Does anyone know the runtime performance I can expect from the anchor(for:) and node(for:) methods on ARSCNView? I don't see this documented. Would it be safe for me to assume this is a constant-time lookup? Would I need to assume this is a linear-time operation that scales up with the number of nodes and anchors active? Is it my responsibility to do my own bookkeeping if I want to look these relationships up in constant-time?

https://developer.apple.com/documentation/swift/imported_c_and_objective-c_apis/working_with_core_foundation_types If we define a C function that returns a CFType, Swift can (sometimes) bridge the memory management semantics. If Swift cannot bridge the memory management semantics, we can end up with an Unmanaged type: CFStringRef StringByAddingTwoStrings(CFStringRef s1, CFStringRef s2); bridges to: public func StringByAddingTwoStrings(_ s1: CFString!, _ s2: CFString!) -> Unmanaged<CFString>! We can improve the bridging with the CF_RETURNS_RETAINED annotation: CFStringRef StringByAddingTwoStrings(CFStringRef s1, CFStringRef s2) CF_RETURNS_RETAINED; now bridges to: public func StringByAddingTwoStrings(_ s1: CFString!, _ s2: CFString!) -> CFString! What does not seem to be documented is how to improve bridging when function pointer return values should be annotated. For example: typedef CFStringRef (*StringByAddingTwoStrings)(CFStringRef, CFStringRef); bridges to: public typealias StringByAddingTwoStrings = @convention(c) (CFString?, CFString?) -> Unmanaged<CFString>? Is there any way to annotate the function pointer to properly communicate the memory management semantics? Adding the CF_RETURNS_RETAINED to the function pointer does not seem to help.

Hi! Any ETA for a KDK for 23A344? The most recent available KDK I see is 22G91. Thanks!

Does anyone have some resources to recommend for learning more about measuring and optimizing SwiftUI performance and rendering? I haven't seen a ton from Apple that looks like it's going to help me more. I did find two sessions from WWDC 2023. The "Demystify SwiftUI performance" session[1] does tell us the _printChanges function can help tell us when component bodies are computed. I see how I can attach this to a component that I built… I'm not (yet) sure if I have the ability to run this on arbitrary system components in my component graph. The "Analyze hangs with Instruments" session[2] does walk us through using the SwiftUI Instruments to measure body computations. Does anyone have any more resources along these lines for learning more? SwiftUI is closed source… so we don't really have easy visibility inside to see for ourselves. Bummer. Are there any additional debug APIs (like _printChanges) that can help for local development? I'm also interested to learn more about view equality[3]… I found this essay but it's four years old and I still can't find more information directly from Apple about EquatableView… I would prefer to find any more documentation or resources directly from Apple… but I would be happy with free third-party resources as long as they have some legit data to back up their code. Thanks! [1] https://developer.apple.com/videos/play/wwdc2023/10160/ [2] https://developer.apple.com/videos/play/wwdc2023/10248/ [3] https://swiftui-lab.com/equatableview/

Hi! I'm experimenting with SwiftData and looking for a situation where one persistentModelID might result in more than one registered model object reference delivered from a fetch from a single context. Here is an example of what I have to experiment: import Foundation import SwiftData @Model class Person { var name: String init(name: String) { self.name = name } } func main() { let configuration = ModelConfiguration( isStoredInMemoryOnly: true, allowsSave: true ) do { let container = try ModelContainer( for: Person.self, configurations: configuration ) let context = ModelContext(container) let person = Person(name: "John Appleseed") context.insert(person) let persistentModelID = person.persistentModelID if let left: Person = context.registeredModel(for: persistentModelID), let right: Person = context.registeredModel(for: persistentModelID) { print(left === right) // true } let descriptor = FetchDescriptor<Person>( predicate: #Predicate { person in person.persistentModelID == persistentModelID } ) if let left = try context.fetch(descriptor).last, let right = try context.fetch(descriptor).last { print(left === right) // true } } catch { print(error) } } main() This is a very simple command line app that attempts to fetch "two different" registered models… but both approaches (querying directly for persistentModelID and wrapping persistentModelID with FetchDescriptor) seem to consistently deliver objects equal by reference. Is there any situation where I could set this code up to deliver two registered models different by reference (but equal by value)? Is this anything I have to think about or manage at an "app" level? Is this behavior documented anywhere? Thanks!

