GDScript function isn't called from C# when parameter types don't match

[DragonAxe]

Godot version

v4.1.2.stable.mono.official [399c9dc]

System information

Godot v4.1.2.stable.mono - Manjaro Linux #1 SMP PREEMPT Sat Sep 23 10:10:02 UTC 2023 - Wayland - Vulkan (Forward+) - integrated Intel(R) UHD Graphics 620 (KBL GT2) () - Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz (8 Threads)

Issue description

When calling a GDScript function from C# (using the .Call function), if the type of a given parameter doesn't match the GDScript type annotation, then the GDScript function is never called and no errors or warnings are given. Not having a runtime error/warning makes it difficult to track down bugs caused by mismatched types across the GDScript/C# boundary.

Update: Just tested by calling a GDScript function that doesn't exist (e.g. .Call("non_existent_function")), and the behavior is identical to calling a function with miss-matched parameter types, i.e. no error or warning is given.

Steps to reproduce

Here is an example:

Create a new C# project.
Create a new Node2D scene.
Attach a new C# script to the Node2D with the following contents (let's call it Main.cs):

using Godot;
public partial class Main : Node2D
{
    public override void _Ready()
    {
        GD.Print("Before GDScript call.");
        GetNode("/root/Singleton").Call("gdscript_function", <<PLACE VALUE HERE>>);
    }
}

Create singleton.gd with the following contents and add it to the list of project autoloads:

extends Node
func gdscript_function(player_name: String):
    print("Hello world says " + player_name + "!")

If <<PLACE VALUE HERE>> is the string "Bill", the output is as expected:

Before GDScript call.
Hello world says Bill!

If <<PLACE VALUE HERE>> is not a string, 1234, the output is not as expected:

Before GDScript call.

Expected output:

Before GDScript call.
Error: Function `gdscript_function` was given a value of type `int`, but `String` was expected.

Everything works as expected if I modify singleton.gd to remove the type annotation (and cast player_name to a string to avoid Invalid operands 'String' and 'int' in operator '+'.):

extends Node
func gdscript_function(player_name):
    print("Hello world says " + str(player_name) + "!")

Minimal reproduction project

godot_project.zip

[raulsntos]

I think this was fixed by #79249. Can you try reproducing in Godot 4.2 beta 2?

[DragonAxe]

Fixed in Godot 4.2 beta 2!

Thank you @raulsntos for finding the associated commit!