Trying to use onPreview with a custom scope

[cgrindel]

I have defined a scope and applied it to a factory. I have also defined an onPreview and onTest context for the factory.

extension Scope {
  static let session = Cached()
}

extension Container {
  var modelData: Factory<ModelData> {
    self { ModelData() }
      .scope(.session)
      .onPreview { ModelData(games: TestData.games) }
      .onTest { ModelData(games: TestData.games) }
  }
}

In one of my preview structs, I have the following:

struct GameDetail_Previews: PreviewProvider {
  static var previews: some View {
    Container.shared.modelData.reset(.scope)
    let modelData = Container.shared.modelData()
    return Group {
      Text("Debug: \(modelData.games.count)") // < === Always 0
    }
  }
}

Unfortunately, the test data is never available in the preview.

It is not clear to me what I am doing wrong. Any pointers would be greatly appreciated. Thanks!

[cgrindel]

From my debugging, it appears that the cast on this line is failing. The options?.factoryForCurrentContext() finds AnyFactory, but the cast to TypedFactory<P,T> is failing and returns nil. I am not sure why. I have printed out type names and things look OK.

*** CHUCK  factoryForContext: Optional(Factory.TypedFactory<(), PinochleScoreApp.ModelData>(factory: (Function)))
*** CHUCK  factoryForContextTyped: nil
*** CHUCK  P.self: ()
*** CHUCK  T.self: ModelData

[cgrindel]

I hacked around a little bit and I am 99% sure that we cannot rely on the cast of a tuple to evaluate to the same value in different contexts (e.g. different threads). When I changed FactoryRegistration to be a class and kept a reference to the factory-specific registrations on that class avoiding the cast with a tuple type, the lookup works properly.

// public struct FactoryRegistration<P, T> {
public class FactoryRegistration<P, T> {
    // ...
    var contextFactories: [String: FactoryType] = [:]

    func context(_ context: FactoryContextType, key _: FactoryKey, factory: @escaping (P) -> T) {
        // ...
        options { options in
            switch context {
            // ...
            default:
                contextFactories["\(context)"] = factory
                // if options.contexts == nil {
                //     options.contexts = [:]
                // }
                // options.contexts?["\(context)"] = TypedFactory(factory: factory)
            }
            // #146 container.manager.cache.removeValue(forKey: key)
        }
    }

    func resolve(with parameters: P) -> T {
        // ...
        // The first clause of the if-else is new. This works!
        if let contextName = options?.contextName, let foundFactory = contextFactories[contextName] {
            current = foundFactory
        } else if let found = options?.factoryForCurrentContext() as? TypedFactory<P, T> {
            current = found.factory
        } else if let found = manager.registrations[key] as? TypedFactory<P, T> {
            current = found.factory
        } else {
            current = factory
        }
        // ...
    }

@hmlongco How would you like to proceed?

[hmlongco]

I'm afraid I'm going to need you to provide a minimum viable project that demonstrates the issue.

I added the following to FactoryDemo

import Factory
import SwiftUI

struct ModelTest: View {
    var modelData: ModelData
    var body: some View {
        Text("Debug: \(modelData.games.count)")
    }
}

#Preview {
    Container.shared.modelData.reset(.scope)
    let modelData = Container.shared.modelData()
    return ModelTest(modelData: modelData)
}

// Didn't provide this so I made up something
struct ModelData {
    var games: [Int] = []
}

struct TestData {
    static let games: [Int] = [1,2,9]
}

extension Container {
    var modelData: Factory<ModelData> {
        self { ModelData() }
            .scope(.session)
            .onPreview { ModelData(games: TestData.games) }
            .onTest { ModelData(games: TestData.games) }
    }
}

And see "Debug: 3" in the Preview. If I comment out the onPreview I see 0, as expected/

[cgrindel]

I have tried updating FactoryDemo to mimic the way that I have my app setup. Unfortunately, I am unable to repro the issue in FactoryDemo. I will let you know if I can come up with a repro. Thanks for your help!