Forget a Rake task

forget_task.rb

class Rake::Task
  # Forget an already defined task.
  #
  # Rake tasks with the same name are cumulative,
  # a new definition adds to an already existing one,
  # it does not override it.
  # In order to completely redefine a task, this
  # method makes rake forget the previous definition(s).
  #
  def forget
    prerequisites.clear
    @actions.clear
    @comment      = nil
    @full_comment = nil
  end
end