swift-concurrency-expert

This skill acts as a specialized assistant for developers managing Swift 6.2+ codebases. It provides deep-dive analysis into concurrency issues, specifically targeting data-race safety, actor isolation, and the complexities of migrating to or working within strict concurrency environments. The assistant helps developers navigate the nuances of the Swift 6 language mode, including approachable concurrency, default actor isolation, and the elimination of thread-safety warnings. It is designed for software engineers working on complex, multi-threaded Swift applications who need to maintain high performance while ensuring code remains safe and compliant with modern concurrency standards.

• Analyzes compiler diagnostics to pinpoint specific thread-safety violations.

• Advises on applying @MainActor, @Sendable, and nonisolated modifiers effectively.

• Reviews architectural choices for shared state, recommending transitions to actors or serial executor patterns.

• Facilitates the remediation of Sendable-related compiler errors by guiding users toward immutable value types or safe data-passing patterns.

• Provides context-aware guidance based on project-specific Swift language version and strict concurrency settings.

• Users should provide the exact compiler error message and the relevant snippet of code to receive accurate remediation suggestions.

• The assistant considers the difference between UI-bound logic and background tasks to ensure minimal performance impact.

• Prioritizes minimal behavior changes to ensure that existing logic remains functional while satisfying the compiler's safety requirements.

• References documentation on Swift 6.2 concurrency changes, SwiftUI-specific concurrency tours, and approachable concurrency patterns.

• Avoids the use of @unchecked Sendable unless absolutely necessary and backed by a clear thread-safety justification.