I've been trying to remove all Swift 5.x dependencies, the last main one is my usage of .userInterfaceIdiom to change font sizes based on device I am on. I have tried to create a simple class that looks like this -

@MainActor
class IsIphone : ObservableObject {
    @Published var iPhone : Bool = false

    @MainActor
    init() {
        if UIDevice.current.userInterfaceIdiom == .phone  { 
            self.iPhone = true
        }
    }
}

And then injecting that into the environment at app launch via - @State var isIphone = IsIphone() However this is generating the error -

swift:14 Accessing Environment<Optional<Color>>'s value outside of being installed on a View. This will always read the default value and will not update.

Which is very weird as I am not addressing <Optional<Color>> at all.

I also get the warning on the same line -

.swift:14:16 Main actor-isolated default value in a nonisolated context; this is an error in Swift 6

Which now moved the error from each location in the code to the initial instansiation.

Additionally, in those views where I was using the .userInterfaceIdiom in the initializer to make a decision in the init() I now get compiler errors of trying to access other variables before their definition, e.g.

@EnvironmentObject var isIphone: IsIphone
private var gridLayout: [GridItem]

init() {
       if isIphone.iPhone {        // UIDevice.current.userInterfaceIdiom == .phone || UIDevice.current.userInterfaceIdiom == .vision
            self.gridLayout = [
                GridItem(.adaptive(minimum: 160), spacing: 10, alignment: .center)
            ]
        } else {
            self.gridLayout = [
                GridItem(.adaptive(minimum: 320), spacing: 20, alignment: .center)
            ]
        }
}

returns the error Variable 'self.gridLayout' used before being initialized

btw, I simplified the init() for this post as I am setting up Query() and other items in the init.

What is the correct way to approach this problem?