Keep the account's checkout attributes when merging a guest cart at login

src/Business/Grand.Business.Checkout/Services/Orders/ShoppingCartService.cs

@@ -392,7 +392,9 @@ public virtual async Task DeleteShoppingCartItem(Customer customer, ShoppingCart
     /// </summary>
     /// <param name="fromCustomer">From customer</param>
     /// <param name="toCustomer">To customer</param>
-    /// <param name="storeId">Store whose selected checkout attributes move along</param>
+    /// <param name="storeId">
+    ///     Store whose selected checkout attributes move along, when the source customer has selected any there
+    /// </param>
     /// <param name="includeCouponCodes">
     ///     A value indicating whether to coupon codes (discount and gift voucher) should be also
     ///     re-applied
@@ -440,10 +442,13 @@ await AddToCart(toCustomer, sci.ProductId, sci.ShoppingCartTypeId, sci.StoreId,
             await _customerService.UpdateUserField(toCustomer, SystemCustomerFieldNames.GiftVoucherCoupons, resultGift);
         }
 
-        //move selected checkout attributes
+        //move selected checkout attributes; the source customer's selection is the most recent one,
+        //but when it has none, the target keeps its own, so logging in from a fresh browser
+        //does not clear a choice saved on the account
         var checkoutAttributes = fromCustomer.GetUserFieldFromEntity<List<CustomAttribute>>(SystemCustomerFieldNames.CheckoutAttributes, storeId);
-        await _customerService.UpdateUserField(toCustomer, SystemCustomerFieldNames.CheckoutAttributes, checkoutAttributes,
-            storeId);
+        if (checkoutAttributes is { Count: > 0 })
+            await _customerService.UpdateUserField(toCustomer, SystemCustomerFieldNames.CheckoutAttributes, checkoutAttributes,
+                storeId);
     }
 
     #endregion

src/Tests/Grand.Business.Checkout.Tests/Services/Orders/ShoppingCartServiceTests.cs

@@ -11,9 +11,11 @@
 using Grand.Domain.Stores;
 using Grand.Domain.Tax;
 using Grand.Infrastructure;
+using Grand.Infrastructure.TypeConverters;
 using Grand.Mediator;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Moq;
+using System.ComponentModel;
 
 namespace Grand.Business.Checkout.Tests.Services.Orders;
 
@@ -27,6 +29,13 @@ public class ShoppingCartServiceTests
     private ShoppingCartSettings _shoppingCartSettings;
     private Mock<IShoppingCartValidator> _shoppingCartValidatorMock;
 
+    [ClassInitialize]
+    public static void InitClass(TestContext context)
+    {
+        //user fields are stored as strings; the converters read them back as typed values
+        new WebTypeConverter().Register();
+    }
+
     [TestInitialize]
     public void Init()
     {
@@ -283,13 +292,76 @@ public async Task MigrateShoppingCart_MovesCheckoutAttributesOfTheGivenStore()
     {
         //Arrange
         var fromCustomer = new Customer();
+        AddCheckoutAttributes(fromCustomer, "store-b", "gift-wrapping", "yes");
         var toCustomer = new Customer();
 
         //Act
         await _shoppingCartService.MigrateShoppingCart(fromCustomer, toCustomer, "store-b", false);
 
         //Assert
         _customerServiceMock.Verify(x => x.UpdateUserField(toCustomer, SystemCustomerFieldNames.CheckoutAttributes,
-            It.IsAny<List<CustomAttribute>>(), "store-b"), Times.Once);
+            It.Is<List<CustomAttribute>>(a => a.Count == 1 && a[0].Key == "gift-wrapping" && a[0].Value == "yes"),
+            "store-b"), Times.Once);
+    }
+
+    [TestMethod]
+    public async Task MigrateShoppingCart_GuestWithoutCheckoutAttributes_KeepsTheAccountAttributes()
+    {
+        //Arrange
+        var guest = new Customer();
+        var customer = new Customer();
+        AddCheckoutAttributes(customer, "store", "gift-wrapping", "yes");
+
+        //Act
+        await _shoppingCartService.MigrateShoppingCart(guest, customer, "store", false);
+
+        //Assert
+        _customerServiceMock.Verify(x => x.UpdateUserField(It.IsAny<Customer>(),
+            SystemCustomerFieldNames.CheckoutAttributes, It.IsAny<List<CustomAttribute>>(), It.IsAny<string>()),
+            Times.Never);
+    }
+
+    [TestMethod]
+    public async Task MigrateShoppingCart_GuestWithCheckoutAttributes_ReplacesTheAccountAttributes()
+    {
+        //Arrange
+        var guest = new Customer();
+        AddCheckoutAttributes(guest, "store", "gift-wrapping", "no");
+        var customer = new Customer();
+        AddCheckoutAttributes(customer, "store", "gift-wrapping", "yes");
+
+        //Act
+        await _shoppingCartService.MigrateShoppingCart(guest, customer, "store", false);
+
+        //Assert
+        _customerServiceMock.Verify(x => x.UpdateUserField(customer, SystemCustomerFieldNames.CheckoutAttributes,
+            It.Is<List<CustomAttribute>>(a => a.Count == 1 && a[0].Value == "no"), "store"), Times.Once);
+    }
+
+    [TestMethod]
+    public async Task MigrateShoppingCart_AccountWithAttributesInAnotherStore_TakesTheGuestAttributes()
+    {
+        //Arrange
+        var guest = new Customer();
+        AddCheckoutAttributes(guest, "store-b", "gift-wrapping", "yes");
+        var customer = new Customer();
+        AddCheckoutAttributes(customer, "store-a", "gift-wrapping", "no");
+
+        //Act
+        await _shoppingCartService.MigrateShoppingCart(guest, customer, "store-b", false);
+
+        //Assert
+        _customerServiceMock.Verify(x => x.UpdateUserField(customer, SystemCustomerFieldNames.CheckoutAttributes,
+            It.Is<List<CustomAttribute>>(a => a.Count == 1 && a[0].Value == "yes"), "store-b"), Times.Once);
+    }
+
+    private static void AddCheckoutAttributes(Customer customer, string storeId, string key, string value)
+    {
+        customer.UserFields.Add(new UserField {
+            Key = SystemCustomerFieldNames.CheckoutAttributes,
+            Value = TypeDescriptor.GetConverter(typeof(List<CustomAttribute>))
+                .ConvertToInvariantString(new List<CustomAttribute> { new() { Key = key, Value = value } }),
+            StoreId = storeId
+        });
     }
 }