CoreModel

Swift Object Graph

Requirements

Swift 6.0 or later, macOS 10.15, iOS 13, tvOS 13, and watchOS 6.

InMemoryStorage, InMemoryModelStorage, and InMemoryViewContext are the exception: they serialize access to their shared backing with Synchronization.Mutex, which is not back-deployed, so on Apple platforms they require macOS 15, iOS 18, tvOS 18, watchOS 11, or visionOS 2. Everything else in CoreModel — the schema types, predicates, and the ModelStorage/ViewContext protocols — is available at the package's own deployment targets, as are third-party backends such as SQLite and MongoDB. Linux, Windows, Android, and WebAssembly have no such restriction.

Backends

• CoreData
• SQLite
• MongoDB

Embedded Swift

The CoreModel target compiles under Embedded Swift, starting with WebAssembly (wasm32-unknown-none-wasm / wasm32-unknown-wasip1 via the embedded Swift SDK). CoreDataModel remains a Foundation/CoreData-only target and is unaffected.

SWIFTPM_ENABLE_MACROS=0 swift build --swift-sdk swift-6.3.2-RELEASE_wasm-embedded

Macros must be disabled (SWIFTPM_ENABLE_MACROS=0) since swift-syntax isn't available under Embedded. This means a few things @Entity normally generates aren't available and must be written by hand:

• Entity.entityName, attributes, and relationships have no default implementation — implement them explicitly.
• Entity.init(from:) / encode() have no default Codable-derived implementation — implement them using ModelData.decode(_:forKey:) / .encode(_:forKey:) (see Person in Tests/CoreModelTests/TestModel.swift for the pattern).
• enum CodingKeys: CodingKey { ... } must declare an explicit String raw value — enum CodingKeys: String, CodingKey { ... } — since Embedded Swift has no Codable/CodingKey synthesis; CoreModel provides its own CodingKey protocol under Embedded that relies on the raw value.
• Model(entities: any Entity.Type...) is unavailable (calls a generic initializer through an existential); use Model(entities: [EntityDescription(entity: Person.self), ...]) with concrete types instead.
• ModelStorage's generic Entity-based convenience methods (fetch<T>, insert<T>, delete<T>, count<T>) and ViewContext are unavailable under Embedded (a compiler limitation in async default protocol-extension methods). Call the ModelStorage protocol requirements directly with ModelData/ObjectID.
• UUID, Date, Data, URL, and Decimal are Foundation-free storage-layer replacements on platforms without Foundation — sufficient for round-tripping through AttributeValue, not general-purpose Foundation substitutes.