Library doesn't compile on wasm

[luca-della-vedova]

Before proceeding, is there an existing issue or discussion for this?

• I have done a search for similar issues and discussions.

Description

As found in open-rmf/rmf_site#233 (comment), the library currently doesn't compile in wasm blocking its usage for rmf_site.

Compile error:

error[E0308]: mismatched types
   --> /home/runner/.cargo/git/checkouts/bevy_impulse-30348e30aae85d7f/ee7858a/src/callback.rs:144:84
    |
144 |         OperateTask::<_, Streams>::new(task_id, session, self.source, self.target, task, None, sender)
    |         ------------------------------ arguments to this function are incorrect    ^^^^ expected `Task<_>`, found `FakeTask`
    |
    = note: expected struct `Task<_>`
               found struct `bevy_tasks::single_threaded_task_pool::FakeTask`
note: associated function defined here
   --> /home/runner/.cargo/git/checkouts/bevy_impulse-30348e30aae85d7f/ee7858a/src/operation/operate_task.rs:89:19
    |
89  |     pub(crate) fn new(
    |                   ^^^
...
94  |         task: BevyTask<Response>,
    |         ------------------------

   Compiling bevy_stl v0.12.0
error[E0308]: mismatched types
   --> /home/runner/.cargo/git/checkouts/bevy_impulse-30348e30aae85d7f/ee7858a/src/impulse/map.rs:182:51
    |
181 |         OperateTask::<_, Streams>::new(
    |         ------------------------------ arguments to this function are incorrect
182 |             task_source, session, source, target, task, None, sender,
    |                                                   ^^^^ expected `Task<_>`, found `FakeTask`
    |
    = note: expected struct `Task<_>`
               found struct `bevy_tasks::single_threaded_task_pool::FakeTask`
note: associated function defined here
   --> /home/runner/.cargo/git/checkouts/bevy_impulse-30348e30aae85d7f/ee[785](https://github.com/open-rmf/rmf_site/actions/runs/10213662123/job/28259507753?pr=233#step:7:786)8a/src/operation/operate_task.rs:89:19
    |
89  |     pub(crate) fn new(
    |                   ^^^
...
94  |         task: BevyTask<Response>,
    |         ------------------------

error[E0308]: mismatched types
   --> /home/runner/.cargo/git/checkouts/bevy_impulse-30348e30aae85d7f/ee7858a/src/operation/operate_map.rs:202:51
    |
201 |         OperateTask::<_, Streams>::new(
    |         ------------------------------ arguments to this function are incorrect
202 |             task_source, session, source, target, task, None, sender,
    |                                                   ^^^^ expected `Task<_>`, found `FakeTask`
    |
    = note: expected struct `Task<_>`
               found struct `bevy_tasks::single_threaded_task_pool::FakeTask`
note: associated function defined here
   --> /home/runner/.cargo/git/checkouts/bevy_impulse-30348e30aae85d7f/ee7858a/src/operation/operate_task.rs:89:19
    |
89  |     pub(crate) fn new(
    |                   ^^^
...
94  |         task: BevyTask<Response>,
    |         ------------------------

error[E0308]: mismatched types
   --> /home/runner/.cargo/git/checkouts/bevy_impulse-30348e30aae85d7f/ee7858a/src/service/async_srv.rs:242:43
    |
241 |     OperateTask::<_, Streams>::new(
    |     ------------------------------ arguments to this function are incorrect
242 |         task_id, session, source, target, task, blocker, sender,
    |                                           ^^^^ expected `Task<_>`, found `FakeTask`
    |
    = note: expected struct `Task<_>`
               found struct `bevy_tasks::single_threaded_task_pool::FakeTask`
note: associated function defined here
   --> /home/runner/.cargo/git/checkouts/bevy_impulse-30348e30aae85d7f/ee7858a/src/operation/operate_task.rs:89:19
    |
89  |     pub(crate) fn new(
    |                   ^^^
...
94  |         task: BevyTask<Response>,
    |         ------------------------

For more information about this error, try `rustc --explain E0308`.
error: could not compile `bevy_impulse` (lib) due to 4 previous errors

[mxgrey]

WASM is working now, as long as the single_threaded_async feature is active.

I've added a WASM CI test to the CI issue #4 and a new issue to document the feature #15 so I think we can close this.