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Customization in Swift ArgumentParser's help command and error output
Hello I want to implement customisation to swift argumentparser, Here are following changes want to do it in my cli changing default footer present in help command output currently help command output coming like this OVERVIEW: clisample USAGE: clisample <subcommand> OPTIONS: --version show the version. -h, --help show the help. SUBCOMMANDS: logs (default) Export logs for clisample processes. See 'clisample --help' for more information.' so instead of See 'clisample --help' for more information.' I want my own string For more details, run 'clisample help <subcommand>' customise error string getting from validation error Error: Missing value for '-t <time>' Help: -t <time> Time window (e.g. 10h, 30m, 2d). Usage: clisample logs --time <time> See 'clisample logs --help' for more information. so I want error output with example and customised footer, like this Error: Missing value for '-t <time>' Help: -t <time> Time window (e.g. 10h, 30m, 2d). Usage: clisample logs --time <time> Example: clisample logs -t 5m For more details, run 'clisample help <subcommand>' Is this changes possible from anyway?
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543
Sep ’25
"_swift_coroFrameAlloc", 报错
Undefined symbols for architecture arm64: "_swift_coroFrameAlloc", referenced from: NvMobileCore.Constraint.isActive.modify : Swift.Bool in NvMobileCore[5] NvMobileCore.Constraint.isActive.modify : Swift.Bool in NvMobileCore[5] NvMobileCore.NvMobileCoreManager.delegate.modify : NvMobileCore.NvPublicInterface? in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.delegate.modify : NvMobileCore.NvPublicInterface? in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.language.modify : Swift.String in NvMobileCore[53] NvMobileCore.NvMobileCoreManager.language.modify : Swift.String in NvMobileCore[53] ld: symbol(s) not found for architecture arm64 clang: error: linker command failed with exit code 1 (use -v to see invocation)
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503
Oct ’25
Attrubute can only be applied to types not declarations
Error: "Attrubute can only be applied to types not declarations" on line 2 : @unchecked @unchecked enum ReminderRow : Hashable, Sendable { case date case notes case time case title var imageName : String? { switch self { case .date: return "calendar.circle" case .notes: return "square.and.pencil" case .time: return "clock" default : return nil } } var image : UIImage? { guard let imageName else { return nil } let configuration = UIImage.SymbolConfiguration(textStyle: .headline) return UIImage(systemName: imageName, withConfiguration: configuration) } var textStyle : UIFont.TextStyle { switch self { case .title : return .headline default : return .subheadline } } }
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330
Oct ’25
App sometimes crashes when inserting String into Set with assertion ELEMENT_TYPE_OF_SET_VIOLATES_HASHABLE_REQUIREMENTS
Xcode downloaded a crash report for my app that crashed when trying to insert a String into a Set<String>. Apparently there was an assertion failure ELEMENT_TYPE_OF_SET_VIOLATES_HASHABLE_REQUIREMENTS. I assume that this assertion failure happened because the hash of the new element didn't match the hash of an equal already inserted element, but regardless, I don't understand how inserting a simple string could trigger this assertion. Here is essentially the code that leads to the crash. path is any file system directory, and basePath is a directory higher in the hierarchy, or path itself. var scanErrorPaths = Set<String>() func main() { let path = "/path/to/directory" let basePath = "/path" let fileDescriptor = open(path, O_RDONLY) if fileDescriptor < 0 { if (try? URL(fileURLWithPath: path, isDirectory: false).checkResourceIsReachable()) == true { scanErrorPaths.insert(path.relativePath(from: basePath)!) return } } extension String { func relativePath(from basePath: String) -> String? { if basePath == "" { return self } guard let index = range(of: basePath, options: .anchored)?.upperBound else { return nil } return if index == endIndex || basePath == "/" { String(self[index...]) } else if let index = self[index...].range(of: "/", options: .anchored)?.upperBound { String(self[index...]) } else { nil } } } crash.crash
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837
Oct ’25
Basic c++xcodeproj call to swift code
I have c++ macOs app(Xcode +14) and I try to add call to swift code. I can't find any simple c++ xcodeproj call to swift code. I create new simple project and fail to build it with error when I try to include #include <SwiftMixTester/SwiftMixTester-Swift.h>: main.m:9:10: error: 'SwiftMixTester/SwiftMixTester-Swift.h' file not found (in target 'CppCallSwift' from project 'CppCallSwift') note: Did not find header 'SwiftMixTester-Swift.h' in framework 'SwiftMixTester' (loaded from '/Users/yanivsmacm4/Library/Developer/Xcode/DerivedData/CppCallSwift-exdxjvwdcczqntbkksebulvfdolq/Build/Products/Debug') . Please help.
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465
Oct ’25
Basic c++ main xcodeproj call to swift struct
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.
