❌

Reading view

↗️

Swift 6.4

✇Michael Tsai
By: Michael Tsai

Swift 6.4 is now available in beta form with Xcode 27. The Swift Evolution proposals are listed here.

What’s new in Swift:

Discover the latest language advancements, including updates for everyday ergonomics, improved concurrency, and safer high-performance code. Explore workflow and language interoperability improvements and updates in embedded Swift.

Build real-time apps and services with gRPC and Swift:

Build engaging live experiences with gRPC in your Swift app and backend. gRPC is an open-source RPC framework designed for high-performance, bidirectional streaming APIs. Explore how the gRPC Swift package provides a modern, safe runtime built with Swift concurrency.

Explore numerical computing in Swift with MLX:

Bring NumPy-style computing natively to Swift with MLX Swift. Discover how to eliminate cross-language friction in your machine learning workflows by handling image processing, tensor operations, and neural network training in a single, type-safe environment. Explore the APIs that let you leverage GPU acceleration while enjoying the compiler, tooling, and debugging experience you already know.

Swift Group Lab:

Join us online for a deep dive into WWDC26 with Apple engineers and designers to ask questions, get advice, and follow the discussion about the week’s biggest Swift announcements.

Matt Massicotte:

There’s a voting system. And that means a number of questions weren’t selected. This time I copied those down and I thought it could be fun to take a shot at answering the ones that are more in my area.

Xcode 27 Beta 2 Release Notes:

The Swift dependency scanner has been optimized to avoid redundant setup work and header searches when looking up Clang modules during a single dependency-scan action, substantially improving scanning performance.

As a consequence of this change, every Clang module reachable from a single Swift dependency-scan action must have a unique module name. If two module maps visible to the same scan declare a Clang module with the same name, the scan may report an error.

[…]

System now provides Swift APIs for the C stat, lstat, fstat, and fstatat system calls. This includes a new Stat type with initializers from FilePath, FileDescriptor, or a C string; FilePath.stat() and FileDescriptor.stat() instance methods; and supporting types (FileType, FileMode, FileFlags, UserID, GroupID, DeviceID, and Inode).

Wade Tregaskis:

The final piece of the Prospective Vision for Accessors, this allows for more efficient accessors on structs, in a nutshell.

[…]

Now there’s a safer version of the existing withUnsafeTemporaryAllocation (first introduced in Swift 5.6). It works just like you’d expect. It comes in both “raw bytes” and typed elements versions, just like its unsafe predecessor.

[…]

The new isTriviallyIdentical(to:) method offers a guaranteed-fast way to check two objects for equality. It is essentially an optimised version of the existing equality condition provided by Equatable and the == operator. It’s useful because it guarantees O(1) time complexity, whereas == makes no formal guarantees at all (and for many types is O(N) or worse). But unlike the existing identity comparison operator === – also O(1) – it promises to do more than just tell if two objects are the exact same pointer, and it works on value types (not just reference types).

[…]

These new types generalise the existing patterns of borrowed and mutable references, that have previously existed in Swift in much more restricted forms (e.g. inout parameters are essentially MutableRef parameters, and Span & MutableSpan are array equivalents).

There’s now a built-in function for demangling Swift symbol names, in the Runtime module (that’s bundled with the Swift toolchain, alongside the stdlib etc).

Khoa Pham:

As Apple has aligned OS version numbers across platforms, Swift 6.4 takes the next step by letting you collapse repetitive availability attributes into a single anyAppleOS token.

[…]

There are situations where you need to call a deprecated API while you plan a migration, or audit a critical function for unsafe usage, without letting those concerns bleed into the rest of the project. The new @diagnose attribute handles both cases.

[…]

Some work should complete even after a task is cancelled, like flushing a file to avoid corruption. withTaskCancellationShield wraps a region where Task.isCancelled always returns false.

Antoine van der Lee:

Swift 6.4 implements SE-0493: Support async calls in defer bodies. This is one of those changes that feels obvious once you need it.

[…]

Swift 6.4 improves error handling for unstructured tasks through SE-0520: Discardable result use in Task initializers. The change helps you catch a subtle bug: creating a throwing task and then ignoring its returned task handle.

[…]

Swift 6.4 also implements SE-0530: Async Result Support.

[…]

Swift 6.4 implements SE-0518: ~Sendable for explicitly marking non-Sendable types. It allows you to communicate that a type has been audited and should not conform to Sendable.

Slava Pestov:

I thought it would be a good time to detail some of the type checker performance improvements we worked on since I shared the type checker performance roadmap last year. I’m also going to outline a couple of things we plan on looking at next.

