How to properly use SwiftUI's .task modifier?

[kakhaberikiknadze]

So, I've just noticed I'm getting this runtime warning

The "Store" class is not thread-safe, and so all interactions with an instance of "Store" (including all of its scopes and derived view stores) must be done on the main thread.
"ViewStore.send" was called on a non-main thread with: AppReducer.Action.foo …

Well, if I wrap viewStore.send(.refresh) inside DispatchQueue.main.async then it will be called on main thread and the warning goes away.

Just wanted to make sure this is a correct implementation for running some background tasks when you navigate to the view.

.task {
    DispatchQueue.main.async {
        viewStore.send(.foo)
    }
}

[kakhaberikiknadze]

I've noticed I'm getting the same warning when I send the action from refreshable as well.

.refreshable {
    await viewStore.send(.refresh)
}

[kakhaberikiknadze]

The solution is to mark func renderContent as @MainActor func renderContent

[kakhaberikiknadze]

Or perhaps the struct itself to @MainActor

[mbrandonw]

Ah yes, you've run into the classic and subtle edge case of "main actor inference" for views. 😕 Read this article for more info.

[kakhaberikiknadze]

Thanks 🙌🏻 And actually, double-thanks for such quick responses 🚀

[tgrapperon]

Yes, there is a very tricky MainActor inheritance behavior in View. There is a nice explanation here. When you wrote your helper functions, you lost the implicit MainActor, but you would had it if your view hosted a @StateObject property for example.
Edit: Ah, sorry, I didn't see Brandon's response, I was on mobile.