Trouble reading file in xcode command line app

Question

I am having trouble reading a file within a command line tool project in Xcode 11.6.

Steps:

Create a new command line tool project using the template in the mac os section.

In main.swift:

import Foundation
let fileURL = URL( fileURLWithPath: "/Users/ausom4/Desktop/myTest.txt" )
var rawDataString: String
var errorString: String?

do {
  rawDataString = try String( contentsOf: fileURL, encoding: .utf8 )
  print(rawDataString)
} catch let error as NSError {
  errorString = error.description
  rawDataString = ""
  print(rawDataString)
}

This will build successfully in Xcode however will always print a null string in the console.

However if I go to the location of my product in terminal and run the build I get the contents of the file.

I do not have sandboxing enabled. Sandboxing is also not enabled by default in this xcode template. I have also given xcode full disk access.

I can run this code in a playground.

What could be the issue here?

Answer 1

It is not sandbox - it is macOS Security & Privacy system.

On first launch you had to get alert asking something like “TestFileReading” would like to access files in your Desktop folder. so you grand access for this application.

If you did not grant access then (or for some reason macOS forgot to ask that) there is possibility to grant access manually in System Preferences at any time:

With all this passed your code snippet works as expected - tested with Xcode 12 / macOS 10.15.6