docker/cli · error

invalid spec: %s: %w

Error message

invalid spec: %s: %w

What it means

Error "invalid spec: %s: %w" thrown in docker/cli.

Source

Thrown at internal/volumespec/volumespec.go:40

	switch len(spec) {
	case 0:
		return volume, errors.New("invalid empty volume spec")
	case 1, 2:
		volume.Target = spec
		volume.Type = string(mount.TypeVolume)
		return volume, nil
	}

	buffer := make([]rune, 0, len(spec))
	for _, char := range spec + string(endOfSpec) {
		switch {
		case isWindowsDrive(buffer, char):
			buffer = append(buffer, char)
		case char == ':' || char == endOfSpec:
			if err := populateFieldFromBuffer(char, buffer, &volume); err != nil {
				populateType(&volume)
				return volume, fmt.Errorf("invalid spec: %s: %w", spec, err)
			}
			buffer = buffer[:0] // reset, but reuse capacity
		default:
			buffer = append(buffer, char)
		}
	}

	populateType(&volume)
	return volume, nil
}

func isWindowsDrive(buffer []rune, char rune) bool {
	return char == ':' && len(buffer) == 1 && unicode.IsLetter(buffer[0])
}

func populateFieldFromBuffer(char rune, buffer []rune, volume *VolumeConfig) error {
	strBuffer := string(buffer)
	switch {

View on GitHub (pinned to e9452d6e78)

When it happens

Trigger: Thrown at internal/volumespec/volumespec.go:40 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/f061a3972f2d919a.json. Report an issue: GitHub.