v10.10.0

Enhancements

• Add a new property wrapper-based declaration syntax for properties on Realm Swift object classes. Rather than using @objc dynamic or the RealmProperty wrapper type, properties can now be declared with @Persisted var property: T, where T is any of the supported property types, including optional numbers and collections. This has a few benefits:

  • All property types are now declared in the same way. No more remembering that this type requires @objc dynamic var while this other type requires let, and the RealmProperty or RealmOptional helper is no longer needed for types not supported by Objective-C.

  • No more overriding class methods like primaryKey(), indexedProperties() or ignoredProperties(). The primary key and indexed flags are set directly in the property declaration with @Persisted(primaryKey: true) var _id: ObjectId or @Persisted(indexed: true) var indexedProperty: Int. If any @Persisted properties are present, all other properties are implicitly ignored.

  • Some performance problems have been fixed. Declaring collection properties as let listProp = List<T>() resulted in the List<T> object being created eagerly when the parent object is read, which could cause performance problems if a class has a large number of List or RealmOptional properties. @Persisted var list: List<T> allows us to defer creating the List<T> until it's accessed, improving performance when looping over objects and using only some of the properties.

    Similarly, let _id = ObjectId.generate() was a convenient way to declare a sync-compatible primary key, but resulted in new ObjectIds being generated in some scenarios where the value would never actually be used. @Persisted var _id: ObjectId has the same behavior of automatically generating primary keys, but allows us to only generate it when actually needed.

  • More types of enums are supported. Any RawRepresentable enum whose raw type is a type supported by Realm can be stored in an @Persisted project, rather than just @objc enums. Enums must be declared as conforming to the PersistableEnum protocol, and still cannot (yet) be used in collections.

  • willSet and didSet can be used with @Persistable properties, while they previously did not work on managed Realm objects.

  While we expect the switch to the new syntax to be very simple for most users, we plan to support the existing objc-based declaration syntax for the foreseeable future. The new style and old style cannot be mixed within a single class, but new classes can use the new syntax while existing classes continue to use the old syntax. Updating an existing class to the new syntax does not change what data is stored in the Realm file and so does not require a migration (as long as you don't also change the schema in the process, of course).

• Add Map.merge(), which adds the key-value pairs from another Map or Dictionary to the map.

• Add Map.asKeyValueSequence() which returns an adaptor that can be used with generic functions that operate on Dictionary-styled sequences.

Fixed

• AnyRealmValue enum values are now supported in more places when creating objects.
• Declaring a property as RealmProperty<AnyRealmValue?> will now report an error during schema discovery rather than doing broken things when the property is used.
• Observing the invalidated property of RLMDictionary/Map via KVO did not set old/new values correctly in the notification (since 10.8.0).

Compatibility

• Realm Studio: 11.0.0 or later.
• APIs are backwards compatible with all previous releases in the 10.x.y series.
• Carthage release for Swift is built with Xcode 12.5.1.
• CocoaPods: 1.10 or later.
• Xcode: 12.2-13.0 beta 2.