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AsyncStream does not cancel inner Task
AsyncStream { continuation in Task { let response = await getResponse() continuation.yield(response) continuation.finish() } } In this WWDC video https://developer.apple.com/videos/play/wwdc2025/231/ at 8:20 the presenter mentions that if the "Task gets cancelled, the Task inside the function will automatically get cancelled too". The documentation does not mention anything like this. From my own testing on iOS 18.5, this is not true.
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603
Jul ’25
XCode not making bridging header file?
Hi, I'm trying to add Swift code to my Obj-C project. I've gone through all the tutorials and troubleshooting advice I can find online, no dice. I would appreciate any help, thank you so much in advance. I add a new swift file to my Obj-C project XCode offers to create a bridging header file for me, yes please New .swift file and .h file are added to my project no problem Header file shows up in build settings no problem I add a new class to my new swift file ("@objc class HelloPrinter: NSObject") When I build the app, nothing is generated in the bridging header file and the class is obviously inaccessible to my obj-c code Is this supposed to work? My understanding is that it's supposed to work. Somewhat concerning is the text that XCode puts in the bridging header file when it's created: "Use this file to import your target's public headers that you would like to expose to Swift." I don't want to use this bridging header file for anything. I want XCode to GENERATE STUFF in the bridging file. I also don't want to expose anything to Swift. I want the opposite to happen. So I don't get this text at all. Thanks in advance again.
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79
Apr ’25
indices(where:) Swift Playgrounds Issue: "Cannot call value of non-function type Range<Int>"
Hey there- I'm having a quite interesting bug on Swift Playgrounds. I am trying to run my app with this following code snippet which does not compile on Swift Playgrounds, yet compiles on XCode (note: this is a Swift Playground app) if #available(iOS 18.0, *) { //simple function to get the indices of other items that have the same date as the "date" variable let indices = data!.indices(where: { item in let sameMonth = Calendar.current.component(.month, from: item.time) == Calendar.current.component(.month, from: date) let sameYear = Calendar.current.component(.year, from: item.time) == Calendar.current.component(.year, from: date) let sameDay = Calendar.current.component(.day, from: item.time) == Calendar.current.component(.year, from: date) return sameDay && sameMonth && sameYear }) However, the indices(where:) codeblock seems to stop the app from compiling (ONLY on Swift Playgrounds - it works perfectly fine on XCode). I am getting the following error: Cannot call value of non-function type 'Range<Array<Int>.Index>' (aka 'Range<Int>') Please let me know if you have any insight regarding this issue. -ColoredOwl
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510
Jan ’25
SwiftData and 'NSKeyedUnarchiveFromData' should not be used to for un-archiving and will be removed in a future release
I get this red warning in Xcode every time my app is syncing to the iCloud. My model has only basic types and enum that conform to Codable so i'm not sure what is the problem. App is working well, synchronization works. But the warning doesn't look good. Maybe someone has idea how to debug it.
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892
Dec ’24
Compiler - method linking issue.
Issue: During app execution, the intended method is not being called; instead, the method preceding (written above the intended method) is being executed. For Example: //In my case the ViewController class is at 3rd level of inheritance. class ViewController: UIViewController { func methodA() { print("methodA") } func methodB() { print("methodB") } } let vc = ViewController() vc.methodB() Output: //"methodA" Expected: //"methodB" Observations: Recent code changes have revealed that enabling the below Swift-6 flag leads to this linking issue. When this flag is commented out, the problem disappears. .enableUpcomingFeature("InternalImportsByDefault") Additionally, moving the intended method into an extension of the same class resolves the issue when the flag is enabled. Conclusion: To resolve the issue: Comment out the Swift-6 flag. Alternatively, move the method into an extension of the same class, which addresses the issue for this specific case. I had similar issue in other class where it crashes with message "method not found", but actually the method is there. When moving the method into an extension of same class resolve this issue. Any help is much appreciated. Thanking you..
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70
May ’25
Calling StoreKit Swift from C++
What is the most obvious method of calling StoreKit from C++. I'm getting blocked by the fact that most of the critical StoreKit calls are async and functions marked a sync don't show up in the swift header for me to call from C++ (at least as far as I can tell). I'm trying to call let result = try await Product.products(for:productIDs) or let result = try await product.purchase() And C++ can't even see any functions I wrap these in as far as I can tell because i have to make them async. What am I missing? I tried a lot of alternates, like wrapping in Task { let result = try await Product.products(for:productIDs) } and it gives me 'Passing closure as a sending parameter' errors. Also when I try to call the same above code it gives me 'initializtion of immutable value never used' errors and the variables never appear. Code: struct storeChooser { public var productIDs: [String] public function checkProduct1 { Task { let result = try await Product.products(for: productIDs) } The above gives the initialization of immutable value skipped, and when I create a @State var products Then I get the 'passing closure as a sending parameter' error when i try to run it in a task it appears if I could make the function async and call it from C++ and have it return nothing it may work, does anyone know how to get C++ to see an async function in the -Swift.h file?
