SFlux Element Type Should be Declared as Covariant Type

[jpork]

In order to get SFlux's element types right for proper inheritance the element type should be declared covariant as it's usually done for container- or collection types in scala. See e.g. immutable.List:

sealed abstract class List[+A]

Currently SFlux's element type is declared invariant:

trait SFlux[T]

Which lets the following code fail for SFlux but not for List:

  trait Component

  trait Container{
    def component: Component

    def components: List[Component]

    def componentsFlux: SFlux[Component]
  }

  trait ComponentExt extends Component

  trait ContainerExt extends Container{
    def component: ComponentExt

    def components: List[ComponentExt]

    def componentsFlux: SFlux[ComponentExt]
  }

[sinwe]

Thank you @jpork.
If you happen to have PR, feel free to raise. Otherwise I'll work on it soon

[sinwe]

@jpork The reason it is using invariant is because it relies on the underlying Java reactor library. As we know Java generic type is invariant.
If you know any easy way to make it compatible with scala invariant, feel free to suggest

[jpork]

I've got SMono compile clean. But there are still lot of places to change. This will keep my busy a few moments.

[sinwe]

Thanks @jpork. I'm intrigue to see.