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NSExpression error handling
Context: SwiftUI TextField with a String for simple math using NSExpression. I first prepare the input string to an extent but a malformed input using valid characters still fails, as expected. Let's say preparedExpression is "5--" let expr = NSExpression(format: preparedExpression) gives FAULT: NSInvalidArgumentException: Unable to parse the format string "5-- == 1"; (user info absent) How can I use NSExpression such that either the preparedExpression is pre-tested before asking for actual execution or the error is handled in a polite way that I can use to alert the user to try again. Is there a Swift alternative to NSExpression that I've missed?
3
0
517
Jan ’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.
2
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86
Apr ’25
Trailing closure passed to parameter of type 'String' that does not accept a closure
import Foundation import FirebaseAuth import GoogleSignIn import FBSDKLoginKit class AuthController { // Assuming these variables exist in your class var showCustomAlertLoading = false var signUpResultText = "" var isSignUpSucces = false var navigateHome = false // Google Sign-In func googleSign() { guard let presentingVC = (UIApplication.shared.connectedScenes.first as? UIWindowScene)?.windows.first?.rootViewController else { print("No root view controller found.") return } GIDSignIn.sharedInstance.signIn(withPresenting: presentingVC) { authentication, error in if let error = error { print("Error: \(error.localizedDescription)") return } guard let authentication = authentication else { print("Authentication is nil") return } guard let idToken = authentication.idToken else { print("ID Token is missing") return } guard let accessToken = authentication.accessToken else { print("Access Token is missing") return } let credential = GoogleAuthProvider.credential(withIDToken: idToken.tokenString, accessToken: accessToken.tokenString) self.showCustomAlertLoading = true Auth.auth().signIn(with: credential) { authResult, error in guard let user = authResult?.user, error == nil else { self.signUpResultText = error?.localizedDescription ?? "Error occurred" DispatchQueue.main.asyncAfter(deadline: .now() + 2) { self.showCustomAlertLoading = false } return } self.signUpResultText = "\(user.email ?? "No email")\nSigned in successfully" self.isSignUpSucces = true DispatchQueue.main.asyncAfter(deadline: .now() + 3) { self.showCustomAlertLoading = false DispatchQueue.main.asyncAfter(deadline: .now() + 1) { self.navigateHome = true } } print("\(user.email ?? "No email") signed in successfully") } } } // Facebook Sign-In func signInWithFacebook(presentingViewController: UIViewController, completion: @escaping (Bool, Error?) -> Void) { let manager = LoginManager() manager.logIn(permissions: ["public_profile", "email"], from: presentingViewController) { result, error in if let error = error { completion(false, error) return } guard let result = result, !result.isCancelled else { completion(false, NSError(domain: "Facebook Login Error", code: 400, userInfo: nil)) return } if let token = result.token { let credential = FacebookAuthProvider.credential(withAccessToken: token.tokenString) Auth.auth().signIn(with: credential) { (authResult, error) in if let error = error { completion(false, error) return } completion(true, nil) } } } } // Email Sign-In func signInWithEmail(email: String, password: String, completion: @escaping (Bool, Error?) -> Void) { Auth.auth().signIn(withEmail: email, password: password) { (authResult, error) in if let error = error { completion(false, error) return } completion(true, nil) } } }
1
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420
Nov ’24
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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387
Jun ’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?
2
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132
May ’25
Working correctly with actor annotated class
Hi, I have a complex structure of classes, and I'm trying to migrate to swift6 For this classes I've a facade that creates the classes for me without disclosing their internals, only conforming to a known protocol I think I've hit a hard wall in my knowledge of how the actors can exchange data between themselves. I've created a small piece of code that can trigger the error I've hit import SwiftUI import Observation @globalActor actor MyActor { static let shared: some Actor = MyActor() init() { } } @MyActor protocol ProtocolMyActor { var value: String { get } func set(value: String) } @MyActor func make(value: String) -> ProtocolMyActor { return ImplementationMyActor(value: value) } class ImplementationMyActor: ProtocolMyActor { private(set) var value: String init(value: String) { self.value = value } func set(value: String) { self.value = value } } @MainActor @Observable class ViewObserver { let implementation: ProtocolMyActor var value: String init() async { let implementation = await make(value: "Ciao") self.implementation = implementation self.value = await implementation.value } func set(value: String) { Task { await implementation.set(value: value) self.value = value } } } struct MyObservedView: View { @State var model: ViewObserver? var body: some View { if let model { Button("Loaded \(model.value)") { model.set(value: ["A", "B", "C"].randomElement()!) } } else { Text("Loading") .task { self.model = await ViewObserver() } } } } The error Non-sendable type 'any ProtocolMyActor' passed in implicitly asynchronous call to global actor 'MyActor'-isolated property 'value' cannot cross actor boundary Occurs in the init on the line "self.value = await implementation.value" I don't know which concurrency error happens... Yes the init is in the MainActor , but the ProtocolMyActor data can only be accessed in a MyActor queue, so no data races can happen... and each access in my ImplementationMyActor uses await, so I'm not reading or writing the object from a different actor, I just pass sendable values as parameter to a function of the object.. can anybody help me understand better this piece of concurrency problem? Thanks
1
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597
Nov ’24
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!
