Looked over the annotations and the original AnnotationFinder.
It looks like we are only talking about Type annotations here, since AnnotationFinder only looks at the class definitions for visible and invisible annotations. Also a scalar (single-valued) property is always overriden by the current logic (and there is no such thing as a missing property on an annotation - it might have a default value - but it has to be there).
So we only need to design for multi-valued properties in Type annotations. That list includes the following:
@UsingSteps - instances
@UsingGuice - modules
@UsingPico - modules
@UsingSpring - resources
All of these have use cases where one would both want to and not want to inherit the values from the super class(es). Fortunately, we only have 1 multi-valued property in each one.
Spring deals with this situation by adding another property to @ContextConfiguration by having a String locations property (what we call resources, with a default of an empty array) and then a boolean inheritLocations property with a default value of true. The code that process this routine walks up the class hierarchy and adds locations to the ultimate array. Spring does this in the same way that AnnotationFinder does. Both use List instead of Set - since the use of the List takes into account duplicates (though, technically, Set would be better).
I'm not sure if Pico or Guice have annotations that create containers so I'm not sure what those do.
I would recommend the same pattern.
@UsingSteps - instances and inheritInstances
@UsingGuice - modules and inheritModules
@UsingPico - modules and inheritModules
@UsingSpring - resources and inheritResources
The problem is now that there is no known property - we would have to code for realizing that the value is an array and then build the name of the inheriting property and check that up the class hierarchy.
But I also think that the existing code, which always inherits/appends isn't the best option either. There are use cases where one wants to turn that off.
What do people think? I'd prefer to have some buy-in before coding.