go-redis/redis · error

redis: ScanSlice index=%d value=%q failed: %w

Error message

redis: ScanSlice index=%d value=%q failed: %w

What it means

Error "redis: ScanSlice index=%d value=%q failed: %w" thrown in go-redis/redis.

Source

Thrown at internal/proto/scan.go:146

func ScanSlice(data []string, slice interface{}) error {
	v := reflect.ValueOf(slice)
	if !v.IsValid() {
		return fmt.Errorf("redis: ScanSlice(nil)")
	}
	if v.Kind() != reflect.Ptr {
		return fmt.Errorf("redis: ScanSlice(non-pointer %T)", slice)
	}
	v = v.Elem()
	if v.Kind() != reflect.Slice {
		return fmt.Errorf("redis: ScanSlice(non-slice %T)", slice)
	}

	next := makeSliceNextElemFunc(v)
	for i, s := range data {
		elem := next()
		if err := Scan([]byte(s), elem.Addr().Interface()); err != nil {
			err = fmt.Errorf("redis: ScanSlice index=%d value=%q failed: %w", i, s, err)
			return err
		}
	}

	return nil
}

func makeSliceNextElemFunc(v reflect.Value) func() reflect.Value {
	elemType := v.Type().Elem()

	if elemType.Kind() == reflect.Ptr {
		elemType = elemType.Elem()
		return func() reflect.Value {
			if v.Len() < v.Cap() {
				v.Set(v.Slice(0, v.Len()+1))
				elem := v.Index(v.Len() - 1)
				if elem.IsNil() {
					elem.Set(reflect.New(elemType))

View on GitHub (pinned to 36d97525cd)

Solutions

1. Check the failing index and value in the error; the element type may not match the slice element type
2. Use a []string destination and convert elements explicitly

When it happens

Trigger: Thrown at internal/proto/scan.go:146 when the library encounters an invalid state.

Common situations: Scan into strings first, then convert with error handling per element.

AI-assisted analysis of go-redis/redis@36d97525cd (2026-08-06). Data as JSON: /data/errors/72bec6425dffdf10.json. Report an issue: GitHub.