Custom trigger with other WASI worlds requires trait implementation for `spin_core::Data<T>`

[smndtrl]

Trying to create a custom trigger, I'm unsuccessful with linking a custom world during the configure_engine step requires me to implement my WasiCustomView for spin_core::Data<CustomRuntimeData>. Implementing WasiCustomView for CustomRuntimeData is not enough. Am I missing something obvious here?

I'm using v2.6.0, wasmtime 21 and wasi_custom_rs also uses 21 for bindgen.

let _ = builder.link_import(| l, _| {
            wasi_custom_rs::add_custom_to_linker(l);
});

the trait bound `spin_core::Data<CustomRuntimeData>: WasiCustomView` is not satisfied

[lann]

This is a limitation of spin-core's design; you can't implement traits on Store's root data type, so an add_to_linker function that requires that won't work.

The upcoming "Spin Factors" design should work for your specific scenario (though only incidentally; the custom interface itself couldn't be a factor).

[smndtrl]

My bad. I tried to copy the add_to_linker pattern from other libraries like wasmtime-wasi-http and wasmtime-wasi. I'll try to find another way then.