Hi everyone, when I was doing some testing on macOS 15 + Xcode 16 Beta 4 I noticed that my app's performance took a significant hit. A simple task that previously was completed within 15 seconds or less now took about a minute to complete. I came to the conclusion that the only plausible cause could be the way .task {} and asynchronous functions are handled. Starting several .task{} and calling async functions from within using macOS 14.5 and Xcode 15.4 results in following log output: task1 started task3 started task2 started task4 started --> task2 ended --> task3 ended --> task4 ended --> task1 ended` Running the same code on macOS 15.0 + Xcode 16 Beta 4 will result in the following log output: task1 started --> task1 ended task2 started --> task2 ended task3 started --> task3 ended task4 started --> task4 ended In the first example the code is executed in 'parallel'. All tasks are started and doing there respective work. In second example a task is started and we are waiting for it to complete before the other tasks are started. I could start to rewrite my code to get the results I desire, however I'm wondering if this is a bug in regards to macOS 15 + Xcode 16 Beta 4 and the way .task {} and asynchronous functions are handled. The output is quite different after all. What's your take on this? If you want to try it out for yourself you can use the following sample code: import SwiftUI struct ContentView: View { func func1() async -> Int { print("task1 started") var myInt: Int = 0 while myInt < 999999999 { myInt += 1 } print(" --> task1 ended") return 1 } func func2() async -> Int { print("task2 started") var myInt: Int = 0 while myInt < 999999 { myInt += 1 } print(" --> task2 ended") return 2 } func func3() async -> Int { print("task3 started") var myInt: Int = 0 while myInt < 999999 { myInt += 1 } print(" --> task3 ended") return 3 } func func4() async -> Int { print("task4 started") var myInt: Int = 0 while myInt < 999999999 { myInt += 1 } print(" --> task4 ended") return 4 } var body: some View { VStack { Text("Hello, world!") } .task { await func1() } .task { await func2() } .task { await func3() } .task { await func4() } } } #Preview { ContentView() }

So any time I create a class that's both @Observable and Codable, e.g. @Observable class GameLocationManager : Codable { I get a warning in the macro expansion code: @ObservationIgnored private let _$observationRegistrar = Observation.ObservationRegistrar() Immutable property will not be decoded because it is declared with an initial value which cannot be overwritten. I've been ignoring them for now, but there are at least a half a dozen of them now in my (relatively small) codebase, and I'd like to find a solution (ideally one that doesn't require me to write init(decoder:) for every @Observable class in my project...), especially since I'm not sure what the actual consequences of ignoring this might be.

Hi, I'm new to swift but have experience with coding in general. Following the app dev training tutorial, came across this line of code: var wrapper: ErrorWrapper { ErrorWrapper(error: someVal) } My question is, why not just do this... var wrapper: ErrorWrapper = ErrorWrapper(error: someVal) Is it a conventions thing or is there some purpose, code seems to work either way. My understanding of closures is that they are just lambda functions, so in the first codeblock, all it's doing is calling a function that returns the instantiated ErrorWrapper object. Why not just assign the variable to it?

Example1: let num = NSDecimalNumber(string: "0.123456789012345678909") let formatter = NumberFormatter() formatter.numberStyle = .decimal formatter.usesGroupingSeparator = true formatter.maximumFractionDigits = 25 formatter.minimumFractionDigits = 25 formatter.minimumIntegerDigits = 1 let str = formatter.string(from: num) ?? "" print(str) output "0.1234567890123460000000000" Example2: let num = NSDecimalNumber(string: "12323.123456789012345678909") let formatter = NumberFormatter() formatter.numberStyle = .decimal formatter.usesGroupingSeparator = true formatter.maximumFractionDigits = 25 formatter.minimumFractionDigits = 25 formatter.minimumIntegerDigits = 1 let str = formatter.string(from: num) ?? "" print(str) output "12,323.1234567890000000000000000" How to correctly format the contents of the above two inputs？

When i try to run break statement in default case, it doesn't run and shows 'Closure containing control flow statement cannot be used with result builder 'ViewBuilder'' error.Why it doesn't run and how to solve this trouble?

Hi, everyone. I am trying to print out “Hello, world” by creating a Command Line tool project. I try to type “swiftc Hello.swift” to compile it in the terminal but instead of having a file named Hello.swift, I have a file named by default Hello.xcodeprojec. How I can solve this issue?

