docker/compose · error

format value %q could not be parsed: %w

Error message

format value %q could not be parsed: %w

What it means

Returned by formatter.Print (used by list-style commands such as `docker compose ls`, `ps`, `images` with --format) when the requested --format value matches none of the accepted cases: table/pretty/empty, the legacy 'json' TemplateLegacyJSON, or 'json' after strings.ToLower normalization — plus any command-specific template handling done before this call. The error wraps api.ErrParsingFailed and echoes the offending value so the user sees exactly what was rejected.

Source

Thrown at cmd/formatter/formatter.go:68

			_, _ = fmt.Fprintln(outWriter, outJSON)
		}
	case JSON:
		switch reflect.TypeOf(toJSON).Kind() {
		case reflect.Slice:
			outJSON, err := ToJSON(toJSON, "", "")
			if err != nil {
				return err
			}
			_, _ = fmt.Fprint(outWriter, outJSON)
		default:
			outJSON, err := ToStandardJSON(toJSON)
			if err != nil {
				return err
			}
			_, _ = fmt.Fprintln(outWriter, outJSON)
		}
	default:
		return fmt.Errorf("format value %q could not be parsed: %w", format, api.ErrParsingFailed)
	}
	return nil
}

View on GitHub (pinned to ddc4b044b6)

Solutions

1. Use a supported value: `--format table` (default), `--format pretty`, or `--format json`.
2. For custom output, consume `--format json` and transform with jq/yq downstream.
3. Check the specific command's --help to see whether Go templates are accepted; if yes use `--format '{{...}}'`, else stick to json.

Example fix

# before
docker compose ls --format yaml

# after
docker compose ls --format json | yq -P

case "$(echo "$FMT" | tr '[:upper:]' '[:lower:]')" in
  table|pretty|json|'') : ;;
  *) echo "unsupported --format: $FMT (use table|pretty|json)" >&2; exit 2;;
esac
docker compose ls --format "$FMT"

When it happens

Trigger: Passing an unsupported format: `docker compose ls --format yaml`, `--format csv`, or a Go template string where templates are not supported for that command; case is normalized (JSON works), but any other token falls to the default branch and errors.

Common situations: Scripts assuming jq-style universal formats (yaml/csv); copy-pasting `--format '{{.Name}}'` from a command that supports templates into one routed through formatter.Print without template support; typos like `--format jso`; version drift where a format existed in another tool (docker CLI supports more formats).

Related errors

• unsupported format %q
• unsupported format %q
• invalid scale specifier: %s
• invalid scale specifier: can't parse replica value as int: %
• cannot combine %s and --remove-orphans

AI-assisted analysis of docker/compose@ddc4b044b6 (2026-08-15). Data as JSON: /api/errors/d4f9f9e9fa70fed2. Report an issue: GitHub.