factory-dependency-injection

Add a computed property returning Factory<T> to an extension of Container, using the closure sugar self { MyService() }. Resolution is Container.shared.myService() or the @Injected(\.myService) property wrapper, and missing registrations fail at compile time.

Factory is compile-time safe because each registration is a typed computed property, so missing registrations fail to compile rather than failing at runtime. It needs no upfront registration of every type, no codegen, and supports scopes, contexts, and Swift Testing traits out of the box.

Import FactoryKit in app and library code; the module is named FactoryKit so it does not collide with the Factory type. In test targets add only FactoryTesting, which transitively exposes FactoryKit, since adding FactoryKit directly to the test target creates duplicate factories.

Annotate the suite or test with the .container trait from FactoryTesting, then call Container.shared.myService.register { MockService() } inside the test. Each test gets a fresh TaskLocal container and a cloned singleton scope, so parallel tests stay isolated.

Modifiers baked into the factory definition are re-applied on every read of the computed property, so the innermost definition wins over call-site overrides. Move the override into autoRegister(), chain it at the resolve site, or add .once() after the baked-in modifier.

Yes, use ParameterFactory<P, T> and resolve with Container.shared.paramService(42) or dependency(\.paramService, parameter: 42). The @Injected property wrapper cannot pass parameters, and per-parameter caching requires .scopeOnParameters with a Hashable parameter.