Isolated var

In the context of migrating to Swift 6, the term "isolated var" refers to the concept of ensuring that variables are safely accessed in a concurrent environment to prevent data races. In Swift 6, you can address data races by using several strategies:

1. Immutable Variables: Convert a var to a let to make it immutable, which prevents data races when accessed from multiple threads.

2. Global Actors: Tie a global variable to a global actor, such as the main actor, to ensure that all access to the variable is isolated to a specific actor.

3. Non-Isolated Unsafe: Use the nonisolated unsafe keyword as a last resort when you have an external mechanism ensuring the safety of the variable, such as a dispatch queue. This approach places the responsibility on the developer to ensure thread safety.

4. Assume Isolated: Use assume isolated to inform the compiler that a piece of code is already running on a specific actor, such as the main actor, without starting a new task.

These strategies are part of the broader effort in Swift 6 to enhance data-race safety and concurrency management. For more detailed information, you can refer to the session Migrate your app to Swift 6 (13:05) which discusses shared mutable state in global variables.