Getting "dependency has no live implementation" warning for DependencyKey-conforming object

[acosmicflamingo]

I'm quite puzzled by what the runtime warning "@Dependency(\.localPersistenceClient)" has no live implementation, but was accessed from a live context means when my dependency does actually conform to DependencyKey:

extension LocalPersistenceClient: DependencyKey {
  private static let userSettingsKey = "co.pointfree.isowords.PersistenceClient.userSettings"

  public static var liveValue: LocalPersistenceClient {
    let defaultUserSettings = UserSettings()
    var userSettings = UserDefaults.standard.data(forKey: userSettingsKey)
      .flatMap({ try? decoder.decode(UserSettings.self, from: $0) }) ?? defaultUserSettings
    {
      didSet {
        UserDefaults.standard.set(
          try? encoder.encode(userSettings),
          forKey: userSettingsKey
        )
      }
    }

    return Self(
      userSettings: { userSettings },
      setUserSettings: { newUserSettings in
        userSettings = newUserSettings
      }
    )
  }
}

This error goes away if I explicitly set it in my AppReducer, but why is this even needed?

@main class AppDelegate: UIResponder, UIApplicationDelegate {
  let store = Store(
    initialState: .init(),
    reducer: AppMainReducer().transformDependency(\.self) {
      $0.localPersistenceClient = .liveValue
    }
  )
}

Isowords does something similar but only for 3 dependencies: https://github.com/pointfreeco/isowords/blob/main/App/iOS/App.swift#L15. What makes those 3 dependencies special enough to require being explicitly set and not the many, many other dependencies that exist in the app?

[tgrapperon]

Hey @acosmicflamingo! This is maybe related to #1640. Maybe you can try to reference .liveValue in the same file as AppDelegate (even without assigning it to your reducer). This is not optimal, but it's maybe enough for the compiler to pick it up.

[acosmicflamingo]

Hi @tgrapperon ! Oh that does seems exactly like what is happening with me :) I'm using Tuist to handle my app/module/etc, so this makes sense. Thank you!