FileManager.default.contentsOfDirectory fails with SMB

• Try passing nil to the includingPropertiesForKeys. That gets you the default behaviour and it’s possible that your current non-default behaviour is provoking the bug.

• Try using a lower-level directory iteration API. For example, does readdir work (see its man page)?

number FB8902970.

I would have thought that I'd be prevented from doing this by the
app's sandbox.

Code Block  
let dir = opendir("/Users/quinn")!
defer {
    closedir(dir)
}
while let ent = readdir(dir) {
    print(String(cString: &ent.pointee.d_name.0))
}

A real app would need some error checking (-:

Code Block 
    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
        guard let folderUrl = urls.first else {return}
        let startAccessing = folderUrl.startAccessingSecurityScopedResource()
        defer { if startAccessing {folderUrl.stopAccessingSecurityScopedResource()}}
        var error : NSError? = nil
        NSFileCoordinator().coordinate(readingItemAt: folderUrl, error: &error) { (url) in
            let rep = (url as NSURL).fileSystemRepresentation
            guard let dir = opendir(rep) else {return}
            defer { closedir(dir) }
            while let ent = readdir(dir) {
                print(String(cString: &ent.pointee.d_name.0))
            }
        }
    }

Code Block 
The operation couldn’t be completed. (POSIX error 10006 - Unknown error: 10006)

I'm having same trouble. I can't scan the contents of folder at QNAP NAS connected with SMB.

import SwiftUI

struct ContentView: View {
	@State private var showPicker = false
	@State private var files: [URL] = []

    var body: some View {

        VStack {
			Button("Open Folder...") { showPicker.toggle() }
				.font(.largeTitle)
				.padding(.bottom)

			if files.isEmpty {
				Text("EMPTY")
					.font(.largeTitle)
					.foregroundColor(.secondary)
					.frame(maxHeight: .infinity)
			} else {
				ScrollView {
					VStack {
						ForEach(files, id: \.self) { url in
							Text(url.lastPathComponent)
								.frame(maxWidth: .infinity, alignment: .leading)
						}
					}
					.padding(.leading)
				}
				.frame(maxHeight: .infinity, alignment: .topLeading)
			}
        }
        .padding()
		.fileImporter(isPresented: $showPicker, allowedContentTypes: [.folder]) { result in
			switch result {
			case .success(let url):
				scanFolder(url)
			case .failure(let error):
				print("[ERROR] \(error)")
			}
		}
   }

	private func scanFolder(_ folderURL: URL) {
		let secure = folderURL.startAccessingSecurityScopedResource()

		do {
			let contents = try FileManager.default.contentsOfDirectory(atPath: folderURL.path)
			files = contents.map { folderURL.appending(path: $0) }
		} catch {
			print("[ERROR] contentsOfDirectory \(error)")
		}

		if secure {
			folderURL.stopAccessingSecurityScopedResource()
		}
	}
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Also, Apple's Folder.app can't copy the folder in NAS to iCloud Drive. When I copy the folder in NAS and paste it in iCloud/On device, the empty folder is created. Of corse I have permission for accessing NAS. I can copy files from NAS to iCloud.