Discuss Swift.

Swift Documentation

Posts under Swift subtopic

Post

Replies

Boosts

Views

Activity

Swift/C++ interoperability issue in std::string
In scope of one of our project we've faced an issue with constant crashes when integrating C++ library in Swift code using Swift/C++ interoperability. Investigating the root causes of the issue we've discovered that with new version of Swift bug was introduced. Long story short: for strings bigger than 27 symbols memory is feed incorrectly that causes the crashes. By creating this post I wanted to draw community's attention to the problem and promote it to be solved quicker as for now it is not addressed.
1
0
522
Jul ’25
How to save a point cloud in the sample code "Capturing depth using the LiDAR camera" with the photoOutput
Hello dear community, I have the sample code from Apple “CapturingDepthUsingLiDAR” to access the LiDAR on my iPhone 12 Pro. My goal is to use the “photo output” function to generate a point cloud from a single image and then save it as a ply file. So far I have tested different approaches to create a .ply file from the depthmap, the intrinsic camera data and the rgba values. Unfortunately, I have had no success so far and the result has always been an incorrect point cloud. My question now is whether there are already approaches to this and whether anyone has any experience with it. Thank you very much in advance!!!
1
0
517
Jan ’25
Strange values written in loop
I don't understand what's happening when I save values via a loop. I initialize an array with default values, then run a loop to assign calculated values to it. In the middle of the loop, I print values, then print values again after the loop is over. The array values sometimes change, even though nothing has been written between print calls (when they change, the values are equal the last value in the array, index 49). I made a test file which writes four types of values to an array: (1) A new class instance, (2) Calculation, (3) Variable, (4) Hard-code. Saving the same value gives different results between the different write methods: import Foundation let numElements : Int = 50 class CustomType{ var x : Double var y : Double init(x: Double = 1.23, y: Double = 2.34) { self.x = x self.y = y } } // Try this four different ways var array1 = [CustomType](repeating:CustomType(), count:numElements) var array2 = [CustomType](repeating:CustomType(), count:numElements) var array3 = [CustomType](repeating:CustomType(), count:numElements) var array4 = [CustomType](repeating:CustomType(), count:numElements) // Checking that defaults were written print("Pre: Point 1: (\(array1[44].x),\(array1[44].y))") print("Pre: Point 2: (\(array2[44].x),\(array2[44].y))") print("Pre: Point 3: (\(array3[44].x),\(array3[44].y))") print("Pre: Point 4: (\(array4[44].x),\(array4[44].y))") // --- Fix 1: Problem goes away if I uncomment this: // array1[44]=CustomType() // array2[44]=CustomType() // array3[44]=CustomType() // array4[44]=CustomType() // --- Fix 2: Or if you swap these two lines for the following line: // let index = 44 // do { for index in 0..