cart: update CartDefaultBehaviour to return real clones (#323)

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Changelog
 ## v3.5.0 [upcoming]
 **cart**
+* Add convenience function to clone carts
+* DefaultCartBehaviour now returns real cart clones to prevent data races on cart fields 
 * API
   * **Breaking**: Update `DELETE /api/v1/cart` to actually clean the whole cart not only removing the cart items (introduces new route for the previous behaviour, see below)
   * Add new endpoint `DELETE /api/v1/cart/deliveries/items` to be able to remove all cart items from all deliveries but keeping delivery info and other cart data untouched

cart/application/cartService.go

@@ -1253,5 +1253,6 @@ func (cs *CartService) UpdateDeliveryAdditionalData(ctx context.Context, session
 		return nil, err
 	}
 
-	return cart, nil
+	cart, _, err = cs.cartReceiverService.GetCart(ctx, session)
+	return cart, err
 }

cart/application/cartService_test.go

@@ -1002,6 +1002,7 @@ func TestCartService_CartInEvent(t *testing.T) {
 func createCartServiceWithDependencies() *cartApplication.CartService {
 	eventRouter := new(MockEventRouter)
 	eventRouter.On("Dispatch", mock.Anything, mock.Anything, mock.Anything).Return()
+	cartCache := new(MockCartCache)
 
 	crs := &cartApplication.CartReceiverService{}
 	crs.Inject(new(MockGuestCartServiceWithModifyBehaviour),
@@ -1021,7 +1022,7 @@ func createCartServiceWithDependencies() *cartApplication.CartService {
 		&struct {
 			CartCache cartApplication.CartCache `inject:",optional"`
 		}{
-			CartCache: new(MockCartCache),
+			CartCache: cartCache,
 		})
 
 	cs := &cartApplication.CartService{}
@@ -1049,7 +1050,14 @@ func createCartServiceWithDependencies() *cartApplication.CartService {
 			DefaultDeliveryCode: "default_delivery_code",
 			DeleteEmptyDelivery: false,
 		},
-		nil,
+		&struct {
+			CartValidator     validation.Validator      `inject:",optional"`
+			ItemValidator     validation.ItemValidator  `inject:",optional"`
+			CartCache         cartApplication.CartCache `inject:",optional"`
+			PlaceOrderService placeorder.Service        `inject:",optional"`
+		}{
+			CartCache: cartCache,
+		},
 	)
 	return cs
 }

cart/domain/cart/cart.go

@@ -1,6 +1,7 @@
 package cart
 
 import (
+	"bytes"
 	"encoding/gob"
 	"fmt"
 	"math/big"
@@ -174,6 +175,23 @@ func (c Cart) GetMainShippingEMail() string {
 	return ""
 }
 
+// Clone the current cart
+func (c Cart) Clone() (Cart, error) {
+	cloned := Cart{}
+
+	b := new(bytes.Buffer)
+	err := gob.NewEncoder(b).Encode(c)
+	if err != nil {
+		return Cart{}, err
+	}
+	err = gob.NewDecoder(b).Decode(&cloned)
+	if err != nil {
+		return Cart{}, err
+	}
+
+	return cloned, nil
+}
+
 // GetContactMail returns the contact mail from the shipping address with fall back to the billing address
 func (c Cart) GetContactMail() string {
 	// Get Email from either the cart

cart/domain/cart/cart_test.go

@@ -1,19 +1,104 @@
 package cart_test
 
 import (
+	"encoding/json"
 	"math/big"
+	"reflect"
 	"testing"
 
-	"flamingo.me/flamingo-commerce/v3/cart/domain/testutils"
-
 	"flamingo.me/flamingo-commerce/v3/cart/domain/placeorder"
+	"flamingo.me/flamingo-commerce/v3/cart/domain/testutils"
+	"github.com/stretchr/testify/require"
 
 	"github.com/stretchr/testify/assert"
 
 	cartDomain "flamingo.me/flamingo-commerce/v3/cart/domain/cart"
 	"flamingo.me/flamingo-commerce/v3/price/domain"
 )
 
+func assertDeepClone(t testing.TB, orig, cloned reflect.Value) {
+	t.Helper()
+	require.Equal(t, orig.Type(), cloned.Type())
+	switch orig.Kind() {
+	case reflect.Struct:
+		for i := 0; i < orig.NumField(); i++ {
+			assertDeepClone(t, orig.Field(i), cloned.Field(i))
+		}
+	case reflect.Slice, reflect.Array:
+		if orig.IsNil() {
+			return
+		}
+		assert.NotEqual(t, orig.Pointer(), cloned.Pointer())
+		for i := 0; i < orig.Len(); i++ {
+			assertDeepClone(t, orig.Index(i), cloned.Index(i))
+		}
+	case reflect.Map:
+		if orig.IsNil() {
+			return
+		}
+		assert.NotEqual(t, orig.Pointer(), cloned.Pointer())
+		iter := orig.MapRange()
+		for iter.Next() {
+			assertDeepClone(t, iter.Value(), cloned.MapIndex(iter.Key()))
+		}
+	case reflect.Ptr:
+		if orig.IsNil() {
+			return
+		}
+		assert.NotEqual(t, orig.Pointer(), cloned.Pointer())
+		assertDeepClone(t, orig.Elem(), cloned.Elem())
+	default:
+	}
+
+}
+
+func TestCart_Clone(t *testing.T) {
+	t.Parallel()
+	cart := cartDomain.Cart{
+		ID:             "original",
+		BillingAddress: &cartDomain.Address{},
+		Purchaser: &cartDomain.Person{
+			Address:              &cartDomain.Address{},
+			PersonalDetails:      cartDomain.PersonalDetails{},
+			ExistingCustomerData: &cartDomain.ExistingCustomerData{ID: "1"},
+		},
+		Deliveries: []cartDomain.Delivery{
+			{
+				DeliveryInfo: cartDomain.DeliveryInfo{
+					Code: "code",
+					DeliveryLocation: cartDomain.DeliveryLocation{
+						Address:           &cartDomain.Address{},
+						UseBillingAddress: false,
+						Code:              "",
+					},
+					AdditionalData:          map[string]string{"hello": "you"},
+					AdditionalDeliveryInfos: map[string]json.RawMessage{"foo": json.RawMessage("test")},
+				},
+				Cartitems: []cartDomain.Item{
+					{
+						AdditionalData: map[string]string{"hello": "you"},
+					},
+				},
+				ShippingItem: cartDomain.ShippingItem{
+					Title: "",
+				},
+			},
+		},
+		AdditionalData: cartDomain.AdditionalData{CustomAttributes: map[string]string{"hello": "you"}},
+	}
+
+	cloned, err := cart.Clone()
+	require.NoError(t, err)
+
+	assert.True(t, reflect.DeepEqual(cart, cloned), "cloned cart should have same values")
+
+	assertDeepClone(t, reflect.ValueOf(cart), reflect.ValueOf(cloned))
+
+	// some alibi changes to check that it is really a clone
+	cloned.AdditionalData.CustomAttributes["hello"] = "bar"
+	assert.Equal(t, "you", cart.AdditionalData.CustomAttributes["hello"])
+}
+
 func TestCart_GetMainShippingEMail(t *testing.T) {
 	t.Parallel()