Question

How to access attr_accessor‘s instance variable from a subclass?

class A
  attr_accessor :somevar
  @somevar = 123
  puts @somevar
end

class B < A
  def meth
    puts @somevar
  end
end

B.new.meth

puts nil…

P.S. I can use ActiveSupport.

Answer 1

You need to set the instance variable in an initialize method — this gets called whenever a new class instance is created:

class A
  attr_accessor :somevar
  def initialize
    @somevar = 123
  end
end