Extension classes cause exception when used from C#

[goncalo]

Calling methods on the physics server causes errors.

Example C# script:

public override void _Ready()
{
    var body = PhysicsServer3D.BodyCreate();
}

Error:

E 0:00:01:0088   ScriptManagerBridge.cs:263 @ System.Type Godot.Bridge.ScriptManagerBridge.<TypeGetProxyClass>g__GetTypeByGodotClassAttr|12_0(System.Reflection.Assembly , System.String ): System.NullReferenceException: Object reference not set to an instance of an object.
  <C# Error>     System.NullReferenceException
  <C# Source>    /root/godot/modules/mono/glue/GodotSharp/GodotSharp/Core/Bridge/ScriptManagerBridge.cs:263 @ System.Type Godot.Bridge.ScriptManagerBridge.<TypeGetProxyClass>g__GetTypeByGodotClassAttr|12_0(System.Reflection.Assembly , System.String )
  <Stack Trace>  ScriptManagerBridge.cs:263 @ System.Type Godot.Bridge.ScriptManagerBridge.<TypeGetProxyClass>g__GetTypeByGodotClassAttr|12_0(System.Reflection.Assembly , System.String )
                 ScriptManagerBridge.cs:257 @ System.Type Godot.Bridge.ScriptManagerBridge.TypeGetProxyClass(System.String )
                 ScriptManagerBridge.cs:101 @ IntPtr Godot.Bridge.ScriptManagerBridge.CreateManagedForGodotObjectBinding(Godot.NativeInterop.godot_string_name* , IntPtr )

[mihe]

Thank you for reporting this!

I'll admit I haven't been testing C# as much as I should have, since I figured things would just work as long as you don't need to interact with any new node types exposed from the extension.

This error seems to be a general problem with objects derived from other GDEXTENSION_CLASS objects, which includes not only PhysicsServer3D but also PhysicsDirectBodyState3D and PhysicsDirectSpaceState3D.

So simply doing this seems to make the C# scripting emit a bunch of errors as well:

public override void _IntegrateForces(PhysicsDirectBodyState3D state)
{
}

I'll look into this right away.

[mihe]

It looks like this is an issue within Godot's C# integration, and not something that I can fix from the extension side of things. The relevant issue seems to be godotengine/godot#74801. I made a PR that seems to fix the problem: godotengine/godot#75955.

[mihe]

The fix for this can be found in the newly released 0.4.0-rc1.

I would love it if everyone/anyone subscribed to this could give it a try and report back how it works for you.

[goncalo]

Seems to be working properly now.
Thank you!

[timshannon]

Same for me. Working great now.

[mihe]

Great to hear. Thank you both.

I'll publish 0.4.0-stable first thing tomorrow.