Xcode has been downloading many similar crash reports for my app for some time now, related to an index out of range runtime exception when accessing a Swift array. The crashes always happen in methods triggered by user input or during menu item validation when I try to access the data source array by using the following code to determine the indexes of the relevant table rows: let indexes = clickedRow == -1 || selectedRowIndexes.contains(clickedRow) ? selectedRowIndexes : IndexSet(integer: clickedRow) I was never able to reproduce the crash until today. When the app crashed in the Xcode debugger, I examined the variables clickedRow and selectedRowIndexes.first, which were 1 and 0 respectively. What's interesting: the table view only contained one row, so clickedRow was effectively invalid. I tried to reproduce the issue several times afterwards, but it never happened again. What could cause this issue? What are the circumstances where it is invalid? Do I always have to explicitly check if clickedRow is within the data source range?

I would like to print a NSTextStorage on multiple pages and add annotations to the side margins corresponding to certain text ranges. For example, for all occurrences of # at the start of a line, the side margin should show an automatically increasing number. My idea was to create a NSLayoutManager and dynamically add NSTextContainer instances to it until all text is laid out. The layoutManager would then allow me to get the bounding rectangle of the interesting text ranges so that I can draw the corresponding numbers at the same height inside the side margin. This approach works well on macOS, but I'm having some issues on iOS. When running the code below in an iPad Simulator, I would expect that the print preview shows 3 pages, the first with the numbers 0-1, the second with the numbers 2-3, and the last one with the number 4. Instead the first page shows the number 4, the second one the numbers 2-4, and the last one the numbers 0-4. It's as if the pages are inverted, and each page shows the text starting at the correct location but always ending at the end of the complete text (and not the range assigned to the relative textContainer). I've created FB17026419. class ViewController: UIViewController { override func viewDidAppear(_ animated: Bool) { let printController = UIPrintInteractionController.shared let printPageRenderer = PrintPageRenderer() printPageRenderer.pageSize = CGSize(width: 100, height: 100) printPageRenderer.textStorage = NSTextStorage(string: (0..<5).map({ "\($0)" }).joined(separator: "\n"), attributes: [.font: UIFont.systemFont(ofSize: 30)]) printController.printPageRenderer = printPageRenderer printController.present(animated: true) { _, _, error in if let error = error { print(error.localizedDescription) } } } } class PrintPageRenderer: UIPrintPageRenderer, NSLayoutManagerDelegate { var pageSize: CGSize! var textStorage: NSTextStorage! private let layoutManager = NSLayoutManager() private var textViews = [UITextView]() override var numberOfPages: Int { if !Thread.isMainThread { return DispatchQueue.main.sync { [self] in numberOfPages } } printFormatters = nil layoutManager.delegate = self textStorage.addLayoutManager(layoutManager) if textStorage.length > 0 { let glyphRange = layoutManager.glyphRange(forCharacterRange: NSRange(location: textStorage.length - 1, length: 0), actualCharacterRange: nil) layoutManager.textContainer(forGlyphAt: glyphRange.location, effectiveRange: nil) } var page = 0 for textView in textViews { let printFormatter = textView.viewPrintFormatter() addPrintFormatter(printFormatter, startingAtPageAt: page) page += printFormatter.pageCount } return page } func layoutManager(_ layoutManager: NSLayoutManager, didCompleteLayoutFor textContainer: NSTextContainer?, atEnd layoutFinishedFlag: Bool) { if textContainer == nil { addPage() } } private func addPage() { let textContainer = NSTextContainer(size: pageSize) layoutManager.addTextContainer(textContainer) let textView = UITextView(frame: CGRect(origin: .zero, size: pageSize), textContainer: textContainer) textViews.append(textView) } }

