From 2396cc317aad7d497a25e8801e5139dd745dc761 Mon Sep 17 00:00:00 2001
From: Michael Bromley <michael@michaelbromley.co.uk>
Date: Wed, 17 Feb 2021 14:09:56 +0100
Subject: [PATCH] fix(core): Remove inapplicable order-level discounts

Fixes #710
---
 packages/core/e2e/order-promotion.e2e-spec.ts | 50 +++++++++++++++++++
 .../order-calculator/order-calculator.ts      | 15 +++++-
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/packages/core/e2e/order-promotion.e2e-spec.ts b/packages/core/e2e/order-promotion.e2e-spec.ts
index fa83cfe297..bbee7c2524 100644
--- a/packages/core/e2e/order-promotion.e2e-spec.ts
+++ b/packages/core/e2e/order-promotion.e2e-spec.ts
@@ -53,6 +53,7 @@ import {
     GetActiveOrder,
     GetOrderPromotionsByCode,
     RemoveCouponCode,
+    RemoveItemFromOrder,
     SetCustomerForOrder,
     SetShippingMethod,
     TestOrderFragmentFragment,
@@ -76,6 +77,7 @@ import {
     GET_ACTIVE_ORDER,
     GET_ORDER_PROMOTIONS_BY_CODE,
     REMOVE_COUPON_CODE,
+    REMOVE_ITEM_FROM_ORDER,
     SET_CUSTOMER,
     SET_SHIPPING_METHOD,
 } from './graphql/shop-definitions';
@@ -1387,6 +1389,54 @@ describe('Promotions applied to Orders', () => {
         });
     });
 
+    // https://github.com/vendure-ecommerce/vendure/issues/710
+    it('removes order-level discount made invalid by removing OrderLine', async () => {
+        const promotion = await createPromotion({
+            enabled: true,
+            name: 'Test Promo',
+            conditions: [minOrderAmountCondition(10000)],
+            actions: [
+                {
+                    code: orderFixedDiscount.code,
+                    arguments: [{ name: 'discount', value: '1000' }],
+                },
+            ],
+        });
+
+        await shopClient.asAnonymousUser();
+        await shopClient.query<AddItemToOrder.Mutation, AddItemToOrder.Variables>(ADD_ITEM_TO_ORDER, {
+            productVariantId: getVariantBySlug('item-1000').id,
+            quantity: 8,
+        });
+        const { addItemToOrder } = await shopClient.query<AddItemToOrder.Mutation, AddItemToOrder.Variables>(
+            ADD_ITEM_TO_ORDER,
+            {
+                productVariantId: getVariantBySlug('item-5000').id,
+                quantity: 1,
+            },
+        );
+        orderResultGuard.assertSuccess(addItemToOrder);
+        expect(addItemToOrder!.discounts.length).toBe(1);
+        expect(addItemToOrder!.discounts[0].description).toBe('Test Promo');
+
+        const { activeOrder: check1 } = await shopClient.query<GetActiveOrder.Query>(GET_ACTIVE_ORDER);
+        expect(check1!.discounts.length).toBe(1);
+        expect(check1!.discounts[0].description).toBe('Test Promo');
+
+        const { removeOrderLine } = await shopClient.query<
+            RemoveItemFromOrder.Mutation,
+            RemoveItemFromOrder.Variables
+        >(REMOVE_ITEM_FROM_ORDER, {
+            orderLineId: addItemToOrder.lines[1].id,
+        });
+
+        orderResultGuard.assertSuccess(removeOrderLine);
+        expect(removeOrderLine.discounts.length).toBe(0);
+
+        const { activeOrder: check2 } = await shopClient.query<GetActiveOrder.Query>(GET_ACTIVE_ORDER);
+        expect(check2!.discounts.length).toBe(0);
+    });
+
     async function getProducts() {
         const result = await adminClient.query<GetProductsWithVariantPrices.Query>(
             GET_PRODUCTS_WITH_VARIANT_PRICES,
diff --git a/packages/core/src/service/helpers/order-calculator/order-calculator.ts b/packages/core/src/service/helpers/order-calculator/order-calculator.ts
index 220d497c02..cf5370194c 100644
--- a/packages/core/src/service/helpers/order-calculator/order-calculator.ts
+++ b/packages/core/src/service/helpers/order-calculator/order-calculator.ts
@@ -265,7 +265,20 @@ export class OrderCalculator {
         promotions: Promotion[],
     ): Promise<OrderItem[]> {
         const updatedItems = new Set<OrderItem>();
-        order.lines.forEach(line => line.clearAdjustments(AdjustmentType.DISTRIBUTED_ORDER_PROMOTION));
+        const orderHasDistributedPromotions = !!order.discounts.find(
+            adjustment => adjustment.type === AdjustmentType.DISTRIBUTED_ORDER_PROMOTION,
+        );
+        if (orderHasDistributedPromotions) {
+            // If the Order currently has any Order-level discounts applied, we need to
+            // mark all OrderItems in the Order as "updated", since one or more of those
+            // Order-level discounts may become invalid, which will require _all_ OrderItems
+            // to be saved.
+            order.lines.forEach(line => {
+                line.clearAdjustments(AdjustmentType.DISTRIBUTED_ORDER_PROMOTION);
+                line.items.forEach(item => updatedItems.add(item));
+            });
+        }
+
         this.calculateOrderTotals(order);
         const applicableOrderPromotions = await filterAsync(promotions, p => p.test(ctx, order));
         if (applicableOrderPromotions.length) {