How should I update my app for strict concurrency checking?

To update your app for strict concurrency checking in Swift 6, you can follow these steps:

1. Enable Swift 6 Mode: Start by enabling the Swift 6 language mode for your project. This mode turns all data race issues into compile-time errors, which helps in improving the security and stability of your app.

2. Enable Complete Concurrency Checking:

   • Go to your target's build settings.
   • Search for the "Swift Concurrency Checking" setting.
   • Set it to "Complete Checking". This will make the compiler emit warnings about code that it cannot confirm is concurrency safe.

3. Address Warnings and Errors:

   • Build your project and review the warnings and errors generated by the compiler.
   • These warnings will guide you on where you need to make changes to ensure your code is concurrency safe.

4. Isolate Data:

   • Use actors to protect mutable state.
   • Ensure that shared data is marked as Sendable to guarantee safe data sharing between threads.

5. Incremental Strategy:

   • Start with simpler targets, such as your UI layer, which often runs on the main thread.
   • Gradually move to more complex modules, addressing concurrency issues step by step.

6. Refactor as Needed:

   • Avoid blending significant refactoring with enabling data race safety. Focus on one at a time to manage changes effectively.

For a detailed walkthrough, you can refer to the session Migrate your app to Swift 6 starting at 11:05.

Relevant Sessions

1. Migrate your app to Swift 6
2. What’s new in Swift

These sessions provide comprehensive guidance on adopting Swift 6 and ensuring data-race safety in your applications.