I'm building a game with a client-server architecture. Using GKMatch.chooseBestHostingPlayer(_:) rarely works. When I started testing it today, it worked once at the very beginning, and since then it always succeeds on one client and returns nil on the other client. I'm testing with a Mac and an iPhone. Sometimes it fails on the Mac, sometimes on the iPhone. On the device that it succeeds on, the provided host can be the device itself or the other one. I created FB9583628 in August 2021, but after the Feedback Assistant team replied that they are not able to reproduce it, the feedback never went forward. import SceneKit import GameKit #if os(macOS) typealias ViewController = NSViewController #else typealias ViewController = UIViewController #endif class GameViewController: ViewController, GKMatchmakerViewControllerDelegate, GKMatchDelegate { var match: GKMatch? var matchStarted = false override func viewDidLoad() { super.viewDidLoad() GKLocalPlayer.local.authenticateHandler = authenticate } private func authenticate(_ viewController: ViewController?, _ error: Error?) { #if os(macOS) if let viewController = viewController { presentAsSheet(viewController) } else if let error = error { print(error) } else { print("authenticated as \(GKLocalPlayer.local.gamePlayerID)") let viewController = GKMatchmakerViewController(matchRequest: defaultMatchRequest())! viewController.matchmakerDelegate = self GKDialogController.shared().present(viewController) } #else if let viewController = viewController { present(viewController, animated: true) } else if let error = error { print(error) } else { print("authenticated as \(GKLocalPlayer.local.gamePlayerID)") let viewController = GKMatchmakerViewController(matchRequest: defaultMatchRequest())! viewController.matchmakerDelegate = self present(viewController, animated: true) } #endif } private func defaultMatchRequest() -> GKMatchRequest { let request = GKMatchRequest() request.minPlayers = 2 request.maxPlayers = 2 request.defaultNumberOfPlayers = 2 request.inviteMessage = "Ciao!" return request } func matchmakerViewControllerWasCancelled(_ viewController: GKMatchmakerViewController) { print("cancelled") } func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFailWithError error: Error) { print(error) } func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFind match: GKMatch) { self.match = match match.delegate = self startMatch() } func match(_ match: GKMatch, player: GKPlayer, didChange state: GKPlayerConnectionState) { print("\(player.gamePlayerID) changed state to \(String(describing: state))") startMatch() } func startMatch() { let match = match! if matchStarted || match.expectedPlayerCount > 0 { return } print("starting match with local player \(GKLocalPlayer.local.gamePlayerID) and remote players \(match.players.map({ $0.gamePlayerID }))") match.chooseBestHostingPlayer { host in print("host is \(String(describing: host?.gamePlayerID))") } } }

In my SceneKit game I'm able to connect two players with GKMatchmakerViewController. Now I want to support the scenario where one of them disconnects and wants to reconnect. I tried to do this with this code: nonisolated public func match(_ match: GKMatch, player: GKPlayer, didChange state: GKPlayerConnectionState) { Task { @MainActor in switch state { case .connected: break case .disconnected, .unknown: let matchRequest = GKMatchRequest() matchRequest.recipients = [player] do { try await GKMatchmaker.shared().addPlayers(to: match, matchRequest: matchRequest) } catch { } @unknown default: break } } } nonisolated public func player(_ player: GKPlayer, didAccept invite: GKInvite) { guard let viewController = GKMatchmakerViewController(invite: invite) else { return } viewController.matchmakerDelegate = self present(viewController) } But after presenting the view controller with GKMatchmakerViewController(invite:), nothing else happens. I would expect matchmakerViewController(_:didFind:) to be called, or how would I get an instance of GKMatch? Here is the code I use to reproduce the issue, and below the reproduction steps. Code Run the attached project on an iPad and a Mac simultaneously. On both devices, tap the ship to connect to GameCenter. Create an automatched match by tapping the rightmost icon on both devices. When the two devices are matched, on iPad close the dialog and tap on the ship to disconnect from GameCenter. Wait some time until the Mac detects the disconnect and automatically sends an invitation to join again. When the notification arrives on the iPad, tap it, then tap the ship to connect to GameCenter again. The iPad receives the call player(_:didAccept:), but nothing else, so there’s no way to get a GKMatch instance again.

I'm trying to update my app to use TextKit 2. The one thing that I'm still not sure about is how I can get the selection frame. My app uses it to auto-scroll the text to keep the cursor at the same height when the text wraps onto a new line or a newline is manually inserted. Currently I'm using NSLayoutManager.layoutManager!.boundingRect(forGlyphRange:in:). The code below almost works. When editing the text or changing the selection, the current selection frame is printed out. My expectation is that the selection frame after a text or selection change should be equal to the selection frame before the next text change. I've noticed that this is not always true when the text has a NSParagraphStyle with spacing > 0. As long as I type at the end of the text, everything's fine, but if I insert some lines, then move the selection somewhere into the middle of the text and insert another newline, the frame printed after manually moving the selection is different than the frame before the newline is inserted. It seems that the offset between the two frames is exactly the same as the paragraph style's spacing. Instead when moving the selection with the arrow key the printed frames are correct. I've filed FB17104954. class ViewController: NSViewController, NSTextViewDelegate { private var textView: NSTextView! override func loadView() { let scrollView = NSScrollView(frame: CGRect(x: 0, y: 0, width: 400, height: 400)) textView = NSTextView(frame: scrollView.frame) textView.autoresizingMask = [.width, .height] textView.delegate = self let paragraphStyle = NSMutableParagraphStyle() paragraphStyle.lineSpacing = 40 textView.typingAttributes = [.foregroundColor: NSColor.labelColor, .paragraphStyle: paragraphStyle] scrollView.documentView = textView scrollView.hasVerticalScroller = true view = scrollView } func textView(_ textView: NSTextView, shouldChangeTextIn affectedCharRange: NSRange, replacementString: String?) -> Bool { print("before", selectionFrame.maxY, selectionFrame) return true } func textDidChange(_ notification: Notification) { print("after ", selectionFrame.maxY, selectionFrame) } func textViewDidChangeSelection(_ notification: Notification) { print("select", selectionFrame.maxY, selectionFrame) } var selectionFrame: CGRect { guard let selection = textView.textLayoutManager!.textSelections.first?.textRanges.first else { return .null } var frame = CGRect.null textView.textLayoutManager!.ensureLayout(for: selection) textView.textLayoutManager!.enumerateTextSegments(in: selection, type: .selection, options: [.rangeNotRequired]) { _, rect, _, _ in frame = rect return false } return frame } }