<numElements{ let rads = Double(index) * 2 * Double.pi/Double(numElements) let sinrads = sin(rads), cosrads = cos(rads) // Four different ways to save to arrays array1[index] = CustomType(x:sin(rads),y:cos(rads)) array2[index].x = sin(rads) array2[index].y = cos(rads) array3[index].x = sinrads array3[index].y = cosrads array4[index].x = -0.684547105928689 array4[index].y = 0.7289686274214113 if(index==44){ print("\n== Printing results mid-loop at index 44 ==") print("During: index: \(index), Calculated Rads: \(rads)") print("During: Calculated Vals: (\(sin(rads)),\(cos(rads)))") print("During: Stored 'let' Vals: (\(sinrads),\(cosrads))") print("During: Point 1: (\(array1[44].x),\(array1[44].y))") print("During: Point 2: (\(array2[44].x),\(array2[44].y))") print("During: Point 3: (\(array3[44].x),\(array3[44].y))") print("During: Point 4: (\(array4[44].x),\(array4[44].y))") } } print("\n== Printing the same results after the loop ==") print("Post: Point 1: (\(array1[44].x),\(array1[44].y))") print("Post: Point 2: (\(array2[44].x),\(array2[44].y))") print("Post: Point 3: (\(array3[44].x),\(array3[44].y))") print("Post: Point 4: (\(array4[44].x),\(array4[44].y))") print("\n== Reverse-calculating results from a correct array (array 1) to get the for loop index ==") print("reverse index calculation 01: \( (atan2(array1[ 1].x,array1[ 1].y) + Double.pi * 0) * Double(numElements)/(2*Double.pi) )") print("reverse index calculation 44: \( (atan2(array1[44].x,array1[44].y) + Double.pi * 2) * Double(numElements)/(2*Double.pi) )") print("reverse index calculation 45: \( (atan2(array1[45].x,array1[45].y) + Double.pi * 2) * Double(numElements)/(2*Double.pi) )") print("\n== Reverse-calculating results from an incorrect array (array 2) to get the for loop index ==") print("reverse index calculation 1: \( (atan2(array2[ 1].x,array2[ 1].y) + Double.pi * 2) * Double(numElements)/(2*Double.pi) )") print("reverse index calculation 44: \( (atan2(array2[44].x,array2[44].y) + Double.pi * 2) * Double(numElements)/(2*Double.pi) )") print("reverse index calculation 45: \( (atan2(array2[45].x,array2[45].y) + Double.pi * 2) * Double(numElements)/(2*Double.pi) )") Which gives the following output: Pre: Point 1: (1.23,2.34) Pre: Point 2: (1.23,2.34) Pre: Point 3: (1.23,2.34) Pre: Point 4: (1.23,2.34) == Printing results mid-loop at index 44 == During: index: 44, Calculated Rads: 5.529203070318036 During: Calculated Vals: (-0.684547105928689,0.7289686274214113) During: Stored 'let' Vals: (-0.684547105928689,0.7289686274214113) During: Point 1: (-0.684547105928689,0.7289686274214113) During: Point 2: (-0.684547105928689,0.7289686274214113) During: Point 3: (-0.684547105928689,0.7289686274214113) During: Point 4: (-0.684547105928689,0.7289686274214113) == Printing the same results after the loop == Post: Point 1: (-0.684547105928689,0.7289686274214113) Post: Point 2: (-0.12533323356430465,0.9921147013144778) Post: Point 3: (-0.12533323356430465,0.9921147013144778) Post: Point 4: (-0.684547105928689,0.7289686274214113) == Reverse-calculating results from a correct array (array 1) to get the for loop index == reverse index calculation 01: 1.0000000000000002 reverse index calculation 44: 43.99999999999999 reverse index calculation 45: 45.0 == Reverse-calculating results from an incorrect array (array 2) to get the for loop index == reverse index calculation 1: 49.0 reverse index calculation 44: 49.0 reverse index calculation 45: 49.0 Program ended with exit code: 0 Re-initializing the objects prior to the loop fixes the problem (see "Fix 1" in the comments), but the elements of the array are all initialized during creation and I don't understand why doing it a second time is helpful. The values should all be the same, am I missing something simple?
2
0
512
Dec ’24
How to implement thread-safe property wrapper notifications across different contexts in Swift?
