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Function types as return types
func oneStepForward(_ input: Int) -> Int { return input + 1 } func oneStepBackward(_ input: Int) -> Int { return input - 1 } func chooseStepFunction(backward: Bool) -> (Int) -> Int { return backward ? oneStepBackward : oneStepForward //Error. type of expression is ambiguous without a type annotation } Why am I getting this error ? If I change this function to the following it works and will compile. func chooseStepFunction(backward: Bool) -> (Int) -> Int { if backward { return oneStepBackward } else { return oneStepForward } } // Why am I getting the error in the previous version while it works in the second version ? Thx in advance.
6
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566
Aug ’25
MPMediaItemPropertyArtwork crashes on Swift 6
Hey all! in my personal quest to make future proof apps moving to Swift 6, one of my app has a problem when setting an artwork image in MPNowPlayingInfoCenter Here's what I'm using to set the metadata func setMetadata(title: String? = nil, artist: String? = nil, artwork: String? = nil) async throws { let defaultArtwork = UIImage(named: "logo")! var nowPlayingInfo = [ MPMediaItemPropertyTitle: title ?? "***", MPMediaItemPropertyArtist: artist ?? "***", MPMediaItemPropertyArtwork: MPMediaItemArtwork(boundsSize: defaultArtwork.size) { _ in defaultArtwork } ] as [String: Any] if let artwork = artwork { guard let url = URL(string: artwork) else { return } let (data, response) = try await URLSession.shared.data(from: url) guard (response as? HTTPURLResponse)?.statusCode == 200 else { return } guard let image = UIImage(data: data) else { return } nowPlayingInfo[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(boundsSize: image.size) { _ in image } } MPNowPlayingInfoCenter.default().nowPlayingInfo = nowPlayingInfo } the app crashes when hitting MPMediaItemPropertyArtwork: MPMediaItemArtwork(boundsSize: defaultArtwork.size) { _ in defaultArtwork } or nowPlayingInfo[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(boundsSize: image.size) { _ in image } commenting out these two make the app work again. Again, no clue on why. Thanks in advance
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3.1k
Sep ’25
Update or remove Ruby 2.6
macOS Tahoe ships with Ruby 2.6.10 which was End Of Life in April 2022 (https://www.ruby-lang.org/en/downloads/branches/). How can I either upgrade it to Ruby 3.4.7 or delete it, so that my mac meets minimum cybersecurity requirements? I use rbenv for more recent versions of Ruby at the moment so don't need any suggestions on how to do add them, I just need rid of the dangerously out of date system Ruby, thanks.
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1
1.8k
Dec ’25
JavaScript/Swift Interoperability
I think that it would be helpful to have better interoperability between Swift and JavaScript. There are a lot of useful packages on NPM that don't have equivalents for Swift. It would be helpful if Apple provided easier ways to use NPM packages in a Swift project. Currently, the JavaScriptCore framework is missing many standard things used in many packages, like the fetch API. It would be helpful to be able to run sandboxed JavaScript code inside of a Swift app but allow access to specific domains, folders, etc., using a permissions system similar to Deno.
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2.7k
2w
Circular Reference Error in Xcode 26
I have my project running perfectly fine on Xcode 16. However, in Xcode 26 it doesn't build due to an error that I do not understand. I have three files that pertain to this error: // FriendListResponse.swift import Foundation struct FriendListResponse: Decodable { var friendships: [Friendship] var collections: [FriendCollection] } // Friendship.swift import Foundation struct Friendship: Decodable { var createdAt: String var friendId: Int var friendUserId: Int // user ID of the friend var friendUsername: String var id: Int var tagNames: [String] } // FriendCollection.swift struct FriendCollection: Decodable { var id: Int var permalink: String var tagNames: [String] var title: String } On the first file, FriendListResponse.swift, I am the simple error message "circular reference." I do not understand how these self-contained structs could create a circular reference. Although I have other data types in my project, none of them are even referenced in these files except for Friendship and FriendCollection. The FriendListResponse is a struct that is created from JSON values that are fetched from an API. This is the function that fetches the JSON: public static func listFriends(username: String) async throws -> [Friendship] { let data = try await sendGETRequest( url: "people/\(username)/friends/list.json" ) print(String(data: data, encoding: .utf8)!) let decoder = JSONDecoder() decoder.keyDecodingStrategy = .convertFromSnakeCase let wrapper = try decoder.decode(FriendListResponse.self, from: data) return wrapper.friendships } // Note: the function sendGETRequest is just // a function that I have created that takes a set // of parameters and returns a data object // using the HTTP GET protocol. I don't think // that it is related to this issue. However, if you // think that it is, I can share the code for that. This error has also happened in a few other cases within contained networks of my data structure. I do not know why this error is only appearing once I launch Xcode 26 beta with my project files. I would think that this error also would appear in Xcode 16.4. Any help would be greatly appreciated in my process to compile my project on Xcode 26!
7
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541
Jun ’25
jmp_buf layout for Apple Silicon
Greetings! I am actively working on porting x64 code to Apple Silicon now that the time is nigh and part of the fundamentals of our software is a coroutine library for handling cooperative multitasking of GUI operations on the main thread. I was hoping to get the locations of the stack pointer and frame pointer in jmp_buf so, after setjmp() can redirect them to the primary handling routines in our coroutine library that handles the cooperative scheduling (which replaced and ported the old classic MP routines) which worked for PowerPC, i386 and x64. Any thoughts on where in the jmp_buf these might be located? I didn't see anything in the XNU open source. Any advice would be much obliged instead of having to dive in and re-implement these routines in assembly myself!
