Use wasm-wasip2 target as default build target

[ifsheldon]

cargo-component/README.md

Line 184 in 1e58afa

When the Rust compiler supports a [_preview2_ version of the WASI target][1],

Hi! I saw this today, but the referred issue has been closed as complete. The latest cargo-component 0.19 still uses wasm-wasip1 as the default build target.

Rust in the latest stable 1.82 has promoted wasm-wasip2 as a tier-2 target, see rust-lang/rust#129997. I think it's time to change the README and the behavior of cargo-component?

[pchickey]

Related: #356

[sunfishcode]

Yes. The current situation is, the wasm32-wasip2 target does a lot of things automatically, which is great and makes it easy to drop into existing Rust development workflows. But, it also doesn't support all the features of cargo component. I looked into it briefly, and didn't see anything supporting import name maps. So there's more to figure out here before we can switch cargo component to using wasm32-wasip2 internally.

[sunfishcode]

I've also now posted #359 to update the README text quoted above.

[ifsheldon]

OK, thanks. I am not super familiar with cargo-component.

I think this issue can be turned into a tracker if you can list missing features on the wasm32-wasip2 target.