concurrency-patterns

To prevent data races in Swift, apply structured concurrency patterns using async/await and actors to establish safe boundaries for shared mutable state. This approach isolates data access and progressively migrates legacy callbacks into race-free asynchronous code.

Migrating legacy callback APIs to async/await involves using continuations to bridge existing asynchronous functions into the modern Swift concurrency model. This allows you to replace nested closures with structured, sequential code while preparing for Swift 6 compatibility.

The best way to use actors for thread-safe state is to declare types with the actor keyword, which serializes access to their mutable properties and prevents data races. This naturally enforces isolation without requiring manual locks in your iOS apps.

Swift 6.2 concurrency migration does not strictly require actors everywhere, but utilizes isolated conformances and MainActor inference to safely manage execution contexts. Actors remain essential for isolating shared mutable state across concurrent tasks.

Continuations are needed when bridging legacy APIs because they expose the control flow of existing callback-based asynchronous code to the async/await syntax. This allows developers to safely resume suspended tasks without breaking structured concurrency boundaries.

Structured concurrency can be used effectively for code review and migration planning by auditing critical code paths for concurrency issues. It provides a reference workflow to progressively apply actor boundaries and replace nested callbacks across iOS and macOS apps.