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error handling - Xcode shows error since Xcode Version > 15
Hello together, since Xcode Version > 15 the following error handling causes following error "Pattern of type 'DecodingError' cannot match 'Never' func getSupportedCountries() async { // fetch all documents from collection "seasons" from firestore let queryCountries = try? await db.collection("countries").getDocuments() if queryCountries != nil { self.countries = (queryCountries!.documents.compactMap({ (queryDocumentSnapshot) -> Country? in let result = Result { try? queryDocumentSnapshot.data(as: Country.self) } switch result { case .success(let country): if let country = country { // A country value was successfully initialized from the DocumentSnapshot self.errorMessage = nil return country } else { // A nil value was successfully initialized from the DocumentSnapshot, // or the DocumentSnapshot was nil self.errorMessage = "Document doesn't exist." return nil } case .failure(let error): // A Country value could not be initialized from the DocumentSnapshot switch error { case DecodingError.typeMismatch(_, let context): self.errorMessage = "\(error.localizedDescription): \(context.debugDescription)" case DecodingError.valueNotFound(_, let context): self.errorMessage = "\(error.localizedDescription): \(context.debugDescription)" case DecodingError.keyNotFound(_, let context): self.errorMessage = "\(error.localizedDescription): \(context.debugDescription)" case DecodingError.dataCorrupted(let key): self.errorMessage = "\(error.localizedDescription): \(key)" default: self.errorMessage = "Error decoding document: \(error.localizedDescription)" } return nil } })) } else { self.errorMessage = "No documents in 'countries' collection" return } } the interesting part of the code where XCODE shows an error is from "switch error" downwards. Does anyone of you have an idea what's wrong? Ay help appreciated ! Thx, Peter
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355
Jan ’25
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?
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555
Jan ’25
Why doesn’t getAPI() show up in autocomplete despite having a default implementation in a protocol extension?
I’m working on a project in Xcode 16.2 and encountered an issue where getAPI() with a default implementation in a protocol extension doesn’t show up in autocomplete. Here’s a simplified version of the code: import Foundation public protocol Repository { func getAPI(from url: String?) } extension Repository { public func getAPI(from url: String? = "https://...") { getAPI(from: url) } } final class _Repository: Repository { func getAPI(from url: String?) { // Task... } } let repo: Repository = _Repository() repo.getAPI( // Autocomplete doesn't suggest getAPI() I’ve tried the following without success: • Clean build folder • Restart Xcode • Reindexing Is there something wrong with the code, or is this a known issue with Xcode 16.2? I’d appreciate any insights or suggestions.
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627
Jan ’25
CryptoTokenKit Network Cryptographic Tokens
Hello, It is mentioned in CryptoTokenKit documentation: You use the CryptoTokenKit framework to easily access cryptographic tokens. Tokens are physical devices built in to the system, located on attached hardware (like a smart card), or accessible through a network connection. However, it looks like there is lack of documentation with simple example, how to access network token. I have a certificates in HSM (hardware secure module), which is accessible on network, and I'd like to access certificates on HSM on my Mac. Does anybody know, where to start with implementation? Thank you.
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1.4k
Mar ’25
How to convert a function into a variable?
Hello, I have a test variable here which works fine: var quotes: [(quote: String, order: Int)] = [ ("I live you the more ...", 1), ("There is nothing permanent ...", 2), ("You cannot shake hands ...", 3), ("Lord, make me an instrument...", 4) ] and I have a test function which successfully pulls data from a mysql database via a web service and displays it via the "print" function: func getPrice(){ if let url = URL(string:"https://www.TEST.com/test_connection.php"){ URLSession.shared.dataTask(with: url) { (data, response, error) in if let data = data{ if let json = try? JSONDecoder().decode([[String:String]].self, from: data){ json.forEach { row in print(row["quote"]!) print(row["order"]!) } } else{ } } else{ print("wrong :-(") } }.resume() } } Please can you tell me how to re-write the quotes variable/array so that it returns the results that are found in the getPrice() function?