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899
Oct ’25
Async function doesn’t see external changes to an inout Bool in Release build
Title Why doesn’t this async function see external changes to an inout Bool in Release builds (but works in Debug)? Body I have a small helper function that waits for a Bool flag to become true with a timeout: public func test(binding value: inout Bool, timeout maximum: Int) async throws { var count = 0 while value == false { count += 1 try await Task.sleep(nanoseconds: 0_100_000_000) if value == true { return } if count > (maximum * 10) { return } } } I call like this: var isVPNConnected = false adapter.start(tunnelConfiguration: tunnelConfiguration) { [weak self] adapterError in guard let self = self else { return } if let adapterError = adapterError { } else { isVPNConnected = true } completionHandler(adapterError) } try await waitUntilTrue(binding: &isVPNConnected, timeout: 10) What I expect: test should keep looping until flag becomes true (or the timeout is hit). When the second task sets flag = true, the first task should see that change and return. What actually happens: In Debug builds this behaves as expected: when the second task sets flag = true, the loop inside test eventually exits. In Release builds the function often never sees the change and gets stuck until the timeout (or forever, depending on the code). It looks like the while value == false condition is using some cached value and never observes the external write. So my questions are: Is the compiler allowed to assume that value (the inout Bool) does not change inside the loop, even though there are await suspension points and another task is mutating the same variable? Is this behavior officially “undefined” because I’m sharing a plain Bool across tasks without any synchronization (actors / locks / atomics), so the debug build just happens to work? What is the correct / idiomatic way in Swift concurrency to implement this kind of “wait until flag becomes true with timeout” pattern? Should I avoid inout here completely and use some other primitive (e.g. AsyncStream, CheckedContinuation, Actor, ManagedAtomic, etc.)? Is there any way to force the compiler to re-read the Bool from memory each iteration, or is that the wrong way to think about it? Environment (if it matters): Swift: [fill in your Swift version] Xcode: [fill in your Xcode version] Target: iOS / macOS [fill in as needed] Optimization: default Debug vs. Release settings I’d like to understand why Debug vs Release behaves differently here, and what the recommended design is for this kind of async waiting logic in Swift.
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1.1k
Nov ’25
App mysteriously crashing in CFNetwork.LoaderQ queue
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
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4k
Nov ’25
Compiler exception when using Binding and Swift 6
In my code I use a binding that use 2 methods to get and get a value. There is no problem with swift 5 but when I swift to swift 6 the compiler fails : Here a sample example of code to reproduce the problem : `import SwiftUI struct ContentView: View { @State private var isOn = false var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") Toggle("change it", isOn: Binding(get: getValue, set: setValue(_:))) } .padding() } private func getValue() -&gt; Bool { isOn } private func setValue(_ value: Bool) { isOn = value } }` Xcode compiler log error : 1. Apple Swift version 6.1.2 (swiftlang-6.1.2.1.2 clang-1700.0.13.5) 2. Compiling with the current language version 3. While evaluating request IRGenRequest(IR Generation for file "/Users/xavierrouet/Developer/TestCompilBindingSwift6/TestCompilBindingSwift6/ContentView.swift") 4. While emitting IR SIL function "@$sSbScA_pSgIeAghyg_SbIeAghn_TR". for &lt;&lt;debugloc at "&lt;compiler-generated&gt;":0:0&gt;&gt;Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var LLVM_SYMBOLIZER_PATH` to point to it): 0 swift-frontend 0x000000010910ae24 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) + 56 1 swift-frontend 0x0000000109108c5c llvm::sys::RunSignalHandlers() + 112 2 swift-frontend 0x000000010910b460 SignalHandler(int) + 360 3 libsystem_platform.dylib 0x0000000188e60624 _sigtramp + 56 4 libsystem_pthread.dylib 0x0000000188e2688c pthread_kill + 296 5 libsystem_c.dylib 0x0000000188d2fc60 abort + 124 6 swift-frontend 0x00000001032ff9a8 swift::DiagnosticHelper::~DiagnosticHelper() + 0 7 swift-frontend 0x000000010907a878 llvm::report_fatal_error(llvm::Twine const&amp;, bool) + 280 8 swift-frontend 0x00000001090aef6c report_at_maximum_capacity(unsigned long) + 0 9 swift-frontend 0x00000001090aec7c llvm::SmallVectorBase::grow_pod(void*, unsigned long, unsigned long) + 384 10 swift-frontend 0x000000010339c418 (anonymous namespace)::SyncCallEmission::setArgs(swift::irgen::Explosion&amp;, bool, swift::irgen::WitnessMetadata*) + 892 11 swift-frontend 0x00000001035f8104 (anonymous namespace)::IRGenSILFunction::visitFullApplySite(swift::FullApplySite) + 4792 12 swift-frontend 0x00000001035c876c (anonymous namespace)::IRGenSILFunction::visitSILBasicBlock(swift::SILBasicBlock*) + 2636 13 swift-frontend 0x00000001035c6614 (anonymous namespace)::IRGenSILFunction::emitSILFunction() + 15860 14 swift-frontend 0x00000001035c2368 swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 2788 15 swift-frontend 0x00000001033e7c1c