[.Net] `Handle is not initialized.` when assigning `TweenMethod` to a later-disposed `Tween`

[Delsin-Yu]

Tested versions

v4.3.stable.mono.official [77dcf97]

System information

Godot v4.3.stable.mono - Windows 10.0.19044 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 4060 Ti (NVIDIA; 32.0.15.6603) - AMD Ryzen 9 5900X 12-Core Processor (24 Threads)

Issue description

Assigning TweenMethod to a Tween that will be disposed later will result in the following counterintuitive error.

ERROR: System.InvalidOperationException: Handle is not initialized.
   at System.Runtime.InteropServices.GCHandle.FromIntPtr(IntPtr value)
   at Godot.Bridge.ScriptManagerBridge.SetGodotObjectPtr(IntPtr gcHandlePtr, IntPtr newPtr) in /root/godot/modules/mono/glue/GodotSharp/GodotSharp/Core/Bridge/ScriptManagerBridge.cs:line 295
   at: void Godot.NativeInterop.ExceptionUtils.LogException(System.Exception) (/root/godot/modules/mono/glue/GodotSharp/GodotSharp/Core/NativeInterop/ExceptionUtils.cs:113)

Steps to reproduce

Run the following code:

using Godot;

public partial class Main : Node
{
    public override void _Process(double delta)
    {
        for (var i = 0; i < 1000; i++)
        {
            var node = new Node2D();
            using var tween = node.CreateTween();
            tween.TweenMethod(
                new(node, CanvasItem.MethodName.SetModulate),
                Colors.Black,
                Colors.White,
                0.1f
            );
            AddChild(node);
        }
    }
}

Please note that removing the using keyword stops the issue from happening.

Minimal reproduction project (MRP)

Mrp_HandleNotInitialized.zip

[zaevi]

More simplified reproduction:

public override void _Process(double delta)
{
	var tree = GetTree();
	for (var i = 0; i < 1000; i++)
	{
		using var timer = tree.CreateTimer(0.1f);
		timer.Timeout += () => { };
	}
}

[Delsin-Yu]

This may boil down to a Callable behavior issue on disposed nodes.

1. Should connected C# Callables stop working after disposing the node?
2. Should non-C# related Callables stop working after disposing of the node, only because they are connected in C#?

Anyway, if things stop working after disposing the node, we should have a more intuitive error message to warn the user.

[zaevi]

I narrowed down the troubleshooting to disposing RefCounted.

It seems that when disposing RefCounted that holds more than 1 ref-count, it doesn't untie the instance binding correctly:

public override void _Ready()
{
	var rc = new RefCounted();
	rc.Reference();

	var id = rc.GetInstanceId();
	rc.Dispose();

	var rc2 = InstanceFromId(id) as RefCounted;

	// rc2.GetReferenceCount(); // ObjectDisposedException
	Debug.Assert(ReferenceEquals(rc, rc2) == false); // Fail
}