UnnecessaryAbstractClass false positive for abstractproperties

[WonderCsabo]

Expected Behavior

UnnecessaryAbstractClass should allow an abstract class with abstract properties

Observed Behavior

UnnecessaryAbstractClass fails on an abstract class with abstract properties

Steps to Reproduce

abstract class ChildViewModel : ViewModel() {

    var parentViewModel: BaseViewModel? = null

    public override fun onCleared() {
        viewModelScope.cancel()
        super.onCleared()
    }
}

abstract class BaseTransferWidgetViewModel : ChildViewModel() {

    abstract val items: LiveData<List<RowViewModel<*>>>

    abstract val widgetListMaxSize: Int

    abstract val selectItemCommand: CommandFactory<RowViewModel<*>>

    abstract val showMoreCommand: Command
}

UnnecessaryAbstractClass fails on BaseTransferWidgetViewModel. It allowed it in detekt 1.7.0

Your Environment

• Version of detekt used: 1.7.1
• Version of Gradle used (if applicable): 6.2.2
• Operating System and version: macOS 10.14.6

[BraisGabin]

🤔 BaseTransferWidgetViewModel could be an interface safely. But maybe that's a bit opinated: "composition over inheritance". I'm not sure if that's what this rule is looking for.

[schalkms]

This is a bug. Thanks for reporting this.
This came in with a bug fix in v1.7.1. Now detekt also considers base classes, when reporting an abstract class without any concrete members. Unfortunately, this case slipped through.
I have a fix in the queue.

[sakthi-logn]

Why does Detekt report this ParentClass as an UnnecessaryAbstractClass ?

abstract class ParentClass {
    abstract val type: String
}
data class ChildOne(val prop1: Int) {
   override val type = "ChildOne"
}
data class ChildTwo(val prop2: Double) {
   override val type = "ChildTwo"
}

Edit: just improve formatting.

[BraisGabin]

I think that the rule tells that it could be replaced by an interface and that's true and the reason yout code is reported:

interface ParentClass {
    val type: String
}