what swift changes relate to concurrency
Asked on 06/11/2025
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In the WWDC sessions, several changes related to concurrency in Swift were discussed. Here are some key points:
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Concurrency Language Changes: Swift 6.2 introduces language changes that make concurrency more approachable. These changes are opt-in and can be enabled in Xcode Build Settings or a Swift package manifest file. The changes aim to make code data race-free by default, providing a safer path to introducing concurrency in projects (What’s new in Swift).
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Data Race Safety: Swift 6 introduces data race safety by default, turning potential data race issues into compile-time errors. This is part of the new Swift 6 language mode, which is opt-in and can be adopted module by module (What’s new in Swift).
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Main Actor and Async Functions: The language changes make it easier to call async functions on types with mutable state. Functions that aren't tied to a specific actor will continue to run on the actor they were called from, eliminating data races (What’s new in Swift).
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Concurrency in Practice: The session "Embracing Swift concurrency" discusses how to use concurrency to improve app performance and responsiveness. It covers the introduction of asynchronous tasks, moving work to background threads, and sharing data across threads without introducing data races (Embracing Swift concurrency).
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Migration to Swift 6: The session "Migrate your app to Swift 6" provides guidance on adopting Swift 6's concurrency features, including enabling the Swift 6 language mode and ensuring data race safety in existing applications (Migrate your app to Swift 6).
These changes and tools are designed to make concurrent programming in Swift safer and more efficient, helping developers avoid common pitfalls like data races.
What’s new in Swift
Join us for an update on Swift. We’ll talk about workflow improvements that make you more productive, and new and modernized library APIs for fundamental programming tasks. We’ll show examples of Swift adoption throughout more layers of the software stack. Finally, we’ll explore new language features for both improving approachability of concurrency, and achieving peak performance when you need it.
Migrate your app to Swift 6
Experience Swift 6 migration in action as we update an existing sample app. Learn how to migrate incrementally, module by module, and how the compiler helps you identify code that’s at risk of data races. Discover different techniques for ensuring clear isolation boundaries and eliminating concurrent access to shared mutable state.
Embracing Swift concurrency
Join us to learn the core Swift concurrency concepts. Concurrency helps you improve app responsiveness and performance, and Swift is designed to make asynchronous and concurrent code easier to write correctly. We’ll cover the steps you need to take an app through from single-threaded to concurrent. We’ll also help you determine how and when to make the best use of Swift concurrency features – whether it’s making your code more asynchronous, moving it to the background, or sharing data across concurrent tasks.