iOS 11+ How to migrate existing Core Data to Shared App Group for use in extension?

Question

When I created an iOS 11 app using the core data template, it auto generated the following code in AppDelete.m.

synthesize persistentContainer = _persistentC         


        

Answer 1

solidsnake4444's answer saves my day. Here is the Swift 5.0 version.

lazy var persistentContainer: NSPersistentContainer = {
    let container = NSPersistentContainer(name: "MyApp")
    let storeURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.com.my.app")!.appendingPathComponent("MyApp.sqlite")

    var defaultURL: URL?
    if let storeDescription = container.persistentStoreDescriptions.first, let url = storeDescription.url {
        defaultURL = FileManager.default.fileExists(atPath: url.path) ? url : nil
    }

    if defaultURL == nil {
        container.persistentStoreDescriptions = [NSPersistentStoreDescription(url: storeURL)]
    }
    container.loadPersistentStores(completionHandler: { [unowned container] (storeDescription, error) in
        if let error = error as NSError? {
            fatalError("Unresolved error \(error), \(error.userInfo)")
        }

        if let url = defaultURL, url.absoluteString != storeURL.absoluteString {
            let coordinator = container.persistentStoreCoordinator
            if let oldStore = coordinator.persistentStore(for: url) {
                do {
                    try coordinator.migratePersistentStore(oldStore, to: storeURL, options: nil, withType: NSSQLiteStoreType)
                } catch {
                    print(error.localizedDescription)
                }

                // delete old store
                let fileCoordinator = NSFileCoordinator(filePresenter: nil)
                fileCoordinator.coordinate(writingItemAt: url, options: .forDeleting, error: nil, byAccessor: { url in
                    do {
                        try FileManager.default.removeItem(at: url)
                    } catch {
                        print(error.localizedDescription)
                    }
                })
            }
        }
    })
    return container
}()