}
	}
	val := os.Getenv(key)
	if val != "" {
		return val
	}
	envCache.once.Do(initEnvCache)
	return envCache.m[key]
}

// CanGetenv reports whether key is a valid go/env configuration key.
func CanGetenv(key string) bool {
	envCache.once.Do(initEnvCache)
	if _, ok := envCache.m[key]; ok {
		// Assume anything in the user file or go.env file is valid.
		return true
	}