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465
Mar ’25
Use String Catalog and Localization with class and struct
Hi Everyone, I was able to create the String Catalog with all my strings getting automatic into the stringCatalog except the strings from my models where is not swiftUI and where all I have a class with a lot of info for my app. Some classes are short and I was able to just make the strings localizable by adding on every line: (String(localized: "Telefone")) But I have one class which has Line: 1071 and Col: 1610 and every line I have 7 strings that needs to get localized. These 7 strings are repeated on every line. So I was trying to create a localization for these 7 strings on this class without having to write (String(localized: "Telefone")) 7 times on every line. is there a way? Here is short version of my class: import Foundation class LensStructFilter: Identifiable { var description: String init(description: String) { self.description = description } } let lensEntriesFilter: [LensStructFilter] = [ LensStructFilter(description: "Focal: 24mm \nAbertura Máxima: F2.8 \nCobertura: FULL FRAME \nBocal: Nikon F \nFoco Mínimo: 0,30m \nDiâmetro Frontal: 52mm \nPeso: 275g \n\nFocal: 35mm \nAbertura Máxima: F2.0 \nCobertura: FULL FRAME \nBocal: Nikon F \nFoco Mínimo: 0,25m \nDiâmetro Frontal: 52mm \nPeso: 205g \n\nFocal: 50mm \nAbertura Máxima: F1.8 \nCobertura: FULL FRAME \nBocal: Nikon F \nFoco Mínimo: 0,45m \nDiâmetro Frontal: 52mm \nPeso: 185g \n\nFocal: 85mm \nAbertura Máxima: F1.8 \nCobertura: FULL FRAME \nBocal: Nikon F \nFoco Mínimo: 0,80m \nDiâmetro Frontal: 67mm \nPeso: 350g \n\nFocal: 105mm MACRO \nAbertura Máxima: F2.8 \nCobertura: FULL FRAME \nBocal: Nikon F \nFoco Mínimo: 0,31m \nDiâmetro Frontal: 62mm \nPeso: 720g"), LensStructFilter(description: "Focal: 16-35mm  \nAbertura Máxima: F2.8 \nCobertura: FULL FRAME  \nBocal: EF \nFoco Mínimo: 0,28m \nDiâmetro Frontal (rosca): 82mm \nPeso: 790Kg"), Thanks
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390
Mar ’25
How to integrate data from a web service into an array
Hello, This test code for creating an array using a loop works: var quotes: [(id: String, name: String)] { var output: [(id: String, name: String)] = [] for i in 1...numberOfRows { let item: (id: String, name: String) = ("\(i)", "Name \(i)") output.append(item) } return output } But if I try to apply this logic to retrieving data from a web service using the below code I am getting 2 errors: For the line “quotes.append(item)” I am getting the error message “Cannot use mutating member on immutable value: ‘quotes’ is a get-only property." For the line “return output” I am getting the error message “Cannot find ‘output’ in scope." if let url = URL(string:"https://www.TEST.com/test_connection.php"){ URLSession.shared.dataTask(with: url) { (data, response, error) in if let data = data{ if let json = try? JSONDecoder().decode([[String:String]].self, from: data){ json.forEach { row in var item: (id: String, name: String) = ("test id value", "test name value") quotes.append(item) } return output } } } }
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394
Mar ’25
Class not being called?
Hello, I was expecting the code below to print the test message "line 25" because the class "API" is being called on line 57. But "line 25" is not being displayed in the debug window, please could you tell me why? This is the debugging window: line 93 0 line 93 0 line 93 0 import UIKit // not sure these 2 below are needed import SwiftUI import Combine struct NewsFeed: Codable { var id: String var name: String var country: String var type: String var situation: String var timestamp: String } let urlString = "https://www.notafunnyname.com/jsonmockup.php" let url = URL(string: urlString) let session = URLSession.shared class API: ObservableObject { let dataTask = session.dataTask(with: url!) { (data, response, error) in print("line 25") var dataString = String(data: data!, encoding: String.Encoding.utf8) if error == nil && data != nil { // Parse JSON let decoder = JSONDecoder() do { var newsFeed = try decoder.decode([NewsFeed].self, from: data!) print("line 38") // print(newsFeed) // print("line 125") // print(newsFeed.count) print(error) } catch{ print("Line 46, Error in JSON parsing") print(error) } } }.resume // Make the API Call - not sure why but error clears if moved to line above // dataTask.resume() } let myAPIarray = API() class QuoteTableViewController: UITableViewController { var newsFeed: [[String: String]] = [] override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { // let selectedQuote = quotes[indexPath.row] // performSegue(withIdentifier: "moveToQuoteDetail", sender: selectedQuote) } override func viewDidLoad() { super.viewDidLoad() // tableView.dataSource = self } // Uncomment the following line to preserve selection between presentations // self.clearsSelectionOnViewWillAppear = false // Uncomment the following line to display an Edit button in the navigation bar for this view controller. // self.navigationItem.rightBarButtonItem = self.editButtonItem // MARK: - Table view data source override func numberOfSections(in tableView: UITableView) -> Int { // #warning Incomplete implementation, return the number of