fix: crash when call SentryUIApplication in background thread

CHANGELOG.md

@@ -8,6 +8,7 @@
 
 ### Fixes
 
+- Crash due to a background call to -[UIApplication applicationState] (#3855)
 - Save framework without UIKit/AppKit as Github Asset for releases (#3858) 
 
 ## 8.24.0

Sources/Sentry/SentryDispatchQueueWrapper.m

@@ -56,23 +56,43 @@
     }
 }
 
+- (nullable id)dispatchSyncOnMainQueueWithResult:(id (^)(void))block
+{
+    return [self dispatchSyncOnMainQueueWithResult:block timeout:DISPATCH_TIME_FOREVER];
+}
+
 - (BOOL)dispatchSyncOnMainQueue:(void (^)(void))block timeout:(NSTimeInterval)timeout
+{
+    NSNumber *result = [self
+        dispatchSyncOnMainQueueWithResult:^id _Nonnull {
+            block();
+            return @YES;
+        }
+                                  timeout:timeout];
+    return result.boolValue;
+}
+
+- (nullable id)dispatchSyncOnMainQueueWithResult:(id (^)(void))block timeout:(NSTimeInterval)timeout
 {
     if ([NSThread isMainThread]) {
-        block();
+        return block();
     } else {
         dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
+        __block id result;
 
         dispatch_async(dispatch_get_main_queue(), ^{
-            block();
+            result = block();
             dispatch_semaphore_signal(semaphore);
         });
 
         dispatch_time_t timeout_t
             = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(timeout * NSEC_PER_SEC));
-        return dispatch_semaphore_wait(semaphore, timeout_t) == 0;
+        if (dispatch_semaphore_wait(semaphore, timeout_t) == 0) {
+            return result;
+        } else {
+            return nil;
+        }
     }
-    return YES;
 }
 
 - (void)dispatchAfter:(NSTimeInterval)interval block:(dispatch_block_t)block

Sources/Sentry/SentryUIApplication.m

@@ -28,7 +28,8 @@ - (instancetype)init
         // We store the application state when the app is initialized
         // and we keep track of its changes by the notifications
         // this way we avoid calling sharedApplication in a background thread
-        appState = self.sharedApplication.applicationState;
+        [SentryDependencyContainer.sharedInstance.dispatchQueueWrapper
+            dispatchOnMainQueue:^{ self->appState = self.sharedApplication.applicationState; }];
     }
     return self;
 }
@@ -63,29 +64,34 @@ - (UIApplication *)sharedApplication
 
 - (NSArray<UIWindow *> *)windows
 {
-    UIApplication *app = [self sharedApplication];
-    NSMutableArray *result = [NSMutableArray array];
-
-    if (@available(iOS 13.0, tvOS 13.0, *)) {
-        NSArray<UIScene *> *scenes = [self getApplicationConnectedScenes:app];
-        for (UIScene *scene in scenes) {
-            if (scene.activationState == UISceneActivationStateForegroundActive && scene.delegate &&
-                [scene.delegate respondsToSelector:@selector(window)]) {
-                id window = [scene.delegate performSelector:@selector(window)];
-                if (window) {
-                    [result addObject:window];
+    return [SentryDependencyContainer.sharedInstance.dispatchQueueWrapper
+        dispatchSyncOnMainQueueWithResult:^id _Nonnull {
+            UIApplication *app = [self sharedApplication];
+            NSMutableArray *result = [NSMutableArray array];
+
+            if (@available(iOS 13.0, tvOS 13.0, *)) {
+                NSArray<UIScene *> *scenes = [self getApplicationConnectedScenes:app];
+                for (UIScene *scene in scenes) {
+                    if (scene.activationState == UISceneActivationStateForegroundActive
+                        && scene.delegate &&
+                        [scene.delegate respondsToSelector:@selector(window)]) {
+                        id window = [scene.delegate performSelector:@selector(window)];
+                        if (window) {
+                            [result addObject:window];
+                        }
+                    }
                 }
             }
-        }
-    }
 
-    id<UIApplicationDelegate> appDelegate = [self getApplicationDelegate:app];
+            id<UIApplicationDelegate> appDelegate = [self getApplicationDelegate:app];
 
-    if ([appDelegate respondsToSelector:@selector(window)] && appDelegate.window != nil) {
-        [result addObject:appDelegate.window];
-    }
+            if ([appDelegate respondsToSelector:@selector(window)] && appDelegate.window != nil) {
+                [result addObject:appDelegate.window];
+            }
 
-    return result;
+            return result;
+        }
+                                  timeout:0.01];
 }
 
 - (NSArray<UIViewController *> *)relevantViewControllers
@@ -109,23 +115,18 @@ - (UIApplication *)sharedApplication
 
 - (nullable NSArray<NSString *> *)relevantViewControllersNames
 {
-    __block NSArray<NSString *> *result = nil;
-
-    void (^addViewNames)(void) = ^{
-        NSArray *viewControllers
-            = SentryDependencyContainer.sharedInstance.application.relevantViewControllers;
-        NSMutableArray *vcsNames = [[NSMutableArray alloc] initWithCapacity:viewControllers.count];
-        for (id vc in viewControllers) {
-            [vcsNames addObject:[SwiftDescriptor getObjectClassName:vc]];
+    return [SentryDependencyContainer.sharedInstance.dispatchQueueWrapper
+        dispatchSyncOnMainQueueWithResult:^id _Nonnull {
+            NSArray *viewControllers
+                = SentryDependencyContainer.sharedInstance.application.relevantViewControllers;
+            NSMutableArray *vcsNames =
+                [[NSMutableArray alloc] initWithCapacity:viewControllers.count];
+            for (id vc in viewControllers) {
+                [vcsNames addObject:[SwiftDescriptor getObjectClassName:vc]];
+            }
+            return [NSArray arrayWithArray:vcsNames];
         }
-        result = [NSArray arrayWithArray:vcsNames];
-    };
-
-    [[SentryDependencyContainer.sharedInstance dispatchQueueWrapper]
-        dispatchSyncOnMainQueue:addViewNames
-                        timeout:0.01];
-
-    return result;
+                                  timeout:0.01];
 }
 
 - (NSArray<UIViewController *> *)relevantViewControllerFromWindow:(UIWindow *)window

Sources/Sentry/include/SentryDispatchQueueWrapper.h

@@ -19,8 +19,13 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)dispatchSyncOnMainQueue:(void (^)(void))block;
 
+- (nullable id)dispatchSyncOnMainQueueWithResult:(id (^)(void))block;
+
 - (BOOL)dispatchSyncOnMainQueue:(void (^)(void))block timeout:(NSTimeInterval)timeout;
 
+- (nullable id)dispatchSyncOnMainQueueWithResult:(id (^)(void))block
+                                         timeout:(NSTimeInterval)timeout;
+
 - (void)dispatchAfter:(NSTimeInterval)interval block:(dispatch_block_t)block;
 
 - (void)dispatchCancel:(dispatch_block_t)block;