All the threads only contain system calls. The crashed thread only contains a single call to my app's code which is main.swift:13. What could cause such a crash? crash.crash

It seems that NSTextView has an issue with deleting text and setting any attribute at the same time, when it also has a textContainerInset. With the code below, after 1 second, the empty line in the text view is automatically deleted and the first line is colored red. The top part of the last line remains visible at its old position. Selecting the whole text and then deselecting it again makes the issue disappear. Is there a workaround? I've created FB16897003. class ViewController: NSViewController { @IBOutlet var textView: NSTextView! override func viewDidAppear() { textView.textContainerInset = CGSize(width: 0, height: 8) let _ = textView.layoutManager textView.textStorage!.setAttributedString(NSAttributedString(string: "1\n\n2\n3\n4")) textView.textStorage!.addAttribute(.foregroundColor, value: NSColor.labelColor, range: NSRange(location: 0, length: textView.textStorage!.length)) DispatchQueue.main.asyncAfter(deadline: .now() + 1) { [self] in textView.selectedRange = NSRange(location: 3, length: 0) textView.deleteBackward(nil) textView.textStorage!.beginEditing() textView.textStorage!.addAttribute(.foregroundColor, value: NSColor.red, range: NSRange(location: 0, length: 2)) textView.textStorage!.endEditing() } } }

When creating a default macOS document-based Xcode project and using the code below (and wiring the File menu's Print item to printDocument: instead of the default print:, which does nothing), opening the print panel causes PrintView.knowsPageRange(_:) to be called twice. Is this a bug? My app populates PrintView dynamically, and for large documents it can be quite inefficient to populate it once, only for the contents to be immediately discarded and populated again. A workaround that came to my mind would be to check if the print options have changed, though I'm not sure if it's a reliable indicator that the print preview is effectively the same. I created FB17018494. class Document: NSDocument { override func makeWindowControllers() { addWindowController(NSStoryboard(name: NSStoryboard.Name("Main"), bundle: nil).instantiateController(withIdentifier: NSStoryboard.SceneIdentifier("Document Window Controller")) as! NSWindowController) } override func printOperation(withSettings printSettings: [NSPrintInfo.AttributeKey : Any]) throws -> NSPrintOperation { return NSPrintOperation(view: PrintView(frame: CGRect(x: 0, y: 0, width: 100, height: 100)), printInfo: NSPrintInfo(dictionary: printSettings)) } } class PrintView: NSView { override func knowsPageRange(_ range: NSRangePointer) -> Bool { print("knowsPageRange") range.pointee = NSRange(location: 1, length: 1) return true } }

I was just having a look at some crash reports downloaded by Xcode, and I noticed the same wrong pattern I already mentioned here: the crash reports indicate that method A calls method B, which is impossible. In the first crash report below, method MainViewController.showSettings seems to be called by ConfirmMoveViewController.openSourceInFinder, which is impossible. ConfirmMoveViewController.openSourceInFinder is a context menu action in a modal window, and MainViewController.showSettings is in a completely different window and the two methods have no relation whatsoever. In the second crash report below, MainViewController.setSortMode is triggered by the press of a button (and nothing else) but seems to be called by OtherViewController.copy that can be triggered by a context menu (or keyboard shortcut). The two methods have no relation whatsoever. The rest of the stack trace confirm that it's indeed the button that was pressed. This seems to me like a quite serious bug in how macOS creates crash reports. 1.crash 2.crash

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)?