sections return 1 } override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { // (viewDidLoad loads after tableView) // #warning Incomplete implementation, return the number of rows print("line 93") print(newsFeed.count) return 10 } override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { // let cell = tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier", for: indexPath) let cell = UITableViewCell () cell.textLabel?.text = "test" return cell } /* // Override to support conditional editing of the table view. override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool { // Return false if you do not want the specified item to be editable. return true } */ /* // Override to support editing the table view. override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) { if editingStyle == .delete { // Delete the row from the data source tableView.deleteRows(at: [indexPath], with: .fade) } else if editingStyle == .insert { // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view } } */ /* // Override to support rearranging the table view. override func tableView(_ tableView: UITableView, moveRowAt fromIndexPath: IndexPath, to: IndexPath) { } */ /* // Override to support conditional rearranging of the table view. override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool { // Return false if you do not want the item to be re-orderable. return true } */ // MARK: - Navigation // In a storyboard-based application, you will often want to do a little preparation before navigation override func prepare(for segue: UIStoryboardSegue, sender: Any?) { // Get the new view controller using segue.destination. // Pass the selected object to the new view controller. // getPrice() print("test_segue") if let quoteViewController = segue.destination as? QuoteDetailViewController{ if let selectedQuote = sender as? String { quoteViewController.title = selectedQuote } } } }
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89
Mar ’25
Why does Array's contains(_:) method cause an error when comparing an optional value with a non-optional value in Swift?
I’m working with Swift and encountered an issue when using the contains method on an array. The following code works fine: let result = ["hello", "world"].contains(Optional("hello")) // ✅ Works fine However, when I try to use the same contains method with the array declared in a separate constant(or variable), I get a compile-time error: let stringArray = ["hello", "world"] let result = stringArray.contains(Optional("hello")) // ❌ Compile-time error The compiler produces the following error message: Cannot convert value of type 'Optional<String>' to expected argument type 'String' Both examples seem conceptually similar, but the second one causes a compile-time error, while the first one works fine. This confuses me because I know that Swift automatically promotes a non-optional value to an optional when comparing it with an optional value. This means "hello" should be implicitly converted to Optional("hello") for the comparison. What I understand so far: The contains(_:) method is defined as: func contains(_ element: Element) -> Bool Internally, it calls contains(where:), as seen in the Swift source code: 🔗 Reference contains(where:) takes a closure that applies the == operator for comparison. Since Swift allows comparing String and String? directly (String is implicitly promoted to String? when compared with an optional), I expected contains(where:) to work the same way. My Questions: Why does the first example work, but the second one fails with a compile-time error? What exactly causes this error in the second case, even though both cases involve comparing an optional value with a non-optional value? Does contains(_:) behave differently when used with an explicit array variable rather than a direct array literal? If so, why? 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?
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145
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 ?
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385
Jun ’25
Type ReferenceWritableKeyPath does not conform to the 'Sendable' protocol
This is not a question but more of a hint where I was having trouble with. In my SwiftData App I wanted to move from Swift 5 to Swift 6, for that, as recommended, I stayed in Swift 5 language mode and set 'Strict Concurrency Checking' to 'Complete' within my build settings. It marked all the places where I was using predicates with the following warning: Type '' does not conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode I had the same warnings for SortDescriptors. I spend quite some time searching the web and wrapping my head around how to solve that issue to be able to move to Swift 6. In the end I found this existing issue in the repository of the Swift Language https://github.com/swiftlang/swift/issues/68943. It says that this is not a warning that should be seen by the developer and in fact when turning Swift 6 language mode on those issues are not marked as errors. So if anyone is encountering this when trying to fix all issues while staying in Swift 5 language mode, ignore those, fix the other issues and turn on Swift 6 language mode and hopefully they are gone.
