Rails::Application::Railties#all

gistfile1.rb

  def all(&block)
    @railties_plus_engines ||= railties + engines
    @railties_plus_engines.each(&block) if block
    # Only after the block has been run against the railties and engines in the application
    # will we call super with the block (which has the effect of running the block against the plugins in the
    # application and returning the array of plugins)
    @railties_plus_engines + super(&block)
  end

What about this:

def all(&block)
  # Pass a block to super so it doesn't pass the current one
  @all ||= railties + engines + super { |x| x }
  @all.each(&block) if block
  @all
end