilterOfCurrentStoreKeepsTheFastPath(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED, 'is_salable' => '1']);
+        $currentStore = $this->createMock(Store::class);
+        $currentStore->method('getId')->willReturn(self::CURRENT_STORE_ID);
+        $this->configurableMock->method('getStoreFilter')->willReturn($currentStore);
+
+        $this->assertTrue($this->plugin->aroundIsSalable($this->configurableMock, $this->failingProceed(), $product));
+    }
+
+    public function testIntegerStoreFilterOfCurrentStoreKeepsTheFastPath(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED, 'is_salable' => '1']);
+        $this->configurableMock->method('getStoreFilter')->willReturn(self::CURRENT_STORE_ID);
+
+        $this->assertTrue($this->plugin->aroundIsSalable($this->configurableMock, $this->failingProceed(), $product));
+    }
+
+    public function testMissingScopeIsDelegated(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED, 'is_salable' => '1'], null);
+        $this->configurableMock->method('getStoreFilter')->willReturn(null);
+
+        $this->assertFalse(
+            $this->plugin->aroundIsSalable($this->configurableMock, static fn () => false, $product)
+        );
+    }
+
+    public function testStoreResolutionFailureFallsBackToTheCore(): void
+    {
+        $product = $this->createProduct(['status' => Status::STATUS_ENABLED, 'is_salable' => '1']);
+        $this->configurableMock->method('getStoreFilter')
+            ->willThrowException(new NoSuchEntityException(__('no store')));
+
+        $this->assertTrue(
+            $this->plugin->aroundIsSalable($this->configurableMock, static fn () => true, $product)
+        );
+    }
+
+    /**
+     * Build a product stub carrying the given data.
+     *
+     * @param array $data
+     * @param int|null $storeId
+     * @return Product|MockObject
+     */
+    private function createProduct(array $data, ?int $storeId = self::CURRENT_STORE_ID)
+    {
+        $product = $this->getMockBuilder(Product::class)
+            ->disableOriginalConstructor()
+            ->onlyMethods(['getStoreId', 'getSku', 'getStatus', 'hasData', 'getData'])
+            ->getMock();
+        $product->method('getStoreId')->willReturn($storeId);
+        $product->method('getSku')->willReturn('sku-1');
+        $product->method('getStatus')->willReturn($data['status']);
+        $product->method('hasData')->with('is_salable')->willReturn(array_key_exists('is_salable', $data));
+        $product->method('getData')->with('is_salable')->willReturn($data['is_salable'] ?? null);
+
+        return $product;
+    }
+
+    /**
+     * A $proceed that must never be reached.
+     *
+     * @return callable
+     */
+    private function failingProceed(): callable
+    {
+        return function () {
+            $this->fail('The core implementation must not be reached');
+        };
+    }
+}

InventoryConfigurableProduct/etc/frontend/di.xml

@@ -11,6 +11,7 @@
     </type>
     <type name="Magento\ConfigurableProduct\Model\Product\Type\Configurable">
         <plugin name="is_option_salable" type="Magento\InventoryConfigurableProduct\Plugin\Model\Product\Type\Configurable\IsSalableOptionPlugin"/>
+        <plugin name="is_salable_from_index" type="Magento\InventoryConfigurableProduct\Plugin\Model\Product\Type\Configurable\IsSalablePlugin"/>
     </type>
     <type name="Magento\CatalogInventory\Helper\Stock">
         <plugin name="adapt_assign_stock_status_to_configurable_product" type="Magento\InventoryConfigurableProduct\Plugin\CatalogInventory\Helper\Stock\AdaptAssignStatusToProductPlugin"/>

InventoryConfigurableProductIndexer/Indexer/SelectBuilder.php

@@ -24,6 +24,7 @@
 use Magento\InventoryMultiDimensionalIndexerApi\Model\IndexNameBuilder;
 use Magento\InventoryMultiDimensionalIndexerApi\Model\IndexNameResolverInterface;
 use Magento\InventoryIndexer\Indexer\SelectBuilderInterface;
+use Magento\Store\Model\Store;
 
 /**
  * Get configurable product for given stock select builder
@@ -122,14 +123,19 @@ public function execute(int $stockId): Select
             $manageStock = "($manageStock)";
         }
 
+        $enabledChildIsSalable = sprintf(
+            'MAX(IF(product_status.value = %d, stock.is_salable, 0))',
+            ProductStatus::STATUS_ENABLED
+        );
+
         $select = $connection->select()
             ->from(
                 ['stock' => $indexTableName],
                 [
                     IndexStructure::SKU => 'parent_product_entity.sku',
                     IndexStructure::QUANTITY => 'SUM(stock.quantity)',
                     IndexStructure::IS_SALABLE =>
-                        "IF(inventory_stock_item.is_in_stock = 0 AND $manageStock, 0, MAX(stock.is_salable))",
+                        "IF(inventory_stock_item.is_in_stock = 0 AND $manageStock, 0, $enabledChildIsSalable)",
                 ]
             )->joinInner(
                 ['product_entity' => $this->resourceConnection->getTableName('catalog_product_entity')],
@@ -148,11 +154,11 @@ public function execute(int $stockId): Select
                 'inventory_stock_item.product_id = parent_product_entity.entity_id'
                 . ' AND inventory_stock_item.stock_id = ' . $this->defaultStockProvider->getId(),
                 []
-            )->joinInner(
+            )->joinLeft(
                 ['product_status' => $this->resourceConnection->getTableName('catalog_product_entity_int')],
                 "product_entity.$linkField = product_status.$linkField"
                 . " AND product_status.attribute_id = $statusAttributeId"
-                . ' AND product_status.value = ' . ProductStatus::STATUS_ENABLED,
+                . ' AND product_status.store_id = ' . Store::DEFAULT_STORE_ID,
                 []
             )
             ->group(['parent_product_entity.sku'])