Type parameter P in AsyncWormhole

[kaimast]

(Yay, this seems to be the first issue :) )

I noticed a small issue with the latest version of async-wormhole. When you do not define a pre_post_poll handler for async wormhole it will throw an error like this one:

error[E0698]: type inside `async fn` body must be known in this context
   --> lib/api/src/instance.rs:190:20
    |
190 |         let task = async_wormhole::AsyncWormhole::new(stack, |yielder| -> Result<Box<[crate::Val]>, RuntimeError> {
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `P`
    |
note: the type is part of the `async fn` body because of this `await`

The easiest way to fix this is to just set an empty lambda function like so, but that's a little ugly.

task.set_pre_post_poll(|| {});

Maybe we can hide function this method feature flag or require the handler to always be set? I think the error might be super confusing for some users.

[bkolobara]

(Yay, this seems to be the first issue :) )

Yay 🎉 !! I was always wondering if anyone outside the Lunatic project would use this. Would love to hear about your use case.

When you do not define a pre_post_poll handler for async wormhole it will throw an error like this one:

You are right! This is super bad DX, sorry about that. I was wondering for a long time what an elegant way would be to solve this, but never got around to test different approaches. Ideally it would be a zero-cost operation if you don't set a pre_post function.

A feature flag could be a good solution. If you would like to contribute this, I would be happy to review it.

[kaimast]

(Yay, this seems to be the first issue :) )

Yay tada !! I was always wondering if anyone outside the Lunatic project would use this. Would love to hear about your use case.

Forgot to reply to this 🙄

I was hoping to get async support into wasmer. There's a pull request (that needs some rework) here: wasmerio/wasmer#2219