Custom extensions_api.json - Returned enum missing class identifier

[Hestia-SGG]

Godot version

v4.5.1.stable.official [f62fdbde1]

godot-cpp version

4.5 (e83fd09)

System information

Windows 10, x86-64, AMD Ryzen 9 5900HX, NVidia GeForce RTX 3070

Issue description

When creating a custom extensions_api.json bindings to include information from the GodotSteam GDExtension, my custom GDExtension creates the C++ header and source files, but any time an enum is returned that is specific to the Steam class, it doesn't have Steam:: in front of it. For example, the return for Steam::getConnectedUniverse method was just Universe instead of Steam::Universe in the steam.cpp file.

Steps to reproduce

From scratch instructions:

• Create an empty project in Godot 4.5.1
• Download GodotSteam GDExtension 4.4+ from the Asset Store
• Close the Godot Editor
• Navigate to the project folder
• Run godot --headless --dump-extension-api to generate the extension_api.json file (saved as steam_extension_api.json)
• Copy this to a blank GDExtension C++ Template project
• Build using scons platform=windows custom_api_file=steam_extension_api.json
• Error as the generated steam.cpp file uses enums without the class identifier

Using minimal reproduction project:

• Navigate to the demo subfolder
• Run godot --headless --dump-extension-api to generate the extension_api.json file (saved as steam_extension_api.json)
• Build using scons platform=windows custom_api_file=steam_extension_api.json

Minimal reproduction project

I have created a copy of my custom GDExtension with all code removed, and the demo project stripped to bare minimum. It includes the download of GodotSteam from the Asset Library at the time of this issue.

godotsteam_extension_enum_project.zip

[Yarwin]

There is a fix for that on godot-steam side: https://codeberg.org/godotsteam/godotsteam/pulls/863. On users side – I think we should check if it can be solved by patching extension_api.json.

---

tl;dr – godot steam has bunch of enums which it registers as enums of Steam class. All good. Unfortunately internally it specifies their type info (via VARIANT_ENUM_CAST) as they would be global enums (which is false) and it leads to mismatch.

The problem is how VARIANT_ENUM_CAST is being used by godot-steam: https://codeberg.org/godotsteam/godotsteam/src/branch/godot4/godotsteam.h#L1255.

You can find some examples here:

godot-cpp/test/src/example.h

Line 223 in 9ae37ac

VARIANT_ENUM_CAST(Example::Constants);

VARIANT_ENUM_CAST is template used to create GetTypeInfo which contains name and whatnot. Currently Godot allows only to register class-specific constants: https://github.com/godotengine/godot/blob/65e73b3a5eec19e3269809b0f00e73a646723067/core/extension/gdextension_interface.json#L8600. I'll underline – there is no API which would allow to register global constant via GDExtension. if I'm not mistaken godot-cpp uses VARIANT_ENUM_CAST to generate bindings and whatnot, and obviously godot uses global enums.

---

Note - I copy paste my comment because this issue surfaced in godot-rust as well. No, I don't use LLMs, I'm just autistic.

[Gramps]

That PR is now merged in and will be live in v4.18 on our side!