module Backports

def self.alias_method_chain(mod, target, feature)
  mod.class_eval do
    # Strip out punctuation on predicates or bang methods since
    # e.g. target?_without_feature is not a valid method name.
    aliased_target, punctuation = target.to_s.sub(/([?!=])$/, ''), $1
    yield(aliased_target, punctuation) if block_given?
    with_method, without_method = "#{aliased_target}_with_#{feature}#{punctuation}", "#{aliased_target}_without_#{feature}#{punctuation}"
    alias_method without_method, target
    alias_method target, with_method
    case
      when public_method_defined?(without_method)
        public target
      when protected_method_defined?(without_method)
        protected target
      when private_method_defined?(without_method)
        private target
    end
  end
end