Hi! I'm building an app from production Xcode_15.4.0 and I'm seeing strange behavior from the Model macro: import SwiftData @Model package class Person { init() { } } Building this from Xcode_15.4.0 or Swift 5.10 leads to these errors: /var/folders/1j/0r1s_v0n4bn200kt9nkm9j5w0000gn/T/swift-generated-sources/@__swiftmacro_9MyLibrary6Person5ModelfMe_.swift:1:1: error: initializer 'init(backingData:)' must be as accessible as its enclosing type because it matches a requirement in protocol 'PersistentModel' extension Person: SwiftData.PersistentModel { ^ /Users/rick/Desktop/MyLibrary/Sources/MyLibrary/MyLibrary.swift:3:1: note: in expansion of macro 'Model' on class 'Person' here @Model package class Person { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /var/folders/1j/0r1s_v0n4bn200kt9nkm9j5w0000gn/T/swift-generated-sources/@__swiftmacro_9MyLibrary6Person5ModelfMm_.swift:19:10: note: mark the initializer as 'package' to satisfy the requirement required init(backingData: any SwiftData.BackingData<Person>) { ^ /Users/rick/Desktop/MyLibrary/Sources/MyLibrary/MyLibrary.swift:3:1: note: in expansion of macro 'Model' on class 'Person' here @Model package class Person { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /var/folders/1j/0r1s_v0n4bn200kt9nkm9j5w0000gn/T/swift-generated-sources/@__swiftmacro_9MyLibrary6Person5ModelfMe_.swift:1:1: error: property 'schemaMetadata' must be as accessible as its enclosing type because it matches a requirement in protocol 'PersistentModel' extension Person: SwiftData.PersistentModel { ^ /Users/rick/Desktop/MyLibrary/Sources/MyLibrary/MyLibrary.swift:3:1: note: in expansion of macro 'Model' on class 'Person' here @Model package class Person { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /var/folders/1j/0r1s_v0n4bn200kt9nkm9j5w0000gn/T/swift-generated-sources/@__swiftmacro_9MyLibrary6Person5ModelfMm_.swift:13:12: note: mark the static property as 'package' to satisfy the requirement static var schemaMetadata: [SwiftData.Schema.PropertyMetadata] { ^ /Users/rick/Desktop/MyLibrary/Sources/MyLibrary/MyLibrary.swift:3:1: note: in expansion of macro 'Model' on class 'Person' here @Model package class Person { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /var/folders/1j/0r1s_v0n4bn200kt9nkm9j5w0000gn/T/swift-generated-sources/@__swiftmacro_9MyLibrary6Person5ModelfMe_.swift:1:1: error: initializer 'init(backingData:)' must be as accessible as its enclosing type because it matches a requirement in protocol 'PersistentModel' extension Person: SwiftData.PersistentModel { ^ /Users/rick/Desktop/MyLibrary/Sources/MyLibrary/MyLibrary.swift:3:1: note: in expansion of macro 'Model' on class 'Person' here @Model package class Person { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /var/folders/1j/0r1s_v0n4bn200kt9nkm9j5w0000gn/T/swift-generated-sources/@__swiftmacro_9MyLibrary6Person5ModelfMm_.swift:19:10: note: mark the initializer as 'package' to satisfy the requirement required init(backingData: any SwiftData.BackingData<Person>) { ^ /Users/rick/Desktop/MyLibrary/Sources/MyLibrary/MyLibrary.swift:3:1: note: in expansion of macro 'Model' on class 'Person' here @Model package class Person { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /var/folders/1j/0r1s_v0n4bn200kt9nkm9j5w0000gn/T/swift-generated-sources/@__swiftmacro_9MyLibrary6Person5ModelfMe_.swift:1:1: error: property 'schemaMetadata' must be as accessible as its enclosing type because it matches a requirement in protocol 'PersistentModel' extension Person: SwiftData.PersistentModel { ^ /Users/rick/Desktop/MyLibrary/Sources/MyLibrary/MyLibrary.swift:3:1: note: in expansion of macro 'Model' on class 'Person' here @Model package class Person { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /var/folders/1j/0r1s_v0n4bn200kt9nkm9j5w0000gn/T/swift-generated-sources/@__swiftmacro_9MyLibrary6Person5ModelfMm_.swift:13:12: note: mark the static property as 'package' to satisfy the requirement static var schemaMetadata: [SwiftData.Schema.PropertyMetadata] { ^ /Users/rick/Desktop/MyLibrary/Sources/MyLibrary/MyLibrary.swift:3:1: note: in expansion of macro 'Model' on class 'Person' here @Model package class Person { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: fatalError Building from Xcode_16_beta_4 or Swift 6.0 builds with no errors. Is this package issue being tracked for SwiftData when building from 5.10? It looks like this is fixed from 6.0… but I would like to build this code from production Swift today. Potential workarounds: Mark the class as internal or public? Use Xcode to inline the macro expansion and directly modify the broken functions with the correct access control? Any more ideas? My preference would be to keep this type package (while also building from 5.10). Any more workarounds (other than expanding the macro and modifying the functions myself by-hand)? Thanks!