I’m trying to create a property wrapper that that can manage shared state across any context, which can get notified if changes happen from somewhere else. I'm using mutex, and getting and setting values works great. However, I can't find a way to create an observer pattern that the property wrappers can use. The problem is that I can’t trigger a notification from a different thread/context, and have that notification get called on the correct thread of the parent object that the property wrapper is used within. I would like the property wrapper to work from anywhere: a SwiftUI view, an actor, or from a class that is created in the background. The notification preferably would get called synchronously if triggered from the same thread or actor, or otherwise asynchronously. I don’t have to worry about race conditions from the notification because the state only needs to reach eventuall consistency. Here's the simplified pseudo code of what I'm trying to accomplish: // A single source of truth storage container. final class MemoryShared<Value>: Sendable { let state = Mutex<Value>(0) func withLock(_ action: (inout Value) -> Void) { state.withLock(action) notifyObservers() } func get() -> Value func notifyObservers() func addObserver() } // Some shared state used across the app static let globalCount = MemoryShared<Int>(0) // A property wrapper to access the shared state and receive changes @propertyWrapper struct SharedState<Value> { public var wrappedValue: T { get { state.get() } nonmutating set { // Can't set directly } } var publisher: Publisher {} init(state: MemoryShared) { // ... } } // I'd like to use it in multiple places: @Observable class MyObservable { @SharedState(globalCount) var count: Int } actor MyBackgroundActor { @SharedState(globalCount) var count: Int } @MainActor struct MyView: View { @SharedState(globalCount) var count: Int } What I’ve Tried All of the examples below are using the property wrapper within a @MainActor class. However the same issue happens no matter what context I use the wrapper in: The notification callback is never called on the context the property wrapper was created with. I’ve tried using @isolated(any) to capture the context of the wrapper and save it to be called within the state in with unchecked sendable, which doesn’t work: final class MemoryShared<Value: Sendable>: Sendable { // Stores the callback for later. public func subscribe(callback: @escaping @isolated(any) (Value) -> Void) -> Subscription } @propertyWrapper struct SharedState<Value> { init(state: MemoryShared<Value>) { MainActor.assertIsolated() // Works! state.subscribe { MainActor.assertIsolated() // Fails self.publisher.send() } } } I’ve tried capturing the isolation within a task with AsyncStream. This actually compiles with no sendable issues, but still fails: @propertyWrapper struct SharedState<Value> { init(isolation: isolated (any Actor)? = #isolation, state: MemoryShared<Value>) { let (taskStream, continuation) = AsyncStream<Value>.makeStream() // The shared state sends new values to the continuation. subscription = state.subscribe(continuation: continuation) MainActor.assertIsolated() // Works! let task = Task { _ = isolation for await value in taskStream { _ = isolation MainActor.assertIsolated() // Fails } } } } I’ve tried using multiple combine subjects and publishers: final class MemoryShared<Value: Sendable>: Sendable { let subject: PassthroughSubject<T, Never> // ... var publisher: Publisher {} // ... } @propertyWrapper final class SharedState<Value> { var localSubject: Subject init(state: MemoryShared<Value>) { MainActor.assertIsolated() // Works! handle = localSubject.sink { MainActor.assertIsolated() // Fails } stateHandle = state.publisher.subscribe(localSubject) } } I’ve also tried: Using NotificationCenter Making the property wrapper a class Using NSKeyValueObserving Using a box class that is stored within the wrapper. Using @_inheritActorContext. All of these don’t work, because the event is never called from the thread the property wrapper resides in. Is it possible at all to create an observation system that notifies the observer from the same context as where the observer was created? Any help would be greatly appreciated!
2
0
473
Mar ’25
Memory leak and a crash when swizzling NSURLRequest initialiser
