fix(promotion, types): non discountable items check (#12644)

* fix(promotions): check if item is discountable

* fix: return earl yonly if non discountable

* fix: update test

* chore: add integration test

.changeset/proud-shirts-leave.md

@@ -0,0 +1,6 @@
+---
+"@medusajs/promotion": patch
+"@medusajs/types": patch
+---
+
+fix(promotion, types): non discountable items check

integration-tests/http/__tests__/cart/store/cart.spec.ts

@@ -2621,6 +2621,96 @@ medusaIntegrationTestRunner({
           )
         })
 
+        it("should only apply promotion on discountable items", async () => {
+          const notDiscountableProduct = (
+            await api.post(
+              "/admin/products",
+              {
+                title: "Medusa T-Shirt not discountable",
+                handle: "t-shirt-not-discountable",
+                discountable: false,
+                options: [
+                  {
+                    title: "Size",
+                    values: ["S"],
+                  },
+                ],
+                variants: [
+                  {
+                    title: "S",
+                    sku: "s-shirt",
+                    options: {
+                      Size: "S",
+                    },
+                    manage_inventory: false,
+                    prices: [
+                      {
+                        amount: 1000,
+                        currency_code: "usd",
+                      },
+                    ],
+                  },
+                ],
+
+                shipping_profile_id: shippingProfile.id,
+              },
+              adminHeaders
+            )
+          ).data.product
+
+          const cartData = {
+            currency_code: "usd",
+            sales_channel_id: salesChannel.id,
+            region_id: region.id,
+            shipping_address: shippingAddressData,
+            items: [
+              { variant_id: product.variants[0].id, quantity: 1 },
+              {
+                variant_id: notDiscountableProduct.variants[0].id,
+                quantity: 1,
+              },
+            ],
+            promo_codes: [promotion.code],
+          }
+
+          const cart = (
+            await api.post(
+              `/store/carts?fields=+items.is_discountable,+items.total,+items.discount_total`,
+              cartData,
+              storeHeaders
+            )
+          ).data.cart
+
+          expect(cart).toEqual(
+            expect.objectContaining({
+              discount_subtotal: 100,
+              items: expect.arrayContaining([
+                expect.objectContaining({
+                  variant_id: product.variants[0].id,
+                  is_discountable: true,
+                  unit_price: 1500,
+                  total: 1395,
+                  discount_total: 100,
+                  adjustments: [
+                    expect.objectContaining({
+                      promotion_id: promotion.id,
+                      amount: 100,
+                    }),
+                  ],
+                }),
+                expect.objectContaining({
+                  variant_id: notDiscountableProduct.variants[0].id,
+                  is_discountable: false,
+                  total: 1000,
+                  unit_price: 1000,
+                  discount_total: 0,
+                  adjustments: [],
+                }),
+              ]),
+            })
+          )
+        })
+
         it("should remove promotion adjustments when promotion is deleted", async () => {
           let cartBeforeRemovingPromotion = (
             await api.get(`/store/carts/${cart.id}`, storeHeaders)

integration-tests/modules/__tests__/cart/store/add-promotions-to-cart.spec.ts

@@ -162,6 +162,71 @@ medusaIntegrationTestRunner({
           )
         })
 
+        it("should add line item adjustments only for discountable items", async () => {
+          const createdPromotion =
+            await promotionModuleService.createPromotions({
+              code: "PROMOTION_TEST",
+              type: PromotionType.STANDARD,
+              status: PromotionStatus.ACTIVE,
+              application_method: {
+                type: "fixed",
+                target_type: "items",
+                allocation: "across",
+                value: 1000,
+                apply_to_quantity: 1,
+                currency_code: "usd",
+              },
+            })
+
+          const cart = await cartModuleService.createCarts({
+            currency_code: "usd",
+            items: [
+              {
+                id: "item-1",
+                unit_price: 2000,
+                quantity: 1,
+                title: "Test item",
+                product_id: "prod_mat",
+              } as any,
+              {
+                id: "item-2",
+                unit_price: 1000,
+                quantity: 1,
+                title: "Test item",
+                product_id: "prod_tshirt",
+                is_discountable: false,
+              } as any,
+            ],
+          })
+
+          const created = await api.post(
+            `/store/carts/${cart.id}/promotions`,
+            { promo_codes: [createdPromotion.code] },
+            storeHeaders
+          )
+
+          expect(created.status).toEqual(200)
+          expect(created.data.cart).toEqual(
+            expect.objectContaining({
+              id: expect.any(String),
+              items: expect.arrayContaining([
+                expect.objectContaining({
+                  id: "item-1",
+                  adjustments: expect.arrayContaining([
+                    expect.objectContaining({
+                      code: createdPromotion.code,
+                      amount: 1000,
+                    }),
+                  ]),
+                }),
+                expect.objectContaining({
+                  adjustments: [],
+                }),
+              ]),
+            })
+          )
+        })
+
         it("should add shipping method adjustments to a cart based on promotions", async () => {
           const [appliedPromotion] =
             await promotionModuleService.createPromotions([

packages/core/types/src/promotion/common/compute-actions.ts

@@ -180,6 +180,11 @@ export interface ComputeActionItemLine extends Record<string, unknown> {
    */
   subtotal: BigNumberInput
 
+  /**
+   * Whether the line item is discountable.
+   */
+  is_discountable: boolean
+
   /**
    * The adjustments applied before on the line item.
    */

packages/modules/promotion/src/utils/compute-actions/line-items.ts

@@ -201,7 +201,15 @@ function getValidItemsForPromotion(
   }
 
   return items.filter((item) => {
-    if (!item || !("subtotal" in item) || MathBN.lte(item.subtotal, 0)) {
+    if (!item) {
+      return false
+    }
+
+    if ("is_discountable" in item && !item.is_discountable) {
+      return false
+    }
+
+    if (!("subtotal" in item) || MathBN.lte(item.subtotal, 0)) {
       return false
     }