Helper app is sandboxed (entitlement + runtime check), but `URLsForDirectory:` returns user home (`/Users//`) instead of container path — why?

How are you starting this helper process? Via NSTask (Process in Swift)? Or posix_spawn? Or something else?

Does the helper have its own bundle structure. So, something like this:

MyApp.app/
    Contents/
        Info.plist
        MacOS/
            MyApp
            MyHelper.app/
                Contents/
                    Info.plist
                    MacOS/
                        MyHelper

Or is it a standalone executable, like this:

MyApp.app/
    Contents/
        Info.plist
        MacOS/
            MyApp
            MyHelper

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Thanks for extra info.

Based on that I set up a quick test with Apple’s native tools:

1. Using Xcode 16.4 on macOS 15.6.1, I created a new project from the macOS > App template.

2. I modified the content view like this:

   struct ContentView: View {
       var body: some View {
           VStack {
               Text("Parent")
               Button("Test") {
                   do {
                       let u = Bundle.main.url(forAuxiliaryExecutable: "Test799357Child.app")!
                       let b = Bundle(url: u)!
                       let e = b.executableURL!
                       print("will spawn child, path: \(e.path)")
                       let p = Process()
                       p.executableURL = e
                       try p.run()
                       print("did spawn child")
                   } catch {
                       print("did not spawn child, error: \(error)")
                   }
               }
           }
           .padding()
       }
   }
   

3. Within that project, I created a new target from macOS > App template.

4. And modified its content view to look like this:

   struct ContentView: View {
       var body: some View {
           VStack {
               Text("Child")
           }
           .padding()
       }
   }
   

   That way I can tell them apart (-:

5. I added com.apple.security.inherit to the entitlements file.

6. And removed com.apple.security.files.user-selected.read-only.

7. I arrange to embed the child app in the parent.

8. In both the parent and child, I added code to log the home directory path:

   struct Test799357App: App {
       init() {
           print("parent home: \(FileManager.default.homeDirectoryForCurrentUser.path)")
       }
       …
   }
   
   struct Test799357ChildApp: App {
       init() {
           print("child home: \(FileManager.default.homeDirectoryForCurrentUser.path)")
       }
       …
   }
   

   I’m using homeDirectoryForCurrentUser but I see the same results with NSHomeDirectory.

9. I ran the parent and clicked the Test button. In Xcode I see:

parent home: /Users/quinn/Library/Containers/com.example.apple-samplecode.Test799357/Data
will spawn child, path: …/Test799357.app/Contents/MacOS/Test799357Child.app/Contents/MacOS/Test799357Child
did spawn child
child home: /Users/quinn/Library/Containers/com.example.apple-samplecode.Test799357/Data

The parent and child both got the same home directory, that being the Data directory of the main app’s container container.

I’m not sure what’s going on in your case but I recommend that you:

• First replicate my test, to verify that it’s not something weird going on with your Mac specifically.
• Then try integrating bits of my test into your main app, to see where things go wrong.

ps It’s better to reply as a reply, rather than in the comments; see Quinn’s Top Ten DevForums Tips for this and other titbits.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Thanks for your kind instructions.

I have tried the following steps:

1. I followed your step and reproduced correct behavior.
2. I replaced my helper app with child.app and child.app got /Users/<me> for home.
3. I replaced child.app with my helper app and my helper app got expected home at /Users/<me>/Library/Containers/<app_id>/Data.

Now it looks like to have something to do with how helper app is launched by electron app.

I finally solved it! It is environment variables that determine the behavior.

The helper app was designed to accept some environment variables given by caller, but in our latest developement implementation, only those environment variables are given, without those from electron app.

After I added them back, those APIs work as expected.

Thanks for your helpful assistance!

A further but less important question is that why temporary path is not affected by missing environment variables?

If macOS can figure out correct sandbox paths without environment variables, why not all of them doing so?