[Bug]: iOS - Permission.location.status / .isGranted can hang the main thread for 2+ seconds

[pfraunlobEurofunk]

Please check the following before submitting a new issue.

• I have searched the existing issues.
• I have carefully read the documentation and verified I have added the required platform specific configuration.

Please select affected platform(s)

• Android
• iOS
• Windows

Steps to reproduce

We collect production crash/ANR data via Sentry (App Hang detection, watchdog
threshold 2000ms). We see repeated "App Hanging" events on iOS whose main
thread stack trace is:

App Hanging: App hanging for at least 2000 ms.

  Runner              0x100794114  +[LocationPermissionStrategy permissionStatus:] (LocationPermissionStrategy.m:166)
  Runner              0x100792ec0  +[PermissionManager checkPermissionStatus:result:] (PermissionManager.m:23)
  Runner              0x100792a70  -[PermissionHandlerPlugin handleMethodCall:result:] (PermissionHandlerPlugin.m:30)
  Flutter             0x101a7dce4  __45-[FlutterMethodChannel setMethodCallHandler:]_block_invoke (FlutterChannels.mm:315)
  Flutter             0x1015dbdf0  flutter::PlatformMessageHandlerIos::HandlePlatformMessage (platform_message_handler_ios.mm:70)

This happens most frequently right at applicationDidBecomeActive /
AppLifecycleState.resumed, when app code calls Permission.location.status
or Permission.location.isGranted to detect whether the user changed the
location permission in Settings while the app was backgrounded.

Root cause: LocationPermissionStrategy.checkPermissionStatus: calls
+[CLLocationManager authorizationStatus] synchronously on whatever thread
invoked the method channel (the main/platform thread by default), with no
dispatch_async off-thread hop.

This is the same class of problem as #1002, which was fixed for
checkServiceStatus (CLLocationManager.locationServicesEnabled) in #1329 /
permission_handler_apple 9.4.5:

- (void)checkServiceStatus:(PermissionGroup)permission completionHandler:(ServiceStatusHandler)completionHandler {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        BOOL isEnabled = [CLLocationManager locationServicesEnabled];
        dispatch_async(dispatch_get_main_queue(), ^(void) {
            completionHandler(isEnabled ? ServiceStatusEnabled : ServiceStatusDisabled);
        });
    });
}

However, checkPermissionStatus: (used by .status / .isGranted) was never given the same treatment and is still synchronous today in the latest published version (9.6.1):

- (PermissionStatus)checkPermissionStatus:(PermissionGroup)permission {
    return [LocationPermissionStrategy permissionStatus:permission];
}

+ (PermissionStatus)permissionStatus:(PermissionGroup)permission {
    CLAuthorizationStatus authorizationStatus = [CLLocationManager authorizationStatus]; // synchronous, can block
    ...
}

Since PermissionManager.checkPermissionStatus:result: calls this synchronously and immediately passes the result to FlutterResult, the main thread is blocked for however long authorizationStatus takes internally (observed 2000ms+ on affected devices/iOS versions in production).

Possible fix

Mirroring the checkServiceStatus fix, checkPermissionStatus could dispatch the location-specific call off the main thread and hop back before invoking the result callback, e.g. (scoped to location permission groups only, to avoid touching the other ~10 permission strategies that don't have this issue):

+ (void)checkPermissionStatus:(enum PermissionGroup)permission result:(FlutterResult)result {
    id<PermissionStrategy> permissionStrategy = [PermissionManager permissionStrategy:permission];

    if (permission == PermissionGroupLocation || permission == PermissionGroupLocationAlways ||
        permission == PermissionGroupLocationWhenInUse) {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            PermissionStatus status = [permissionStrategy checkPermissionStatus:permission];
            dispatch_async(dispatch_get_main_queue(), ^{ result(@(status)); });
        });
        return;
    }

    PermissionStatus status = [permissionStrategy checkPermissionStatus:permission];
    result(@(status));
}

Expected results

Permission.location.status / .isGranted should never be able to block the calling (main) thread for multiple seconds, consistent with how serviceStatus already behaves after #1329.

Actual results

Main thread hangs 2000ms+ inside [CLLocationManager authorizationStatus], reported by Sentry's App Hang detector on iOS, primarily right after the app becomes active again.

Code sample

Code sample

[Paste your code here]

Screenshots or video

Screenshots or video demonstration

[Upload media here]

Version

permission_handler: 13.0.1 / permission_handler_apple: 9.6.1

Flutter Doctor output

Doctor output

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.44.8, on macOS 26.5.2 25F84 darwin-arm64, locale de-AT)
[✓] Android toolchain - develop for Android devices (Android SDK version 37.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 26.6)
[✓] Chrome - develop for the web
[✓] Connected device (2 available)
[✓] Network resources

• No issues found!