[NSKeyedUnarchiver decodeObjectForKey:]: cannot decode object of class (Installation) for key

问题：

[NSKeyedUnarchiver decodeObjectForKey:]: cannot decode object of class (Installation) for key (root); the class may be defined in source code or a library that is not linked

一般出现在用archive序列化存储一个对象A，然后后来的某个版本中在对象A中添加了属性。然后解档老的序列化数据时crash

解决方案:

NSKeyedArchiver.setClassName("Employee", for: Employee.self)
//before serializing
let employeeData = NSKeyedArchiver.archivedData(withRootObject: employee)


NSKeyedUnarchiver.setClass(Employee.self, forClassName: "Employee")
//before deserializing
NSKeyedUnarchiver.unarchiveObject(with: decoded) as? Employee