cmd.Stdout = &stdout
		if err := cmd.Run(); err == nil {
			fs = append(fs, dataFile{name: "LICENSE", data: stdout.Bytes()})
		}
	}

	return fs, nil
}

// isGitRepo reports whether the given directory is a git repo.
func isGitRepo(dir string) bool {
	stdout := &bytes.Buffer{}
	cmd := exec.Command("git", "rev-parse", "--git-dir")
	cmd.Dir = dir
	cmd.Env = append(os.Environ(), "PWD="+dir)
	cmd.Stdout = stdout

	// Cache version.
	writefile(version, path, 0)

	return version
}

// isGitRepo reports whether the working directory is inside a Git repository.
func isGitRepo() bool {
	// NB: simply checking the exit code of `git rev-parse --git-dir` would
	// suffice here, but that requires deviating from the infrastructure
	// provided by `run`.