wasip2 / wit-bindgen: restore older versions compatible with rustc 1.81

[justin-robinson]

Summary

All published versions of wasip2 (and its wit-bindgen dependency) require rustc 1.82+, but we're on rustc 1.81.0. The oldest version on crates.io (1.0.0+wasi-0.2.4) is only a few months old, while the project is much older, suggesting older versions compatible with rustc 1.81 were removed.

Error

error: rustc 1.81.0 is not supported by the following packages:
  wasip2@1.0.0+wasi-0.2.4 requires rustc 1.82.0
  wit-bindgen@0.45.1 requires rustc 1.82.0
  ...
Either upgrade rustc or select compatible dependency versions with
`cargo update <name>@<current-ver> --precise <compatible-ver>`
where `<compatible-ver>` is the latest version supporting rustc 1.81.0

Pinning wasip2 to an older version doesn't work: there is no published version of wasip2 that supports rustc 1.81 (only three versions exist on crates.io, all requiring ≥1.82).

Request

Please restore older versions of wasip2 that are compatible with rustc 1.81.0, or publish a new version that supports rustc 1.81.0.

Context

wasip2 is a transitive dependency in our project (via getrandom → rand_core → rand → ulid → common crates). We cannot upgrade to rustc 1.82+ immediately, so we need versions compatible with rustc 1.81.

[pchickey]

The oldest version on crates.io (1.0.0+wasi-0.2.4) is only a few months old, while the project is much older, suggesting older versions compatible with rustc 1.81 were removed.

What you're seeing here is that the wasip2 crate name was recently introduced as part of an effort to also introduce wasip3 on a separate crate versioning track.

Prior to introducing the wasip2 crate name, the project published the wasip2 bindings under the crate name wasi, with version metadata indicating what preview release of the wasi interfaces the bindings are for - anything with +wasi-0.2.x suffix is p2 bindings.

I just went backwards through the wasi crate's version history and https://crates.io/crates/wasi/0.13.3+wasi-0.2.2 is the most recent version that succeeds with cargo +1.81 check.

[alexcrichton]

I'm not opposed myself to taking a relatively conservative MSRV for this crate, although that will transitively apply to the wit-bindgen crate itself. Would you, or others, be willing to help reduce the MSRV of wit-bindgen, and then subsequently lower it here too?