rails--rails/activesupport/CHANGELOG.md

*   Introduce Module#delegate_missing_to.

    When building a decorator, a common pattern emerges:

        class Partition
          def initialize(first_event)
            @events = [ first_event ]
          end

          def people
            if @events.first.detail.people.any?
              @events.collect { |e| Array(e.detail.people) }.flatten.uniq
            else
              @events.collect(&:creator).uniq
            end
          end

          private
            def respond_to_missing?(name, include_private = false)
              @events.respond_to?(name, include_private)
            end

            def method_missing(method, *args, &block)
              @events.send(method, *args, &block)
            end
        end

    With `Module#delegate_missing_to`, the above is condensed to:

        class Partition
          delegate_missing_to :@events

          def initialize(first_event)
            @events = [ first_event ]
          end

          def people
            if @events.first.detail.people.any?
              @events.collect { |e| Array(e.detail.people) }.flatten.uniq
            else
              @events.collect(&:creator).uniq
            end
          end
        end

    *Genadi Samokovarov*, *DHH*

*   Rescuable: If a handler doesn't match the exception, check for handlers
    matching the exception's cause.

    *Jeremy Daer*

Please check [5-0-stable](https://github.com/rails/rails/blob/5-0-stable/activesupport/CHANGELOG.md) for previous changes.