Whats new in swift concurrency
Asked on 2025-06-16
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At WWDC, Apple introduced several updates to Swift concurrency, particularly with the release of Swift 6. Here are some of the key highlights:
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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 significantly enhances the security of apps and reduces debugging time. This feature can be adopted module by module, allowing for gradual migration (What’s new in Swift).
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Concurrency Model Enhancements: Swift 6.2 changes the concurrency model to be single-threaded by default until concurrency is explicitly introduced. This makes it easier to write data race-free code by default and provides a more approachable path to introducing concurrency in projects (What’s new in Swift).
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Improved Debugging in Xcode: Xcode 26 has improved its debugging tools for Swift concurrency. It now follows execution into asynchronous functions, even across threads, and provides better visibility into concurrency types like tasks, task groups, and actors (What’s new in Xcode).
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Low-Level Synchronization Primitives: Swift 6 introduces new low-level primitives for synchronization, such as atomics and mutexes, which provide efficient, lock-free implementations for safe concurrent access (What’s new in Swift).
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Migration Tools: Swift 6.2 includes migration tooling to help developers automatically make necessary code changes to adopt new concurrency features. This is part of Apple's effort to make concurrency more approachable and safer (What’s new in Swift).
For a deeper dive into these updates, you can explore sessions like "Embracing Swift Concurrency" and "Code-along: Elevate an App with Swift Concurrency" which provide practical techniques and examples for using Swift concurrency effectively.
What’s new in Swift
Join us for an update on Swift. We’ll briefly go through a history of Swift over the past decade, and show you how the community has grown through workgroups, expanded the package ecosystem, and increased platform support. We’ll introduce you to a new language mode that achieves data-race safety by default, and a language subset that lets you run Swift on highly constrained systems. We’ll also explore some language updates including noncopyable types, typed throws, and improved C++ interoperability.
What’s new in Xcode
Discover the latest productivity and performance advancements in Xcode 26. Learn how to leverage large language models in your development workflow. Explore editing and debugging enhancements, improved performance and testing tools, and Swift Build - the open-source build system engine used by Xcode.
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.