unexposure is unaware of nesting

[marshall-lee]

def self.unexpose(attribute)
  exposures.delete(attribute)
end

It just deletes attribute from exposures table. Of course, it's possible to call it like unexpose(:some__nested) but it's a hack that lacks internal representation which now is going to be removed(#151). It also doesn't clear the nested_exposures table which is potentially buggy.

I propose to temporarily forbid calling unexpose inside of nesting exposure (with exception) because it's unclear what to unexpose in this case. Current documentation says nothing about the calling unexpose withing nesting exposure so I think it's safe.

[marshall-lee]

For ones who want to 'unexpose' nested exposure for now the solution would be a good combination of two approaches:

• conditional exposures(:if, :unless)
• extract nested things to separate entity classes and expose them via :using.

[dblock]

Right on @marshall-lee, your suggestion of raising an exception on unexpose inside nesting exposure is good.