DeleteSelfChild - Parent is null after updating from 8.2.9 to 9.1.0

[ajohnstone-ks]

We're trying to update from Csla 8.2.9 to 9.1.0, and immediately hit an issue in a DeleteSelfChild method; we're trying to use the Parent property to get to the root object to get its Id, but it seems like this is null now. Was this intentional or is it a bug? If its intentional, what would be the proposed workaround? I'd rather not have to add an id property to every child instance and keep it in sync with the parent.

[StefanOssendorf]

Hi. That's a bug. The for deletion marked child should still know it's parent.
I can reproduce this issue with this code:

using Csla;
using Csla.Configuration;
using Csla.Serialization;
using Microsoft.Extensions.DependencyInjection;

using var sp = new ServiceCollection()
    .AddCsla()
    .BuildServiceProvider();

var rootPortal = sp.GetRequiredService<IDataPortal<Root>>();

var root = await rootPortal.FetchAsync();
//root.Delete();

root.Childs.RemoveAt(0);

//var formatter = SerializationFormatterFactory.GetFormatter(sp.GetRequiredService<ApplicationContext>()); // CSLA 8.X
var formatter = sp.GetRequiredService<ISerializationFormatter>(); // CSLA 9.x+

var data = formatter.Serialize(root);

var deserialized = formatter.Deserialize(data);

_ = deserialized; // here the child in the Childs.DeletedList should still have it's parent set

[CslaImplementProperties, Serializable]
public partial class Root : BusinessBase<Root> {
    public partial Guid Id { get; set; }
    public partial FooChilds Childs { get; set; }

    [Fetch]
    private async Task Fetch([Inject] IChildDataPortal<FooChilds> fooPortal) {
        Id = Guid.NewGuid();
        Childs = await fooPortal.FetchChildAsync();
    }

    [Update]
    [DeleteSelf]
    private async Task DeleteSelf() {
        await FieldManager.UpdateAllChildrenAsync();
    }
}


[Serializable]
public partial class FooChilds : BusinessListBase<FooChilds, FooChild> {
    [FetchChild]
    private async Task FetchChild([Inject] IChildDataPortal<FooChild> fooPortal) {
        for (int i = 0; i < 3; i++) {
            Add(await fooPortal.FetchChildAsync());
        }
    }
}

[CslaImplementProperties, Serializable]
public partial class FooChild : BusinessBase<FooChild> {
    public partial Guid? Id { get; set; }

    [FetchChild]
    private void CreateChild() {
        Id = Guid.NewGuid();
    }

    [DeleteSelfChild]
    private void DeleteSelfChild() {
        Id = null;
    }

    [UpdateChild]
    private void UpdateChild() {
        _ = this;
    }
}

[StefanOssendorf]

Created a bug out of this discussion: #4761

[ajohnstone-ks]

TY!