I’m stuck with repeated production crashes in my SwiftUI app and I can’t make sense of the traces on my own. The symbolicated reports show the same pattern: Crash on com.apple.CFNetwork.LoaderQ with EXC_BAD_ACCESS / PAC failure Always deep in CFNetwork, most often in URLConnectionLoader::loadWithWhatToDo(NSURLRequest*, _CFCachedURLResponse const*, long, URLConnectionLoader::WhatToDo) No frames from my code, no sign of AuthManager or tokens. What I’ve tried: Enabled Address Sanitizer, Malloc Scribble, Guard Malloc, Zombies. Set CFNETWORK_DIAGNOSTICS=3 and collected Console logs. Stress-tested the app (rapid typing, filter switching, background/foreground, poor network with Network Link Conditioner). Could not reproduce the crash locally. So far: Logs show unrelated performance faults (I/O on main thread, CLLocationManager delegate), but no obvious CFNetwork misuse. My suspicion is a URLSession lifetime or delegate/auth-challenge race, but I can’t confirm because I can’t trigger it. Since starting this investigation, I also refactored some of my singletons into @State/@ObservedObject dependencies. For example, my app root now wires up AuthManager, BackendService, and AccountManager (where API calls happen using async/await) as @State properties: @State var authManager: AuthManager @State var accountManager: AccountManager @State var backendService: BackendService init() { let authManager = AuthManager() self._authManager = .init(wrappedValue: authManager) let backendService = BackendService(authManager: authManager) self._backendService = .init(wrappedValue: backendService) self._accountManager = .init(wrappedValue: AccountManager(backendService: backendService)) } I don’t know if this refactor is related to the crash, but I am including it to be complete. Apologies that I don’t have a minimized sample project — this issue seems app-wide, and all I have are the crash logs. Request: Given the crash location (URLConnectionLoader::loadWithWhatToDo), can Apple provide guidance on known scenarios or misuses that can lead to this crash? Is there a way to get more actionable diagnostics from CFNetwork beyond CFNETWORK_DIAGNOSTICS to pinpoint whether it’s session lifetime, cached response corruption, or auth/redirect? Can you also confirm whether my dependency setup above could contribute to URLSession or backend lifetime issues? I can’t reliably reproduce the crash, and without Apple’s insight the stack trace is effectively opaque to me. Thanks for your time and help. Happy to send multiple symbolicated crash logs at request. Thanks for any help. PS. Including 2 of many similar crash logs. Can provide more if needed. Atlans-2025-07-29-154915_symbolicated (cfloader).txt Atlans-2025-08-08-124226_symbolicated (cfloader).txt

Hi In C#, one can define associated functions by the following. Notice that "Declarations DE" is a reference to a function in another C# project file. This lets the compiler know that there are other references in the project. Likewise, "Form_Load" is the entry point of the code, similar to "main" in C. Any calls to related functions can be made in this section, to the functions that have been previously defined above. So I set out trying to find similar information about SwiftUI, and found several, but only offer partial answers to my questions. The YouTube video... Extracting functions and subviews in SwiftUI | Bootcamp #20 - YouTube ... goes into some of the details, but still leaves me hanging. Likewise... SOLVED: Swift Functions In Swift UI – SwiftUI – Hacking with Swift forums ... has further information, but nothing concrete that I am looking for. Now in the SwiftUI project, I tried this... The most confusing thing for me, is where is "main"? I found several examples that call functions from the structure shown above, BUT I have no reason as to why. So one web example on StackOverFlow called the function from position 1. That did not work. Position 2 worked to call the function at position 3, but really, why? All this activity brings up a lot of questions for me, such as: Does SwiftUI need function callouts similar to C#, and they are called out even before running "main". I seem to recall Borland Delphi being this way as well. How does SwiftUI make references to other classes (places where other functions are stored in separate files)? Does SwiftUI actually make use of "main" in the normal sense, i.e. similar to C, C#, Rust and so on? I did notice that once a SwiftUI function is called, it makes reference to data being passed very similar to other languages, at least for the examples I found. Note that I looked at official SwiftUI documentation, but did not come across information that answers the above.