When swizzling NSURLRequest initialiser and returning a mutable copy, the original instance does not get deallocated and eventually gets leaked and a crash follows after that. Here's the swizzling setup: static func swizzleInit() { let initSel = NSSelectorFromString("initWithURL:cachePolicy:timeoutInterval:") guard let initMethod = class_getInstanceMethod(NSClassFromString("NSURLRequest"), initSel) else { return } let origInitImp = method_getImplementation(initMethod) let block: @convention(block) (AnyObject, Any, NSURLRequest.CachePolicy, TimeInterval) -> NSURLRequest = { _self, url, policy, interval in typealias OrigInit = @convention(c) (AnyObject, Selector, Any, NSURLRequest.CachePolicy, TimeInterval) -> NSURLRequest let origFunc = unsafeBitCast(origInitImp, to: OrigInit.self) let request = origFunc(_self, initSel, url, policy, interval) return request.tagged() } let newImplementation = imp_implementationWithBlock(block as Any) method_setImplementation(initMethod, newImplementation) } // create a mutable copy if needed and add a header private func tagged() -> NSURLRequest { guard let mutableRequest = self as? NSMutableURLRequest ?? self.mutableCopy() as? NSMutableURLRequest else { return self } mutableRequest.setValue("test", forHTTPHeaderField: "test") return mutableRequest } Then, we have a few test cases: // memory leak and crash func testSwizzleNSURLRequestInit() { let request = NSURLRequest(url: URL(string: "https://example.com")!) XCTAssertEqual(request.value(forHTTPHeaderField: "test"), "test") } // no crash, as the request is mutable, so no copy is created func testSwizzleNSURLRequestInit2() { let request = URLRequest(url: URL(string: "https://example.com")!) XCTAssertEqual(request.value(forHTTPHeaderField: "test"), "test") } // no crash, as the request is mutable, so no copy is created func testSwizzleNSURLRequestInit3() { let request = NSMutableURLRequest(url: URL(string: "https://example.com")!) XCTAssertEqual(request.value(forHTTPHeaderField: "test"), "test") } // no crash, as the new instance does not get deallocated // when the test method completes (?) var request: NSURLRequest? func testSwizzleNSURLRequestInit4() { request = NSURLRequest(url: URL(string: "https://example.com")!) XCTAssertEqual(request?.value(forHTTPHeaderField: "test"), "test") } It appears a memory leak occurs only when any other instance except for the original one is being returned from the initialiser. Is there a workaround to prevent the leak, while allowing for modifications of all requests?
3
0
582
Nov ’24
Get CloudKit records created by specific user
I've been searching all over the web trying to find the proper way to get all records created by a specific user in CloudKit. I am able to get the correct id using: guard let userRecordID = try? await container.userRecordID() else { return } I can see that the id returned is associated with records in my CloudKit dashboard. So I would expect that the following would get those records: let predicate = NSPredicate(format: "%K == %@", #keyPath(CKRecord.creatorUserRecordID), userRecordID) let query = CKQuery(recordType: "CKUser", predicate: predicate) But instead when I use that query it returns nothing. It is successful but with nothing returned... Any ideas why this would be happening? P.S. I have also tried constructing the predicate using the reference, but I get the same result - success with no results. P.S.2 Also worth mentioning that I am trying to get the results from the public database and I have set my CKContainer to the correct container id.
5
0
927
Dec ’24
Using `@ObservedObject` in a function
No real intruduction for this, so I'll get to the point: All this code is on GitHub: https://github.com/the-trumpeter/Timetaber-for-iWatch But first, sorry; /* I got roasted, last time I posted; for not defining my stuff. This'll be different, but's gonna be rough; 'cuz there's lots and lots to get through: */ //this is 'Timetaber Watch App/Define (No expressions)/Courses_vDef.swift' on the GitHub: struct Course { let name: String let icon: String let room: String let colour: String let listName: String let listIcon: String let joke: String init(name: String, icon: String, room: String? = nil, colour: String, listName: String? = nil, listIcon: String? = nil, joke: String? = nil) { self.name = name self.icon = icon self.room = room ?? "None" self.colour = colour self.listName = listName ?? name self.listIcon = listIcon ?? (icon+".circle.fill") self.joke = joke ?? "" } } //this is 'Timetaber Watch App/TimeManager_fDef.swift' on the GitHub: func getCurrentClass(date: Date) -> Array<Course> { //returns the course in session depending on the input date //it is VERY long but //all you really need to know is what it returns: //basically: return [rightNow, nextUp] } /* I thought that poetry would be okay, But poorly thought things through: For I'll probably find that people online will treat my rhymes like spew. */ So into the question: I have a bunch of views, all (intendedly) watching two variables inside of a class: //Github: 'Timetaber Watch App/TimetaberApp.swift' class GlobalData: ObservableObject { @Published var currentCourse: Course = getCurrentClass(date: .now)[0] // the current timetabled class in session. @Published var nextCourse: Course = getCurrentClass(date: .now)[1] // the next timetabled class in session } ...and a bunch of views using them in different ways as follows: (Sorry, don't have the characters to define functions called in these) import SwiftUI //Github: 'Timetaber Watch App/Views/HomeView.swift' struct HomeView: View { @StateObject var data = GlobalData() var body: some View { //HERE: let icon = data.currentCourse.icon let name = data.currentCourse.name let colour = data.currentCourse.colour let room = roomOrBlank(course: data.currentCourse) let next = data.nextCourse VStack { //CURRENT CLASS Image(systemName: icon) .foregroundColor(Color(colour))//add an SF symbol element .imageScale(.large) .font(.system(size: 25).weight(.semibold)) Text(name) .font(.system(size:23).weight(.bold)) .foregroundColor(Color(colour)) .padding(.bottom, 0.1) //ROOM Text(room+"\n") .multilineTextAlignment(.center) .foregroundStyle(.gray) .font(.system(size: 15)) if next.name != noSchool.name { Spacer() //NEXT CLASS Text(nextPrefix(course: next)) .font(.system(size: 15)) Text(getNextString(course: next)) .font(.system(size: 15)) .multilineTextAlignment(.center) } }.padding() } } // Github: 'Timetaber Watch App/Views/ListView.swift' struct listTemplate: View { @StateObject var data = GlobalData() var listedCourse: Course = failCourse(feedback: "lT.12") var courseTime: String = "" init(course: Course, courseTime: String) { self.courseTime = courseTime self.listedCourse = course } var body: some View { let localroom = if listedCourse.room == "None" { "" } else { listedCourse.room } let image = if listedCourse.listIcon == "custom1" { Image(.paintbrushPointedCircleFill) } else { Image(systemName: listedCourse.listIcon) } HStack{ image .foregroundColor(Color(listedCourse.colour)) .padding(.leading, 5) Text(listedCourse.name) .bold() Spacer() Text(courseTime) Text(localroom).bold().padding(.trailing, 5) } .padding(.bottom, 1) .background(data.currentCourse.name==listedCourse.name ? Color(listedCourse.colour).colorInvert(): nil) //HERE } } struct listedDay: View { let day: Dictionary<Int, Course> var body: some View { let dayKeys = Array(day.keys).sorted(by: <) List { ForEach((0...dayKeys.count-2), id: \.self) { let num = $0 listTemplate(course: day[dayKeys[num]] ?? failCourse(feedback: "lD.53"), courseTime: time24toNormal(time24: dayKeys[num])) } } } } struct ListView: View { var body: some View { if storage.shared.termRunningGB && weekdayFunc(inDate: .now) != 1 && weekdayFunc(inDate: .now) != 7 { ScrollView { listedDay( day: getTimetableDay( isWeekA: getIfWeekIsA_FromDateAndGhost( originDate: .now, ghostWeek: storage.shared.ghostWeekGB ), weekDay: weekdayFunc(inDate: .now) ) ) } } else if !storage.shared.termRunningGB { Text("There's no term running.\nThe day's classes will be displayed here.") .multilineTextAlignment(.center) .foregroundStyle(.gray) .font(.system(size: 13)) } else { Text("No school today.\nThe day's classes will be displayed here.") .multilineTextAlignment(.center) .foregroundStyle(.gray) .font(.system(size: 13)) } } } //There's one more view but I can't fit it for characters. //On GitHub: 'Timetaber Watch App/Views/SettingsView.swift' So... THE FUNCTION: This function is called when changes are made that will affect the correct output of getCurrentClass. It is intended to reload the views and the current/next variables to reflect those changes.\ //GHub: 'Timetaber Watch App/StorageManager.swift' func reload() -> Void { @ObservedObject var globalData: GlobalData //this line is erroring, I don't know how to fix it. Is this even the best/proper way to do this? let courseData = getCurrentClass(date: .now) globalData.currentCourse = courseData[0] globalData.nextCourse = courseData[1] //Variable '_globalData' used by function definition before being initialized //that is the error appearing on those above two redefinitions. print("Setup done\n") } Thanks! -Gill
