with_scope (ActiveRecord::Base)

    # File lib/active_record/base.rb, line 1956
            def with_scope(method_scoping = {}, action = :merge, &block)
              method_scoping = method_scoping.method_scoping if method_scoping.respond_to?(:method_scoping)

              # Dup first and second level of hash (method and params).
              method_scoping = method_scoping.inject({}) do |hash, (method, params)|
                hash[method] = (params == true) ? params : params.dup
                hash
              end

              method_scoping.assert_valid_keys([ :find, :create ])

              if f = method_scoping[:find]
                f.assert_valid_keys(VALID_FIND_OPTIONS)
                set_readonly_option! f
              end

              # Merge scopings
              if action == :merge && current_scoped_methods
                method_scoping = current_scoped_methods.inject(method_scoping) do |hash, (method, params)|
                  case hash[method]
                    when Hash
                      if method == :find
                        (hash[method].keys + params.keys).uniq.each do |key|
                          merge = hash[method][key] && params[key] # merge if both scopes have the same key
                          if key == :conditions && merge
                            hash[method][key] = merge_conditions(params[key], hash[method][key])
                          elsif key == :include && merge
                            hash[method][key] = merge_includes(hash[method][key], params[key]).uniq
                          elsif key == :joins && merge
                            hash[method][key] = merge_joins(params[key], hash[method][key])
                          else
                            hash[method][key] = hash[method][key] || params[key]
                          end
                        end
                      else
                        hash[method] = params.merge(hash[method])
                      end
                    else
                      hash[method] = params
                  end
                  hash
                end
              end

              self.scoped_methods << method_scoping

              begin
                yield
              ensure
                self.scoped_methods.pop
              end
            end