What's new in Swift

Presenters:

Mishal Shah, Swift Team
Meghana Gupta, Swift Team

Link: https://developer.apple.com/wwdc24/10136

10 years since Swift was announced!

Swift project update

New platform steering group to focus on bringing Swift to more places
Core team is working on putting together a new ecosystem steering group
Also, a new embedded working group

Check it out on swift.org/community

Guides and tutorials on the website
Swift.org/packages to explore the package ecosystem

Swift Everywhere

Swift officially supported on Apple, Linux and Windows
Additional supported platforms expanded to Fedora and Debian (and a bunch of other things)
Developed SourceKit LSP to integrate Swift support
Community has adopted in VSCode, Neovim, and more

Cross compiling

Introducing a static Linux SDK for Swift to build Linux binaries on macOS
Demo of cross-compiling a service built for macOS for Linux

Foundation

Foundation
swift-corelibs-foundation (for other platforms)
Rewrote to a modern single codebase - swift-foundation
Shipped in iOS and macOS last fall
swift-foundation is open source

Swift Testing

Takes advantage of macros, integrates with concurrency
Developed in open source with cross-platform in mind
Vision is to become the official default testing solution

Building

Improvements to how Xcode builds your code
Implicitly built modules
Instead, adding explicitly built modules
More parallelism, better visibility into build steps, improved reliability

Swift is moving

github.com/swiftlang

Starting migration soon, details posted on swift.org

Swift 6

Noncopyable types
Embedded Swift
C++ interoperability
Typed throws
Data-race safety

Noncopyable types

All Swift types are copyable by default
Noncopyable types let you express unique ownership
Swift 6 introduces support for all generic contexts
You can now write failable initializers for generic types (Optional, Result, Unsafe Pointers)
Fine-grained control over performance

Embedded Swift

C and C++ have been choices for resource-constrained environments
Embedded Swift is a new language subset - turns off certain language features that need runtime (reflection, "any" types)
Special compiler techniques
Embedded Swift is close to full Swift
Brings memory safety to embedded systems
Incremental adoption with Swift interoperability with C++

C++ Interoperabililty

Virtual methods, default arguments, move-only types can be directly imported into Swift
Virtual & default mapped to equivalent Swift versions
Move-only types mapped to noncopyable types
Can incrementally adopt Swift in C++ projects

Typed throws

Swift 6 introduces typed throws to let you specify the error type
No type erasure, the typed error appears
You can continue using untyped throws to evolve APIs

Data-race safety

Swift 6 language mode
Achieves data race safety by default, turning data race issues into compile-time errors
Can adopt module-by-module and interoperate with dependencies that may not have updated
Big improvements to data race safety
Swift 6 recognizes that it's safe to pass non-Sendable values sometimes
New Atomic low-level synchronization primitives
Synchronization module also introduces Mutex

Check out: Migrate your app to Swift 6