docker/cli · error

invalid utf8 bytes at line %d: %v

Error message

invalid utf8 bytes at line %d: %v

What it means

Error "invalid utf8 bytes at line %d: %v" thrown in docker/cli.

Source

Thrown at pkg/kvfile/kvfile.go:88

// ParseFromReader parses a line-delimited key/value pairs separated by equal sign.
// It accepts a lookupFn to lookup default values for keys that do not define
// a value. An error is produced if parsing failed, the content contains invalid
// UTF-8 characters, or a key contains whitespaces.
func ParseFromReader(r io.Reader, lookupFn func(key string) (value string, found bool)) ([]string, error) {
	return parseKeyValueFile(r, lookupFn)
}

const whiteSpaces = " \t"

func parseKeyValueFile(r io.Reader, lookupFn func(string) (string, bool)) ([]string, error) {
	lines := []string{}
	scanner := bufio.NewScanner(r)
	utf8bom := []byte{0xEF, 0xBB, 0xBF}
	for currentLine := 1; scanner.Scan(); currentLine++ {
		scannedBytes := scanner.Bytes()
		if !utf8.Valid(scannedBytes) {
			return []string{}, fmt.Errorf("invalid utf8 bytes at line %d: %v", currentLine, scannedBytes)
		}
		// We trim UTF8 BOM
		if currentLine == 1 {
			scannedBytes = bytes.TrimPrefix(scannedBytes, utf8bom)
		}
		// trim the line from all leading whitespace first. trailing whitespace
		// is part of the value, and is kept unmodified.
		line := strings.TrimLeftFunc(string(scannedBytes), unicode.IsSpace)

		if len(line) == 0 || line[0] == '#' {
			// skip empty lines and comments (lines starting with '#')
			continue
		}

		key, _, hasValue := strings.Cut(line, "=")
		if len(key) == 0 {
			return []string{}, fmt.Errorf("no variable name on line '%s'", line)
		}

View on GitHub (pinned to e9452d6e78)

When it happens

Trigger: Thrown at pkg/kvfile/kvfile.go:88 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of docker/cli@e9452d6e78 (2026-08-01). Data as JSON: /data/errors/d24134b9d0070a9e.json. Report an issue: GitHub.