swift::irgen::IRGenerator::emitLazyDefinitions() + 5288 16 swift-frontend 0x0000000103573d6c swift::IRGenRequest::evaluate(swift::Evaluator&amp;, swift::IRGenDescriptor) const + 4528 17 swift-frontend 0x00000001035c15c4 swift::SimpleRequest&lt;swift::IRGenRequest, swift::GeneratedModule (swift::IRGenDescriptor), (swift::RequestFlags)17&gt;::evaluateRequest(swift::IRGenRequest const&amp;, swift::Evaluator&amp;) + 180 18 swift-frontend 0x000000010357d1b0 swift::IRGenRequest::OutputType swift::Evaluator::getResultUncached&lt;swift::IRGenRequest, swift::IRGenRequest::OutputType swift::evaluateOrFatalswift::IRGenRequest(swift::Evaluator&amp;, swift::IRGenRequest)::'lambda'()&gt;(swift::IRGenRequest const&amp;, swift::IRGenRequest::OutputType swift::evaluateOrFatalswift::IRGenRequest(swift::Evaluator&amp;, swift::IRGenRequest)::'lambda'()) + 812 19 swift-frontend 0x0000000103576910 swift::performIRGeneration(swift::FileUnit*, swift::IRGenOptions const&amp;, swift::TBDGenOptions const&amp;, std::__1::unique_ptr&lt;swift::SILModule, std::__1::default_deleteswift::SILModule&gt;, llvm::StringRef, swift::PrimarySpecificPaths const&amp;, llvm::StringRef, llvm::GlobalVariable**) + 176 20 swift-frontend 0x0000000102f61af0 generateIR(swift::IRGenOptions const&amp;, swift::TBDGenOptions const&amp;, std::__1::unique_ptr&lt;swift::SILModule, std::__1::default_deleteswift::SILModule&gt;, swift::PrimarySpecificPaths const&amp;, llvm::StringRef, llvm::PointerUnion&lt;swift::ModuleDecl*, swift::SourceFile*&gt;, llvm::GlobalVariable*&amp;, llvm::ArrayRef&lt;std::__1::basic_string&lt;char, std::__1::char_traits, std::__1::allocator&gt;&gt;) + 156 21 swift-frontend 0x0000000102f5d07c performCompileStepsPostSILGen(swift::CompilerInstance&amp;, std::__1::unique_ptr&lt;swift::SILModule, std::__1::default_deleteswift::SILModule&gt;, llvm::PointerUnion&lt;swift::ModuleDecl*, swift::SourceFile*&gt;, swift::PrimarySpecificPaths const&amp;, int&amp;, swift::FrontendObserver*) + 2108 22 swift-frontend 0x0000000102f5c0a8 swift::performCompileStepsPostSema(swift::CompilerInstance&amp;, int&amp;, swift::FrontendObserver*) + 1036 23 swift-frontend 0x0000000102f5f654 performCompile(swift::CompilerInstance&amp;, int&amp;, swift::FrontendObserver*) + 1764 24 swift-frontend 0x0000000102f5dfd8 swift::performFrontend(llvm::ArrayRef&lt;char const*&gt;, char const*, void*, swift::FrontendObserver*) + 3716 25 swift-frontend 0x0000000102ee20bc swift::mainEntry(int, char const**) + 5428 26 dyld 0x0000000188a86b98 start + 6076 Using Xcode 16.4 / Mac OS 16.4
4
0
1.4k
4w
How to disable native Full Screen and implement custom "Zoom to Fill" with minimum window constraints in MacOs SwiftUI / Appkit
I am creating a macOs SwiftUI document based app, and I am struggling with the Window sizes and placements. Right now by default, a normal window has the minimize and full screen options which makes the whole window into full screen mode. However, I don't want to do this for my app. I want to only allow to fill the available width and height, i.e. exclude the status bar and doc when the user press the fill window mode, and also restrict to resize the window beyond a certain point ( which ideally to me is 1200 x 700 because I am developing on macbook air 13.3-inch in which it looks ideal, but resizing it below that makes the entire content inside messed up ). I want something like this below instead of the default full screen green When the user presses the button, it should position centered with perfect aspect ratio from my content ( or the one I want like 1200 x 700 ) and can be able to click again to fill the available width and height excluding the status bar and docs. Here is my entire @main code :- @main struct PhiaApp: App { @NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate var body: some Scene { DocumentGroup(newDocument: PhiaProjectDocument()) { file in ContentView( document: file.$document, rootURL: file.fileURL ) .configureEditorWindow(disableCapture: true) .background(AppColors.background) .preferredColorScheme(.dark) } .windowStyle(.hiddenTitleBar) .windowToolbarStyle(.unified) .defaultLaunchBehavior(.suppressed) Settings { SettingsView() } } } struct WindowAccessor: NSViewRepresentable { var callback: (NSWindow?) -> Void func makeNSView(context: Context) -> NSView { let view = NSView() DispatchQueue.main.async { [weak view] in callback(view?.window) } return view } func updateNSView(_ nsView: NSView, context: Context) { } } extension View { func configureEditorWindow(disableCapture: Bool = true) -> some View { self.background( WindowAccessor { window in guard let window else { return } if let screen = window.screen ?? NSScreen.main { let visible = screen.visibleFrame window.setFrame(visible, display: true) window.minSize = visible.size } window.isMovable = true window.isMovableByWindowBackground = false window.sharingType = disableCapture ? .captureBlocked : .captureAllowed } ) } } This is a basic setup I did for now, this automatically fills the available width and height on launch, but user can resize and can go beyond my desired min width and height which makes the entire content inside messy. As I said, I want a native way of doing this, respect the content aspect ratio, don't allow to enter full screen mode, only be able to fill the available width and height excluding the status bar and doc, also don't allow to resize below my desired width and height.