Previously:

Update (2026-07-09): I was optimistic about improvements to the type checker making compilation faster, but I found that compiling my predominantly Swift project with Xcode 27 Beta 3 was only 0.3% faster than with Xcode 26.6. I wonder if there’s some extra setting I’m supposed to enable.

  •  
  • ↗️
↗️

SwiftData in appleOS 27

✇Michael Tsai
By: Michael Tsai

SwiftData updates:

Section your query results by creating your query with a macro that takes a sectionBy parameter, as listed on the Additional query macros page.

Use types that conform to Codable in a model, including types you don’t control directly, by using the codable option for Schema.Attribute.

Receive real-time updates to models that match specified fetch criteria by using the ResultsObserver type.

Observe remote model changes with the HistoryObserver type.

What’s new in SwiftData:

Discover the latest enhancements to SwiftData. We’ll show you how to persist custom and third-party types using Codable, and group fetched data into sections in your SwiftUI app. We’ll also explore how to observe data store changes anywhere else using ResultsObserver and HistoryObserver, giving you the flexibility to drive powerful state objects and react precisely to model updates.

Again, there seems to be nothing new in Core Data this year, nor any communication about it. There’s still no interoperability for object IDs. The SwiftData changes seem fine but don’t really address the new framework’s deficiencies relative to Core Data. It seems like there are still basic problems with threading. I just don’t understand how Apple is deciding what to prioritize with this framework.

With SwiftUI, the bones seem questionable, but at least we can see that Apple is full steam ahead, with substantial progress to address limitations and pain points. SwiftData seemed to have better bones and is much less ambitious. Getting it right seemed like just a matter of follow through. But, for some inexplicable reason, it seems to lack the resources and/or urgency to reach its potential. And even though SwiftUI is clearly the chosen one, AppKit remains in development. Meanwhile, Core Data seems to be abandoned, even though SwiftData feels more like a side quest than a genuine attempt to supplant it.

The implicit message, for those who have build the core of their app on top of Apple’s old persistence framework, seems to be that Apple is not looking out for their needs. Core Data will surely get maintenance to the extent that Apple’s own apps need it, but there’s no evidence of a future or even a migration plan. The answer, I guess, is third-party frameworks, but that’s not an easy migration, either, since none is even as close a match as SwiftData.

Add persistence with SwiftData:

Experience SwiftData in action as we add persistence to an existing app. We’ll show you how to define your data models and seamlessly integrate persistent data with SwiftUI. You’ll also learn foundational skills for managing your app’s state using this expressive, declarative API.

SwiftData Group Lab:

Join us online for a deep dive into WWDC26 with Apple engineers and designers to ask questions, get advice, and follow the discussion about the week’s biggest SwiftData announcements.

macOS Golden Gate 27 Beta Release Notes:

Fixed: You might experience a deadlock for @Query when saving a ModelContext on a background actor while scheduling new async tasks for a ModelActor.

Paul Hudson:

I am so pleased to say these words: IT IS A BIG YEAR FOR SWIFTDATA! 🎉

Mohammad Azam:

SwiftData predicates can now work directly with enum values, resulting in cleaner models and simpler query code.

[…]

In iOS 27, Apple introduced support for compound predicates through the Predicate(all:) and Predicate(any:) initializers, making it easier to build queries dynamically based on user input.

I’m not sure why that took so long.

The framework is gradually moving beyond simple demos and becoming easier to use in larger, more sophisticated projects.

[…]

iOS 27 is the first release where many of the framework’s early rough edges have started to disappear.

Matt Massicotte:

Results of my now-yearly check to see if SwiftData’s ModelActor continues to sometimes run code on the main thread: yes it does

Fatbobman:

Compared with @Query gaining support for section fetches, and ResultsObserver enabling observation of query result changes outside views, I am more interested in @Attribute(.codable). It provides a clearer storage intent and gives developers a way to avoid falling into the black box of composition.

Of course, @Attribute(.codable) is not a silver bullet. It is more like a clearly defined escape hatch SwiftData provides for opaque Codable types: suitable for storing external types that you cannot model yourself, but still genuinely need to persist. The cost is that this content cannot participate in SwiftData’s predicate, sort, or migration awareness. Precisely for this reason, its value lies not in being “more powerful,” but in being “more explicit.”

However, SwiftData still does not provide cloud syncing for public / shared data, nor have I seen a clearer signal of performance improvements. These issues will continue to limit its adoption. For many developers, SwiftData this year feels more like it is filling key gaps rather than making a leap significant enough to fundamentally change confidence in it.

Helge Heß:

Codable types in SwiftData seem pretty lame given that SQLite absolutely does have JSON support and does support queries on it?

But the funnier thing in the MKMapItem.Identifier example is that MKMapItem.Identifier is a RawRepresentable==String, so it could actually be stored as a String in the store.

