Your @MainActor Code Was Never Promised the Main Thread. Swift's About to Make That Official.
Swift Evolution's fourth pitch for Custom Main and Global Executors quietly confirms something most iOS developers get wrong: @MainActor guarantees serialized isolation, not literally Thread.main. Here's what changes and why it matters.
Migrating a Real App to Swift 6.2 Strict Concurrency: 86 Errors, One Afternoon, One Race Condition I Didn't Know I Had
I migrated Invoize from Swift 6.0 strict mode to Swift 6.2 approachable concurrency on a Sunday afternoon. Every warning, every fix, the one real race condition the compiler finally surfaced — and the TDD seams I leaned on so the migration wasn't just compiler-driven guessing.
@concurrent vs nonisolated vs @MainActor: The Swift 6.2 Decision Tree That Fits on a Napkin
Four real scenarios — UI update, network call, image decode, file IO — and exactly which Swift 6.2 isolation keyword each one needs. A TDD walk-through with Swift Testing, no whiteboard ceremony required.
MainActor by Default: Why Apple Just Reversed Swift's Concurrency Story
Xcode 26 flips the default — your code now runs on the main actor unless you say otherwise. Here's why Apple changed direction, what it actually means for your existing project, and a TDD walk-through showing the migration in real Swift.