Hi! I'm attempting to run the Quakes Sample App^1 from macOS. I am running breakpoints and confirming the mapCameraKeyframeAnimator is being called: .mapCameraKeyframeAnimator(trigger: selectedId) { initialCamera in let start = initialCamera.centerCoordinate let end = quakes[selectedId]?.location.coordinate ?? start let travelDistance = start.distance(to: end) let duration = max(min(travelDistance / 30, 5), 1) let finalAltitude = travelDistance > 20 ? 3_000_000 : min(initialCamera.distance, 3_000_000) let middleAltitude = finalAltitude * max(min(travelDistance / 5, 1.5), 1) KeyframeTrack(\MapCamera.centerCoordinate) { CubicKeyframe(end, duration: duration) } KeyframeTrack(\MapCamera.distance) { CubicKeyframe(middleAltitude, duration: duration / 2) CubicKeyframe(finalAltitude, duration: duration / 2) } } But I don't actually see any map animations taking place when that selection changes. Running the application from iPhone simulator does show the animations. I am building from Xcode Version 16.2 and macOS 15.2. Are there known issues with this API on macOS?

Hi! I'm seeing some weird animation issues building the Food Truck sample application.^1 I'm running from macOS 15.4 and Xcode 16.3. I'm building the Food Truck application for macOS. I'm not focusing on iOS for now. The FoodTruckModel adds new Order values with an animation: // FoodTruckModel.swift withAnimation(.spring(response: 0.4, dampingFraction: 1)) { self.orders.append(orderGenerator.generateOrder(number: orders.count + 1, date: .now, generator: &generator)) } This then animates the OrdersTable when new Order values are added. Here is a small change to OrdersTable: // OrdersTable.swift - @State private var sortOrder = [KeyPathComparator(\Order.status, order: .reverse)] + @State private var sortOrder = [KeyPathComparator(\Order.creationDate, order: .reverse)] Running the app now inserts new Order values at the top. The problem is I seem to be seeing some weird animation issues here. It seems that as soon as the new Order comes in there is some kind of weird glitch where it appears as if part the animation is coming from the side instead of down from the top: What's then more weird is that if I seem to affect the state of the Table in any way then the next Order comes in with perfect animation. Scrolling the Table fixes the animation. Changing the creationData sort order from reverse to forward and back to reverse fixes the animation. Any ideas? Is there something about how the Food Truck product is built that would cause this to happen? Is this an underlying issue in the SwiftUI infra?

https://github.com/apple/sample-food-truck Hi! I'm seeing what looks like some weird navigation issue in the Food Truck app. It's from the Live Activity that should deep link to a specific point in the app. There seems be some state where the app is not linking to the correct component. Here are my repro steps on iPhone: Start live activity from OrderDetailView. Navigate to Sidebar component. Tap the Live Activity. App opens TruckView. The App should be opening the OrderDetailView for the Order that was passed to the Live Activity. This seems to work when the app is not currently on Sidebar. Any ideas? I'm testing this on iPhone OS 18.4.1. Is this an issue inside NavigationSplitView? Is this an issue with how Food Truck handles deeplinking?

