Swift Professional Usage

swift-professional-usage

Registry Trigger

Use when

• Swift code changes value/reference or copy-on-write semantics, Optional APIs, ARC, actor isolation, Sendable, cancellation, type erasure, Objective-C interop, SwiftUI state, or module visibility.
• A compiler, deployment target, imported module, runtime, or UI lifecycle can change behavior beyond compilation.

Do not use when

• Swift appears only in comments/generated output, or another-language change has no Swift source or imported boundary.
• The change is only an iOS/macOS entitlement, signing, provisioning, packaging, or platform configuration with no Swift semantic decision.

Skill Role

Own Swift language, memory, concurrency, type, interop, SwiftUI, and module semantics. Leave Apple platform/release contracts and generic concerns to their owners.

High-Value Rules

• Choose value/reference and copy-on-write semantics from identity, aliasing, mutation isolation, copy cost, concurrency, and nested-reference evidence.
• Prove ARC teardown ownership across closures, delegates, callbacks, tasks, Objective-C edges, and cycle-breaking edges.
• Treat actor isolation and Sendable as access contracts; identify hops, unsafe escapes, inherited isolation, and UI owner.
• Preserve caller-visible cancellation semantics across task groups, unstructured tasks, continuations, and cleanup.
• Choose generics, some, or any from identity, storage, dispatch, associated-type, and compatibility needs.
• Define each Optional's absent-state meaning, safe unwrapping/defaulting, API exposure, and Objective-C import behavior.
• At Objective-C boundaries, inspect nullability, selector exposure, ownership, bridging copies, availability, and exception limits.
• In SwiftUI, bind state identity and lifetime to the correct view/model owner; prove observation, main-actor mutation, task cancellation, restoration, and package visibility.

Anti-Patterns

• A struct, let, protocol, or Sendable conformance is treated as deep immutability or race-freedom proof.
• weak, unowned, or [weak self] is applied mechanically without proving lifetime and required work completion.
• @MainActor is treated as proof that every synchronous caller runs on the main thread.
• A detached task, continuation, or SwiftUI task hides cancellation, double resume, retention, or repeated effects.

Stop Conditions

• Stop until behavior-controlling compiler, deployment, OS, package, Objective-C, and observation versions are known.
• Route entitlements, signing, lifecycle policy, notifications, background modes, and Apple platform APIs to their domain owner.
• Route generic concurrency, API evolution, security, persistence, performance, and testing to their owners.
• Stop on an unknown callback/continuation owner, isolation domain, Objective-C ownership annotation, or view identity.

Output Contract

• Swift decision with identity ownership isolation cancellation type error interop SwiftUI module lifecycle invalid teardown outcomes evidence limits and residual risk

Targeted References