2
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178
May ’25
Range For Keys and Values Of Dictionary
I came across a code let myFruitBasket = ["apple":"red", "banana": "yellow", "budbeeri": "dark voilet", "chikoo": "brown"] Can we have range for keys and values of dictionary, it will be convenient for keys print(myFruitBasket.keys[1...3]) // banana, budbeeri, chikoo same for values print(myFruitsBasket.values[1...3]) // yellow, voilet, brown
4
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472
Aug ’25
Issue with Swift 6 migration issues
We are migrating to swift 6 from swift 5 using Xcode 16.2. we are getting below errors in almost each of our source code files : Call to main actor-isolated initializer 'init(storyboard:bundle:)' in a synchronous non isolated context Main actor-isolated property 'delegate' can not be mutated from a nonisolated context Call to main actor-isolated instance method 'register(cell:)' in a synchronous nonisolated context Call to main actor-isolated instance method 'setup()' in a synchronous nonisolated context Few questions related to these compile errors. Some of our functions arguments have default value set but swift 6 does not allow to set any default values. This requires a lot of code changes throughout the project. This would be lot of source code re-write. Using annotations like @uncheck sendable , @Sendable on the class (Main actor) name, lot of functions within those classes , having inside some code which coming from other classes which also showing main thread issue even we using @uncheck sendable. There are so many compile errors, we are still seeing other than what we have listed here. Fixing these compile errors throughout our project, would be like a re-write of our whole application, which would take lot of time. In order for us to migrate efficiently, we have few questions where we need your help with. Below are the questions. Are there any ways we can bypass these errors using any keywords or any other way possible? Can Swift 5 and Swift 6 co-exist? so, we can slowly migrate over a period of time.
1
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160
Jun ’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: (() -> 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?() } } }
2
0
168
Jun ’25
Timeline refresh issue for widget on ios 18.2
I use AppIntent to trigger a widget refresh, Appint is used on Button or Toggle,as follows var isAudibleArming = false struct SoundAlarmIntent: AppIntent { static var title: LocalizedStringResource = "SoundAlarmIntent" func perform() async throws -> some IntentResult { isAudibleArming = true return .result() } } func timeline( for configuration: DynamicIntentWidgetPersonIntent, in context: Context ) async -> Timeline { var entries: [Entry] = [] let currentDate = Date() let entry = Entry(person: person(for: configuration)) entries.append(entry) if isAudibleArming { let entry2 = Entry(person: Person(name: "Friend4", dateOfBirth: currentDate.adding(.second, value: 6))) entries.append(entry2) } return .init(entries: entries, policy: .never) } The timeline function fires, with entry corresponding to view1 and entry2 corresponding to view2. I expect to show view1 immediately and view2 6 seconds later. You get the correct response on iOS17. But the 6 second delay function on the discovery code in iOS18.2 takes effect immediately, view1 flashes, view2 appears immediately instead of waiting 6 seconds to appear.
7
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651
Dec ’24
DebugDescription macro causing “String Interpolation” warnings
Using the DebugDescription macro to display an optional value produces a “String interpolation produces a debug description for an optional value” build warning. For example: @DebugDescription struct MyType: CustomDebugStringConvertible { let optionalValue: String? public var debugDescription: String { "Value: \(optionalValue)" } } The DebugDescription macro does not allow (it is an error) "Value: \(String(describing: optionalValue))" or "Value: \(optionalValue ?? "nil")" because “Only references to stored properties are allowed.” Is there a way to reconcile these? I have a build log full of these warnings, obscuring real issues.
2
0
467
Feb ’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
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165
Aug ’25
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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442
Aug ’25
@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.
2
0
920
Nov ’24
Equatable with default actor isolation of MainActor
I filed the following issue on swiftlang/swift on GitHub (Aug 8th), and a followup the swift.org forums, but not getting any replies. As we near the release of Swift 6.2, I want to know if what I'm seeing below is expected, or if it's another case where the compiler needs a fix. protocol P1: Equatable { } struct S1: P1 { } // Error: Conformance of 'S1' to protocol 'P1' crosses into main actor-isolated code an can cause data races struct S1Workaround: @MainActor P1 { } // OK // Another potential workaround if `Equatable` conformance can be moved to the conforming type. protocol P2 { } struct S2: Equatable, P2 { } // OK There was a prior compiler bug fix which addressed inhereted protocols regarding @MainActor. For Equatable, one still has to use @MainActoreven when the default actor isolation is MainActor. Also affects Hashable and any other protocol inheriting from Equatable.
3
0
1.1k
Aug ’25
Snapshot error
Hey everyone, I have a problem with an app im creating. The code doesn't have any errors but the console has this that pops up: Snapshot request 0x1054191d0 complete with error: <NSError: 0x10541a970; domain: FBSSceneSnapshotErrorDomain; code: 4; "an unrelated condition or state was not satisfied"> { NSLocalizedDescription = an error occurred during a scene snapshotting operation; }
1
0
101
Jun ’25
Module compiled with Swift 6.0.3 cannot be imported by the Swift 6.1 compiler
Module compiled with Swift 6.0.3 cannot be imported by the Swift 6.1 compiler: /private/var/tmp/_bazel_xx/8b7c61ad484d9da1bf94a11f12ae6ffd/rules_xcodeproj.noindex/build_output_base/execroot/main/CustomModules/BIYThred/CocoaLumberjack/framework/CocoaLumberjack.framework/Modules/CocoaLumberjack.swiftmodule/arm64-apple-ios.swiftmodule
1
0
719
Jul ’25
How swift string is internally managing memory ?
When i create a intance of swift String : Let str = String ("Hello") As swift String are immutable, and when we mutate the value of these like: str = "Hello world ......." // 200 characters Swift should internally allocate new memory and copy the content to that buffer for update . But when i checked the addresses of original and modified str, both are same? Can you help me understand how this allocation and mutation working internally in swift String?
1
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523
Nov ’24