fix: Ensure tax lines are generated for all items and shipping methods in cart (#10372)

* fix: Generate tax lines for all items in cart

* fix: Correct test

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

@@ -362,6 +362,91 @@ medusaIntegrationTestRunner({
           )
         })
 
+        it("should add item to cart with tax lines multiple times", async () => {
+          let response = await api.post(
+            `/store/carts/${cart.id}/line-items`,
+            {
+              variant_id: product.variants[0].id,
+              quantity: 1,
+            },
+            storeHeaders
+          )
+
+          expect(response.status).toEqual(200)
+          expect(response.data.cart).toEqual(
+            expect.objectContaining({
+              id: cart.id,
+              currency_code: "usd",
+              items: expect.arrayContaining([
+                expect.objectContaining({
+                  unit_price: 1500,
+                  compare_at_unit_price: null,
+                  is_tax_inclusive: true,
+                  title: "S / Black",
+                  quantity: 2,
+                  tax_lines: [
+                    expect.objectContaining({
+                      description: "CA Default Rate",
+                      code: "CADEFAULT",
+                      rate: 5,
+                      provider_id: "system",
+                    }),
+                  ],
+                }),
+              ]),
+            })
+          )
+
+          response = await api.post(
+            `/store/carts/${cart.id}/line-items`,
+            {
+              variant_id: product.variants[1].id,
+              quantity: 1,
+            },
+            storeHeaders
+          )
+
+          expect(response.status).toEqual(200)
+          expect(response.data.cart).toEqual(
+            expect.objectContaining({
+              id: cart.id,
+              currency_code: "usd",
+              items: expect.arrayContaining([
+                expect.objectContaining({
+                  unit_price: 1500,
+                  compare_at_unit_price: null,
+                  is_tax_inclusive: true,
+                  quantity: 2,
+                  title: "S / Black",
+                  tax_lines: [
+                    expect.objectContaining({
+                      description: "CA Default Rate",
+                      code: "CADEFAULT",
+                      rate: 5,
+                      provider_id: "system",
+                    }),
+                  ],
+                }),
+                expect.objectContaining({
+                  unit_price: 1500,
+                  compare_at_unit_price: null,
+                  is_tax_inclusive: true,
+                  quantity: 1,
+                  title: "S / White",
+                  tax_lines: [
+                    expect.objectContaining({
+                      description: "CA Default Rate",
+                      code: "CADEFAULT",
+                      rate: 5,
+                      provider_id: "system",
+                    }),
+                  ],
+                }),
+              ]),
+            })
+          )
+        })
+
         describe("with sale price lists", () => {
           let priceList
 

integration-tests/modules/__tests__/cart/store/carts.spec.ts

@@ -876,7 +876,14 @@ medusaIntegrationTestRunner({
                   is_tax_inclusive: false,
                   quantity: 1,
                   title: "Test item",
-                  tax_lines: [],
+                  tax_lines: [
+                    expect.objectContaining({
+                      code: "CADEFAULT",
+                      description: "CA Default Rate",
+                      provider_id: "system",
+                      rate: 5,
+                    }),
+                  ],
                   adjustments: [
                     expect.objectContaining({
                       id: expect.not.stringContaining(lineItemAdjustment.id),

packages/core/core-flows/src/cart/workflows/add-shipping-method-to-cart.ts

@@ -132,7 +132,7 @@ export const addShippingMethodToCartWorkflow = createWorkflow(
       return cart.shipping_methods.map((sm) => sm.id)
     })
 
-    const [, shippingMethodsToAdd] = parallelize(
+    parallelize(
       removeShippingMethodFromCartStep({
         shipping_method_ids: currentShippingMethods,
       }),
@@ -148,7 +148,6 @@ export const addShippingMethodToCartWorkflow = createWorkflow(
     updateTaxLinesWorkflow.runAsStep({
       input: {
         cart_id: input.cart_id,
-        shipping_methods: shippingMethodsToAdd,
       },
     })
 

packages/core/core-flows/src/cart/workflows/add-to-cart.ts

@@ -133,7 +133,6 @@ export const addToCartWorkflow = createWorkflow(
     updateTaxLinesWorkflow.runAsStep({
       input: {
         cart_id: input.cart.id,
-        items,
       },
     })
 

packages/core/core-flows/src/cart/workflows/refresh-cart-items.ts

@@ -88,7 +88,7 @@ export const refreshCartItemsWorkflow = createWorkflow(
       return items
     })
 
-    const items = updateLineItemsStep({
+    updateLineItemsStep({
       id: cart.id,
       items: lineItems,
     })
@@ -103,7 +103,7 @@ export const refreshCartItemsWorkflow = createWorkflow(
     refreshCartShippingMethodsStep({ cart: refetchedCart })
 
     updateTaxLinesWorkflow.runAsStep({
-      input: { cart_id: cart.id, items },
+      input: { cart_id: cart.id },
     })
 
     const cartPromoCodes = transform({ cart, input }, ({ cart, input }) => {

packages/core/core-flows/src/cart/workflows/update-tax-lines.ts

@@ -86,9 +86,8 @@ export const updateTaxLinesWorkflow = createWorkflow(
     const taxLineItems = getItemTaxLinesStep(
       transform({ input, cart }, (data) => ({
         orderOrCart: data.cart,
-        items: data.input.items || data.cart.items,
-        shipping_methods:
-          data.input.shipping_methods || data.cart.shipping_methods,
+        items: data.cart.items,
+        shipping_methods: data.cart.shipping_methods,
         force_tax_calculation: data.input.force_tax_calculation,
       }))
     )