redis/go-redis · error

invalid field value format

Error message

invalid field value format

What it means

Inside the FT.SEARCH fields array, every odd-position element (the field value) must be a string. RediSearch returns field values as bulk strings; any other Go type at that position (int64, nil, nested array) makes the parser abort with this error.

Source

Thrown at search_commands.go:2678

			fields, ok := data[i].([]interface{})
			if !ok {
				if data[i] == proto.Nil || data[i] == nil {
					doc.Error = proto.Nil
					doc.Fields = map[string]string{}
					fields = []interface{}{}
				} else {
					return FTSearchResult{}, fmt.Errorf("invalid document fields format")
				}
			}

			for j := 0; j < len(fields); j += 2 {
				key, ok := fields[j].(string)
				if !ok {
					return FTSearchResult{}, fmt.Errorf("invalid field key format")
				}
				value, ok := fields[j+1].(string)
				if !ok {
					return FTSearchResult{}, fmt.Errorf("invalid field value format")
				}
				doc.Fields[key] = value
			}
			i++
		}

		results = append(results, doc)
	}
	return FTSearchResult{
		Total: int(total),
		Docs:  results,
	}, nil
}

type FTSearchCmd struct {
	baseCmd
	val     FTSearchResult
	options *FTSearchOptions

View on GitHub (pinned to c5cad058c7)

Solutions

1. Inspect the raw reply to find the non-string value
2. Fix the mock/proxy so all field values are bulk strings
3. Confirm you're on genuine Redis Stack / RediSearch (not a fork altering encodings)
4. Upgrade go-redis in case a newer parser handles your server's encoding

Example fix

// before: mock uses an int field value
mock := []interface{}{int64(1), "doc:1", []interface{}{"count", 42}}

// after: values must be strings (as RediSearch sends them)
mock := []interface{}{int64(1), "doc:1", []interface{}{"count", "42"}}

// All field values in mocks must be strings, mirroring bulk-string encoding
for j := 1; j < len(fields); j += 2 {
	if _, ok := fields[j].(string); !ok {
		panic("field values must be strings")
	}
}

func isStringValue(v interface{}) bool {
	_, ok := v.(string)
	return ok
}

res, err := rdb.FTSearch(ctx, "idx", q).Result()
if err != nil {
	if strings.Contains(err.Error(), "invalid field value") {
		log.Printf("non-string field value in reply: %v", err)
		return fallbackDocs, nil
	}
	return err
}

When it happens

Trigger: FTSearch reply where a field value decodes to a non-string — e.g. numeric fields returned as RESP integers by a patched/proxied server, nil values, or mocks using non-string values.

Common situations: Proxies or middleware altering value encoding; hand-written mocks storing ints/floats for field values; module versions or third-party Redis forks changing field encoding.

Related errors

• unexpected search result format
• invalid total results format
• invalid document ID format
• invalid score format
• invalid document fields format

AI-assisted analysis of redis/go-redis@c5cad058c7 (2026-09-01). Data as JSON: /api/errors/e34391a5b5908e75. Report an issue: GitHub.