go-redis/redis · error

redis: unexpected type=%T for String

Error message

redis: unexpected type=%T for String

What it means

Returned by Cmd.Text() (via toString, command.go:646) when the reply value stored in the Cmd is not a Go string. toString only accepts the string RESP scalar type; any other concrete type (e.g. []interface{} from an array reply, or nil) yields this error. It indicates the wrong accessor was used for the reply shape the command actually produced.

Solutions

  1. Use the typed command method that matches the reply shape (e.g. client.HGetAll → a StringStringMapCmd; client.LRange → StringSliceCmd).
  2. If using Do(), call cmd.Result() and type-switch on the returned interface{} before coercing.
  3. Check cmd.Err() first and handle redis.Nil before accessing the value.

Example fix

// before
res, err := client.Do(ctx, "HGETALL", "k").Text() // HGETALL returns an array → error

// after
m, err := client.HGetAll(ctx, "k").Result() // StringStringMapCmd, correct shape
Defensive patterns

Strategy: type-guard

Type guard

func asString(cmd *redis.Cmd) (string, error) {
    if err := cmd.Err(); err != nil { return "", err }
    switch v := cmd.Val().(type) {
    case string:
        return v, nil
    default:
        return "", fmt.Errorf("not a string: %T", v)
    }
}

Try / catch

s, err := cmd.Text()
if err != nil && strings.Contains(err.Error(), "unexpected type") {
    // wrong accessor for the reply shape — switch to a typed command
}

Prevention

When it happens

Trigger: Calling cmd.Text() on a Cmd that holds an array reply — e.g. issuing Do(ctx, "HGETALL", key) (raw Cmd) and calling Text(); calling Text() on a nil val when an earlier nil-check was skipped; calling Text() on a result whose accessor should be Slice()/Int64Slice().

Common situations: Using the generic Cmd from client.Do or client.Process for a command that returns a non-string reply instead of the typed Cmd (e.g. StringSliceCmd, XMessageSliceCmd); mis-typing a command that returns an integer/array.

Related errors

AI-assisted analysis of go-redis/redis@36d97525cd (2026-08-06). Data as JSON: /api/errors/686ae5e1619235cc. Report an issue: GitHub.

Appendix: source

Thrown at command.go:651

func (cmd *Cmd) Result() (interface{}, error) {
	cmd.await()
	return cmd.val, cmd.err
}

func (cmd *Cmd) Text() (string, error) {
	cmd.await()
	if cmd.err != nil {
		return "", cmd.err
	}
	return toString(cmd.val)
}

func toString(val interface{}) (string, error) {
	switch val := val.(type) {
	case string:
		return val, nil
	default:
		err := fmt.Errorf("redis: unexpected type=%T for String", val)
		return "", err
	}
}

func (cmd *Cmd) Int() (int, error) {
	cmd.await()
	if cmd.err != nil {
		return 0, cmd.err
	}
	switch val := cmd.val.(type) {
	case int64:
		return int(val), nil
	case string:
		return strconv.Atoi(val)
	default:
		err := fmt.Errorf("redis: unexpected type=%T for Int", val)
		return 0, err
	}

View on GitHub (pinned to 36d97525cd)