Hi friends, I’m troubleshooting what seems to be a type issue, when trying to interact with some KMM...

# multiplatform

[Tim Malseed]

Hi friends, I’m troubleshooting what seems to be a type issue, when trying to interact with some KMM code in iOS

I have a few different KMM gradle modules, which are interdependent. When trying to call these from iOS, there seems to be a casting issue, due to the iOS classes having the framework name prefixed to the class name

[Tim Malseed]

So, for example, I have the following on Android:

class RoutineViewModel(val context: Context) {

    val driverFactory = DriverFactory(context)

    val databaseHelper = DatabaseHelper(driverFactory)

    val dataSource = AppDataSource(databaseHelper.database)

    val repository = LocalAppRepository(dataSource)

}

This compiles fine. Note that these classes come from a couple of different gradle modules.

[Tim Malseed]

But on iOS:

class RoutineViewModel {
         
  private let repository: LocalAppRepository
   
  init() {
     
    let driverFactory = DriverFactory()
     
    let databaseHelper = DatabaseHelper(driverFactory: driverFactory)
     
    let dataSource = AppDataSource(database: databaseHelper.database)
     
    self.repository = LocalAppRepository(dataSource: dataSource)
  }

[Tim Malseed]

This fails to compile, as it cannot convert`AppDataSource` to expected type DatabaseAppDataSource

[Tim Malseed]

DirverFactory, DatabaseHelper and AppDataSource are part of the same database gradle module (and ‘database’ swift framework).
LocalAppRepository is part of the data gradle module (and data framework)

[Tim Malseed]

I’m sure this is just a misunderstanding/misuse of kmm somehow, but I’m not quite sure where I’m going wrong

[Tim Malseed]

Ohh OK, I think the problem I’m describing is with ‘transitive dependencies’ in the iOS frameworks.

I found this:
https://stackoverflow.com/questions/70266716/how-do-transitive-dependencies-in-kmm-and-ios-work

Which suggests that you need a sort of ‘umbrella’ gradle module, which you then export as a single framework to iOS

[Tim Malseed]

Also relevant:
https://youtrack.jetbrains.com/issue/KT-42250