fix: cocoa SDK init after hot-restart

CHANGELOG.md

@@ -30,7 +30,7 @@
     },
     appRunner: () => runApp(MyApp()),
   );
-  ```  
+  ```
 - Linux native error & obfuscation support ([#2431](https://github.com/getsentry/sentry-dart/pull/2431))
 - Improve Device context on plain Dart and Flutter desktop apps ([#2441](https://github.com/getsentry/sentry-dart/pull/2441))
 - Add debounce to capturing screenshots ([#2368](https://github.com/getsentry/sentry-dart/pull/2368))
@@ -53,6 +53,7 @@
 ### Fixes
 
 - OS & device contexts missing on Windows ([#2439](https://github.com/getsentry/sentry-dart/pull/2439))
+- Native iOS/macOS SDK session didn't start after Flutter hot-restart ([#2452](https://github.com/getsentry/sentry-dart/pull/2452))
 
 ### Dependencies
 

flutter/ios/Classes/SentryFlutterPluginApple.swift

@@ -16,18 +16,6 @@ public class SentryFlutterPluginApple: NSObject, FlutterPlugin {
 
     private static let nativeClientName = "sentry.cocoa.flutter"
 
-    // The Cocoa SDK is init. after the notification didBecomeActiveNotification is registered.
-    // We need to be able to receive this notification and start a session when the SDK is fully operational.
-    private var didReceiveDidBecomeActiveNotification = false
-
-    private var didBecomeActiveNotificationName: NSNotification.Name {
-#if os(iOS)
-        return UIApplication.didBecomeActiveNotification
-#elseif os(macOS)
-        return NSApplication.didBecomeActiveNotification
-#endif
-    }
-
     private static var pluginRegistrationTime: Int64 = 0
 
     public static func register(with registrar: FlutterPluginRegistrar) {
@@ -40,7 +28,6 @@ public class SentryFlutterPluginApple: NSObject, FlutterPlugin {
 #endif
 
         let instance = SentryFlutterPluginApple(channel: channel)
-        instance.registerObserver()
         registrar.addMethodCallDelegate(instance, channel: channel)
     }
 
@@ -51,22 +38,6 @@ public class SentryFlutterPluginApple: NSObject, FlutterPlugin {
 
     private lazy var sentryFlutter = SentryFlutter()
 
-    private func registerObserver() {
-        NotificationCenter.default.addObserver(self,
-                                               selector: #selector(applicationDidBecomeActive),
-                                               name: didBecomeActiveNotificationName,
-                                               object: nil)
-    }
-
-    @objc private func applicationDidBecomeActive() {
-        didReceiveDidBecomeActiveNotification = true
-        // we only need to do that in the 1st time, so removing it
-        NotificationCenter.default.removeObserver(self,
-                                                  name: didBecomeActiveNotificationName,
-                                                  object: nil)
-
-    }
-
     private lazy var iso8601Formatter: DateFormatter = {
         let formatter = DateFormatter()
         formatter.locale = Locale(identifier: "en_US_POSIX")
@@ -352,15 +323,17 @@ public class SentryFlutterPluginApple: NSObject, FlutterPlugin {
             }
         }
 
-       if didReceiveDidBecomeActiveNotification &&
-            (PrivateSentrySDKOnly.options.enableAutoSessionTracking ||
-             PrivateSentrySDKOnly.options.enableWatchdogTerminationTracking) {
-            // We send a SentryHybridSdkDidBecomeActive to the Sentry Cocoa SDK, so the SDK will mimics
-            // the didBecomeActiveNotification notification. This is needed for session and OOM tracking.
-           NotificationCenter.default.post(name: Notification.Name("SentryHybridSdkDidBecomeActive"), object: nil)
-           // we reset the flag for the sake of correctness
-           didReceiveDidBecomeActiveNotification = false
-       }
+        #if os(iOS) || targetEnvironment(macCatalyst)
+        let appIsActive = UIApplication.shared.applicationState == .active
+        #else
+        let appIsActive = NSApplication.shared.isActive
+        #endif
+
+        // We send a SentryHybridSdkDidBecomeActive to the Sentry Cocoa SDK, to mimic
+        // the didBecomeActiveNotification notification. This is needed for session, OOM tracking, replays, etc.
+        if appIsActive {
+            NotificationCenter.default.post(name: Notification.Name("SentryHybridSdkDidBecomeActive"), object: nil)
+        }
 
 #if canImport(UIKit) && !SENTRY_NO_UIKIT
 #if os(iOS) || os(tvOS)