Prompting for Bluetooth permission on Big Sur (11.0.1)

Question

Upon upgrading to Big Sur (macOS 11.0.1), our app is now asking the user to grant permission to use Bluetooth. However, we are not running any bluetooth code to my knowledge. We do link to CoreBluetooth, but it's been like that for a long time, and this prompt has not appeared.

When running in Xcode 12.2 it does crash with this message:

2020-11-13 13:21:58.685610-0800 Fuze[31049:200367] [access] This app has crashed because it attempted to access privacy-sensitive data without a usage description.  The app's Info.plist must contain an NSBluetoothAlwaysUsageDescription key with a string value explaining to the user how the app uses this data.

But to my knowledge, NSBluetoothAlwaysUsageDescription is only applicable for iOS devices.

I suspect this is something new with Big Sur, because the System Preferences UI for Security & Privacy -> Privacy, did not have a Bluetooth section in Catalina, and it does in Bug Sur. But the Apple documentation does not make mention of this key being applicable for macOS. https://developer.apple.com/documentation/bundleresources/information_property_list/nsbluetoothalwaysusagedescription

So my questions are:

1. Is this key now applicable for macOS and we should have it, even though the documentation says it's only for other platforms, or is there a different key for bluetooth for macOS? I haven't found one.
2. Is there a way to control this prompting or not, because we aren't actually using the bluetooth code. We need the framework for a particular feature, but it's not applicable for many users, so it's confusing to ask permission for it right when the app launches.

Thank you!

Answer 1

I'm not confident about this, but I've been running into some Bluetooth on Big Sur strangeness today as well. In my case, I run a Bluetooth peripheral from the Terminal, and I was also recently prompted to provide the Terminal with Bluetooth permission (which I'd never seen before).

For testing purposes, you can try the "Privacy — Bluetooth Peripheral Usage Description" or "Privacy - Bluetooth Always Usage Description" - and see whether that resolves the crash (I assume it would). It's strange, as I didn't think either of these were required in the past - but it looks like Big Sur is definitely cracking down on permissions.

When you go to "Signing and Capabilities", if there is an option to enable "Hardware -> Bluetooth" in the "App Sandbox" - I would try that out too (you may also need to enable Location, but I can't recall). I'm curious if modifying that flag would change anything regarding permissions.

When you link to CoreBluetooth, are you using the API at all? Because the permission check should happen on the first API call. But, Bluetooth is weird, so it might kick in as soon as the app launches...

In thinking about it, I've actually never optionally used Bluetooth in an app - it's always initialized from app start, so I can't say when the permission check occurs.