Swift 未调用MappingModel migrationPolicy

我创建了一个

MappingModel

，成功地迁移了我的

DataModels

。但是-我有一个属性，我想用自定义方法设置它，但是由于某些原因，

MigrationPolicy

没有被调用

这是我的MigrationPolicy子类中的内容：

@objc open class MigrationPolicy_2_to_3: NSEntityMigrationPolicy {
    
    @objc func migrateCodeTo(lang: String) -> String {
        if let definedData = DbTypeDefines.data.first(where: { $0.language == lang }) {
            return definedData.code
        }
        return lang
    }
}

这些是我的映射模型设置：

这是店面协调员：

// MARK: - Core Data stack

lazy var persistentContainer: NSPersistentContainer = {
    /*
     The persistent container for the application. This implementation
     creates and returns a container, having loaded the store for the
     application to it. This property is optional since there are legitimate
     error conditions that could cause the creation of the store to fail.
    */
    let container = NSPersistentContainer(name: "ZoomQuiz")
    container.loadPersistentStores(completionHandler: { (storeDescription, error) in
        if let error = error as NSError? {
            // Replace this implementation with code to handle the error appropriately.
            // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
             
            /*
             Typical reasons for an error here include:
             * The parent directory does not exist, cannot be created, or disallows writing.
             * The persistent store is not accessible, due to permissions or data protection when the device is locked.
             * The device is out of space.
             * The store could not be migrated to the current model version.
             Check the error message to determine what the actual problem was.
             */
            fatalError("Unresolved error \(error), \(error.userInfo)")
        }
    })
    return container
}()

func managedObjectContext() -> NSManagedObjectContext {
    return persistentContainer.viewContext
}

// MARK: - Core Data Saving support

func saveContext () {
    let context = persistentContainer.viewContext
    if context.hasChanges {
        do {
            try context.save()
        } catch {
            // Replace this implementation with code to handle the error appropriately.
            // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            let nserror = error as NSError
            fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
        }
    }
}