go-redis/redis · error

redis: RESP3 map key must be a scalar type, got %T

Error message

redis: RESP3 map key must be a scalar type, got %T

What it means

Error "redis: RESP3 map key must be a scalar type, got %T" thrown in go-redis/redis.

Source

Thrown at internal/proto/reader.go:469

func (r *Reader) readMap(line []byte) (map[interface{}]interface{}, error) {
	n, err := replyLen(line)
	if err != nil {
		return nil, err
	}
	m := make(map[interface{}]interface{}, n)
	for i := 0; i < n; i++ {
		k, err := r.ReadReply()
		if err != nil {
			return nil, err
		}

		// Reject unhashable keys (arrays/maps) before they are used as a map
		// key, which would otherwise panic. This check must run before the
		// value is read so it also guards the Nil and RedisError paths below,
		// which write the key into the map and continue.
		switch k.(type) {
		case []interface{}, map[interface{}]interface{}:
			return nil, fmt.Errorf("redis: RESP3 map key must be a scalar type, got %T", k)
		}

		v, err := r.ReadReply()
		if err != nil {
			if err == Nil {
				m[k] = nil
				continue
			}
			if err, ok := err.(RedisError); ok {
				m[k] = err
				continue
			}
			return nil, err
		}

		m[k] = v
	}
	return m, nil

View on GitHub (pinned to 36d97525cd)

Solutions

1. Ensure map keys in RESP3 replies are scalar (string/int/float/bool); nested aggregates as keys are unsupported
2. Handle the raw reply manually if the server emits non-scalar keys

When it happens

Trigger: Thrown at internal/proto/reader.go:469 when the library encounters an invalid state.

Common situations: For commands with unusual replies, read into a raw/generic type instead of a typed map.

AI-assisted analysis of go-redis/redis@36d97525cd (2026-08-06). Data as JSON: /data/errors/6c8ff7efdcfb980c.json. Report an issue: GitHub.