1
0
265
Mar ’25
Function types as return types
Greetings, func stepForward(_ input: Int) -> Int { return input + 1 } func stepBackward(_ input: Int) -> Int { return input - 1 } func chooseStepFunction(backward: Bool) -> (Int) -> Int { return backward ? stepBackward : stepForward /* Error type of expression is ambiguous without a type annotation */ } Why am I getting this error. If I change the function to func chooseStepFunction(backward: Bool) -> (Int) -> Int { if backward { return stepBackward else { return stepForward } } Why is the previous chooseStepFunction giving me an error ? Thx in advance
3
0
166
Aug ’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
2.2k
Mar ’25
Capturing self instead of using self. in switch case in DispatchQueue causes compiler error
I have an @objC used for notification. kTag is an Int constant, fieldBeingEdited is an Int variable. The following code fails at compilation with error: Command CompileSwift failed with a nonzero exit code if I capture self (I edited code, to have minimal case) @objc func keyboardDone(_ sender : UIButton) { DispatchQueue.main.async { [self] () -> Void in switch fieldBeingEdited { case kTag : break default : break } } } If I explicitly use self, it compiles, even with self captured: @objc func keyboardDone(_ sender : UIButton) { DispatchQueue.main.async { [self] () -> Void in switch fieldBeingEdited { // <<-- no need for self here case self.kTag : break // <<-- self here default : break } } } This compiles as well: @objc func keyboardDone(_ sender : UIButton) { DispatchQueue.main.async { () -> Void in switch self.fieldBeingEdited { // <<-- no need for self here case self.kTag : break // <<-- self here default : break } } } Is it a compiler bug or am I missing something ?
3
0
343
Jun ’25
json array shows in debugger but can't parse
Hello, I asked this question on 9th March but was asked to provide a project file and can't edit the original post. Please find the original question below and please find the new test project file at https://we.tl/t-fqAu8FrgUw. I have a json array showing in Xcode debugger (from the line "print(dataString)"): Optional("[{\"id\":\"8e8tcssu4u2hn7a71tkveahjhn8xghqcfkwf1bzvtrw5nu0b89w\",\"name\":\"Test name 0\",\"country\":\"Test country 0\",\"type\":\"Test type 0\",\"situation\":\"Test situation 0\",\"timestamp\":\"1546848000\"},{\"id\":\"z69718a1a5z2y5czkwrhr1u37h7h768v05qr3pf1h4r4yrt5a68\",\"name\":\"Test name 1\",\"country\":\"Test country 1\",\"type\":\"Test type 1\",\"situation\":\"Test situation 1\",\"timestamp\":\"1741351615\"},{\"id\":\"fh974sv586nhyysbhg5nak444968h7hgcgh6yw0usbvcz9b0h69\",\"name\":\"Test name 2\",\"country\":\"Test country 2\",\"type\":\"Test type 2\",\"situation\":\"Test situation 2\",\"timestamp\":\"1741351603\"},{\"id\":\"347272052385993\",\"name\":\"Test name 3\",\"country\":\"Test country 3\",\"type\":\"Test type 3\",\"situation\":\"Test situation 3\",\"timestamp\":\"1741351557\"}]") But my JSON decoder is throwing the catch error "Error in JSON parsing" This is the code: let urlString = "https://www.notafunnyname.com/jsonmockup.php" let url = URL(string: urlString) guard url != nil else { return } let session = URLSession.shared let dataTask = session.dataTask(with: url!) { (data, response, error) in var dataString = String(data: data!, encoding: String.Encoding.utf8) print(dataString) if error == nil && data != nil { // Parse JSON let decoder = JSONDecoder() do { let newsFeed = try decoder.decode(NewsFeed.self, from: data!) print(newsFeed) print(error) } catch{ print("Error in JSON parsing") } } } // Make the API Call dataTask.resume() } And this is my Codable file NewsFeed.swift: struct NewsFeed: Codable { var id: String var name: String var country: String var type: String var overallrecsit: String var dlastupd: String var doverallrecsit: String } Please do you know why the parsing may be failing? Is it significant that in the debugging window the JSON is displaying backslashes before the quotation marks? Thank you for any pointers :-)
1
0
333
Mar ’25
How to run `xctest` bundle - or how to add `entitlement` to test?
