if err != nil {
		if ee, ok := err.(*exec.ExitError); ok && len(ee.Stderr) > 0 {
			return errorf("%v: %s", cmd, ee.Stderr)
		}
		return errorf("%v: %w", cmd, err)
	}

	parts := strings.SplitN(string(bytes.TrimSpace(out)), ":", 4)
	if len(parts) < 2 {
		return errorf("%v: missing ':' in output: %q", cmd, out)
	}
	importPath = parts[0]
	if importPath == "" || importPath == "." {