Should the context be inside an Option and then expect() in the WASI traits, or is the default context fine?

For ResourceTable I think it's ok to leave it there on-by-default, but for wasmtime_wasi::p2::WasiCtx yeah let's have that be an option which panics if it's not set.

How to specify your own context, perhaps wasmtime_context_set_wasi_p2()?

Right now wasi.h is a binding to the wasip1 builder API, and I think we'll want a new API for the wasip2 builder API (e.g. bindings for wasmtime_wasi::p2::WasiCtx::builder). Once that structure is built yeah a new API of wasmtime_context_set_wasi_p2 would take the builder and then insert it into the store. Then afterwards the Option in the store would be Some and everything should work.

On resources, I think I'm getting stuck on ResourceTypeKind::Host using TypeId.

This has tripped me up in the past as well, I think it might be reasonable to add ResourceTypeKind::HostId(u64) where the host just provides a 64-bit integer. That could be added for the C API and that way the C API could take integers to differentiate resource types?

we'll want a new API for the wasip2 builder API (e.g. bindings for wasmtime_wasi::p2::WasiCtx::builder)

Where should I place this? Maybe include/wasmtime/wasi/p2.h? Or should I place it next to the include/wasi.h, i.e. include/wasi_p2.h?

And how should the naming convention be? Similar to how it is in wasi.h, e.g. wasi_p2_config_inherit_stdout(), or something more similar to the rust side, maybe wasmtime_wasi_p2_builder_inherit_stdout()?

I think it might be reasonable to add ResourceTypeKind::HostId(u64) where the host just provides a 64-bit integer. That could be added for the C API and that way the C API could take integers to differentiate resource types?

Seems like a nice solution, I think I'll try that in a next PR?

I've long wanted to move wasi.h and scope it under the "wasmtime" namespace. Additionally we try to consider "wasipN" a unit as oppose to "wasi pN", so how about include/wasmtime/wasip2.h and wasmtime_wasip2_config_*?

Does that look correct?

I've long wanted to move wasi.h and scope it under the "wasmtime" namespace

Should I do that also here? Would that include adding wasmtime_wasip1_ prefix to everything?