Previously:

  •  
  • ↗️
↗️

SwiftUI in appleOS 27

✇Michael Tsai
By: Michael Tsai

macOS Golden Gate 27 Beta Release Notes:

AsyncImage now automatically caches downloaded images using HTTP caching protocols, allowing servers to control caching behavior via standard headers.

[…]

Xcode 27 introduces a new @State implementation that avoids this repeated evaluation. This new behavior back-deploys to iOS 17 aligned OSes. The new @State is implemented with a Swift macro. It is largely source compatible with the property wrapper version, with a few exceptions.

[…]

Text views now support TextRenderer.

[…]

In apps built with the 27.0 SDKs, the new ReadableDocument and WritableDocument protocols support asynchronous reading and writing, progress reporting, and direct access to document URLs. New DocumentGroup initializers that adopt these protocols let you disable document creation for editing-only apps and present custom UI before any document is opened.

[…]

TextField respects custom font and color styling applied to its prompt.

[…]

List accepts drops in two cases that previously didn’t work: drags with compatible transfer representations are accepted into reorderable content even when the .reorderableItem transfer type isn’t present, and a .dropDestination(…) modifier declared on a list item now performs the drop.

SwiftUI updates:

Build your project in Xcode 27 or later to construct type-agnostic content from closures that you mark with ContentBuilder, which serves as the unified replacement for type-specific builders like ToolbarContentBuilder and CommandsBuilder.

Add reordering by drag-and-drop in containers such as lists, stacks, grids, or custom layouts with reorderable() and reorderContainer(for:isEnabled:move:).

Add custom swipe actions to views in containers such as scroll views, stacks, grids, or custom layouts using swipeActions(edge:allowsFullSwipe:content:onPresentationChanged:) and swipeActionsContainer().

[…]

Use the visibilityPriority(_:) modifier to prioritize important toolbar actions so SwiftUI keeps them visible as space shrinks, moving lower-priority items to the overflow menu first.

[…]

Present an alert or confirmation dialog from an optional data item or error object, and use that data to produce the content and title[…]

What’s new in SwiftUI:

Explore the latest additions to SwiftUI and discover how they can improve your apps. We’ll introduce a new Document protocol with direct disk access and snapshot-based diffing for building high-performance apps; new APIs for reordering content in lists, grids, and sections; and toolbar enhancements including visibility priority and auto-minimizing behavior. We’ll also cover expanded presentation APIs — including swipe actions on any view — plus AsyncImage caching improvements and lazy state initialization for Observable types.

Use SwiftUI with AppKit and UIKit:

Discover how to incrementally adopt SwiftUI in your existing AppKit or UIKit app. We’ll show you how to use the Observation framework to automatically update your views, integrate SwiftUI components into an existing view hierarchy, and bring gesture recognizers into SwiftUI. We’ll also explore how to add complete SwiftUI scenes to your app without changing your overall architecture.

Dive into lazy stacks and scrolling with SwiftUI:

Discover the inner workings of lazy stacks in SwiftUI. We’ll explore how LazyVStack and LazyHStack estimate sizes, lazily load subviews, and prefetch content to deliver smooth scrolling experiences. We’ll also cover advanced performance optimizations, state management best practices, and tips for precise programmatic scrolling. To get the most out of this session, we recommend basic familiarity with SwiftUI layout using stacks.

Compose advanced graphics effects with SwiftUI:

Discover how to craft rich, custom experiences by creatively composing SwiftUI layout and graphics APIs. We’ll show you how to break down complex designs and use a creative pipeline to chain simple building blocks together. Learn how to draw with layer shaders, animate with timelines, and anchor views with alignment guides.

Build powerful drag and drop in SwiftUI:

Follow along as we build a game of Solitaire to explore the latest drag-and-drop capabilities in SwiftUI. We’ll show you how to use the new reordering API to let people arrange content, implement drag containers to move multiple items at once, and customize the drag-and-drop lifecycle to fit your app’s rules.

There are also a bunch of labs.

Natalia Panferova:

Up until now it was a property wrapper conforming to the DynamicProperty protocol, but in Xcode 27 it becomes a Swift macro. In this post we will look at what the change means for @Observable models stored in @State.

Malcolm Hall:

Only took 3 years lol!

Majid Jabrayilov:

SwiftUI also introduces a new prominent tab role. You can use the prominent role for trailing-separated tabs, similar to search.

[…]

Document-based apps get a refreshed look and feel, along with a performance boost. It looks like Xcode has started using these improvements, which might explain why we see so much work around document-based apps this year. And finally, Xcode introduces SwiftUI Specialist and What’s New in SwiftUI skills for agentic coding in Xcode.

