fix: UIWindow being possibly accessed from a background thread in SentryCrashWrapper

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Fixes
+
+- Fix UIWindow being possibly accessed from a background thread in SentryCrashWrapper (#6905)
+
 ## 9.0.0-rc.1
 
 ### Breaking Changes

Sources/Sentry/SentryDependencyContainerSwiftHelper.m

@@ -13,6 +13,11 @@ @implementation SentryDependencyContainerSwiftHelper
     return [SentryDependencyContainer.sharedInstance.application getWindows];
 }
 
++ (CGSize)activeScreenSize
+{
+    return [SentryDependencyContainer.sharedInstance.application getActiveWindowSize];
+}
+
 #endif // SENTRY_HAS_UIKIT
 
 + (NSString *)release:(SentryOptions *)options

Sources/Sentry/include/SentryDependencyContainerSwiftHelper.h

@@ -30,6 +30,7 @@ NS_ASSUME_NONNULL_BEGIN
 #if SENTRY_HAS_UIKIT
 
 + (nullable NSArray<UIWindow *> *)windows;
++ (CGSize)activeScreenSize;
 
 #endif // SENTRY_HAS_UIKIT
 

Sources/Swift/Helper/SentryApplication.swift

@@ -23,6 +23,8 @@ import UIKit
  */
     func getWindows() -> [UIWindow]?
 
+    func getActiveWindowSize() -> CGSize
+
     var connectedScenes: Set<UIScene> { get }
 
     var delegate: UIApplicationDelegate? { get }

Sources/Swift/Helper/SentryApplicationExtensions.swift

@@ -13,6 +13,10 @@ import UIKit
         internal_getWindows()
     }
 
+    @objc public func getActiveWindowSize() -> CGSize {
+        internal_getActiveWindowSize()
+    }
+
     @objc public func relevantViewControllersNames() -> [String]? {
         internal_relevantViewControllersNames()
     }
@@ -55,6 +59,19 @@ extension SentryApplication {
         return Array(windows)
     }
 
+    public func internal_getActiveWindowSize() -> CGSize {
+        var size = CGSize.zero
+        Dependencies.dispatchQueueWrapper.dispatchSyncOnMainQueue({ [weak self] in
+            guard let self,
+                  let window = self.internal_getWindows()?.first else {
+                return
+            }
+
+            size = window.bounds.size
+        }, timeout: 0.01)
+        return size
+    }
+
     // This cannot be declared with @objc so until we delete more ObjC code it needs a separate
     // function than the objc visible one.
     public func internal_relevantViewControllersNames() -> [String]? {

Sources/Swift/SentryCrash/SentryCrashWrapper.swift

@@ -265,10 +265,10 @@ public final class SentryCrashWrapper: NSObject {
     private func setScreenDimensions(_ deviceData: inout [String: Any]) {
         // The UIWindowScene is unavailable on visionOS
 #if (os(iOS) || os(tvOS)) && !SENTRY_NO_UIKIT
-        if let appWindows = SentryDependencyContainerSwiftHelper.windows(),
-           let appScreen = appWindows.first?.screen {
-            deviceData["screen_height_pixels"] = appScreen.bounds.size.height
-            deviceData["screen_width_pixels"] = appScreen.bounds.size.width
+        let screenSize = SentryDependencyContainerSwiftHelper.activeScreenSize()
+        if screenSize != CGSize.zero {
+            deviceData["screen_height_pixels"] = screenSize.height
+            deviceData["screen_width_pixels"] = screenSize.width
         }
 #endif // (os(iOS) || os(tvOS)) && !SENTRY_NO_UIKIT
     }

Tests/SentryTests/TestSentryUIApplication.swift

@@ -9,6 +9,10 @@ final class TestSentryUIApplication: SentryApplication {
         return internal_getWindows()
     }
 
+    func getActiveWindowSize() -> CGSize {
+        return internal_getActiveWindowSize()
+    }
+
     private var _windows: [UIWindow]?
     private(set) var calledOnMainThread = true
     var windows: [UIWindow]? {