I am writing a SPM based project for MacOS. In this project? I need to access MacOS Keychain. I am write a swift test built by SPM testTarget(). I can see it generates a bundle ./.build/x86_64-apple-macosx/debug/MyProjectTests.xctest with an executable: % file ./.build/x86_64-apple-macosx/debug/MyProjectPackageTests.xctest/Contents/MacOS/MyProjectPackageTests ./.build/x86_64-apple-macosx/debug/MyProjectPackageTests.xctest/Contents/MacOS/MyProjectPackageTests: Mach-O 64-bit bundle x86_64 This bundle file cannot be executed. How can I execute its tests? I tried with xcodebuild test-without-building -xctestrun ./.build/x86_64-apple-macosx/debug/MyProjectPackageTests.xctest -destination 'platform=macOS' without any chance. Obviously the next question is can I 'simply' add entitlement to this bundle with codesign to fix my enttilement error. My error when running the test is A required entitlement isn't present.
2
0
1.4k
Mar ’25
Best way to measure days between dates
Hey team I'm facing an issue where startDate is 1 January 2025 and endDate is 31 March 2025 between this 2 dates is 90 days, but on my code is being taken as 89 days I've seen the math of the code excludes the first partial day (from midnight to 06:00) on 2025-01-01, which results in 89 full days instead of 90 days. startDate: 2025-01-01 06:00:00 +0000 endDate: 2025-03-31 06:00:00 +0000 this is my function func daysBetweenDates() -> Int? { guard let selectedStartDate = selectedStartDate?.date else { return nil } guard let selectedEndDate = selectedEndDate?.date else { return 0 } let calendar = Calendar.current let dateComponents = calendar.dateComponents([.day], from: selectedStartDate, to: selectedEndDate) return dateComponents.day } what I've tried is reset the hours to 0 so it can take the full day and return 90 days like this func daysBetweenDates() -> Int? { guard let selectedStartDate = selectedStartDate?.date else { return nil } guard let selectedEndDate = selectedEndDate?.date else { return 0 } var calendar = Calendar(identifier: .gregorian) calendar.timeZone = TimeZone(secondsFromGMT: 0) ?? .current let cleanMidNightStartDate = calendar.startOfDay(for: selectedStartDate) let cleanMidNightEndDate = calendar.startOfDay(for: selectedEndDate.addingTimeInterval(24 * 60 * 60)) let dateComponents = calendar.dateComponents([.day], from: cleanMidNightStartDate, to: cleanMidNightEndDate) let daysCount = dateComponents.day ?? 0 return daysCount } this worked for that date specifically but when I tried to change the date for example startDate: 18 December 2024. endDate: 18 March 2025. between those dates we have 90 days but this function now reads 91. what I'm looking is a cleaver solution for this problem so I can have the best posible quality code, thanks in advance!
1
0
493
Dec ’24
json array shows in debugger but can't parse (corrected question)
Hello, Please see the test project at https://we.tl/t-aWAu7kk9lD I have a json array showing in Xcode debugger (from the line "print(dataString)"): Optional("[{\"id\":\"8e8tcssu4u2hn7a71tkveahjhn8xghqcfkwf1bzvtrw5nu0b89w\",\"name\":\"Test name 0\",\"country\":\"Test country 0\",\"type\":\"Test type 0\",\"situation\":\"Test situation 0\",\"timestamp\":\"1546848000\"},{\"id\":\"z69718a1a5z2y5czkwrhr1u37h7h768v05qr3pf1h4r4yrt5a68\",\"name\":\"Test name 1\",\"country\":\"Test country 1\",\"type\":\"Test type 1\",\"situation\":\"Test situation 1\",\"timestamp\":\"1741351615\"},{\"id\":\"fh974sv586nhyysbhg5nak444968h7hgcgh6yw0usbvcz9b0h69\",\"name\":\"Test name 2\",\"country\":\"Test country 2\",\"type\":\"Test type 2\",\"situation\":\"Test situation 2\",\"timestamp\":\"1741351603\"},{\"id\":\"347272052385993\",\"name\":\"Test name 3\",\"country\":\"Test country 3\",\"type\":\"Test type 3\",\"situation\":\"Test situation 3\",\"timestamp\":\"1741351557\"}]") But my JSON decoder is throwing a catch error Line 57, Error in JSON parsing typeMismatch(Swift.Dictionary<Swift.String, Any>, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Dictionary<String, Any> but found an array instead.", underlyingError: nil)) This is the code: let urlString = "https://www.notafunnyname.com/jsonmockup.php" let url = URL(string: urlString) guard url != nil else { return } let session = URLSession.shared let dataTask = session.dataTask(with: url!) { (data, response, error) in var dataString = String(data: data!, encoding: String.Encoding.utf8) print(dataString) if error == nil && data != nil { // Parse JSON let decoder = JSONDecoder() do { let newsFeed = try decoder.decode(NewsFeed.self, from: data!) print("line 51") print(newsFeed) print(error) } catch{ print("Line 57, Error in JSON parsing") print(error) } } } // Make the API Call dataTask.resume() } And this is my Codable file NewsFeed.swift: struct NewsFeed: Codable { var id: String var name: String var country: String var type: String var situation: String var timestamp: String } Please do you know how to resolve the typeMismatch error?
