Question

I want to find what modules were included into a specific class, excluding its ancestors. E.g.:

module M; end
module N; end

class A; include M; end
class B < A; include N; end

p B.included_modules

#=> [N, M, Kernel]
# I want only N

I can’t use B.included_modules[0] since I don’t know how many modules B includes.

Answer 1

If you know A is the superclass of B then

p B.included_modules - A.included_modules should give you what you are looking for else

p B.included_modules - B.superclass.included_modules

module M; end
module N; end
module O; end

class A; include M; end
class B < A; include N; include O; end

p B.included_modules - A.included_modules
#=> [O, N]