constants problem asked in http://blog.arkency.com/2014/11/dont-forget-about-eager-load-when-extending-autoload/#comment-1782745182

1.rb

# keep in one file
class Whatever
  class A
    def self.interface_method
    end
  end

  class B
    def self.interface_method
    end
  end

  def something
  end
end

2.rb

class Whatever
  def something
  end
end

# force loading by using class names
Whatever::A
Whatever::B

3.rb

class Whatever
  def something
  end
end

# force loading by requiring files (in a way compatibile with rails dependency tracking)
require_dependency 'whatever/a'
require_dependency 'whatever/b'

4.rb

class Whatever
  def something
  end

  def self.constants
    # force loading by requiring files but only when someone needs it
    require_dependency 'whatever/a'
    require_dependency 'whatever/b'
    super
  end
end