can not use Action type with async handler

[basaran]

Describe the bug

I have an async fuction that I use in my use directive, but LSP gives me a type error although the code works as intended.
I use async in my handler because I use dynamic imports in my action.

export async function doSomething(
    node: HTMLElement,
    jsonData: JsonData,
): Promise<ActionReturn>

Argument of type 'Promise<ActionReturn<undefined, Record<never, any>>> is not assignable to parameter of type '__sveltets_2_SvelteActionReturnType'.

If I use:

export async function doSomething(
    node: HTMLElement,
    jsonData: JsonData,
): ActionReturn

The type error disappears from the parent component, but I get a "you must use Promise.." in my handler.

Reproduction

The type for Action is here:
https://github.com/sveltejs/svelte/blob/83b92372c22da2f8a0f8350fa856087a7170275b/packages/svelte/types/index.d.ts#L434

Logs

No response

System Info

System:
    OS: Linux 6.6 Manjaro Linux
    CPU: (3) x64 Intel(R) Core(TM) i5-8365U CPU @ 1.60GHz
    Memory: 7.05 GB / 15.40 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 21.5.0 - /usr/bin/node
    npm: 10.3.0 - /usr/bin/npm
    pnpm: 8.14.1 - /usr/bin/pnpm

Severity

annoyance

[basaran]

I was informed on the discord by MotionlessTrain that the actions are supposed to sync, but instead suggested to use promises. On another site I also found example of using an async function inside the action handler, and assigning it to an event. Sorry for the inconvenience, I will close the issue.

Perhaps, the documentation could be updated to make this requirement stated for other users?