wasmtime-wasi fails to compile on latest nightly

[aumetra]

Test Case

Steps to Reproduce

• Install latest rustc version (rustc 1.86.0-nightly (f027438f8 2025-02-03))
• Create new cargo project
• Add wasmtime-wasi dependency
• Try to compile

Expected Results

The program compiles without issues

Actual Results

error[E0080]: evaluation of constant value failed
   --> /home/aumetra/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/wasmtime-wasi-29.0.1/src/bindings.rs:147:9
    |
147 | /         wasmtime::component::bindgen!({
148 | |             path: "wit",
149 | |             world: "wasi:cli/command",
150 | |             tracing: true,
...   |
180 | |             require_store_data_send: true,
181 | |         });
    | |__________^ the evaluated program panicked at 'assertion failed: 1 == <DirectoryEntry as wasmtime::component::ComponentType>::ALIGN32', /home/aumetra/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/wasmtime-wasi-29.0.1/src/bindings.rs:147:9
    |
    = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0080]: evaluation of constant value failed
   --> /home/aumetra/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/wasmtime-wasi-29.0.1/src/bindings.rs:327:5
    |
327 | /     wasmtime::component::bindgen!({
328 | |         path: "wit",
329 | |         world: "wasi:cli/command",
330 | |         tracing: true,
...   |
416 | |         },
417 | |     });
    | |______^ the evaluated program panicked at 'assertion failed: 1 == <DirectoryEntry as wasmtime::component::ComponentType>::ALIGN32', /home/aumetra/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/wasmtime-wasi-29.0.1/src/bindings.rs:327:5

Versions and Environment

Wasmtime version or commit: 29.0.1 on crates.io

Operating system: Linux 6.13.0 #1-NixOS SMP PREEMPT_DYNAMIC Sun Jan 19 23:51:45 UTC 2025 x86_64 GNU/Linux

Architecture: x85_64

Extra Info

N/A

[alexcrichton]

Thanks for the report! This is due to bytecodealliance/wasm-tools#1999 which was a buggy implementation in a dependency of Wasmtime. I'll work on getting this fix out for Wasmtime as well. Fixing end-user builds will requiring updating the wit-parser crate that Wasmtime depends on. It'll take a moment to publish builds of fixed versions of wit-parser though because that will require a lot of patch releases for a crate where we don't have a great patch release process.

At this time there's unfortunately no fix though, so if folks run into this you'll need to pin nightlies to an older nightly temporarily.

[alexcrichton]

Ok here's what I've done to fix this:

• I've made a patch release of the wit-parser crate, the crate at fault here, for all versions that are affected.
• I've updated Wasmtime's main and release-{30,29.28}.0.0 branches.

This means that cargo install [email protected] --locked will continue to fail, but if --locked is removed, for example, then it will succeed. Embedders using Wasmtime shouldn't be affected since they should be able to use the latest wit-parser dependency which will fix this issue.

The only remaining question is whether we want to publish a patch release of Wasmtime's release branches with an updated lock file. Personally I'd lean towards "no" but others might feel differently so I don't want to prematurely close this.

@aumetra can you confirm on your end that if you run cargo update -p wit-parser that the issue is resolved?

[pchickey]

The only remaining question is whether we want to publish a patch release of Wasmtime's release branches with an updated lock file. Personally I'd lean towards "no" but others might feel differently so I don't want to prematurely close this.

I also lean towards "no" since in this case its as easy as dropping --locked on the cli install, and there is no bug in any of the published binaries. If a user can present some case we haven't thought of where they can't be flexible, I guess we can do it, but lets not unless asked.

[aumetra]

can you confirm on your end that if you run cargo update -p wit-parser that the issue is resolved?

Verified. Updated the dependency on my program and now it successfully builds again

[alexcrichton]

I've added this as a discussion item to our next agenda which is in a bit due to the wasm cg meeting happening next week. Regardless though thanks @aumetra for confirming that updating wit-parser works!