2
0
337
Mar ’25
Why does Array.contains cause a compile-time error when comparing an optional value with a non-optional value in Swift?
I’m working with Swift and ran into an issue when using the contains(_:) method on an array. The following code works fine: let result = ["hello", "world"].contains(Optional("hello")) // ✅ Works fine But when I try to use the same contains method with the array declared in a separate variable, I get a compile-time error: let stringArray = ["hello", "world"] let result = stringArray.contains(Optional("hello")) // ❌ Compile-time error Both examples seem conceptually similar, but the second one causes a compile-time error, while the first one works fine. I understand that when comparing an optional value (Optional("hello")) with a non-optional value ("hello"), Swift automatically promotes the non-optional value to an optional (i.e., "hello" becomes Optional("hello")). 🔗 reference What I don’t understand is why the first code works but the second one doesn’t, even though both cases involve comparing an optional value with a non-optional value. I know that there are different ways to resolve this, like using nil coalescing or optional binding, but what I’m really looking for is a detailed explanation of why this issue occurs at the compile-time level. Can anyone explain the underlying reason for this behavior?
1
0
81
Mar ’25
New unexpected compile behavior in Xcode 16.3
I have a macro that converts expression into a string literal, e.g.: #toString(variable) -> "variable" #toString(TypeName) -> "TypeName" #toString(\TypeName.property) -> "property" In Xcode 16.3 #toString(TypeName) stopped to work, compilation throws 'Expected member name or initializer call after type name' error. Everything works fine in Xcode 16.2. I tried to compare build settings between 16.2 and 16.3 but haven't noticed differences that may cause this new error. The following works in both Xcode versions: #toString(variable) -> "variable" #toString(\TypeName.property) -> "property" Seems like Xcode tries to compile code that shouldn't be compiled because of macro expansion. Does anybody know what new has appeared in 16.3 and, perhaps, how to fix the problem?
5
1
201
Apr ’25
Database Download Record Fetch Fails in MacOS 15.2
A program I wrote in Swift that uploads and downloads to a private database in iCloud is failing for downloads since the the 15.2 update. It still works for uploads. I.e., I can download uploads made from the program under 15.2 on another computer running the same program under 15.1 The Fetch operation does not return an error, but the returnRecord is empty! I do get the error below after the fact of the failure, don't know if it's related. "ViewBridge to RemoteViewService Terminated: Error Domain=com.apple.ViewBridge Code=18 "(null)" UserInfo={com.apple.ViewBridge.error.hint=this process disconnected remote view controller -- benign unless unexpected, com.apple.ViewBridge.error.description=NSViewBridgeErrorCanceled}" To be clear, I assume I do have access to the database since it works for upload under 15.2, as well as upload and download under 15.1, and from a very similar program on my iPhone (which I haven't updated yet!) Questions? Comments? Thanks!
0
1
403
Dec ’24