Accessing wired instances within modules defined as classes

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
25/100
Issue type
Documentation
Clarity
Needs clarification
Activity status
Stale
Tech stack
scala

Research direction

Start by reviewing MacWire's module composition and lookup APIs, especially the UserModule, DatabaseConnectionModule, @Module, wiredInModule, and classOf[UserFinder] examples in the issue. Clarify the supported way to access a wired instance from composed class-based modules, and document the required setup and completion example for this use case.

Written by the indexing model from the issue text.

Description

I am new to Scala and Macwire and trying to figure out how to access instances that are wired using modules organized as classes. If modules are defined as traits, one can extend them and access the wired instances in them as below,

trait UserModule {
  lazy val userFinder: UserFinder = wire[UserFinder]
}

class UserFinderSpec extends FlatSpec with UserModule {
 assert userFinder.find(...) should ...
}

If my modules are organized as classes with composition, how do I access the instances?

class UserFinder(databaseConnection: databaseConnection) {
}

@Module
class DatabaseConnectionModule {
   lazy val databaseConnection: DatabaseConnection = ...
}

@Module
class UserModule(databaseConnectionModule: DatabaseConnectionModule) {
    lazy val userFinder:UserFinder = wire[UserFinder]
}
class UserFinderSpec extends FlatSpec {
    //How to access UserFinder here?
    //val wired = wiredInModule(new UserModule(new DatabaseConnectionModule))
    //val userFinder = wired.lookup(classOf[UserFinder]
    //Above way to access the instances seems complicated 
    //as I need to instantiate the modules with it's dependency chain which can be very long in my use-case.
}
Dominant language
Scala
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