ACP2E-1290: Cart Rule discount issue on shipping price

Author: bubasuma

app/code/Magento/SalesRule/Model/Validator.php

@@ -372,8 +372,7 @@ public function processShippingAmount(Address $address)
                         $cartRules[$rule->getId()] = $rule->getDiscountAmount();
                     }
                     if ($cartRules[$rule->getId()] > 0) {
-                        $shippingQuoteAmount = (float) $address->getShippingAmount()
-                            - (float) $address->getShippingDiscountAmount();
+                        $shippingQuoteAmount = (float) $address->getShippingAmount();
                         $quoteBaseSubtotal = (float) $quote->getBaseSubtotal();
                         $isMultiShipping = $this->cartFixedDiscountHelper->checkMultiShippingQuote($quote);
                         if ($isAppliedToShipping) {

app/code/Magento/SalesRule/Test/Fixture/Rule.php

@@ -116,7 +116,9 @@ public function apply(array $data = []): ?DataObject
 
         $model->setActionsSerialized($this->serializer->serialize($actions));
         $model->setConditionsSerialized($this->serializer->serialize($conditions));
-        $this->resourceModel->save($model);
+        //FIXME: plug-ins are configured for \Magento\SalesRule\Model\Rule::save
+        // instead of \Magento\SalesRule\Model\ResourceModel\Rule::save()
+        $model->save();
 
         return $model;
     }

dev/tests/integration/testsuite/Magento/SalesRule/Model/Rule/Action/Discount/CartFixedTest.php

@@ -12,7 +12,10 @@
 use Magento\Catalog\Model\Product\Attribute\Source\Status;
 use Magento\Catalog\Model\Product\Visibility;
 use Magento\Catalog\Model\ProductRepository;
+use Magento\Catalog\Test\Fixture\Product as ProductFixture;
+use Magento\Checkout\Api\Data\TotalsInformationInterface;
 use Magento\Checkout\Model\Session as CheckoutSession;
+use Magento\Checkout\Model\TotalsInformationManagement;
 use Magento\Framework\Api\SearchCriteriaBuilder;
 use Magento\Framework\Exception\CouldNotSaveException;
 use Magento\Framework\Exception\InputException;
@@ -22,20 +25,28 @@
 use Magento\Multishipping\Model\Checkout\Type\Multishipping;
 use Magento\Quote\Api\CartRepositoryInterface;
 use Magento\Quote\Api\Data\CartItemInterface;
+use Magento\Quote\Api\Data\TotalsInterface;
 use Magento\Quote\Api\GuestCartItemRepositoryInterface;
 use Magento\Quote\Api\GuestCartManagementInterface;
 use Magento\Quote\Api\GuestCartTotalRepositoryInterface;
 use Magento\Quote\Api\GuestCouponManagementInterface;
 use Magento\Quote\Model\Quote;
+use Magento\Quote\Model\Quote\Address;
+use Magento\Quote\Model\Quote\AddressFactory;
 use Magento\Quote\Model\QuoteIdMask;
+use Magento\Quote\Test\Fixture\AddProductToCart as AddProductToCartFixture;
+use Magento\Quote\Test\Fixture\GuestCart as GuestCartFixture;
 use Magento\Sales\Api\Data\OrderInterface;
 use Magento\Sales\Api\OrderRepositoryInterface;
 use Magento\Sales\Model\Order;
 use Magento\Sales\Model\Order\Email\Sender\OrderSender;
 use Magento\SalesRule\Api\RuleRepositoryInterface;
 use Magento\SalesRule\Model\Rule;
 use Magento\SalesRule\Model\RuleFactory;
+use Magento\SalesRule\Test\Fixture\Rule as RuleFixture;
 use Magento\Store\Model\StoreManagerInterface;
+use Magento\TestFramework\Fixture\DataFixture;
+use Magento\TestFramework\Fixture\DataFixtureStorageManager;
 use Magento\TestFramework\Helper\Bootstrap;
 use PHPUnit\Framework\TestCase;
 
@@ -506,7 +517,7 @@ public function testDiscountsWhenByPercentRuleAppliedFirstAndCartFixedRuleSecond
         $expectedDiscounts
     ): void {
         //Update rule discount
-        /** @var \Magento\SalesRule\Model\Rule $rule */
+        /** @var Rule $rule */
         $rule = $this->getRule('50% off - July 4');
         $rule->setDiscountAmount($percentDiscount);
         $this->saveRule($rule);
@@ -577,6 +588,41 @@ public function testCartFixedDiscountPriceIncludeTax()
         $this->assertEquals(-5, $quote->getShippingAddress()->getDiscountAmount());
     }
 
+    #[
+        DataFixture(ProductFixture::class, ['price' => 15], 'p1'),
+        DataFixture(ProductFixture::class, ['price' => 10], 'p2'),
+        DataFixture(
+            RuleFixture::class,
+            [
+                'simple_action' => Rule::BY_PERCENT_ACTION,
+                'discount_amount' => 50,
+                'apply_to_shipping' => 1,
+                'stop_rules_processing' => 0,
+                'sort_order' => 1,
+            ]
+        ),
+        DataFixture(
+            RuleFixture::class,
+            [
+                'simple_action' => Rule::CART_FIXED_ACTION,
+                'discount_amount' => 40,
+                'apply_to_shipping' => 1,
+                'stop_rules_processing' => 0,
+                'sort_order' => 2
+            ]
+        ),
+        DataFixture(GuestCartFixture::class, as: 'cart'),
+        DataFixture(AddProductToCartFixture::class, ['cart_id' => '$cart.id$', 'product_id' => '$p1.id$', 'qty' => 2]),
+        DataFixture(AddProductToCartFixture::class, ['cart_id' => '$cart.id$', 'product_id' => '$p2.id$', 'qty' => 2])
+    ]
+    public function testCarFixedDiscountWithApplyToShippingAmountAfterADiscount(): void
+    {
+        $cart = DataFixtureStorageManager::getStorage()->get('cart');
+        $totals = $this->getTotals((int) $cart->getId());
+        $this->assertEquals(0, $totals->getGrandTotal());
+        $this->assertEquals(-70, $totals->getDiscountAmount());
+    }
+
     /**
      * Get list of orders by quote id.
      *
@@ -632,4 +678,31 @@ private function saveRule(Rule $rule): void
         $resourceModel = $this->objectManager->get(\Magento\SalesRule\Model\ResourceModel\Rule::class);
         $resourceModel->save($rule);
     }
+    /**
+     * @param int $cartId
+     * @return TotalsInterface
+     */
+    private function getTotals(int $cartId): TotalsInterface
+    {
+        /** @var Address $address */
+        $address = $this->objectManager->get(AddressFactory::class)->create();
+        $totalsManagement = $this->objectManager->get(TotalsInformationManagement::class);
+        $address->setAddressType(Address::ADDRESS_TYPE_SHIPPING)
+            ->setCountryId('US')
+            ->setRegionId(12)
+            ->setRegion('California')
+            ->setPostcode('90230');
+        $addressInformation = $this->objectManager->create(
+            TotalsInformationInterface::class,
+            [
+                'data' => [
+                    'address' => $address,
+                    'shipping_method_code' => 'flatrate',
+                    'shipping_carrier_code' => 'flatrate',
+                ],
+            ]
+        );
+
+        return $totalsManagement->calculate($cartId, $addressInformation);
+    }
 }