swift-concurrency-expert

Fix Swift concurrency data races by analyzing compiler diagnostics and actor isolation context to apply minimal safe patches like @MainActor annotations, isolated conformances, and centralized mutable state. This eliminates data races while preserving original behavior.

Actor isolation in Swift 6 restricts mutable state access to prevent data races. You need @MainActor defaults in UI-centric apps to ensure main-thread safety. The skill identifies isolation issues and annotates types to guarantee safe concurrent access.

Migrate to strict concurrency by analyzing source files to surface data-race risks, then applying minimal safe patches: annotate types with @MainActor, switch conformances to isolated or nonisolated, and use @concurrent for background work. The skill provides guided migration steps and references.

Yes, this Swift concurrency migration approach works for libraries and multi-module projects. It addresses actor isolation, Sendable safety, and safe offloading across modules and files, targeting both UI-centric apps and libraries with minimal, behavior-preserving patches.

The best way to handle Sendable misuse and unsafe concurrent state is to analyze the project's actor isolation context and apply minimal safe fixes: mark types with @MainActor, update conformances to isolated or nonisolated, and centralize mutable state on the main actor.

Swift 6 code fails actor isolation checks across modules due to unsafe mutable state access and Sendable violations. The skill identifies these cross-module data-race risks and remediates them by switching conformances and applying isolated or nonisolated annotations.