How to migrate to Swift 6?

To migrate your app to Swift 6, you can follow a structured process that ensures a smooth transition while taking advantage of the new features and safety guarantees provided by Swift 6. Here are the key steps:

Enable Complete Concurrency Checking: This is a per-module setting that leaves your project in Swift 5 mode but enables warnings for all the code that would fail with Swift 6's enforced data isolation. This helps you identify and fix potential issues before fully migrating to Swift 6.

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Resolve Warnings: Go through the warnings generated by the concurrency checking and resolve them. This step ensures that your code is ready for the stricter data isolation rules in Swift 6.
Enable Swift 6 Mode: Once all warnings are resolved for a target, enable Swift 6 mode for that target. This locks in your changes and prevents future regressions to an unsafe state.
Repeat for Each Target: Repeat the above steps for each target in your project. This incremental approach allows you to migrate one module at a time, making the process more manageable.
Refactor if Necessary: After enabling Swift 6 mode for all targets, you might want to do some whole-app refactoring to optimize your code further and ensure it adheres to the new safety standards.
Adopt Concurrency Features: If you're actively working on integrating more concurrency to improve responsiveness and performance, adopting Swift 6 mode can ensure that those changes don't risk introducing new data races.

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Follow the Migration Guide: Swift.org provides a migration guide with insights and patterns on how best to modify your code to eliminate data races. This guide can be a valuable resource throughout the migration process.

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By following these steps, you can methodically migrate your app to Swift 6, taking advantage of its new features and safety guarantees while minimizing disruptions to your development process.