Checking access for Shiny's IBeaconRangingManager crashes on iOS 13.5

Question

What we do

We are developing a mobile app in .NET MAUI that uses the Shiny NuGet packages to detect Bluetooth Beacons. I have a check in place (see code below) that is executed before the user opens a module in our app which uses Bluetooth Beacon detection to ensure that all necessary hardware is enabled.

The problem

This code works for any Android version from 8.1 to 14 that we tested and it works well on new iPhones, but it crashes for iOS 13.5 when calling RequestAccess and I fail to understand why.

The source code

public async Task<string?> CheckAccess()
{
   var beaconRangingManager = _serviceProvider.GetService<IBeaconRangingManager>();
   
   var translationService = _serviceProvider.GetService<ITranslationService>();

   if (beaconRangingManager != null && translationService != null)
   {
      var accessState = await beaconRangingManager.RequestAccess();
      if (accessState != AccessState.Available)
      {
         return translationService.GetText("global_syn_permission_bluetooth");
      }
   }

   return null;
}

The crash log

This is from the Visual Studio output when opening a module that uses Bluetooth Beacon detection and calls the code above. This happens every time on an iOS 13.5 device, but is fine for new iOS and any Android.

    [0:] An error occurred: 'Objective-C exception thrown.  Name: NSInvalidArgumentException Reason: -[CLLocationManager authorizationStatus]: unrecognized selector sent to instance 0x2918e2ed0
    Native stack trace:
        0   CoreFoundation                      0x000000019a8a8314 AF42303F-57B6-3C11-8F18-8E80ABF7D886 + 1254164
        1   libobjc.A.dylib                     0x000000019a5bcc1c objc_exception_throw + 60
        2   CoreFoundation                      0x000000019a7a6a90 AF42303F-57B6-3C11-8F18-8E80ABF7D886 + 199312
        3   CoreFoundation                      0x000000019a8aca60 AF42303F-57B6-3C11-8F18-8E80ABF7D886 + 1272416
        4   CoreFoundation                      0x000000019a8aed60 _CF_forwarding_prep_0 + 96
        5   Xamarin.PreBuilt.iOS                0x0000000100cffcbc xamarin_get_original_working_directory_path + 8596
        6   Xamarin.PreBuilt.iOS                0x0000000100cbd95c Xamarin.PreBuilt.iOS + 12573020
        7   Xamarin.PreBuilt.iOS                0x000000010102b434 AppleCryptoNative_X509ImportCollection + 2882424
        8   Xamarin.PreBuilt.iOS                0x000000010101fb90 AppleCryptoNative_X509ImportCollection + 2835156
        9   Xamarin.PreBuilt.iOS                0x000000010101d650 AppleCryptoNative_X509ImportCollection + 2825620
        10  Xamarin.PreBuilt.iOS                0x0000000100fec228 AppleCryptoNative_X509ImportCollection + 2623852
        11  Xamarin.PreBuilt.iOS                0x0000000100f938ec AppleCryptoNative_X509ImportCollection + 2261040
        12  Xamarin.PreBuilt.iOS                0x0000000100f97670 AppleCryptoNative_X509ImportCollection + 2276788
        13  Xamarin.PreBuilt.iOS                0x0000000100cf844c xamarin_get_runtime_arch + 35572
        14  Xamarin.PreBuilt.iOS                0x0000000100cfedac xamarin_get_original_working_directory_path + 4740
        15  Xamarin.PreBuilt.iOS                0x0000000100cffb90 xamarin_get_original_working_directory_path + 8296
        16  UIKitCore                           0x000000019e5ad90c 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 6469900
        17  UIKitCore                           0x000000019e5b6f10 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 6508304
        18  UIKitCore                           0x000000019e5b3908 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 6494472
        19  UIKitCore                           0x000000019e5b2e50 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 6491728
        20  UIKitCore                           0x000000019e5a67f0 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 6440944
        21  UIKitCore                           0x000000019e5a5f84 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 6438788
        22  UIKitCore                           0x000000019e5a5d40 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 6438208
        23  UIKitCore                           0x000000019ea2f2d4 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 11195092
        24  UIKitCore                           0x000000019ea0a45c 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 11043932
        25  UIKitCore                           0x000000019ea8da54 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 11582036
        26  UIKitCore                           0x000000019ea90648 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 11593288
        27  UIKitCore                           0x000000019ea88578 32D99ABD-E47B-38D8-BBD1-68AEA293A9A6 + 11560312
        28  CoreFoundation                      0x000000019a823af4 AF42303F-57B6-3C11-8F18-8E80ABF7D886 + 711412
        29  CoreFoundation                      0x000000019a823a48 AF42303F-57B6-3C11-8F18-8E80ABF7D886 + 711240
        30  CoreFoundation                      0x000000019a823198 AF42303F-57B6-3C11-8F18-8E80ABF7D886 + 709016
        31  CoreFoundation                      0x000000019a81df38 AF42303F-57B6-3C11-8F18-8E80ABF7D886 + 687928
