Lack of <Suspense> wrapping an async setup component should warn

[altinselimi]

Version

3.0.2

Reproduction link

https://codesandbox.io/s/competent-darwin-lv4zh?file=/src/use/usePropsLoaded.js

Steps to reproduce

Open the codesandbox link and wait 2 seconds.
The usePropsLoaded hook returns a promise which resolves when all props of said component are filled.
Or thats what it tries to do.
Neither #fallback or #default renders at all.

What is expected?

#fallback (at least) to render

What is actually happening?

An warning is thrown on the console:
Unhandled error during execution of scheduler flush. This is likely a Vue internals bug.

[posva]

You have to use Suspense on the parent (App.vue) of hello world.
There use to be a warning for that, It's weird it's gone

[jods4]

While adding Suspense warnings, for as long that #2215 isn't fixed is it possible to also add a warning when a Suspense catches a nested async setup but doesn't recede to pending. I mentioned it in the comments of that other issue, the code that needs a warning is here:

https://github.com/vuejs/vue-next/blob/0227b4a697afd598f6fa279a1a7ce84242e68f43/packages/runtime-core/src/components/Suspense.ts#L545-L546

Currently your async setup component just doesn't show up. Blank screen, no warning on console, no error in JS.

[tvkit]

You have to use Suspense on the parent (App.vue) of hello world.

@posva what about detecting that a Promise was returned, and then await automatically? What's the downside to that?

[cexbrayat]

It used to warn but was removed (in this commit https://github.com/vuejs/vue-next/pull/2099/files#diff-56930a63772d2e89f19432918b9d6ed851ede4159b0d32404e0c1d8c159fec99L1241)

PR #3657 should fix it when merged

[homersimpsons]

This now seems fixed. In fact the warning appears correctly, the fallback won't appear as it is not at the right place.