Fatbobman:

For me, the biggest change in SwiftUI comes from its comprehensive support for document-based apps. It not only adds a large number of new APIs, but also shifts the mental model toward “observable document objects + asynchronous snapshots + dedicated readers / writers.” This is clearly better suited to complex document apps, and it also aligns more closely with the overall evolution of modern Swift around Observation and Concurrency.

The sessions also mentioned that SwiftUI continues to optimize layout- and container-related implementations, bringing noticeable performance improvements in some scenarios. This is an improvement developers have urgently needed. However, SwiftUI still does not provide the ability to create custom Lazy containers, which remains a clear disappointment.

Natalia Panferova:

iOS 27 introduces new reordering APIs that work with any container. We can mark dynamic content with reorderable() and define the scope of the interaction with reorderContainer(for:). SwiftUI handles the drag preview, insertion placeholder, and drop animation, while our code applies the resulting change to the model.

SwiftUI’s drag container APIs are also now available on iPhone and iPad, after previously being limited to macOS. They let us make items in a collection draggable without making the collection reorderable, and include multiple selected items in the same drag. The APIs also support lazy generation of transferable values and drag-session observation.

robb:

I love the new #SwiftUI Text selection but without a way to make selection span multiple Texts in a group, it doesn’t really address our needs at Linear – here’s hoping we see an update in a later seed 🤞

Natalia Panferova:

The NavigationTransition protocol has been available in SwiftUI since iOS 18, letting us control how views animate when pushed onto a NavigationStack and when presenting sheets and full-screen covers. We specify the transition using the navigationTransition(_:) modifier on the destination or presented view, and SwiftUI uses it instead of the default animation for that context. Before iOS 27, SwiftUI provided two built-in conforming types: AutomaticNavigationTransition, used via the automatic static value, which defers to the system default for the current context, and ZoomNavigationTransition, used via zoom(sourceID:in:), which animates the presented view expanding from a source view marked with matchedTransitionSource(). iOS 27 introduces CrossFadeNavigationTransition, a new built-in transition that cross-fades between views without requiring a source, and adds AnyNavigationTransition, a type eraser that lets us select a transition at runtime.

Kyle Howells:

The last few years watching WWDC has been a mixed experience for me, because I honestly believe Swift and SwiftUI are actively either bad or being made worst.

Yet every year, the problems I have with them are doubled down on, not improved.

Kyle-Ye:

The FB21333309 cache bug I submitted is now confirmed to be fixed on iOS 27.

Instead of introducing a new CacheKey like I suggested, SwiftUI team choose to move the intensity payload out of the FeedbackType enum to a new Payload enum and add a new payload var to SensoryFeedback storage.

dasdom:

A few weeks ago I realised that most iOS jobs require knowledge of SwiftUI. So I started to rebuild my Mastodon client in SwiftUI. Then I got an offer for a new job and accepted it. This means I can get back to working on the ObjC version. Feels good. :)

Previously:

Update (2026-06-23): Natalia Panferova:

iOS 27 adds new AsyncImage initializers that accept a URLRequest instead of a URL. We can now configure request headers, cache policy, and timeout interval while continuing to use the built-in loading and phase handling provided by AsyncImage. A new asyncImageURLSession(_:) modifier also lets us provide the URL session used by asynchronous images in a view hierarchy.

Update (2026-07-10): Luc Vandal:

SwiftUI .reorderable() crashes when the reordered view body contains if #available: “Unexpected identifier type. Expected [Type], got [Type]”

[…]

Even attaching a .popover to an item causes it to crash when reordering.

Update (2026-07-23): Yakov Manshin (video, via Mohammad Azam):

Seven years after its blockbuster 2019 announcement, SwiftUI was supposed to be the mature, production-grade future of cross-platform UI development on all Apple platforms. Instead, SwiftUI feels like a perpetual beta, even in 2026. In this deep dive, I break down why the initial excitement has given way to deep professional frustration for senior engineers. I analyze the systemic issues with performance and layout predictability, the chaotic state of SwiftUI’s ever-changing data flow, and the frustrating lack of backward compatibility that forces developers into a nightmare of shims and workarounds.

Through real-world examples—including Apple’s own SwiftUI tutorial (which is broken) and a head-to-head performance comparison with UIKit (guess who wins)—I demonstrate how SwiftUI trades precise engineering for an illusion of convenience.

Beyond the code, this video explores a broader, more concerning shift in Cupertino: a transition away from the uncompromising craftsmanship of the original era of Cocoa, Aqua, and Auto Layout toward a modern corporate culture of “good enough” products.

  •  
  • ↗️
↗️

WWDC 2026 Links

✇Michael Tsai
By: Michael Tsai

General:

Documentation:

Sessions:

Podcasts:

Previously:

  •  
  • ↗️
❌