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116
May ’25
Runtime race condition warning when calling PHPhotoLibrary.shared().performChanges async
I have enabled runtime concurrency warnings to check for future problems concerning concurrency: Build Setting / Other Swift Flags: -Xfrontend -warn-concurrency -Xfrontend -enable-actor-data-race-checks When trying to call the async form of PHPhotoLibrary.shared().performChanges{} I get the following runtime warning: warning: data race detected: @MainActor function at ... was not called on the main thread in the line containing performChanges. My sample code inside a default Xcode multi platform app template is as follows: import SwiftUI import Photos @MainActor class FotoChanger{     func addFotos() async throws{         await PHPhotoLibrary.requestAuthorization(for: .addOnly)         try! await PHPhotoLibrary.shared().performChanges{             let data = NSDataAsset(name: "Swift")!.data             let creationRequest = PHAssetCreationRequest.forAsset()             creationRequest.addResource(with: .photo, data: data, options: PHAssetResourceCreationOptions())         }     } } struct ContentView: View {     var body: some View {         ProgressView()             .task{                 try! await FotoChanger().addFotos()             }     } } You would have to have a Swift data asset inside the asset catalog to run the above code, but the error can even be recreated if the data is invalid. But what am I doing wrong? I have not found a way to run perform changes, the block or whatever causes the error on the main thread. PS: This is only test code to show the problem, don't mind the forced unwraps.
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2.3k
Dec ’24
Swift / C++ Interop with Storekit - actor isolated structure cannot be exported to C++
I can't find a viable path to call StoreKit from C++ right now and would love some ideas. I'm implementing the code exactly as shown at 4:09 in https://developer.apple.com/videos/play/wwdc2023/10172/ However when I add any StoreKit functionality in I immediately get "Actor isolated structure cannot be exposed in C++" This makes me think I can't create a StoreKit view and call it from C++? Am I missing a better way? I don't think I can have another structure that holds the storeChooser in it because it will have the same problem (I assume, although I will check). Part of the issue seems to be that my app is C++ so there is no main function called in the swift for me to open this view with either, I was going to use the present function Zoe described (as below). I've tried a lot of alternative approaches but it seems to be blocking async functions from showing in C++ as well. So I'm not sure how to access the basic product(for:) and purchase(product) functions. import Foundation import StoreKit import SwiftUI public struct storeChooser: View { public var productIDs: [String] public var fetchError: String //@State //Note this is from the UI @State public var products: [Product] = [] // @State private var isPresented = true // weak private var host: UIViewController? = nil public init() { productIDs = ["20_super_crystals_v1"] products = [] self.fetchError = "untried" } public var body: some View { VStack(spacing: 20) { Text( "Products") ForEach(self.products) { product in Button { //dont do anything yet } label: { Text("\(product.displayPrice) - \(product.displayName)") } } }.task { do { try await self.loadProducts() } catch { print(error) } } } public func queryProducts() { Task { do { try await self.loadProducts() } catch { print(error) } } } public func getProduct1Name() -> String { if self.products.count > 0 { return self.products[0].displayName } else { return "empty" } } private func loadProducts() async throws { self.products = try await Product.products(for: self.productIDs) } /* public mutating func present(_ viewController: UIViewController) { isPresented = true; let host = UIHostingController(rootView: self) host.rootView.host = host viewController.present(host, animated: true) } */ }
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102
May ’25
Best practice: Use of enum without cases for static helper functions?
Hi all, In Swift, I often see static helper functions grouped in an enum without any cases, like this: enum StringUtils { static func camelCaseToSnakeCase(_ input: String) -> String { // implementation } } Since this enum has no cases, it cannot be instantiated – which is exactly the point. It’s meant to group related functionality without any stored state, and without the need for instantiation. This pattern avoids writing a struct with a private init() and makes the intent clearer: "This is just a static utility, not an object." You’ll often see this used for things like: AnalyticsEvents.track(_:) My question: Is this use of a case-less enum considered good practice in Swift when building static-only helpers? Or is there a better alternative for expressing intent and preventing instantiation? I’d appreciate any insight – especially if there’s official guidance or references from the Swift core team. Thanks!
