Overriding dependencies with liveValue only

[Budyn]

Hello!

I'm migrating the Dependencies package to 1.2, so the new overriding dependecies technique can be used.

My project has protocol oriented dependencies.

In order to use this syntax:
@Dependency(FetchServiceKey.self) var fetchService

I have to include the testValue inside the DependencyKey object:

protocol FetchService {
    // ...
}

enum FetchServiceKey: DependencyKey {
    static let liveValue: EntryService = LiveEntryService()

    // It has to be present in order to unlock the new overriding method
    static let testValue = liveValue
}

struct LiveFetchService: FetchService {
    // ...
}

By commenting out the testValue from the DependencyKey, I can't build the project and have a warning:

Variable 'fetchService' inferred to have type 'FetchServiceKey', which is an enum with no cases
Add an explicit type annotation to silence this warning

Do we need to include the testValue each time for this overriding method?

[mbrandonw]

Hi @Budyn, can you provide a complete, compiling sample that demonstrates the problem? This compiles just fine with no warnings:

protocol FetchService {}
struct LiveFetchService: FetchService {}
enum FetchServiceKey: DependencyKey {
  static let liveValue: any FetchService = LiveFetchService()
}
func foo() {
  @Dependency(FetchServiceKey.self) var fetchService
}

[Budyn]

Hello @mbrandonw, thank you for the quick response.

This is the extended example, that invokes the mentioned earlier warning:

protocol FetchService {
    func doWork()
}

struct LiveFetchService: FetchService {
    func doWork() {}
}

enum FetchServiceKey: DependencyKey {
    static let liveValue: any FetchService = LiveFetchService()
}

protocol ClientService {
    func doWork()
}

struct LiveClientService: ClientService {

    @Dependency(FetchServiceKey.self) var fetchService

    func requestWork() {
        fetchService.doWork()
    }
}

enum ClientServiceKey: DependencyKey {
    static let liveValue: any ClientService = LiveClientService()
}

func foo() {
    @Dependency(ClientServiceKey.self) var clientService
    clientService.doWork()
}

[mbrandonw]

Hi @Budyn, that code does not compile because you use requestWork instead of doWork in LiveClientService, but once you make that change it compiles just fine with no warnings.