Why doesn't Module.method_defined?(:method) work correctly?

Question

I'm trying to check if a method is defined in a module using Module.method_defined?(:method) and it is returning false it should be returing true.

module Something
  def self.another
    1
  end
end

Something.methods has 'another' listed but Something.method_defined?(:another) returns false.

Is this maybe not working because the method is defined on self? If this is the case is there another way to check if the method is defined on the module other than using method_defined??

Answer 1

I'm adding my version of the answer

Using the singleton_methods method:

module Something
  def self.another
  end
end

Something.singleton_methods.include?(:another) #=> true, with all parent modules
Something.singleton_methods(false).include?(:another) #=> true, will check only in the Something module

Answer 2

Modules methods are defined in its metaclass. So you can also check for method inclusion with:

k = class << Something; self; end # Retrieves the metaclass
k.method_defined?(:another)  #=> true

You can read more about it in Understanding Ruby Metaclasses.