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158
May ’25
Can I use @_implementationOnly import in my Framework
We have FrameworkA which needs to use another FrameworkB internally to fetch a token. Now when I try to use this FrameworkA, we are seeing an issue with internal framework i.e. No such module 'FrameworkB'. But when I use @_implementationOnly import for the internal FrameworkB, I didn't see any issues. So just wanted to check If I can go ahead and use this @_implementationOnly import flag in Production?
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99
May ’25
Trailing closure bug?
i am trying to build my code and have ran into this error. "Trailing closure passed to parameter of type 'DispatchWorkItem' that does not accept a closure" i have been trying to figure it out for so long, and even ai cant figure it out. is this a bug, or am i missing some obvious way to fix this ? func loadUser(uid: String, completion: (() -&gt; Void)? = nil) { db.collection("users").document(uid).getDocument { [weak self] snapshot, error in guard let data = snapshot?.data(), error == nil else { completion?(); return } DispatchQueue.main.async { self?.currentUser = User( username: data["username"] as? String ?? "Learner", email: data["email"] as? String ?? "", profileImageName: "person.circle.fill", totalXP: data["totalXP"] as? Int ?? 0, currentStreak: data["currentStreak"] as? Int ?? 0, longestStreak: data["longestStreak"] as? Int ?? 0, level: data["level"] as? Int ?? 1, levelProgress: data["levelProgress"] as? Double ?? 0.0, xpToNextLevel: data["xpToNextLevel"] as? Int ?? 100, completedLessons: data["completedLessons"] as? [String] ?? [] ) self?.saveUser() completion?() } } }
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155
Jun ’25
Using InlineArray on older OS versions
Hi, I’m trying to use the new InlineArray type, but noticed that it is unfortunately only available on macOS 26 and not on macOS 15 and others. As this is quite an essential type, I was wondering if this is intended or will this change in later beta’s? Not having it available on older Darwin platforms would severily limit it’s usage in the coming years. Thanks!
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108
Jun ’25
Understanding an assertion failure in a crash log
Last night my iPhone game crashed while running in debug mode on my iPhone. I just plugged it into my Mac, and was able to find the ips file. The stack trace shows the function in my app where it crashed, and then a couple of frames in libswiftCore.dylib before an assertion failure. My question is - I've got absolutely no idea what the assertion failure actually was, all I have is... 0 libswiftCore.dylib 0x1921412a0 closure #1 in closure #1 in closure #1 in _assertionFailure(_:_:file:line:flags:) + 228 1 libswiftCore.dylib 0x192141178 closure #1 in closure #1 in _assertionFailure(_:_:file:line:flags:) + 327 2 libswiftCore.dylib 0x192140b4c _assertionFailure(_:_:file:line:flags:) + 183 3 MyGame.debug.dylib 0x104e52818 SentryBrain.takeTurn(actor:) + 1240 ... How do I figure out what the assertion failure was that triggered the crash? How do I figure out what line of code in takeTurn(...) triggered the failing assertion failure?
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99
Jun ’25
Default Actor Isolation and foundational protocols
I've been testing my open source libraries with Swift 6.2 and the new Default Actor Isolation concurrency build setting set to MainActor (with Complete strict concurrency turned on). My library Destinations uses protocols extensively, often applying conformance to foundational Swift protocols like Hashable and Identifiable. Many of these basic protocols are not flagged as running on the @MainActor in Beta 1, leading to situations like this: Given this example code: public protocol Contentable: Identifiable { var id: UUID { get } } final class ContentModel: Contentable { let id: UUID = UUID() } I get the warning: Multiline Conformance of 'ContentModel' to protocol 'Contentable' crosses into main actor-isolated code and can cause data races; this is an error in the Swift 6 language mode The fix it suggests is to put a @MainActor before the Contentable protocol declaration in ContentModel, which seems to be a new attribute configuration in Swift 6.2. This solves the warning, but would create a lot of extra noise across the codebase. Was it an oversight or a temporary omission that protocols like Hashable and Identifiable do not run on @MainActor by default, or is there some other reason they are excluded? Considering how often protocols in our code may conform to foundational protocols like this, it seems at odds to the MainActor mode of the Default Actor Isolation setting given that it was created to make concurrency easier and less boilerplate to implement.
