.onPreview not working when having set up defaultScope for whole SharedContainer

[davidpetrina]

Hi! I would like to ask about the behaviour of .onPreview { } for registered service while having set up defaultScope for the whole container.

For the debug purposes I'm having a ContentView with ContentViewModel:

import Factory
import SwiftUI

struct ContentView: View {

    @StateObject private var viewModel = ContentViewModel()

    var body: some View {
        VStack {
            Text(viewModel.dataString)
        }
        .padding()
        .onAppear(perform: viewModel.reloadData)
    }
}

struct ContentView_Previews: PreviewProvider {

    static var previews: some View {
        ContentView()
    }
}

final class ContentViewModel: ObservableObject {

    @Published var dataString: String = ""
    @Injected(\DataServiceContainer.dataService) private var dataService

    func reloadData() {
        Task { @MainActor in
            dataString = dataService.fetchString()
        }
    }
}

And having a DataService:

protocol DataService {

    func fetchString() -> String
}

class DataServiceImpl: DataService {

    func fetchString() -> String {
        "PRODUCTION"
    }
}

class DataServiceMock: DataService {

    func fetchString() -> String {
        "DEBUG"
    }
}

While setting up .onPreview { } and .singleton to the factory itself, preview in ContentView displays correctly mocked data (from DataServiceMock). However while having set up defaultScope = .singleton to the manager for the whole container (I assume every registered service should have now .singleton scope instead of .unique), preview is not showing up mocked data, but instead shows from the DataServiceImpl class.

Preview showing mocked data:

import Factory

final class DataServiceContainer: SharedContainer {

    static let shared = DataServiceContainer()
    let manager = ContainerManager()

    var dataService: Factory<DataService> {
        self { DataServiceImpl() }
            .onPreview { DataServiceMock() }
            .singleton
    }
}

Preview showing real data:

import Factory

final class DataServiceContainer: SharedContainer {

    static let shared = DataServiceContainer()
    var manager: ContainerManager {
        let manager = ContainerManager()
        manager.defaultScope = .singleton
        return manager
    }

    var dataService: Factory<DataService> {
        self { DataServiceImpl() }
            .onPreview { DataServiceMock() }
    }
}

Is there anything I'm missing out while setting up scope for the whole container?

[hmlongco]

Not sure if this is the or just a problem, but manager stores caches, registrations, and options for the container. The following code basically creates a new manager every single time it's needed.

    var manager: ContainerManager {
        let manager = ContainerManager()
        manager.defaultScope = .singleton
        return manager
    }

At the very least that should be...

    var manager: ContainerManager = {
        let manager = ContainerManager()
        manager.defaultScope = .singleton
        return manager
    }()