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477
Aug ’25
App sometimes crashes when inserting String into Set with assertion ELEMENT_TYPE_OF_SET_VIOLATES_HASHABLE_REQUIREMENTS
Xcode downloaded a crash report for my app that crashed when trying to insert a String into a Set<String>. Apparently there was an assertion failure ELEMENT_TYPE_OF_SET_VIOLATES_HASHABLE_REQUIREMENTS. I assume that this assertion failure happened because the hash of the new element didn't match the hash of an equal already inserted element, but regardless, I don't understand how inserting a simple string could trigger this assertion. Here is essentially the code that leads to the crash. path is any file system directory, and basePath is a directory higher in the hierarchy, or path itself. var scanErrorPaths = Set<String>() func main() { let path = "/path/to/directory" let basePath = "/path" let fileDescriptor = open(path, O_RDONLY) if fileDescriptor < 0 { if (try? URL(fileURLWithPath: path, isDirectory: false).checkResourceIsReachable()) == true { scanErrorPaths.insert(path.relativePath(from: basePath)!) return } } extension String { func relativePath(from basePath: String) -> String? { if basePath == "" { return self } guard let index = range(of: basePath, options: .anchored)?.upperBound else { return nil } return if index == endIndex || basePath == "/" { String(self[index...]) } else if let index = self[index...].range(of: "/", options: .anchored)?.upperBound { String(self[index...]) } else { nil } } } crash.crash
7
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894
Oct ’25
CGSWindowShmemCreateWithPort log message
After ther Mac application is launched: Log error: CGSWindowShmemCreateWithPort failed on port 0 and when the application quit: No error handler for XPC error: Connection invalid Appear with Xcode 15.4 but not with 12.4 As repported by Steve4442 in "Can someone explain this message" https://Forums.Developer.Apple.com/Forums/Thread/727803 . The code don't use "windowNumbersWithOptions" Can I ignore this log message ?
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869
Feb ’25
Weird crashes when accessing Swift Array
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)?
16
0
2.4k
Mar ’25
What is the future of Objective-C?
Will Apple continue to support it, or will we wake up one day to find that Swift is the only viable language?It's a serious question. Careers depend on it. I don't accept the "No comment" approach that Apple usually takes. It's cruel.I'm willing to put the time into learning Swift if I have to. I'm not going to do it if I don't. I want to know.Frank
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34k
Oct ’25
Crash with Progress type, Swift 6, iOS 18
We are getting a crash _dispatch_assert_queue_fail when the cancellationHandler on NSProgress is called. We do not see this with iOS 17.x, only on iOS 18. We are building in Swift 6 language mode and do not have any compiler warnings. We have a type whose init looks something like this: init( request: URLRequest, destinationURL: URL, session: URLSession ) { progress = Progress() progress.kind = .file progress.fileOperationKind = .downloading progress.fileURL = destinationURL progress.pausingHandler = { [weak self] in self?.setIsPaused(true) } progress.resumingHandler = { [weak self] in self?.setIsPaused(false) } progress.cancellationHandler = { [weak self] in self?.cancel() } When the progress is cancelled, and the cancellation handler is invoked. We get the crash. The crash is not reproducible 100% of the time, but it happens significantly often. Especially after cleaning and rebuilding and running our tests. * thread #4, queue = 'com.apple.root.default-qos', stop reason = EXC_BREAKPOINT (code=1, subcode=0x18017b0e8) * frame #0: 0x000000018017b0e8 libdispatch.dylib`_dispatch_assert_queue_fail + 116 frame #1: 0x000000018017b074 libdispatch.dylib`dispatch_assert_queue + 188 frame #2: 0x00000002444c63e0 libswift_Concurrency.dylib`swift_task_isCurrentExecutorImpl(swift::SerialExecutorRef) + 284 frame #3: 0x000000010b80bd84 MyTests`closure #3 in MyController.init() at MyController.swift:0 frame #4: 0x000000010b80bb04 MyTests`thunk for @escaping @callee_guaranteed @Sendable () -&gt; () at &lt;compiler-generated&gt;:0 frame #5: 0x00000001810276b0 Foundation`__20-[NSProgress cancel]_block_invoke_3 + 28 frame #6: 0x00000001801774ec libdispatch.dylib`_dispatch_call_block_and_release + 24 frame #7: 0x0000000180178de0 libdispatch.dylib`_dispatch_client_callout + 16 frame #8: 0x000000018018b7dc libdispatch.dylib`_dispatch_root_queue_drain + 1072 frame #9: 0x000000018018bf60 libdispatch.dylib`_dispatch_worker_thread2 + 232 frame #10: 0x00000001012a77d8 libsystem_pthread.dylib`_pthread_wqthread + 224 Any thoughts on why this is crashing and what we can do to work-around it? I have not been able to extract our code into a simple reproducible case yet. And I mostly see it when running our code in a testing environment (XCTest). Although I have been able to reproduce it running an app a few times, it's just less common.
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7
2.9k
Apr ’25