Inspecting Marshal methods

Question

Marshal.dump is unable to dump classes that include a singleton(eigenclass). I\'d like to see how the method determines the presence of this singleton but I do not know how to

Answer 1

The check is here, but it is in C - and MRI code is infamously opaque.

I believe a check similar to that, but in Ruby, would be:

obj.singleton_class.instance_methods(false).empty? &&
obj.singleton_class.instance_variables.empty?

If that is false (i.e. if anything is defined on the singleton), no dump for you.