I am a Chinese student beginner ,do you have any advice for me to learn swift？I don't know how to start it.Please!🙏

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.

I have a Settings class that conform to the TestProtocol. From the function of the protocol I need to call the setString function and this function needs to be on the MainActor. Is there a way of make this work in Swift6, without making the protocol functions running on @MainActor The calls are as follows: class Settings: TestProtocol{ var value:String = "" @MainActor func setString( _ string:String ){ value = string } func passString(string: String) { Task{ await setString(string) } } } protocol TestProtocol{ func passString( string:String ) }

Consider this Swift struct: public struct Example { public func foo(callback: ()->Void) { .... } public func blah(i: Int) { .... } .... } Using Swift/C++ interop, I can create Example objects and call methods like blah. But I can't call foo because Swift/C++ interop doesn't currently support passing closures (right?). On the other hand, Swift/objC does support passing objC blocks to Swift functions. But I can't use that here because Example is a Swift struct, not a class. So I could change it to a class, and update everything to work with reference rather than value semantics; but then I also have to change the objC++ code to create the object and call its methods using objC syntax. I'd like to avoid that. Is there some hack that I can use to make this possible? I'm hoping that I can wrap a C++ std::function in some sort of opaque wrapper and pass that to swift, or something. Thanks for any suggestions!

Hello, I am getting an error message "Cannot convert value of type 'URLSessionDataTask' to expected argument type 'Data'" for the last line of this code. Please can you tell me what the problem is? Thank you struct Item : Codable { var id: String var name: String var country: String var type: String var overallrecsit: String var dlastupd: String var doverallrecsit: String } let url = URL(string:"https://www.TEST_URL.com/api_ios.php") let json = try? JSONDecoder().decode(Item.self, from: URLSession.shared.dataTask(with: url!))

Just read about the new @concurrent option coming to Swift 6.2 and lover it, but... It just me, but I which these options would pick a case and stick with it... @Sendable @unchecked @MainActor @concurrent @Observable @ObservationIgnored

The following code works when compiling for macOS: print(NSMutableDictionary().isEqual(to: NSMutableDictionary())) but produces a compiler error when compiling for iOS: 'NSMutableDictionary' is not convertible to '[AnyHashable : Any]' NSDictionary.isEqual(to:) has the same signature on macOS and iOS. Why does this happen? Can I use NSDictionary.isEqual(_:) instead?

Hi Apple Developer Community, I'm facing a crash when updating an array of tuples from both a background thread and the main thread simultaneously. Here's a simplified version of the code in a macOS app using AppKit: class ViewController: NSViewController { var mainthreadButton = NSButton(title: "test", target: self, action: nil) var numbers = Array(repeating: (dim: Int, key: String)(0, "default"), count: 1000) override func viewDidLoad() { super.viewDidLoad() view.addSubview(mainthreadButton) mainthreadButton.translatesAutoresizingMaskIntoConstraints = false mainthreadButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true mainthreadButton.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true mainthreadButton.widthAnchor.constraint(equalToConstant: 100).isActive = true mainthreadButton.heightAnchor.constraint(equalToConstant: 100).isActive = true mainthreadButton.target = self mainthreadButton.action = #selector(arraytest(_:)) } @objc func arraytest(_ sender: NSButton) { print("array update started") // Background update DispatchQueue.global().async { for i in 0..<1000 { self.numbers[i].dim = i } } // Main thread update var sum = 0 for i in 0..<1000 { numbers[i].dim = i + 1 sum += numbers[i].dim print("test \(sum)") } mainthreadButton.title = "test = \(sum)" } } This results in a crash with the following message: malloc: double free for ptr 0x136040c00 malloc: *** set a breakpoint in malloc_error_break to debug What's interesting: This crash only happens when the tuple contains a String ((dim: Int, key: String)) If I change the tuple type to use two Int values ((dim: Int, key: Int)), the crash does not occur My Questions: Why does mutating an array of tuples containing a String crash when accessed from multiple threads? Why is the crash avoided when the tuple contains only primitive types like Int? Is there an underlying memory management issue with value types containing reference types like String? Any explanation about this behavior and best practices for thread-safe mutation of such arrays would be much appreciated. Thanks in advance!

