deep_freeze_constants

❄️ Deep Freeze Constants to Enforce Immutability

Top‐level constants can still refer to mutable structures. To guarantee true immutability, apply a deep freeze that traverses nested arrays and hashes, preventing accidental modifications at any level. This pattern is essential for configuration objects, ensuring your constants remain pristine once initialized.

module AppConfig
  SETTINGS = {
    timeout: 30,
    endpoints: {
      users: '/users',
      orders: '/orders'
    }
  }

  def self.deep_freeze(obj)
    case obj
    when Hash
      obj.each_value { |v| deep_freeze(v) }
    when Array
      obj.each { |v| deep_freeze(v) }
    end
    obj.freeze
  end

  deep_freeze(SETTINGS)
end

# Attempting to modify SETTINGS now raises a RuntimeError