Make wasm-wave support no_std

[wilfreddenton]

• Imports String, Vec, etc. from core and alloc instead of std.
• Removes indexmap dep in favor of alloc::collections::BTreeMap
• std::collections::HashMap is replaced with alloc::collections::BTreeMap
• ui test is conditioned on wit feature
• added std feature and included it in default list

Crate tests pass for me locally for both:

cargo test --no-default-features

and

cargo test

#2399

[alexcrichton]

Oh, also, mind adding checks to CI that this builds with various combinations of features? We do similar for other crates in .github/workflows/main.yml

[wilfreddenton]

Addressing the remaining CI failures:

One of the jobs is failing on:

 --> crates/wasm-wave/src/parser.rs:3:12
  |
3 | use core::{error::Error, fmt::Display};
  |            ^^^^^^^^^^^^
  |
  = note: see issue #103765 <https://github.com/rust-lang/rust/issues/103765> for more information

core::error::Error was stabilized in 1.81.0 but the job is using 1.76.0. Can this version be updated?

The other job is failing on the wit-dylib tests/all.rs. After installing the wasi-sdk and the wasmtime cli I am able to run

cargo test --locked --all

successfully locally so I am unable to reproduce this.

[alexcrichton]

Ah the msrv policy of this workspace is here, and it looks like 1.81 is now possible too so I've sent #2402 to update the msrv.

The other job is failing on the wit-dylib

I'll look into that, I agree it's probably unrelated to this PR

[alexcrichton]

Ok #2402 should address the CI issues here. Once that is merged if you can rebase on top of that I think that'll have everything "just work"

[lann]

This is a (small) functional change, switching the ordering of serialized flags from definition-ordered to lexicographical. I don't see this behavior documented anywhere so its probably fine. Clearly it wasn't important enough to me to assert it in a test case. 😅