I have a class object created dynamically using Runtime, and I want to release some manually allocated memory resources when this object is deallocated. To achieve this, I added a custom implementation of the dealloc method using the following code: SEL aSel = NSSelectorFromString(@"dealloc"); class_addMethod(kvoClass, aSel, (IMP)custom_dealloc, method_getTypeEncoding(class_getInstanceMethod(kvoClass, aSel))); However, I encountered some issues. If I don't call the superclass's dealloc method in the cus_dealloc function, the superclass's dealloc implementation will not be executed. On the other hand, if I explicitly call the superclass's dealloc method, the program crashes. Here is the implementation of the cus_dealloc function: void custom_dealloc(id self, SEL _cmd) { // Release other memory ![]("https://developer.apple.com/forums/content/attachment/c7b0c16b-be23-4776-b8db-f22b661c5e7d" "title=iShot_2025-01-03_19.31.34.png;width=1080;height=1895") Class superClass = class_getSuperclass(object_getClass(self)); void (*originIMP)(struct objc_super *, SEL, ...) = (void *)objc_msgSendSuper; struct objc_super *objcSuper = &(struct objc_super){self, superClass}; originIMP(objcSuper, _cmd); } demo

and yeah, swift vaguely is reminiscent of a programming language I developed, but I want swift To do return if (var blah:Int32 == 43){ blah = blah2; } your welcome !! thank me on my new accounting job lol =/ basically I want to return conditional statements for a private reason

I can't find any simple c++ xcodeproj call to swift struct using modern c++ swift mix. there is the fibonacci example that is swift app call to c++. Base on fibonacci example I create new simple project and fail to build it with error when I try to include #include <SwiftMixTester/SwiftMixTester-Swift.h> What is wrong? Is it the right place to ask this? Any work project link? Xcode 26.

I get many warnings like this when I build an old project. I asked AI chatbot which gave me several solutions, the recommended one is: var hashBag = [String: Int]() func updateHashBag() async { var tempHashBag = hashBag // make copy await withTaskGroup(of: Void.self) { group in group.addTask { tempHashBag["key1"] = 1 } group.addTask { tempHashBag["key2"] = 2 } } hashBag = tempHashBag // copy back? } My understanding is that in the task group, the concurrency engine ensures synchronized modifications on the temp copy in multiple tasks. I should not worry about this. My question is about performance. What if I want to put a lot of data into the bag? Does the compiler do some kind of magics to optimize low level memory allocations? For example, the temp copy actually is not a real copy, it is a special reference to the original hash bag; it is only grammar glue that I am modifying the copy.

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 ?

I notice that Swift Data type's hashValue collision when first 80 byte of data and data length are same because of the Implementation only use first 80 bytes to compute the hash. https://web.archive.org/web/20120605052030/https://opensource.apple.com/source/CF/CF-635.21/CFData.c also, even if hash collision on the situation like this, I can check data is really equal or not by == does there any reason for this implementation(only use 80 byte of data to make hashValue)? test code is under below let dataArray: [UInt8] = [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ] var dataArray1: [UInt8] = dataArray var dataArray2: [UInt8] = dataArray dataArray1.append(contentsOf: [0x00, 0x00, 0x00, 0x00]) dataArray2.append(contentsOf: [0xff, 0xff, 0xff, 0xff]) let data1 = Data(dataArray1) let data2 = Data(dataArray2) // Only last 4 byte differs print(data1.hashValue) print(data2.hashValue) print(data1.hashValue == data2.hashValue) // true print(data1 == data2) // false

Last night my iPhone game crashed while running in debug mode on my iPhone. I just plugged it into my Mac, and was able to find the ips file. The stack trace shows the function in my app where it crashed, and then a couple of frames in libswiftCore.dylib before an assertion failure. My question is - I've got absolutely no idea what the assertion failure actually was, all I have is... 0 libswiftCore.dylib 0x1921412a0 closure #1 in closure #1 in closure #1 in _assertionFailure(_:_:file:line:flags:) + 228 1 libswiftCore.dylib 0x192141178 closure #1 in closure #1 in _assertionFailure(_:_:file:line:flags:) + 327 2 libswiftCore.dylib 0x192140b4c _assertionFailure(_:_:file:line:flags:) + 183 3 MyGame.debug.dylib 0x104e52818 SentryBrain.takeTurn(actor:) + 1240 ... How do I figure out what the assertion failure was that triggered the crash? How do I figure out what line of code in takeTurn(...) triggered the failing assertion failure?