I was just comparing the build settings of two of my apps to try to understand why they behave differently (one of them uses the full screen on iPad, and the other one has small top and bottom black borders, although that's not the issue I want to discuss now). I saw that the option CLANG_CXX_LANGUAGE_STANDARD is set to gnu++0x for the older project, while it's set to gnu++17 for the newer one. The documentation lists different possible values and also a default one: Compiler Default: Tells the compiler to use its default C++ language dialect. This is normally the best choice unless you have specific needs. (Currently equivalent to GNU++98.) If it really is the best choice (normally), why is it not used when creating a new default Xcode project? Or is it better to select a newer compiler version (GNU++98 sounds quite old compared to GNU++17)? Also, does this affect Swift code?

This crash report for one of my apps was downloaded by Xcode. Apparently the app crashed while releasing an object of type Scan.File, which is a Swift class held in an array in the Scan.Directory class. I'm not doing any manual reference counting or low-level stuff with that object. What could cause such a crash? crash.crash

On macOS, the Finder allows to connect to a server and store the login credentials. When creating a bookmark to a file on a server and resolving it again, the server is mounted automatically (unless I provide the option URL.BookmarkResolutionOptions.withoutMounting). I just tried connecting to my Mac from my iPad via SMB in the Files app and storing a bookmark to a file on the server, but disconnecting the server and trying to resolve the bookmark throws the error (I translated the English text from Italian): Error Domain=NSFileProviderErrorDomain Code=-2001 "No file provider was found with the identifier "com.apple.SMBClientProvider.FileProvider"'" UserInfo={NSLocalizedDescription=No file provider was found with the identifier "com.apple.SMBClientProvider.FileProvider"., NSUnderlyingError=0x302a1a340 {Error Domain=NSFileProviderErrorDomain Code=-2013 "(null) "}} Every time I disconnect and reconnect to the server, selecting the same file returns a different path. The first time I got /private/var/mobile/Library/LiveFiles/com.apple.filesystems.smbclientd/WtFD3Ausername/path/to/file.txt The next time WtFD3A changed to EqHc2g and so on. Is it not possible to automatically mount a server when resolving a bookmark on iOS? The following code allows to reproduce the issue: struct ContentView: View { @State private var isPresentingFilePicker = false @AppStorage("bookmarkData") private var bookmarkData: Data? @State private var url: URL? @State private var stale = false @State private var error: Error? var body: some View { VStack { Button("Open") { isPresentingFilePicker = true } if let url = url { Text(url.path) } else if bookmarkData != nil { Text("couldn't resolve bookmark data") } else { Text("no bookmark data") } if stale { Text("bookmark is stale") } if let error = error { Text("\(error)") .foregroundStyle(.red) } } .padding() .fileImporter(isPresented: $isPresentingFilePicker, allowedContentTypes: [.data]) { result in do { let url = try result.get() if url.startAccessingSecurityScopedResource() { bookmarkData = try url.bookmarkData() } } catch { self.error = error } } .onChange(of: bookmarkData, initial: true) { _, bookmarkData in if let bookmarkData = bookmarkData { do { url = try URL(resolvingBookmarkData: bookmarkData, bookmarkDataIsStale: &amp;stale) } catch { self.error = error } } } } }

On macOS, we have didMountNotification but there doesn't seem to be an equivalent for iOS. Is there a way to be notified when a volume is mounted on iOS? I would like to use it in my iOS app I'm currently porting from macOS, which starts a synchronization from the volume (which has been previously selected in a NSOpenPanel) as soon as it's mounted.

Some time ago I read somewhere that one can get a file icon on iOS like this: UIDocumentInteractionController(url: url).icons.last!) but this always returns the following image for every file: Today I tried the following, which always returns nil: (try? url.resourceValues(forKeys: [.effectiveIconKey]))?.allValues[.effectiveIconKey] as? UIImage Is there any way to get a file icon on iOS? You can try the above methods in this sample app: struct ContentView: View { @State private var isPresentingFilePicker = false @State private var url: URL? var body: some View { VStack { Button("Open") { isPresentingFilePicker = true } if let url = url { Image(uiImage: UIDocumentInteractionController(url: url).icons.last!) if let image = (try? url.resourceValues(forKeys: [.effectiveIconKey]))?.allValues[.effectiveIconKey] as? UIImage { Image(uiImage: image) } else { Text("none") } } } .padding() .fileImporter(isPresented: $isPresentingFilePicker, allowedContentTypes: [.data]) { result in do { let url = try result.get() if url.startAccessingSecurityScopedResource() { self.url = url } } catch { preconditionFailure(error.localizedDescription) } } } }