thread 'main' panicked at 'spawn_local called from outside of a task::LocalSet'

[afidegnum]

I have introduced the dynamic block using transitions into the component and I'm facing the following perseus compilation error:

warning: `linksapp` (bin "linksapp") generated 11 warnings
    Finished dev [unoptimized + debuginfo] target(s) in 51.78s
     Running `dist/target_engine/debug/linksapp`
thread 'main' panicked at '`spawn_local` called from outside of a `task::LocalSet`', /home/afidegnum/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/task/local.rs:316:25
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

What could be the cause?

[arctic-hen7]

The file you've linked to has no Perseus imports, so I'm pretty sure this isn't a Perseus problem. The Perseus build process can't cause panics on its own, it will be your code that's somehow breaking. Beyond that, I'm not very familiar with Sycamore's suspense system, sorry, so I don't think I'll be much help on this one.

[afidegnum]

Can you please shed more light? I'm trying to import a sycamore's component into a perseus page which would respond to an event with a transition.

What do you suggest to use?

[afidegnum]

from this example, I noticed perseus::spawn_local_scoped is being used. How can it be used in this example?

[arctic-hen7]

I don't have time to review all your code right now, sorry. If you can create a minimal app that reproduces the problem, then I might be able to help further. Otherwise, I would recommend asking this question on the Sycamore repo. (Any Sycamore component should work fine with Perseus.)

[arctic-hen7]

Are you using this component inside a Perseus page? If you gave me the code for that, I might be of more use. There might be an issue with using async components, but there shouldn't be...

spawn_local_scoped is a Sycamore function that runs some async code in the browser. You can use it instead of an async component in your use case I think.

[afidegnum]

Here is the code. you can find it on gitpod

[lukechu10]

It's not transitions that are causing the issue. It's the async that is the problem. I believe this is because somewhere in Perseus, the app is rendered outside of a render_to_string scope so there is no access to the tokio::LocalSet which should be provided by provide_executor_scope.

[arctic-hen7]

How does one render outside a render_to_string scope?

[lukechu10]

For example:

let node = App(cx);
let string = render_to_string(|_| node);

Here, App is being called outside the scope created by render_to_string.

[arctic-hen7]

Oh I see! I hadn't understood that. That shouldn't be too hard to fix, I'll have a look into it soon.

[arctic-hen7]

I've opened #225 for this, since there seems to be a bigger problem underlying this. Sorry it took me so long to get to! In the meantime, anyone wanting to use a Suspense in Perseus should only do so behind a #[cfg(target_arch = "wasm32")] target-gate.