Isolation, actors, sendable… a concurrency deep dive
summary
Swift 6’s concurrency turns runtime races into compile errors by enforcing three concrete rules: isolation (state belongs to one context), actors (convert a sync class to an actor to stop concurrent mutations but calls become implicitly async and require await), and sendable/sending (only Sendable values cross isolation boundaries; use the new sending keyword or make a type Sendable). Examples: turning a shared formatter class into an actor prevents crashes; tasks now accept sending closures so non‑Sendable captures must be moved or transferred; annotate with @MainActor to keep contexts aligned.
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chapters (11)
- 0:00Swift 6 concurrency changes
- 1:45Data race protection pillars
- 4:14Protecting state before actors
- 7:05Actors prevent data races
- 10:38Actor isolation explained
- 13:25Global actors and boundaries
- 17:59Apple’s concurrency push
- 21:09Sendable types
- 25:03Sendable closures and keyword
- 28:55Compiler errors and fixes
- 30:39Swift 6 concurrency best practices
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