magento/magento2#40104

app/code/Magento/ConfigurableProduct/Model/ConfigurableMaxPriceCalculator.php

@@ -49,7 +49,7 @@ public function __construct(
      * @param int $productId
      * @return float
      */
-    public function getMaxPriceForConfigurableProduct($productId)
+    public function getMaxPriceForConfigurableProduct(int $productId): float
     {
         $connection = $this->resourceConnection->getConnection();
         $superLinkTable = $this->resourceConnection->getTableName('catalog_product_super_link');
@@ -63,7 +63,7 @@ public function getMaxPriceForConfigurableProduct($productId)
         $result = $connection->fetchRow($select);
 
         if ($result && isset($result['max_price'])) {
-            return $result['max_price'];
+            return (float)$result['max_price'];
         }
 
         // Return a default value or handle the case where there's no max price

app/code/Magento/ConfigurableProduct/Pricing/Price/ConfigurableRegularPrice.php

@@ -196,26 +196,25 @@ public function _resetState(): void
     }
 
     /**
-     * Check whether Configurable Product have more than one children products
+     * Check whether Configurable options do not have price difference
      *
      * @param SaleableInterface $product
      * @return bool
      */
     public function isChildProductsOfEqualPrices(SaleableInterface $product): bool
     {
         $minPrice = $this->getMinRegularAmount()->getValue();
-        $final_price = $product->getFinalPrice();
-        $productId = $product->getId();
-        if ($final_price < $minPrice) {
+        $finalPrice = $product->getFinalPrice();
+        $productId = (int)$product->getId();
+        if ($finalPrice < $minPrice) {
             return false;
         }
-        $attributes = $product->getTypeInstance()->getConfigurableAttributes($product);
-        $items = $attributes->getItems();
-        $options = reset($items);
+
         $maxPrice = $this->configurableMaxPriceCalculator->getMaxPriceForConfigurableProduct($productId);
-        if ($maxPrice == 0) {
+        if ($maxPrice === 0.0) {
             $maxPrice = $this->getMaxRegularAmount()->getValue();
         }
-        return (count($options->getOptions()) > 1) && $minPrice == $maxPrice;
+
+        return $minPrice === $maxPrice;
     }
 }

dev/tests/integration/testsuite/Magento/ConfigurableProduct/Block/Product/View/Type/ConfigurableViewOnCategoryPageTest.php

@@ -129,6 +129,17 @@ public function testCheckConfigurablePriceOnSecondWebsite(): void
         $this->assertProductPrice('configurable', '$150.00');
     }
 
+    /**
+     * @magentoDataFixture Magento/ConfigurableProduct/_files/configurable_product_with_one_simple_with_category.php
+     *
+     * @return void
+     */
+    public function testCheckConfigurablePriceOnOneSimple(): void
+    {
+        $this->resetPageLayout();
+        $this->assertProductPrice('configurable', '$10.00');
+    }
+
     /**
      * @param string $sku
      * @param string $priceString

dev/tests/integration/testsuite/Magento/ConfigurableProduct/_files/configurable_product_with_one_simple_with_category.php

@@ -0,0 +1,24 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+use Magento\Catalog\Api\CategoryLinkManagementInterface;
+use Magento\Catalog\Helper\DefaultCategory;
+use Magento\TestFramework\Helper\Bootstrap;
+use Magento\TestFramework\Workaround\Override\Fixture\Resolver;
+
+Resolver::getInstance()->requireDataFixture('Magento/Catalog/_files/category.php');
+Resolver::getInstance()->requireDataFixture('Magento/ConfigurableProduct/_files/configurable_product_with_one_simple.php');
+
+$objectManager = Bootstrap::getObjectManager();
+/** @var CategoryLinkManagementInterface $categoryLinkManagement */
+$categoryLinkManagement = $objectManager->create(CategoryLinkManagementInterface::class);
+/** @var DefaultCategory $categoryHelper */
+$categoryHelper = $objectManager->get(DefaultCategory::class);
+
+foreach (['simple_1', 'configurable'] as $sku) {
+    $categoryLinkManagement->assignProductToCategories($sku, [$categoryHelper->getId(), 333]);
+}

dev/tests/integration/testsuite/Magento/ConfigurableProduct/_files/configurable_product_with_one_simple_with_category_rollback.php

@@ -0,0 +1,11 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+use Magento\TestFramework\Workaround\Override\Fixture\Resolver;
+
+Resolver::getInstance()->requireDataFixture('Magento/Catalog/_files/category_rollback.php');
+Resolver::getInstance()->requireDataFixture('Magento/ConfigurableProduct/_files/configurable_product_with_one_simple_with_category.php');