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162
Jun ’25
Tuple Comparision
I was trying to evaulate let myTuple = ("blue", false) let otherTuple = ("blue", true) if myTuple &lt; otherTuple { print("yes it evaluates") } Ans I got /tmp/S9jAk7P7KW/main.swift:5:12: error: binary operator '&lt;' cannot be applied to two '(String, Bool)' operands if myTuple &lt; otherTuple { My question is why there is no compile time issue in first place where the declaration is let myTuple = ("blue", false) ~~~~~~ something like above
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441
Jul ’25
Sending 'self' risks causing data races
Hi! I'm trying to implement Swift 6 in my code but can't fix one problem. Here is my code example which could be run in playground: import UIKit import WatchConnectivity public final class MulticastDelegate<T>: Sendable { nonisolated(unsafe) private var delegates = [WeakWrapper]() public init() { } public var isEmpty: Bool { return delegates.isEmpty } public func addDelegate(_ delegate: T) { let wrapper = WeakWrapper(value: delegate as AnyObject) delegates.append(wrapper) } public func removeDelegate(_ delegate: T) { delegates = delegates.filter { $0.value !== delegate as AnyObject } } public func invokeDelegates(_ invocation: (T) -> Void) { for (index, delegate) in delegates.enumerated().reversed() { if let delegate = delegate.value as? T { invocation(delegate) } else { delegates.remove(at: index) } } } public func invokeDelegatesCheckingResponse(_ invocation: (T) -> Bool) -> Bool { var isHandled = false for delegate in delegates { if let delegate = delegate.value as? T { if invocation(delegate) { isHandled = true break } } } return isHandled } private final class WeakWrapper: Sendable { nonisolated(unsafe) weak var value: AnyObject? init(value: AnyObject) { self.value = value } } } @globalActor public actor WatchActor { public static var shared = WatchActor() } @MainActor @objc public protocol WatchCommunicatorDelegate: NSObjectProtocol { @objc optional func watchCommunicatorDidRequestDataUpdate(_ controller: WatchCommunicator) } @WatchActor @objc public final class WatchCommunicator: NSObject { private let multicastDelegate = MulticastDelegate<WatchCommunicatorDelegate>() } extension WatchCommunicator: @preconcurrency WCSessionDelegate { public func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: (any Error)?) { multicastDelegate.invokeDelegates { delegate in Task { @MainActor in delegate.watchCommunicatorDidRequestDataUpdate?(self) } } } public func sessionDidBecomeInactive(_ session: WCSession) { } public func sessionDidDeactivate(_ session: WCSession) { } } I want to work with WatchCommunicator in global actor and WatchCommunicatorDelegate should be call in main actor and should have reference to WatchCommunicator. Help please
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3.6k
Oct ’24
@Observable class not compatible with Codable?
So any time I create a class that's both @Observable and Codable, e.g. @Observable class GameLocationManager : Codable { I get a warning in the macro expansion code: @ObservationIgnored private let _$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.
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907
Nov ’24
Strange crash when using .values from @Published publisher
Given the below code with Swift 6 language mode, Xcode 16.2 If running with iOS 18+: the app crashes due to _dispatch_assert_queue_fail If running with iOS 17 and below: there is a warning: warning: data race detected: @MainActor function at Swift6Playground/PublishedValuesView.swift:12 was not called on the main thread Could anyone please help explain what's wrong here? import SwiftUI import Combine @MainActor class PublishedValuesViewModel: ObservableObject { @Published var count = 0 @Published var content: String = "NA" private var cancellables: Set<AnyCancellable> = [] func start() async { let publisher = $count .map { String(describing: $0) } .removeDuplicates() for await value in publisher.values { content = value } } } struct PublishedValuesView: View { @ObservedObject var viewModel: PublishedValuesViewModel var body: some View { Text("Published Values: \(viewModel.content)") .task { await viewModel.start() } } }
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559
Dec ’24
Model instance invalidated, backing data could no longer be found in the store
I have been recently getting the following error seemingly randomly, when an event handler of a SwiftUI view accesses a relationship of a SwiftData model the view holds a reference to. I haven't yet found a reliable way of reproducing it: SwiftData/BackingData.swift:866: Fatal error: This model instance was invalidated because its backing data could no longer be found the store. PersistentIdentifier(id: SwiftData.PersistentIdentifier.ID(url: COREDATA_ID_URL), implementation: SwiftData.PersistentIdentifierImplementation) What could cause this error? Could you suggest me a workaround?
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911
Dec ’24