Monkeypatch to get https://github.com/expectedbehavior/acts_as_archival to behave in Rails 3

acts_as_archival_rails3_fix.rb

module ExpectedBehavior
  module ActsAsArchival

    module ActMethods
      def acts_as_archival
        unless included_modules.include? InstanceMethods
          include InstanceMethods

          before_save :raise_if_not_archival

          scope :archived, :conditions => ARCHIVED_CONDITIONS.call(self)
          scope :unarchived, :conditions => UNARCHIVED_CONDITIONS
          scope :archived_from_archive_number, lambda { |head_archive_number| {:conditions => [archived_at IS NOT NULL AND archive_number = ?', head_archive_number] } }

          callbacks = ['archive','unarchive']
          define_callbacks *[callbacks, {:terminator => 'result == false'}].flatten
          callbacks.each do |callback|
            eval <<-end_callbacks
               def before_#{callback}(*args, &blk)
                set_callback(:#{callback}, :before, *args, &blk)
              end
              def after_#{callback}(*args, &blk)
                set_callback(:#{callback}, :after, *args, &blk)
              end
            end_callbacks
          end
        end
      end
    end

    module InstanceMethods
      def archive(head_archive_number=nil)
        self.class.transaction do
          begin
            run_callbacks :archive, :before
            unless self.archived?
              head_archive_number ||= Digest::MD5.hexdigest("#{self.class.name}#{self.id}")
              self.archived_at = DateTime.now
              self.archive_number = head_archive_number
              self.save!
              self.archive_associations(head_archive_number)
            end
            run_callbacks :archive, :after
          rescue
            raise ActiveRecord::Rollback
          end
        end
        self
      end

      def unarchive(head_archive_number=nil)
        self.class.transaction do
          begin
            run_callbacks :unarchive, :before
            if self.archived?
              head_archive_number ||= self.archive_number
              self.unarchive_associations(head_archive_number)
              self.archived_at = nil
              self.archive_number = nil
              self.save!
            end
            run_callbacks :unarchive, :after
          rescue
            raise ActiveRecord::Rollback
          end
        end
        self
      end
    end

  end
end