For some time now Xcode has been downloading crash reports from users of my app about crashes related to arrays. One of them looks like this: ... Code Type: ARM-64 Parent Process: launchd [1] User ID: 501 Date/Time: 2024-07-18 14:59:40.4375 +0800 OS Version: macOS 15.0 (24A5289h) ... Crashed Thread: 0 Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x00000001045048b8 Termination Reason: Namespace SIGNAL, Code 5 Trace/BPT trap: 5 Terminating Process: exc handler [1771] Thread 0 Crashed: 0 MyApp 0x00000001045048b8 specialized Collection.map<A>(_:) + 596 1 MyApp 0x00000001045011e4 MyViewController.validateToolbarButtons() + 648 (MyViewController.swift:742) ... The relevant code looks like this: class MyViewController { func validateToolbarButtons() { let indexes = tableView.clickedRow == -1 || tableView.selectedRowIndexes.contains(tableView.clickedRow) ? tableView.selectedRowIndexes : IndexSet(integer: tableView.clickedRow) let items = indexes.map({ myArray[$0] }) ... } } The second crash looks like this: ... Code Type: X86-64 (Native) Parent Process: launchd [1] User ID: 502 Date/Time: 2024-07-15 15:53:35.2229 -0400 OS Version: macOS 15.0 (24A5289h) ... Crashed Thread: 0 Exception Type: EXC_BAD_INSTRUCTION (SIGILL) Exception Codes: 0x0000000000000001, 0x0000000000000000 Termination Reason: Namespace SIGNAL, Code 4 Illegal instruction: 4 Terminating Process: exc handler [13244] Thread 0 Crashed: 0 libswiftCore.dylib 0x00007ff812904fc0 _assertionFailure(_:_:flags:) + 288 1 MyApp 0x0000000101a31e04 specialized _ArrayBuffer._getElementSlowPath(_:) + 516 2 MyApp 0x00000001019d04eb MyObject.myProperty.setter + 203 (MyObject.swift:706) 3 MyApp 0x000000010192f66e MyViewController.controlTextDidChange(_:) + 190 (MyViewController.swift:166) ... And the relevant code looks like this: class MyObject { var myProperty: [MyObject] { get { ... } set { let items = newValue.map({ $0.id }) ... } } } What could cause such crashes? Could they be caused by anything other than concurrent access from multiple threads (which I'm quite sure is not the case here, as I only access these arrays from the main thread)?

Just when I think I am finally starting to understand Swift I come across a gotcha like the following: I have two object, a swiftui display and one of data to be displayed. Ok, sounds easy. The data is read out of a JSON file so I have a set of arrays and dictionaries. The data is valid when read, it is definitely there, but when I go to display it, its gone. Just vanished. Wasted about a day on this so far, and I’ve seen it before, the inability to pass out of an object an array or dictionary with contents intact. If I create an array var, and not let the system do it, contents are preserved. So, in the data object I’ll have something like this: struct DataObject{ var item: [String:Any] item=JSONData serialized out of memory, and may have say, 12 fields } In my SwiftUI module I have: var item=dataObject.item dataObject.item now has 0 fields. I can allocate and initialize a dictionary in DataObject and those elements come through fine. So it seems like the stuff being serialized from JSON is being deleted out from under me.

Hi all, I just wanted to ask how people were using ModelActor with the Swift 6 language mode enabled. My current implementation involves passing the ModelContainer to my ModelActor, which worked in Sonoma and previous betas of Sequoia, however in the current Beta 3, I get this error: "Sending 'self.modelContext.container' risks causing data races" I am a bit confused by this, as from what I understand, ModelContainer conforms to Sendable, so ideally this error should not be thrown. Is this a bug in Beta 3? Thanks in advance.

Why doesn’t deinit support async? At the end of a test, I want to wipe data from HealthKit, and it’s delete function is asynchronous.

We use XCode 15.2 to build our application, but we found that the app crashes on iOS 12.1.1, while it works without crashing on iOS 12.5.7. We discovered that the crash is related to ImageLoaderMachO::doModInitFunctions. We're not sure what is causing this.

When I run the code, xCode shows me this error "Expressions are not allowed at the top level" While the code is correct and runs in the main.swift file only. And also runs in online compilers. please give me solution...

Hi @all, I get follow error: needs -Onone Swift optimization level. how can I solve this? thank you for the help greeting Fabian

I came across a useful repo on GitHub: https://github.com/GianniCarlo/DirectoryWatcher/blob/master/Sources/DirectoryWatcher/DirectoryWatcher.swift self.queue = DispatchQueue.global() self.source = DispatchSource.makeFileSystemObjectSource(fileDescriptor: descriptor, eventMask: .write, queue: self.queue) self.source?.setEventHandler { [weak self] in self?.directoryDidChange() } self.source?.setCancelHandler() { close(descriptor) } self.source?.resume() How do I translate this to OC version? I have an app that was written in OC and I plan to incorporate this directory watcher into the project.

