Thanks for your detailed answer. It's not my intention to implement a custom exception handler, I was just wondering about how I could include additional information in the crash report. You're right that the one I included at the beginning already says that the array is empty, I didn't even remember. I was actually thinking about Swift arrays, for which an out of bounds exception causes a crash report with only this information: Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x00000001a6002c24 Termination Reason: Namespace SIGNAL, Code 5 Trace/BPT trap: 5 Terminating Process: exc handler [28880] Hence my idea of putting the array count and the invalid index as the thread name. I got many crash reports recently because of invalid Swift array accesses and I was looking for a way of debugging them without asking the user for help, which can be helpful but I think most users would not be happy to do. but, using it as an example, it would be much safer to create a sleeping thread at launch and then rename it with "pthread_setname_np" vs. creating a new thread and naming it via NSThread. I wasn't suggesting to create a new thread and naming it, but simply naming the current thread.

What are you actually trying to do/capture? I'm hoping to understand the issue better by seeing what the invalid index is. My idea was to check that the index is valid, and if not, set the thread name to some debug message and then let the app crash. Even if it sounds like a bad idea, I think it's still better than keep letting the app crash without having a clue about the cause and hence being unable to fix it.

For a different app of mine I was thinking of how I can include interesting data in a crash report. One thing that came to my mind, and seems to work, is to set the current thread's name with Thread.current.name = (Thread.current.name ?? "") + ". Invalid index \(i) for count \(array.count)" All thread names are included in the crash report. I don't think this is a good idea (and I'm surprised this even works, thinking of the privacy implications). Am I allowed to do this and is there a better alternative? The messages passed to preconditionFailure and fatalError are not included in the crash report.

Changing the order of the file formats in the Info.plist file is reflected in the save panel popup button, and putting Markdown before Plain Text solves this particular issue. But it seems that regardless which file format is selected in the save panel, the produced file always gets the .md extension.

I just tried, but it doesn't change anything. The documentation also states that it already returns true by default.

allowsOtherFileTypes alone makes the file format popup button appear, but then setting accessoryView makes it disappear again. Is it possible to have both? override func prepareSavePanel(_ savePanel: NSSavePanel) -> Bool { savePanel.allowsOtherFileTypes = true savePanel.accessoryView = NSTextField(labelWithString: "asdf") return true }

It would still be great if an Apple engineer could comment on whether this can indeed happen (and when) or if it's likely a macOS issue. Not only was clickedRow outside of the valid index range, but it was also not -1, and I thought that it would only be set for the duration of table view action methods (e.g. context menu item actions, double click action), not during methods called by buttons outside of the table view.

I'm not sure anymore, but it's possible that it had two rows at some point. Then I would have clicked a button that changed the data source array and the table view would have been reloaded with reloadData(). And in the end I clicked another button to add a new item to the data source array and insert the corresponding row in the table view, but since clickedRow was invalid, it crashed. I have been using NSTableView for different apps for more than 10 years now so I have some experience with it, and the implementation in this case is quite simple. array is the one that can gets swapped whenever category changes, and otherArray is another one that is displayed when no category is selected. func numberOfRows(in tableView: NSTableView) -> Int { return array.isEmpty ? 0 : category.map({ array[$0]?.count ?? 0 }) ?? otherArray.count } func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? { let cell = MyTableCellView() ... return cell } func tableView(_ tableView: NSTableView, rowActionsForRow row: Int, edge: NSTableView.RowActionEdge) -> [NSTableViewRowAction] { ... } func tableView(_ tableView: NSTableView, shouldSelectRow row: Int) -> Bool { ... } func tableViewSelectionDidChange(_ notification: Notification) { ... }

