Swift Concurrency provides us with loads of cool and interesting capabilities. For example, Structured Concurrency allows us to write a hierarchy of tasks that always ensures all child tasks are completed before the parent task can complete. We also have features like cooperative cancellation in Swift Concurrency which means that whenever we want to cancel a task, that task must proactively check for cancellation, and exit when needed. One API that Swift Concurrency doesn't provide out of the box is an API to have tasks that timeout when they take too long. More generally speaking, we don't have an API...

Swift 6 has been available to us for the better part of a year now, and more and more teams are considering or looking at migrating to the Swift 6 language mode. This typically involves trying to turn on the language mode or turning on strict concurrency, seeing a whole bunch of warnings or errors, and then deciding that today is not the day to proceed with this migration. Today I would like to propose an approach to how you can plan your migration in a way that won’t scare you out of attempting the migration before you’ve even started....

The Xcode 16.3 beta is out, which includes a new version of Swift. Swift 6.1 is a relatively small release that comes with bug fixes, quality of life improvements, and some features. In this post, I’d like to explore two of the new features that come with Swift 6.1. One that you can start using immediately, and one that you can opt-in on if it makes sense for you. The features I’d like to explore are the following: Changes to Task Groups in Swift 6.1 Changes to member visibility for imported code We’ll start by looking at the changes in...

When you're using Git for version control, you're already doing something great for your codebase: maintaining a clear history of changes at every point in time. This helps you rewind to a stable state, track how your code has evolved, and experiment with new ideas without fully committing to them right away. However, for many developers, Git is just another tool they have to use for work. They write a lot of code, make commits, and push their changes without giving much thought to how their commits are structured, how big their branches are, or whether their commit history is...

On iOS 17 and newer, you have access to the Observable macro. This macro can be applied to classes, and it allows SwiftUI to officially observe properties on an observable class. If you want to learn more about Observable or if you're looking for an introduction, definitely go ahead and check out my introduction to @Observable in SwiftUI. In this post, I would like to explore how you can observe properties on an observable class. While the ObservableObject protocol allowed us to easily observe published properties, we don't have something like that with Observable. However, that doesn't mean we cannot...

When you turn on strict concurrency checking or you start using the Swift 6 language mode, there will be situations where you run into an error that looks a little bit like the following: Main actor-isolated property can not be referenced from a Sendable closure What this error tells us is that we're trying to use something that we're only supposed to use on or from the main actor inside of a closure that's supposed to run pretty much anywhere. So that could be on the main actor or it could be somewhere else. The following code is an example...

When Apple released Xcode 16 last year, they made the Swift 6 compiler available along with it. This means that we can create new projects using Swift 6 and its compile-time data race protections. However, the big question for many developers is: Is 2025 the right time to adopt Swift 6 fully, or should we stick with Swift 5 for now? In this post, I won’t give you a definitive answer. Instead, I’ll share my perspective and reasoning to help you decide whether adopting Swift 6 is right for you and your project(s). The right answer depends on loads of...

With Swift 6, we have an entirely new version of the language that has all kinds of data race protections built-in. Most of these protections were around with Swift 5 in one way or another and in Swift 6 they've refined, updated, improved, and expanded these features, making them mandatory. So in Swift 5 you could get away with certain things where in Swift 6 these are now compiler errors. Swift 6 also introduces a bunch of new features, one of these is the sending keyword. Sending closely relates to Sendable, but they are pretty different in terms of why...

Unit tests should be as free of external dependencies as possible. This means that you want to have full control over everything that happens in your tests. For example, if you're working with a database, you want the database to be empty or in some predefined state before your test starts. You operate on the database during your test and after your test the database can be thrown away. By making your tests not depend on external state, you make sure that your tests are repeatable, can run in parallel and don't depend on one test running before another test....

Swift's new modern testing framework is entirely driven by asynchronous code. This means that all of our test functions are async and that we have to make sure that we perform all of our assertions “synchronously”. This also means that completion handler-based code is not as straightforward to test as code that leverages structured concurrency. In this post, we’ll explore two approaches that can be useful when you’re testing code that uses callbacks or completion handlers in Swift Testing. First, we’ll look at the built-in confirmation method from the Swift Testing framework and why it might not be what you...