ERR Client sent AUTH, but no password is set

patch.rb

class Redis
  class Client
    class Connector
      class Sentinel
        def sentinel_detect
          @sentinels.each do |sentinel|
            client = Client.new(@options.merge({
              :host => sentinel[:host],
              :port => sentinel[:port],
              :password => sentinel[:password], # patch!
              :reconnect_attempts => 0,
            }))

            begin
              if result = yield(client)
                # This sentinel responded. Make sure we ask it first next time.
                @sentinels.delete(sentinel)
                @sentinels.unshift(sentinel)

                return result
              end
            rescue BaseConnectionError
            ensure
              client.disconnect
            end
          end

          raise CannotConnectError, "No sentinels available."
        rescue Redis::CommandError => err
          # this feature is only available starting with Redis 5.0.1
          raise if err.message !~ /ERR unknown command (`|')auth(`|')/
          @options[:password] = DEFAULTS.fetch(:password)
          retry
        end
      end
    end
  end
end