WWDC24: Migrate your app to Swift 6 | Apple

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. Discuss this video on the Apple Developer Forums: https://developer.apple.com/forums/topics/programming-languages-topic?cid=yt-w-0011 Explore related documentation, sample code, and more: Swift 6 Migration Guide: https://www.swift.org/migration/documentation/migrationguide/ Updating an app to use strict concurrency: https://developer.apple.com/documentation/Swift/updating-an-app-to-use-strict-concurrency Swift concurrency: Update a sample app: https://developer.apple.com/videos/play/wwdc2021/10194 00:00 - Introduction 00:33 - The Coffee Tracker app 00:45 - Review the refactor from WWDC21 03:20 - Swift 6 and data-race safety 04:40 - Swift 6 migration in practice 07:26 - The strategy 08:53 - Adopting concurrency features 11:05 - Enabling complete checking in the watch extension 13:05 - Shared mutable state in global variables 17:04 - Shared mutable state in global instances and functions 19:29 - Delegate callbacks and concurrency 23:40 - Guaranteeing data-race safety with code you don’t maintain 25:51 - Enabling the Swift 6 language mode in the watch extension 26:35 - Moving on to CoffeeKit 27:24 - Enabling complete checking in CoffeeKit 27:47 - Common patterns and an incremental strategy 29:55 - Global variables in CoffeeKit 31:05 - Sending an array between actors 33:53 - What if you can’t mark something as Sendable? 35:23 - Enabling the Swift 6 language mode in CoffeeKit 35:59 - Adding a new feature with guaranteed data-race safety 40:43 - Wrap up and the Swift 6 migration guide More Apple Developer resources: Video sessions: https://apple.co/VideoSessions Documentation: https://apple.co/DeveloperDocs Forums: https://apple.co/DeveloperForums App: https://apple.co/DeveloperApp