Document based app shows 2 back chevrons on iPad - swiftui

Question

I did a small sample application to show my problem. I used the multi-platform document app template that Xcode 14.0.1 offers, creating my own package file format for this.
I want to create a document based app running on macOS and on iPad.
When running on macOS, everything works as expected.
On the iPad, when opening the app, the file chooser opens.
On opening an existing or creating a new file, the screen looks like this:
The left chevron does nothing, while the right chevron shows the document chooser again.
What's the left, ever so slightly larger chevron on the left doing here and how can I get of it? Is this an error with the framework that should be reported to Apple?
PS don't get distracted by the name of this sample app–the real app will need some navigation and I first thought the 2nd chevron show up cause of this–in the sample I built for this post, there is no navigation though. So this 2nd chevron seems to be a "built in" issue...
For the sake of completeness, here's my code:
import SwiftUI
#main
struct so_DocumentAppWithNavigationShowsMultipleChevronsApp: App {
var body: some Scene {
DocumentGroup(newDocument: so_DocumentAppWithNavigationShowsMultipleChevronsDocument()) { file in
ContentView(document: file.$document)
}
}
}
import UniformTypeIdentifiers
extension UTType {
static var appfroschFile: UTType {
UTType(importedAs: "ch.appfros.so-DocumentAppWithNavigationShowsMultipleChevrons")
}
}
struct so_DocumentAppWithNavigationShowsMultipleChevronsDocument: FileDocument {
var document: Document
init(document: Document = Document(text: "Hello, world!")) {
self.document = document
}
static var readableContentTypes: [UTType] { [.appfroschFile] }
init(configuration: ReadConfiguration) throws {
guard let fileWrappers = configuration.file.fileWrappers
else {
throw CocoaError(.fileReadCorruptFile)
}
guard let documentFileWrapper = fileWrappers["document"],
let data = documentFileWrapper.regularFileContents,
let string = String(data: data, encoding: .utf8)
else {
throw CocoaError(.fileReadCorruptFile)
}
document = try JSONDecoder().decode(Document.self, from: data)
}
func fileWrapper(configuration: WriteConfiguration) throws -> FileWrapper {
let data = try JSONEncoder().encode(document)
let documentFileWrapper = FileWrapper(regularFileWithContents: data)
let mainFileWrapper = FileWrapper(directoryWithFileWrappers: [
"document": documentFileWrapper
])
return mainFileWrapper
}
}
struct Document: Codable {
var text: String
}
struct ContentView: View {
#Binding var document: so_DocumentAppWithNavigationShowsMultipleChevronsDocument
var body: some View {
TextEditor(text: $document.document.text)
}
}

Answer 1

Can see the same problem with the default Document based app when using Xcode 14.1 (14B47) running on the iPad simulator with iOS 16.1. So definitely a bug (and worth reporting to A as such).
At a guess, the second, non-functional back button is what would have been the back button for navigating in SideBar. And the logic to not display when working on a document is what has been broken.
Fortunately simple workaround for the bug is to explicitly specify toolbar's role using the toolbarRole modifier, e.g.
#main
struct so_DocumentAppWithNavigationShowsMultipleChevronsApp: App {
var body: some Scene {
DocumentGroup(newDocument: so_DocumentAppWithNavigationShowsMultipleChevronsDocument()) { file in
ContentView(document: file.$document)
.toolbarRole(.navigationStack) // <-- Specifying this gets rid of double chevron on iOS
}
}
}