During my analysis of the binary size changes after compiling Swift source code, I discovered symbols with the ".island" suffix. I couldn't find meaningful information about this suffix through my search, so I decided to reach out for assistance. While comparing the changes in binary size after modifying specific code, I noticed a significant increase (from 33MB to 520MB). Upon analyzing the symbols of the enlarged binary using the nm command, I found the following pattern: t _$s12{SomeSymbol}WOb t _$s12{SomeSymbol}WOb.island t _$s12{SomeSymbol}WOb.island2 t _$s12{SomeSymbol}WOb.island3 When I output the symbols of the binary using nm, I noticed many symbols with the same name but different ".island", ".island2", ".island3" suffixes. Disassembling the binary showed that functions with these suffixes simply delegate calls sequentially: x.island3 -> x.island2 -> x.island1 -> x. It appears that these symbols serve as delegates for function calls, but I would like to understand why such duplicated functions with these suffixes are generated. Could someone help me to provide some insights on this matter?

'consume' applied to value that the compiler does not support. This is a compiler bug. Please file a bug with a small example of the bug. public func requestTopicsAndSubTopics() async throws -> (topics: [Topic], subTopics: [String: [SubTopic]]) { var subTopics = [String: [SubTopic]]() let topics = try await getTopics().sorted { $0.index < $1.index } try await withThrowingTaskGroup(of: ([SubTopic], String).self) { [weak self] group in guard let self else { return } for topic in topics { guard let topicId = topic.id else { throw Error.missingId } group.addTask { let subTopics = try await self.getSubtopics(topicId: topicId).sorted { $0.name < $1.name } return (consume subTopics, topicId) } } for try await (resultedSubTopics, topicId) in group { subTopics.updateValue(resultedSubTopics, forKey: topicId) } } return (consume topics, consume subTopics) }

I need to decode JSON into a class. The JSON has a field called "Type", and I cannot declare a property with that name in my class since Type is a reserved word. I tried declaring CodingKeys, but that doesn't work unless I declare EVERY property in the CodingKeys. This class has about a hundred properties and I have others like it, I do not want to do this. Is there a better solution?

I got the error and I don’t how can I fix it help please struct MovieDetail: View { var movie: Movie let screen = UIScreen.main.bounds @State private var showSeasonPicker = true @State private var selectedSeason = 0 var body: some View { ZStack { Color.black .ignoresSafeArea() ZStack { VStack { HStack { Spacer() Button() { // Closing Button }label: { Image(systemName: "xmark.circle") .font(.system(size: 28)) } } .padding(.horizontal, 22) ScrollView (.vertical, showsIndicators: false){ VStack { StandardHomeMovie(movie: movie) .frame(width: screen.width / 2.5) MovieInfoSubheadline(movie: movie) if movie.promotionHeadline != nil { Text(movie.promotionHeadline!) .bold() .font(.headline) } PlayButton(text: "Play", imagename: "play.fill", backgroundColor: .red) { // } CurrentEpisodeInformation(movie: movie) CastInfo(movie: movie) HStack(spacing: 60){ SmallVerticalButton(text: "My List", isOnImage: "checkmark", isOffImage: "plus", isOn: true) { // } SmallVerticalButton(text: "Rate", isOnImage: "hand.thumbsup.fill", isOffImage: "hand.thumbsup", isOn: true) { // } SmallVerticalButton(text: "Share", isOnImage: "square.and.arrow.up", isOffImage: "square.and.arrow.up", isOn: true) { // } Spacer() } .padding(.leading, 20) CustomTabSwitcher(tabs: [.episodes, .trailers, .more], movie: movie, showSeasonPicker: $showSeasonPicker, selectedSeason: $selectedSeason) } .padding(.horizontal, 10) } Spacer() } .foregroundStyle(.white) if showSeasonPicker { Group { Color.black.opacity(0.9) VStack(spacing: 40){ Spacer() ForEach(0..<(movie.numberOfSeasons ?? 0)) { season in Button(action: { self.selectedSeason = (season != 0) self.showSeasonPicker = false }, label: { Text("Season: \(season + 1)") .foregroundStyle(selectedSeason == season + 1 ? .white : .gray) .bold() .font(.title2) }) } Spacer() Button(action: { self.showSeasonPicker = false }, label: { Image(systemName: "xmark.circle.fill") .foregroundStyle(.white) .font(.system(size: 40)) .scaleEffect(x: 1.1) }) .padding(.bottom, 30) } } .ignoresSafeArea() } } } } } #Preview { MovieDetail(movie: exampleMovie2) } struct MovieInfoSubheadline: View { var movie: Movie var body: some View { HStack(spacing: 20){ Image(systemName: "hand.thumbsup.fill") .foregroundStyle(.white) Text(String(movie.year)) RatingView(rating: movie.rating) Text(movie.numberOfSeasonsDisplay) ZStack{ Text("HD") .foregroundStyle(.white) .font(.system(size: 12)) .bold() Rectangle() .stroke(.gray, lineWidth: 2) .frame(width: 30, height: 20) } } .foregroundStyle(.gray) .padding(.vertical, 6) } } struct RatingView: View { var rating: String var body: some View { ZStack { Rectangle() .foregroundStyle(.gray) Text(rating) .foregroundStyle(.white) .font(.system(size: 12)) .bold() } .frame(width: 50, height: 20) } } struct CastInfo: View { var movie: Movie var body: some View { VStack(spacing: 3) { HStack { Text("Cast: \(movie.cast)") Spacer() } HStack { Text("Creaters: \(movie.creaters)") Spacer() } } .font(.caption) .foregroundStyle(.gray) .padding(.vertical, 10) } } struct CurrentEpisodeInformation: View { var movie: Movie var body: some View { Group { HStack { Text(movie.episodeInfoDisplay) .bold() Spacer() } .padding(.vertical, 4) HStack { Text(movie.episodeDescriptionDisplay) .font(.subheadline) Spacer() } } } }