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1k
Jun ’25
Bridging Headers is unsupported or Module compiled with Swift 5.5.1 cannot be imported by the Swift 5.6 complier
Hello guys! I faced a problem with building... My device suddenly updated to iOS 15.4.1, my Xcode was 13.2 and I had to update it to the latest version (13.3.1) to build the app. After the update, I had a few problems which were successfully solved but one of them stopped me for a few hours. The problem is with Bridging Headers or Swift Compiler, I really don't know what I did badly, and what causes problems. On several forums I often read that is important to set: Build Settings &gt; Build Options &gt; Build Libraries for Distribution But in any case it doesn't work, on yes: error: using bridging headers with module interfaces is unsupported on no: (line with import framework SWXMLHash) /Users/blablabla/SSLModel.swift:9:8: error: module compiled with Swift 5.5.1 cannot be imported by the Swift 5.6 compiler: /Users/blablabla2/Build/Products/Debug-iphoneos/SWXMLHash.framework/Modules/SWXMLHash.swiftmodule/arm64-apple-ios.swiftmodule import SWXMLHash It will be important that I use Carthage. What should I do? Clone all 10 frameworks that I use and re-build them with a new Xcode which includes compiler 5.6? That may be a bad solution... Any answers on similar topics don't help..
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3.0k
Jul ’25
Passing string between Swift and C++
I want to understand what the recommended way is for string interoperability between swift and c++. Below are the 3 ways to achieve it. Approach 2 is not allowed at work due to restrictions with using std libraries. Approach 1: In C++: char arr[] = "C++ String"; void * cppstring = arr; std::cout<<"before:"<<(char*)cppstring<<std::endl;           // C++ String // calling swift function and passing the void buffer to it, so that swift can update the buffer content Module1::SwiftClass:: ReceiveString (cppstring, length);   std::cout<<"after:"<<(char*)cppstring<<std::endl;             // SwiftStr      In Swift: func ReceiveString (pBuffer : UnsafeMutableRawPointer , pSize : UInt ) -> Void { // to convert cpp-str to swift-str: let swiftStr = String (cString: pBuffer.assumingMemoryBound(to: Int8.self)); print("pBuffer content: \(bufferAsString)"); // to modify cpp-str without converting: let swiftstr:String = "SwiftStr"      _ =  swiftstr.withCString { (cString: UnsafePointer<Int8>) in pBuffer.initializeMemory(as: Int8.self, from: cString, count: swiftstr.count+1) } }  Approach 2:  The ‘String’ type returned from a swift function is received as ‘swift::String’ type in cpp. This is implicitly casted to std::string type. The std::string has the method available to convert it to char *. void TWCppClass::StringConversion () {     // GetSwiftString() is a swift call that returns swift::String which can be received in std::string type     std::string stdstr = Module1::SwiftClass::GetSwiftString ();     char * cstr = stdstr.data ();     const char * conststr= stdstr.c_str (); }    Approach 3: The swift::String type that is obtained from a swift function can be received in char * by directly casting the address of the swift::String. We cannot directly receive a swift::String into a char *. void TWCppClass::StringConversion () {    // GetSwiftString() is a swift call that returns swift::String    swift::String swiftstr = Module1::SwiftClass::GetSwiftString ();    // obtaining the address of swift string and casting it into char *    char * cstr = (char*)&swiftstr; }
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1
453
Jul ’25
C++ and Swift in Xcode 16 broke my audio unit
I'm developing an audio unit for use on iOS. The AUv3 worked fine with xcode 15.X and swift 5.X. I recently tried to submit an update to my plug-in but Apple refused submission because my Xcode was not the latest. Now that I'm on Xcode 16.4 I can't get my project to compile, even when following all of the same previous steps. As one example of a change, Xcode doesn't appear to include the “C++ and Objective-C interoperability” build setting that it used to. This setting is noted in the Swift documentation and I used to need it, https://www.swift.org/documentation/cxx-interop/project-build-setup/#mixing-swift-and-c-using-xcode Currently my C++ code can't see anything from Swift, and I get a "Use of undeclared identifier 'project_name'". I've selected Switch support for version 5.0 in an attempt to minimize changes from Apple. My process is I generate an Xcode project file from my audio plugin support, JUCE. Then I add in the swift files, click yes to create bridging headers, but c++ doesn't see swift anymore. I'd greatly appreciate any suggestions.
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339
Aug ’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
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195
Aug ’25