1
0
510
1w
indices(where:) Swift Playgrounds Issue: "Cannot call value of non-function type Range<Int>"
Hey there- I'm having a quite interesting bug on Swift Playgrounds. I am trying to run my app with this following code snippet which does not compile on Swift Playgrounds, yet compiles on XCode (note: this is a Swift Playground app) if #available(iOS 18.0, *) { //simple function to get the indices of other items that have the same date as the "date" variable let indices = data!.indices(where: { item in let sameMonth = Calendar.current.component(.month, from: item.time) == Calendar.current.component(.month, from: date) let sameYear = Calendar.current.component(.year, from: item.time) == Calendar.current.component(.year, from: date) let sameDay = Calendar.current.component(.day, from: item.time) == Calendar.current.component(.year, from: date) return sameDay && sameMonth && sameYear }) However, the indices(where:) codeblock seems to stop the app from compiling (ONLY on Swift Playgrounds - it works perfectly fine on XCode). I am getting the following error: Cannot call value of non-function type 'Range<Array<Int>.Index>' (aka 'Range<Int>') Please let me know if you have any insight regarding this issue. -ColoredOwl
2
1
578
Jan ’25
Unexpected behavior of dispatch_main on macOS
Hi! We are seeing a bit surprising behavior of dispatch_main on macOS where it seems to spawn a different thread instead of preserving the one it gets called from. Managed to reproduce it in a completely empty command-line tool project in Xcode int main(int argc, const char * argv[]) { @autoreleasepool { dispatch_main(); return 0; } } I put a breakpoint on the line with dispatch_main and see that I am on Thread 1 and inside main function. That makes sense. I resume execution and pause again. Looking at Thread output in Xcode, I can only see Thread 2. Thread 1 is gone and the executable keeps on running. So dispatch_main did what was expected (prevented the process from termination) but throws out the thread it was called from and creates a new one? Is that behavior expected or am I missing something? Just a brain teaser at this point. But we could not make sense out of it. :)
4
1
575
Jan ’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
107
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
224
Apr ’25
Open any Swift view from C++
I've narrowed down my question after many rabbit holes - how can C++ code open any view in Swift. I can call functions in swift from C++ (works great), but not async or main actor (or actor at all) functions. And if I'm not mistaken all views are actors if not main actors? When calling from C+ I think its necessary that the first view be the main actor? I've implemented the code from the WWDC23 C++ interop video (Zoe's image picker) where I made a view in a struct, and just want to call it and let the view do the work. The compiler immediately gives me 'cannot expose main actors to C++'. If I'm not mistaken, doesn't this block the opening of any kind of swift view from C++? Hopefully I'm missing something obvious, which is likely :) In Zoe's code was his entry point into the program still Swift and not actually C++ app? Thanks! Thanks!
1
1
128
May ’25
libsystem_c.dylib: Assertion failed: (p->val == key), function lookup_substsearch, file collate.c, line 596.
At least with macOS Sequoia 15.5 and Xcode 16.3: $ cat test.cc #include &amp;lt;locale.h&amp;gt; #include &amp;lt;string.h&amp;gt; #include &amp;lt;xlocale.h&amp;gt; int main(void) { locale_t l = newlocale(LC_ALL_MASK, "el_GR.UTF-8", 0); strxfrm_l(NULL, "ό", 0, l); return 0; } $ c99 test.c &amp;amp;&amp;amp; ./a.out Assertion failed: (p-&amp;gt;val == key), function lookup_substsearch, file collate.c, line 596. Abort trap: 6
3
1
215
May ’25