        32  CoreFoundation                      0x000000019a81d8f4 CFRunLoopRunSpecific + 480
        33  GraphicsServices                    0x00000001a4c34604 GSEventRunModal + 164
        34  UIKitCore                           0x000000019e9f1358 UIApplicationMain + 1944
        35  Xamarin.PreBuilt.iOS                0x0000000100cd45f4 xamarin_UIApplicationMain + 60
        36  Xamarin.PreBuilt.iOS                0x000000010102c7a8 AppleCryptoNative_X509ImportCollection + 2887404
        37  Xamarin.PreBuilt.iOS                0x000000010102b0a8 AppleCryptoNative_X509ImportCollection + 2881516
        38  Xamarin.PreBuilt.iOS                0x000000010101fab8 AppleCryptoNative_X509ImportCollection + 2834940
        39  Xamarin.PreBuilt.iOS                0x000000010101d650 AppleCryptoNative_X509ImportCollection + 2825620
        40  Xamarin.PreBuilt.iOS                0x0000000100fec228 AppleCryptoNative_X509ImportCollection + 2623852
        41  Xamarin.PreBuilt.iOS                0x0000000100f938ec AppleCryptoNative_X509ImportCollection + 2261040
        42  Xamarin.PreBuilt.iOS                0x0000000100f9b370 AppleCryptoNative_X509ImportCollection + 2292404
        43  Xamarin.PreBuilt.iOS                0x0000000100f57e90 AppleCryptoNative_X509ImportCollection + 2016724
        44  Xamarin.PreBuilt.iOS                0x0000000100f6252c AppleCryptoNative_X509ImportCollection + 2059376
        45  Xamarin.PreBuilt.iOS                0x000000010102c774 AppleCryptoNative_X509ImportCollection + 2887352
        46  Xamarin.PreBuilt.iOS                0x000000010102b0e0 AppleCryptoNative_X509ImportCollection + 2881572
        47  Xamarin.PreBuilt.iOS                0x000000010101fab8 AppleCryptoNative_X509ImportCollection + 2834940
        48  Xamarin.PreBuilt.iOS                0x000000010101d650 AppleCryptoNative_X509ImportCollection + 2825620
        49  Xamarin.PreBuilt.iOS                0x0000000100fec228 AppleCryptoNative_X509ImportCollection + 2623852
        50  Xamarin.PreBuilt.iOS                0x0000000100f938ec AppleCryptoNative_X509ImportCollection + 2261040
        51  Xamarin.PreBuilt.iOS                0x0000000100f99be8 AppleCryptoNative_X509ImportCollection + 2286380
        52  Xamarin.PreBuilt.iOS                0x0000000100ff1844 AppleCryptoNative_X509ImportCollection + 2645896
        53  Xamarin.PreBuilt.iOS                0x0000000100cfec2c xamarin_get_original_working_directory_path + 4356
        54  Xamarin.PreBuilt.iOS                0x000000010105a07c AppleCryptoNative_X509ImportCollection + 3073984
        55  libdyld.dylib                       0x000000019a6992dc 322C4E05-D0CF-33F5-B996-CE5C67DF59B6 + 4828
    '. Callstack: '   at CoreLocation.CLLocationManager.get_AuthorizationStatus() in /Users/builder/azdo/_work/1/s/xamarin-macios/src/build/dotnet/ios/generated-sources/CoreLocation/CLLocationManager.g.cs:line 697
       at Shiny.Locations.LocationExtensions.GetCurrentStatus(CLLocationManager locationManager, Boolean background)
       at Shiny.Locations.LocationExtensions.RequestAccess(CLLocationManager locationManager, Boolean background)
       at MSS.App.Views.Pages.Patrol.PatrolPage.CheckAccess() in C:\Projects\Git\MSS.App\MSS.App\Views\Pages\Patrol\PatrolPage.xaml.cs:line 74
       at MSS.App.ViewModels.MainMenuPageViewModel.<Update>b__5_0(ModuleModel selectedModule) in C:\Projects\Git\MSS.App\MSS.App\ViewModels\MainMenuPageViewModel.cs:line 59
       at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_0(Object state)
       at Foundation.NSAsyncSynchronizationContextDispatcher.Apply() in /Users/builder/azdo/_work/1/s/xamarin-macios/src/Foundation/NSAction.cs:line 179
       at UIKit.UIApplication.UIApplicationMain(Int32 argc, String[] argv, IntPtr principalClassName, IntPtr delegateClassName) in /Users/builder/azdo/_work/1/s/xamarin-macios/src/UIKit/UIApplication.cs:line 61
       at UIKit.UIApplication.Main(String[] args, Type principalClass, Type delegateClass) in /Users/builder/azdo/_work/1/s/xamarin-macios/src/UIKit/UIApplication.cs:line 96
       at MSS.App.Program.Main(String[] args) in C:\Projects\Git\MSS.App\MSS.App\Platforms\iOS\Program.cs:line 13
       at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
       at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)'

Answer 1

This appears to be a bug in the Shiny NuGet package.

The iOS code crashes checking the authorization status. There are two variations on this API, one that works on iOS 14.0+ and the other on 4.2-13.x. (See below.) It appears that the Shiny is incorrectly calling the new API introduced in 14.0 even when the iOS version is 13.5. They will need to fix that code.

You may want to open an issue in the Github repo here: https://github.com/shinyorg/shiny and reference this analysis.

I had a poke around in their source code, but I couldn't quickly find where they are making the iOS call that causes the crash. If somebody can find that, then the fix should be trivial to make.

    @available(iOS 14.0, *)
    open var authorizationStatus: CLAuthorizationStatus { get }

    /*
     *  authorizationStatus
     *
     *  Discussion:
     *      Deprecated.  Use the instance property authorizationStatus instead.
     */
    @available(iOS, introduced: 4.2, deprecated: 14.0)
    open class func authorizationStatus() -> CLAuthorizationStatus