Hi! I'm investigating some crashes that seem to be related to ModelContext.autosaveEnabled^1. I don't have a very clean repro test case at this time… but I seem to be seeing crashes when a SwiftUI app moves to the background. I am testing an app built for macOS 14.6.1. I am building from Xcode_16_beta_5. My app is not using a mainContext. My app is building a ModelActor that is running on a background thread (off main). The modelContext inside my ModelActor is set with autosaveEnabled equal to true. The mutations on my state are not being explicitly saved (I am waiting for the system to save automatically). My guess (so far) is that transitioning into the background from SwiftUI is kicking off some kind of logic that is specifically being tied to the main thread… but this is causing problems when my modelContext is created from a background thread. My understanding was that ModelActor could help to defend against threading problems… but this might be a different problem that I did not expect. I am unblocked for now by turning off autosaveEnabled (and manually saving from my ModelActor). That fixes the crashes. Any more thoughts or insight about what could be causing these crashes when my app transitions into the background? Thanks! Thread 1 Queue : com.apple.main-thread (serial) #0 0x000000023108beb8 in ___lldb_unnamed_symbol2827 () #1 0x000000023108ef30 in ___lldb_unnamed_symbol2847 () #2 0x000000023108eca8 in ___lldb_unnamed_symbol2845 () #3 0x000000019bac6144 in __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ () #4 0x000000019bb5a3d8 in ___CFXRegistrationPost_block_invoke () #5 0x000000019bb5a320 in _CFXRegistrationPost () #6 0x000000019ba94678 in _CFXNotificationPost () #7 0x000000019cbb12c4 in -[NSNotificationCenter postNotificationName:object:userInfo:] () #8 0x000000019f489408 in -[NSApplication _handleDeactivateEvent:] () #9 0x000000019fb24380 in -[NSApplication(NSEventRouting) sendEvent:] () #10 0x000000019f771d9c in -[NSApplication _handleEvent:] () #11 0x000000019f322020 in -[NSApplication run] () #12 0x000000019f2f9240 in NSApplicationMain () #13 0x00000001c74c73b8 in ___lldb_unnamed_symbol83060 () #14 0x00000001c7c30ddc in ___lldb_unnamed_symbol132917 () #15 0x00000001c802be0c in static SwiftUI.App.main() -> () () Thread 5 Queue : NSManagedObjectContext 0x6000009c38e0 (serial) #0 0x000000019ba66f94 in constructBuffers () #1 0x000000019ba65e30 in _CFURLCreateWithURLString () #2 0x000000019bad6e7c in _CFURLComponentsCopyURLRelativeToURL () #3 0x000000019cbde864 in -[__NSConcreteURLComponents URL] () #4 0x000000019d3782f8 in -[NSURL(NSURL) initWithString:relativeToURL:encodingInvalidCharacters:] () #5 0x000000019cbdd4d4 in +[NSURL(NSURL) URLWithString:relativeToURL:] () #6 0x00000001a23feef0 in -[NSTemporaryObjectID URIRepresentation] () #7 0x00000002310e0878 in ___lldb_unnamed_symbol4176 () #8 0x00000002310ef480 in ___lldb_unnamed_symbol4401 () #9 0x00000002310eb6e0 in ___lldb_unnamed_symbol4385 () #10 0x00000002310a22b4 in ___lldb_unnamed_symbol3130 () #11 0x00000002310ed4e8 in ___lldb_unnamed_symbol4390 () #12 0x00000002310883dc in ___lldb_unnamed_symbol2799 () #13 0x0000000231087edc in ___lldb_unnamed_symbol2798 () #14 0x000000023109fd24 in ___lldb_unnamed_symbol3021 () #15 0x0000000231086acc in ___lldb_unnamed_symbol2784 () #16 0x00000001a2392144 in developerSubmittedBlockToNSManagedObjectContextPerform () #17 0x00000001a2392004 in -[NSManagedObjectContext performBlockAndWait:] () #18 0x00000002310879ac in ___lldb_unnamed_symbol2797 ()

Hi! I believe there might be a small bug in the SwiftData Quakes Sample App.^1 The Quakes app requests a JSON feed from USGS.^2 What seems to be breaking is that apparently earthquake entities from USGS can return with null magnitudes. That is throwing errors from the decoder: struct GeoFeatureCollection: Decodable { let features: [Feature] struct Feature: Decodable { let properties: Properties let geometry: Geometry struct Properties: Decodable { let mag: Double let place: String let time: Date let code: String } struct Geometry: Decodable { let coordinates: [Double] } } } which is expecting mag to not be nil. Here is my workaround: struct GeoFeatureCollection: Decodable { let features: [Feature] struct Feature: Decodable { let properties: Properties let geometry: Geometry struct Properties: Decodable { let mag: Double? let place: String let time: Date let code: String } struct Geometry: Decodable { let coordinates: [Double] } } } And then: extension Quake { /// Creates a new quake instance from a decoded feature. convenience init(from feature: GeoFeatureCollection.Feature) { self.init( code: feature.properties.code, magnitude: feature.properties.mag ?? 0.0, time: feature.properties.time, name: feature.properties.place, longitude: feature.geometry.coordinates[0], latitude: feature.geometry.coordinates[1] ) } }

