rails--rails/activesupport/CHANGELOG.md

• HashWithIndifferentAccess better respects #to_hash on objects it's given. In particular, .new, #update, #merge, #replace all accept objects which respond to #to_hash, even if those objects are not Hashes directly.

  Peter Jaros

• Deprecate Class#superclass_delegating_accessor, use Class#class_attribute instead.

  Akshay Vishnoi

• Ensure classes which include Enumerable get #to_json in addition to #as_json.

  Sammy Larbi

• Change the signature of fetch_multi to return a hash rather than an array. This makes it consistent with the output of read_multi.

  Parker Selbert

• Introduce Concern#class_methods as a sleek alternative to clunky module ClassMethods. Add Kernel#concern to define at the toplevel without chunky module Foo; extend ActiveSupport::Concern boilerplate.

  # app/models/concerns/authentication.rb
  concern :Authentication do
    included do
      after_create :generate_private_key
    end
  
    class_methods do
      def authenticate(credentials)
        # ...
      end
    end
  
    def generate_private_key
      # ...
    end
  end
  
  # app/models/user.rb
  class User < ActiveRecord::Base
    include Authentication
  end
  

  Jeremy Kemper

Please check 4-1-stable for previous changes.