Swift Concurrency

Priority: P0

Implementation Guidelines

async/await

• Async Functions: Mark with async, call with await.
• Error Handling: Combine with throws for async throwing functions.
• No Completion Handlers: Prefer async over callback-based APIs.

Actors

• Data Isolation: Use actor for mutable state accessed from multiple tasks.
• MainActor: Annotate UI code with @MainActor for main thread execution.
• Actor Isolation: All actor properties/methods are isolated automatically.

Task Management

• Structured Concurrency: Use Task {}, async let, TaskGroup.
• Cancellation: Check Task.isCancelled, propagate cancellation.
• Detached Tasks: Avoid Task.detached unless necessary.

Anti-Patterns

• Blocking Main Thread: **No synchronous work in @MainActor**: Use Task.
• Missing MainActor: **UI updates must be @MainActor**: Compiler error.
• Ignoring Cancellation: **Check Task.isCancelled**: Respect cancellation.

References

• async/await & Actors