Prebuilt gdext binaries for godot are missing and wasm32/linux32 bit ones fail

[Ughuuu]

When building for regular targets for godot-4-5, there are no prebuilt binaries for web and other common targets. Also, when using GODOT4_BIN, linux32 and web (wasm32) builds fail (at least for my use case it seems). I'm getting the following error when doing so:

error[E0080]: attempt to compute `16_usize - 24_usize`, which would overflow
 --> /home/runner/work/godot-rapier-physics/godot-rapier-physics/target/i686-unknown-linux-gnu/release/build/godot-ffi-b20c06a89280b89c/out/gdextension_interface.rs:3:4336
  |
3 | ...lign_t"] [:: std :: mem :: size_of :: < max_align_t > () - 24usize] ; ["Alignment of max_align_t"] [:: std :: mem :: align_of :: < max...
  |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `gen::gdextension_interface::_` failed here

For now, I disabled linux32 and wasm32 builds. Repo I use for builds (I commented out the wasm32 and linux32 bit) is here: https://github.com/appsinacup/godot-rapier-physics

[Ughuuu]

Equivalent issue on godot-rapier repo appsinacup/godot-rapier-physics#388

[PgBiel]

Seems related: #1275

• Fix godot4-prebuilt templates assuming 64-bit architecture (instead of wasm 32-bit) leading to failing struct size assertions

There aren't wasm unit tests running on CI yet; my initial attempt has failed on prebuilt because struct size assertions are failing, since they all assume 64 bit. But it didn't seem to become a hard error outside of debug assertions until (perhaps) now.

[Bromeon]

Wasm makes total sense, but why Linux 32?

[PgBiel]

In that case I think it's just for completeness, but for practical usage, besides for testing 32-bit support outside of a Wasm environment (which might be useful), I suppose it might be desirable to build certain games to run in certain older 32-bit architectures. Notably, I think Steam has a 32-bit runtime on Linux to support older games. (I've read this but couldn't confirm the details or an official source)

But that's all I can think of. I guess it's worth it when considering that gdext is more of a library, when compared to e.g. binaries.

[Bromeon]

The thing is, there's a cost to supporting prebuilt targets, and we're also limited by GitHub runners. For example, macOS Intel is already being phased out.

So I'd rather focus on very common ones. It's not like the others are unsupported, but the bindgen step would need api-custom feature + LLVM toolchain.

[PgBiel]

I think supporting Wasm will already be great, and we could look into Linux 32-bit in the future if there is a good enough reason for it. (I myself fail to make a case for it as I don't use it...)

[Ughuuu]

Yeah, true, linux 32 bit I could live without. I just had it because godot also had that target. I just reported it as both were failing on my ci/cd.