Thanks, that almost solves all of my issues. On macOS, and when showing the text views directly in the iOS view hierarchy, using the page break character produces the expected result. For example with the string (0..<1).map({ "\($0)" }).joined(separator: "\n") + String(UnicodeScalar(12)) + (0..<5).map({ "\($0)" }).joined(separator: "\n") the view hierarchy looks like this: But when printing them, the text views seem to overlap. I'm afraid this is now a question for a printing expert. The code below produces both the view hierarchy and the print preview. class ViewController: UIViewController { override func viewDidAppear(_ animated: Bool) { let printController = UIPrintInteractionController.shared let printPageRenderer = PrintPageRenderer() printController.printPageRenderer = printPageRenderer printController.present(animated: true) { _, _, error in if let error = error { print(error.localizedDescription) } } var y = 0.0 for textView in printPageRenderer.createTextViews.textViews { textView.frame.origin = CGPoint(x: 0, y: y) view.addSubview(textView) y += textView.frame.height } } } class CreateTextViews: NSObject, NSLayoutManagerDelegate { let pageSize: CGSize let textStorage: NSTextStorage private let layoutManager = NSLayoutManager() private(set) var textViews = [UITextView]() override init() { pageSize = CGSize(width: 100, height: 100) textStorage = NSTextStorage(string: (0..<1).map({ "\($0)" }).joined(separator: "\n") + String(UnicodeScalar(12)) + (0..<5).map({ "\($0)" }).joined(separator: "\n"), attributes: [.font: UIFont.systemFont(ofSize: 30)]) super.init() 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) } for textContainer in layoutManager.textContainers { let textView = UITextView(frame: CGRect(origin: .zero, size: pageSize), textContainer: textContainer) textViews.append(textView) } } 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) } } class PrintPageRenderer: UIPrintPageRenderer { let createTextViews = CreateTextViews() override var numberOfPages: Int { if !Thread.isMainThread { return DispatchQueue.main.sync { [self] in numberOfPages } } printFormatters = nil var page = 0 for textView in createTextViews.textViews { let printFormatter = textView.viewPrintFormatter() printFormatter.maximumContentHeight = createTextViews.pageSize.height addPrintFormatter(printFormatter, startingAtPageAt: page) page += 1 } return page } }

Thanks for the suggestion, that solves the issue with the reversed pages. But each text view still contains the actual text I would expect it to contain, plus the text of all the following ones. 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) } for textContainer in layoutManager.textContainers { let textView = UITextView(frame: CGRect(origin: .zero, size: pageSize), textContainer: textContainer) textViews.append(textView) } for textView in textViews { let _ = layoutManager.glyphRange(for: textView.textContainer) } 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) } }

Are you still there?

I have created a TSI on January 14 and after some initial questions for which I had already provided answers, I haven't been hearing anything for the last 3 weeks, even after writing again last week. Can someone see what's going on?

For instance take the following code: class AppDelegate: NSObject, NSApplicationDelegate { func applicationDidFinishLaunching(_ aNotification: Notification) { DispatchQueue.main.async { let document = try! NSDocumentController.shared.makeUntitledDocument(ofType: "net.daringfireball.markdown") print(document.fileType!, UTType(document.fileType!)!) NSDocumentController.shared.addDocument(document) document.makeWindowControllers() document.windowControllers[0].window!.title = "Markdown" document.showWindows() } } } And Info.plist: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>UTImportedTypeDeclarations</key> <array> <dict> <key>UTTypeConformsTo</key> <array> <string>public.plain-text</string> </array> <key>UTTypeDescription</key> <string>Markdown</string> <key>UTTypeIcons</key> <dict/> <key>UTTypeIdentifier</key> <string>net.daringfireball.markdown</string> <key>UTTypeTagSpecification</key> <dict> <key>public.filename-extension</key> <array> <string>md</string> <string>mdown</string> <string>markdown</string> <string>text</string> </array> <key>public.mime-type</key> <array> <string>text/markdown</string> <string>text/x-markdown</string> <string>text/x-web-markdown</string> </array> </dict> </dict> </array> <key>CFBundleDocumentTypes</key> <array> <dict> <key>CFBundleTypeName</key> <string>Plain Text</string> <key>CFBundleTypeRole</key> <string>Editor</string> <key>LSHandlerRank</key> <string>Default</string> <key>LSItemContentTypes</key> <array> <string>public.plain-text</string> </array> <key>NSDocumentClass</key> <string>$(PRODUCT_MODULE_NAME).Document</string> <key>NSUbiquitousDocumentUserActivityType</key> <string>org.desairem.uFocus.OpenDocument</string> </dict> <dict> <key>CFBundleTypeName</key> <string>Markdown</string> <key>CFBundleTypeRole</key> <string>Editor</string> <key>LSHandlerRank</key> <string>Default</string> <key>LSItemContentTypes</key> <array> <string>net.daringfireball.markdown</string> </array> <key>NSDocumentClass</key> <string>$(PRODUCT_MODULE_NAME).Document</string> <key>NSUbiquitousDocumentUserActivityType</key> <string>org.desairem.uFocus.OpenDocument</string> </dict> </array> </dict> </plist> After making sure that the document with the window title Markdown is active, press Command-S to open the default save panel: Plain Text is selected instead of Markdown.

Sorry, I copied the wrong number. That one had the same title but was actually addressing TextKit 1. The correct number is FB17103305.

I'm interested in adding a margin to a NSTextView by wrapping it in a custom view or adding sibling views, but wasn't able to get the scroll view to keep showing the entire text view. Would you mind sharing your code?