Hello, I am developing a private internal Flutter app for our customer, which will not be published on the Apple Store. One of the key features of this app is to collect RF strength metrics to share user experience with the network. For Android, we successfully implemented the required functionality and are able to collect the following metrics: Signal strength level (0-4) Signal strength in dBm RSSI RSRQ Cell ID Location Area Code Carrier name Mobile country code Mobile network code Radio access technology Connection status Duplex mode However, for iOS, we are facing challenges with CoreTelephony, which is not returning the necessary data. We are aware that CoreTelephony is deprecated and are looking for alternatives. We noticed that a lot of the information we need is available via FTMInternal-4. Is there a way to access this data for a private app? Are there any other recommended approaches or frameworks that can be used to gather cellular network information on iOS for an app that won't be distributed via the Apple Store? my swift code import Foundation import CoreTelephony class RfSignalStrengthImpl: RfSignalStrengthApi { func getCellularSignalStrength(completion: @escaping (Result<CellularSignalStrength, Error>) -> Void) { let networkInfo = CTTelephonyNetworkInfo() guard let carrier = networkInfo.serviceSubscriberCellularProviders?.values.first else { completion(.failure(NSError(domain: "com.xxxx.yyyy", code: 0, userInfo: [NSLocalizedDescriptionKey: "Carrier not found"]))) return } let carrierName = carrier.carrierName ?? "Unknown" let mobileCountryCode = carrier.mobileCountryCode ?? "Unknown" let mobileNetworkCode = carrier.mobileNetworkCode ?? "Unknown" let radioAccessTechnology = networkInfo.serviceCurrentRadioAccessTechnology?.values.first ?? "Unknown" var connectionStatus = "Unknown" ... ... } Thank you for your assistance.

According to the doc: The value returned is the same as the value returned in the kEventParamKeyCode when using Carbon Events. So where can I find kEventParamKeyCode?

I've got a watch app, still with storyboard, WKInterfaceController and WatchConnectivity. After updating it for swift 6 concurrency I thought I'd keep it for a little while without swift 6 concurrency dynamic runtime check. So I added -disable-dynamic-actor-isolation in OTHER_SWIFT_FLAGS, but it doesn't seem to have an effect for the Apple Watch target. Without manually marking callbacks where needed with @Sendable in dynamic checks seem to be in place. swiftc invocation is as (includes -disable-dynamic-actor-isolation): swiftc -module-name GeoCameraWatchApp -Onone -enforce-exclusivity\=checked ... GeoCameraWatchApp.SwiftFileList -DDEBUG -enable-bridging-pch -disable-dynamic-actor-isolation -D DEBUG -enable-experimental-feature DebugDescriptionMacro -sdk /Applications/Xcode.app/Contents/Developer/Platforms/WatchOS.platform/Developer/SDKs/WatchOS11.2.sdk -target arm64_32-apple-watchos7.0 -g -module-cache-path /Users/stand/Library/Developer/Xcode/DerivedData/ModuleCache.noindex -Xfrontend -serialize-debugging-options -enable-testing -index-store-path /Users/stand/Library/Developer/Xcode/DerivedData/speedo-almhjmryctkitceaufvkvhkkfvdw/Index.noindex/DataStore -enable-experimental-feature OpaqueTypeErasure -Xcc -D_LIBCPP_HARDENING_MODE\=_LIBCPP_HARDENING_MODE_DEBUG -swift-version 6 ... -disable-dynamic-actor-isolation flag seems to be working for the iOS targets, I believe. The flag is described here Am I missing something? Should the flag work for both iOS and Apple Watch targets?