`2.0.0-beta.4` onSettled async callback prevents a component from unmounting

[aekobear]

Describe the bug

If an async function is passed to onSettled() the function is called correctly when the component mounts, but when the component is supposed to be unmounted, an error about "call not being a function" prevents it from unmounting.

My guess is that solid is getting the Promise as a return value from the function call and assuming it is the clean-up function. Later when it tries to call the Promise as a typical callback, it fails.

Your Example Website or App

https://solid2.netlify.app/#solidjs-repl:gIRySxz_QjKFyTW8zLCCxg

Steps to Reproduce the Bug or Issue

1. go to https://solid2.netlify.app/#solidjs-repl:gIRySxz_QjKFyTW8zLCCxg
2. click the [SUBMIT] button which should unmount the "unmount me!" component
3. note the error that appears

Expected behavior

I expect async functions to be supported like they were with onMount().
If that is impossible, I expect a more explicit error to be presented when an async function is passed in so that I know what I am doing wrong and how to fix it

Screenshots or Videos

No response

Platform

• OS: linux
• Browser: chrome
• Version: 146.0.7680.153

Additional context

No response

[ryansolid]

I suppose. TypeScript says it isn't allowed. It does error but we can consider making effects that return non-functions have a clearer error.

[aekobear]

I suppose. TypeScript says it isn't allowed. It does error but we can consider making effects that return non-functions have a clearer error.

I did notice that once I made the reproduction, which is nice, but my actual codebase doesn't use TS. I think the main issue here is that onMount did support async, so it's worth mentioning in the migration documentation, at the very least.

[ryansolid]

Oh for sure.. onSettled is a lot more limited than onMount was and for very good reason. Initially I was going to remove that whole usage but I think there is still some usage cases. It is just very hard to have a non-split effect (even if it is untracked) to behave in an expected way.