Public method overriden in internal class: call from JS error

[ezolotko]

The code below produces Microsoft.ClearScript.ScriptEngineException: 'TypeError: myobj.MyMethod() is not a function', while the MyMethod method is public and is defined in a public class.

    public abstract class MyBase
    {
        public abstract void MyMethod();
    }
    internal class MyDerived : MyBase
    {
        public override void MyMethod()
        {
            Console.WriteLine("MyMethod");
        }
    }

    var engine = new V8ScriptEngine();
    var myobj = new MyDerived();

    myobj.MyMethod();

    engine.AddHostObject("myobj", myobj);

    // Microsoft.ClearScript.ScriptEngineException: 'TypeError: myobj.MyMethod() is not a function'
    engine.Execute("myobj.MyMethod();");

If I change internal class MyDerived to public, the method is called as expected. Here is a project that reproduces the problem:
ClearScriptTypeError.zip
It also includes the WpfTest() method, which reproduces what seems to be the same problem, but with a real-world class from WPF (System.Windows.Media.VisualDrawingContext). This is how we encountered this issue in the first place.

[ClearScriptLib]

Hi @ezolotko,

This looks like a bug. Here's a workaround. Instead of this:

engine.AddHostObject("myobj", myobj);

do this:

engine.AddRestrictedHostObject<MyBase>("myobj", myobj);

Thank you!

[ezolotko]

@ClearScriptLib Thank you for your reply.

We are experiencing this issue in a scenario like this:

            var engine = new V8ScriptEngine();
            engine.Execute("function f(o) { o.MyMethod(); }");
            engine.Invoke("f", new MyDerived());

As I understand, the workaround with AddRestrictedHostObject is not applicable here. Do you have any advice on this scenario?
Thank you.

[ClearScriptLib]

Hi @ezolotko,

You can do this:

var host = engine.Script.host = new HostFunctions();
engine.Invoke("f", host.cast<MyBase>(new MyDerived()));

Cheers!

[ezolotko]

@ClearScriptLib the workaround works, thank you very much!

[ClearScriptLib]

@ezolotko Thanks for reporting this issue. The next release will include a fix as well as an easier way to pass a type-bound ("restricted") object to script code.

[ClearScriptLib]

ClearScript 5.6 includes a fix for this issue.