https://gist.github.com/vanvoorden/37ff2b2f9a2a0d0657a3cc5624cc9139 Hi! I'm experimenting with the Entry macro in a SwiftUI app. I'm a little confused about how to stored a defaultValue to prevent extra work from creating this more than once. A "legacy" approach to defining an Environment variable looks something like this: struct StoredValue { var value: String { "Hello, world!" } init() { print("StoredValue.init()") } } extension EnvironmentValues { var storedValue: StoredValue { get { self[StoredValueKey.self] } set { self[StoredValueKey.self] = newValue } } struct StoredValueKey: EnvironmentKey { static let defaultValue = StoredValue() } } The defaultValue is a static stored property. Here is a "modern" approach using the Entry macro: struct ComputedValue { var value: String { "Hello, world!" } init() { print("ComputedValue.init()") } } extension EnvironmentValues { @Entry var computedValue: ComputedValue = ComputedValue() } From the perspective of the product engineer, it looks like I am defining another stored defaultValue property… but this actually expands to a computed property: extension EnvironmentValues { var computedValue: ComputedValue { get { self[__Key_computedValue.self] } set { self[__Key_computedValue.self] = newValue } } private struct __Key_computedValue: SwiftUICore.EnvironmentKey { static var defaultValue: ComputedValue { get { ComputedValue() } } } } If I tried to use both of these Environment properties in a SwiftUI component, it looks like I can confirm the computedValue is computing its defaultValue several times: @main struct EnvironmentDemoApp: App { var body: some Scene { WindowGroup { ContentView() } } } struct ContentView: View { @Environment(\.computedValue) var computedValue @Environment(\.storedValue) var storedValue var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") } .padding() } } And then when I run the app: ComputedValue.init() StoredValue.init() ComputedValue.init() ComputedValue.init() ComputedValue.init() ComputedValue.init() ComputedValue.init() ComputedValue.init() ComputedValue.init() Is there any way to use the Entry macro in a way that we store the defaultValue instead of computing it on-demand every time?

Hi! I'm experimenting with Xcode performance testing. I'm specifically focusing on XCTMemoryMetric. I have a demo project with two performance tests that do some work wrapped with XCTestCase.measure. I can navigate to my Report navigator in Xcode and see the memory footprints of these two tests… but I only see how to view them individually: From this screen it looks like I have the ability to Export this benchmark to CSV. My question is what my options are for viewing all my XCTestCase.measure tests together. I see the Duration for both tests… but I don't see any way to view the memory benchmarks for all my tests in just one place: Ideally… I would also like to run these tests and produce one CSV file (or XML or JSON) report. I'm not opposed to using command line for this (if the option exists there) but Xcode also works for me. I'm also flexible whether or not these tests live in a Swift Package or directly in an Xcode project if that makes any difference. Any more advice about how to set up these performance tests? Thanks!

Hi! I am seeing some unexpected behavior when attempting to create a Model instance with a variable named updated. I start with a simple Model: @Model final public class Item { var timestamp: Int var updated: Int public init(timestamp: Int = 1, updated: Int = 1) { self.timestamp = timestamp self.updated = updated } } I then attempt to create an item instance: func main() throws { let schema = Schema([Item.self]) let configuration = ModelConfiguration(isStoredInMemoryOnly: true) let container = try ModelContainer( for: schema, configurations: configuration ) let modelContext = ModelContext(container) let item = Item() print(item.timestamp) print(item.updated) } try main() The value of item.timestamp is printing as 1 and the value of item.updated is printing as 0. I have no idea what could be causing that to happen… why would both those values not be printing as 1? Is there some private API that is somehow colliding with the (public) updated variable and causing the item instance to report back with a value of 0? Is there documentation warning engineers that a variable named updated is off-limits and results in undefined behavior? I can fix that by renaming the variable: @Model final public class Item { var timestamp: Int var updatedTimestamp: Int public init() { self.timestamp = 1 self.updatedTimestamp = 1 } } I am unblocked on this (because renaming the variable seems to work fine)… but is there any insight on why this might be happening in the first place? I am building from Xcode_16_beta_5. Thanks!

Hi! I have a stateful object that should be created in my app entry point and delivered through my component graph: @main @MainActor struct MyApp : App { @State private var myAppState = MyAppState() var body: some Scene { ... } } The MyApp is a struct value type… in a SwiftUI world that seems to imply it could "go away" and be recreated as the system sees appropriate. We see this with view components all the time (hence the State wrapper to help preserve our instance across the lifecycle of our identity)… but I'm wondering if this State wrapper is even necessary with an App entry point. Could this struct ever go away? Would there be any legit reasons that this struct should go away and recreate over one SwiftUI app lifecycle (other than terminating the app and starting a whole new process of course)? And what lifecycle is the SwiftUI.State tied to in this example? In a view component our SwiftUI.State is tied to our component identity. In this example… we are tied to app component identity? Is there ever going to be multiple legit app component identities live in the same process? I'm thinking I could just go ahead and keep using State as a best practice… but is this just overkill or is there a real best practice lurking under here? Any more ideas about that? Thanks!