Usage of multiple async lets crashes the app in a nondeterministic fashion. We are experiencing this crash in production, but it is rare. 0 libswift_Concurrency.dylib 0x20a8b89b4 swift_task_create_commonImpl(unsigned long, swift::TaskOptionRecord*, swift::TargetMetadata<swift::InProcess> const*, void (swift::AsyncContext* swift_async_context) swiftasynccall*, void*, unsigned long) + 384 1 libswift_Concurrency.dylib 0x20a8b6970 swift_asyncLet_begin + 36 We managed to isolate the issue, and we submitted a technical incident (Case-ID: 8007727). However, we were completely ignored, and referred to the developer forums. To reproduce the bug you need to run the code on a physical device and under instruments (we used swift concurrency). This bug is present on iOS 17 and 18, Xcode 15.1, 15.4 and 16 beta, swift 5 and 6, including strict concurrency. Here's the code for Swift 6 / Xcode 16 / strict concurrency: (I wanted to attach the project but for some reason I am unable to) typealias VoidHandler = () -> Void enum Fetching { case inProgress, idle } protocol PersonProviding: Sendable { func getPerson() async throws -> Person } actor PersonProvider: PersonProviding { func getPerson() async throws -> Person { async let first = getFirstName() async let last = getLastName() async let age = getAge() async let role = getRole() return try await Person(firstName: first, lastName: last, age: age, familyMemberRole: role) } private func getFirstName() async throws -> String { try await Task.sleep(nanoseconds: 1_000_000_000) return ["John", "Kate", "Alex"].randomElement()! } private func getLastName() async throws -> String { try await Task.sleep(nanoseconds: 1_400_000_000) return ["Kowalski", "McMurphy", "Grimm"].randomElement()! } private func getAge() async throws -> Int { try await Task.sleep(nanoseconds: 2_100_000_000) return [56, 24, 11].randomElement()! } private func getRole() async throws -> Person.Role { try await Task.sleep(nanoseconds: 500_000_000) return Person.Role.allCases.randomElement()! } } @MainActor final class ViewModel { private let provider: PersonProviding = PersonProvider() private var fetchingTask: Task<Void, Never>? let onFetchingChanged: (Fetching) -> Void let onPersonFetched: (Person) -> Void init(onFetchingChanged: @escaping (Fetching) -> Void, onPersonFetched: @escaping (Person) -> Void) { self.onFetchingChanged = onFetchingChanged self.onPersonFetched = onPersonFetched } func fetchData() { fetchingTask?.cancel() fetchingTask = Task { do { onFetchingChanged(.inProgress) let person = try await provider.getPerson() guard !Task.isCancelled else { return } onPersonFetched(person) onFetchingChanged(.idle) } catch { print(error) } } } } struct Person { enum Role: String, CaseIterable { case mum, dad, brother, sister } let firstName: String let lastName: String let age: Int let familyMemberRole: Role init(firstName: String, lastName: String, age: Int, familyMemberRole: Person.Role) { self.firstName = firstName self.lastName = lastName self.age = age self.familyMemberRole = familyMemberRole } } import UIKit class ViewController: UIViewController { @IBOutlet private var first: UILabel! @IBOutlet private var last: UILabel! @IBOutlet private var age: UILabel! @IBOutlet private var role: UILabel! @IBOutlet private var spinner: UIActivityIndicatorView! private lazy var viewModel = ViewModel(onFetchingChanged: { [weak self] state in switch state { case .idle: self?.spinner.stopAnimating() case .inProgress: self?.spinner.startAnimating() } }, onPersonFetched: { [weak self] person in guard let self else { return } first.text = person.firstName last.text = person.lastName age.text = "\(person.age)" role.text = person.familyMemberRole.rawValue }) @IBAction private func onTap() { viewModel.fetchData() } }

It seems I can declare variables like below in a source file: private let var1 = 1234 fileprivate let var2 = "abcd" class MyClass { // ... } So what's the difference between the 2 vars here?