Agent skill · affaan-m
swift-concurrency-6-2
Swift 6.2 Approachable Concurrency — single-threaded by default, @concurrent for explicit background offloading, isolated conformances for main actor types. Use when adopting Swift 6.2 concurrency — offloading with @concurrent or resolving main-actor isolation.
What it needs
About 4k tokens when loaded.
What this skill does
Swift 6.2 Approachable Concurrency Patterns for adopting Swift 6.2's concurrency model where code runs single-threaded by default and concurrency is introduced explicitly. Eliminates common data-race errors without sacrificing performance. When to Activate Migrating Swift 5.x or 6.0/6.1 projects to Swift 6.2 Resolving data-race safety compiler errors Designing MainActor-based app architecture Offloading CPU-intensive work to background threads Implementing protocol conformances on MainActor-isolated types Enabling Approachable Concurrency build settings in Xcode 26 Core Problem: Implicit Background Offloading In Swift 6.1 and earlier, async functions could be implicitly offloaded to background threads, causing data-race errors even in seemingly safe code: Swift 6.2 fixes this: async functions stay on the calling actor by default. Core Pattern — Isolated Conformances MainActor types can now conform to non-isolated protocols safely: The compiler ensures the conformance is only used on the main actor: Core Pattern — Global and Static Variables Protect global/static state with MainActor: MainActor Default Inference Mode Swift 6.2 introduces a mode where MainActor is inferred by default — no manual annotations needed: This mode is opt-in and recommended for apps, scripts, and other executable targets. Core Pattern — @concurrent for Background Work When you need actual parallelism, explicitly offload with @concurrent: Important: This example requires Approachable Concurrency build settings — SE-0466 (MainActor default isolation) and SE-0461 (NonisolatedNonsendingByDefault). With these enabled, extractSticker stays on the caller's actor, making mutable state access safe. Without these settings, this code has a data race — the compiler will flag it. To use @concurrent: 1. Mark the containing type as nonisolated 2. Add @concurrent to the function 3. Add async if not already asynchronous 4. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills affaan-m/swift-concurrency-6-2--3ec430