C# Markup + MVUX: More than one model named as <somethingModel> produces a source generator error.

[mcNets]

Testing C# Markup + MVUX, while trying to reproduce the Counter example, I encountered an error when adding the second partial record, the BindableViewModel is not accessible anymore. I tried this in two different projects.

Build started at 10:55...
1>------ Build started: Project: UnoMvux1, Configuration: Debug Any CPU ------
1>Skipping analyzers to speed up the build. You can execute 'Build' or 'Rebuild' command to run analyzers.
1>CSC : warning CS8785: Generator 'FeedsGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'ArgumentException' with message 'The hintName 'UnoMvux1.MachineModel.g.cs' of the added source file must be unique within a generator.
1>c:\Test\UnoMvux1\UnoMvux1\MainPage.cs(9,30,9,47): error CS0246: The type or namespace name 'BindableMainModel' could not be found (are you missing a using directive or an assembly reference?)
1>Done building project "UnoMvux1.csproj" -- FAILED.

MainPage

public sealed partial class MainPage : Page
{
    public MainPage()
    {
        this
            .Background(ThemeResource.Get<Brush>("ApplicationPageBackgroundThemeBrush"))
            .DataContext(new BindableMainModel(), (page, vm) => page
                .Content(new StackPanel()
                .VerticalAlignment(VerticalAlignment.Center)
                .HorizontalAlignment(HorizontalAlignment.Center)
                .Children(
                    new StackPanel()
                        .Orientation(Orientation.Vertical)
                        .Children(
                            new TextBlock()
                                .Text("Hello Uno Platform!")
                                .FontSize(24)
                                .Margin(10),

                            new Button()
                                .Content("Click me!")
                                .Margin(10)
                        )
                )));
    }
}

MainModel

internal partial record MainModel
{
    public IState<MachineModel> Machine => State.Value(this, () => new MachineModel("", ""));

    public ValueTask GetMachine() => Machine.UpdateAsync(m => m?.Load("100"));
}

MachineModel

internal partial record MachineModel(string Id, string Name)
{
    public MachineModel Load(string id)
    {
        return new MachineModel(id, $"Machine {id}");
    }
}

UnoMvux1.zip

[mcNets]

If I rename the machine model as internal partial record Machine(string Id, string Name) the error dissapear.

Having a look at binlog I found this warning (text could be innacurated, I translated it):

System.ArgumentException: The hintName item "OsmoUI.Models.MaquinaModel.g.cs" of the added source file must be unique within a generator. (Parameter 'hintName')
at Uno.Extensions.Reactive.Generator.FeedsGenerator.Execute(GeneratorExecutionContext context)
at Microsoft.CodeAnalysis.SourceGeneratorAdaptor.<Initialize>b__5_5(SourceProductionContext productionContext, GeneratorContextBuilder contextBuilder)
at Microsoft.CodeAnalysis.UserFunctionExtensions.<>c__DisplayClass3_0`2.<WrapUserAction>b__0(TInput1 input1, TInput2 input2, CancellationToken token)

[dr1rrb]

Humm on my side I'm not even able to compile the project until I rename the MachineModel to something else. The BindableMainModel is not being generated otherwise 🤔 (The generator probably crashing for the same reason as you).

So this confirms my hypothesis : we have a name conflict between your McahineModel and stuff generated for the public IState<MachineModel> Machine in the MainModel. And actually changing the MachineModel to be class instead of a record works ...

Will investigate it.

[dr1rrb]

Ok so:

1. As the type end by Model we are generating the BindableMachineModel (to be used as DataContext of a Page);
2. As the MachineModel is being used in a State<MachineModel> (in MainModel) and it is a record, we are generating a BindableMachineModel to support 2-way bindings on sub-properties. This one being designed to be used as a property of the BindableMainModel.

The issue is that both are being generated with file name MachineModel.g.cs AND they are not compatible!

WORKAROUND

As in this example we don't need the first kind of generation, on the MachineModel add the attribute [Uno.Extensions.Reactive.ReactiveBindable(false)]

Note: Changing the MachineModel to be a class instead of a record will disable second kind of generation, but it's not expected here.

[dr1rrb]

Created an issue to track that #2310

[sasakrsmanovic]

@agneszitte Do you think we can take a look at this please?

[dansiegel]

cc: @dr1rrb