AnimationPlayer: Call Method track, unable to select Object type in Args of AnimationTrackKeyEdit inspector

[krazzei]

Tested versions

• Reproducible in: 4.3.dev (4a01602), 4.2.1

System information

Godot v4.3.dev (4a01602) - Windows 10.0.22631 - Vulkan (Forward+) - dedicated AMD Radeon RX 7900 XTX (Advanced Micro Devices, Inc.; 31.0.24027.1012) - AMD Ryzen 9 7950X3D 16-Core Processor (32 Threads)

Issue description

When adding arguments to a method call on an AnimationPlayer track, you are unable to select Object from Nil. You can select other types from Nil and it works as expected. And converting from a non-Nil types to Object works.

I've found in editor/animation_track_editor.cpp on about line 217 is the start of the problem, we seem to be copying the original Variant (which is type Nil) in the code above. See the d_new variable. Then we pass the old variant (still Nil type) into the Variant::construct as a parameter. The crux of the problem is that Variant::construct doesn't set the type to Object in this case. Other cases seem to use the case below (line 219) with a nullptr argument, which calls a different construct that ends up calling a VariantDefaultInitializer for the desired type.

Steps to reproduce

extract the attached test.zip and open it with godot (4.3 dev)

• Open the scene "node_3d.tscn" if it isn't already
• Click on the AnimationPlayer in the scene
• Navigate to the Animation Editor (if it isn't already opened)
• Select the "new_animation" animation in the animation drop down (if not already selected)
• click on one of the spawnObject key frames (or create a new one and select it)
• In the Key Frame inspector increase arg count if it is 0
• Drop down the Args until you find an arg with with a nil type
• Try to select the Object type and notice that it remains Nil.

Minimal reproduction project (MRP)

test.zip