Reworked ios app lifecycle events to be more accurate.

Sources/Segment/Plugins/Platforms/iOS/iOSLifecycleEvents.swift

@@ -24,6 +24,9 @@ class iOSLifecycleEvents: PlatformPlugin, iOSLifecycle {
     @Atomic
     private var didFinishLaunching = false
 
+    @Atomic
+    private var wasBackgrounded = false
+
     func application(_ application: UIApplication?, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) {
         // Make sure we aren't double calling application:didFinishLaunchingWithOptions
         // by resetting the check at the start
@@ -83,19 +86,26 @@ class iOSLifecycleEvents: PlatformPlugin, iOSLifecycle {
                 ])
             }
         }
+
+        // Only fire if we were actually backgrounded
+        if wasBackgrounded {
+            if analytics?.configuration.values.trackedApplicationLifecycleEvents.contains(.applicationForegrounded) == true {
+                analytics?.track(name: "Application Foregrounded")
+            }
+            _wasBackgrounded.set(false)
+        }
     }
 
     func applicationDidEnterBackground(application: UIApplication?) {
         _didFinishLaunching.set(false)
+        _wasBackgrounded.set(true)
         if analytics?.configuration.values.trackedApplicationLifecycleEvents.contains(.applicationBackgrounded) == true {
             analytics?.track(name: "Application Backgrounded")
         }
     }
 
     func applicationDidBecomeActive(application: UIApplication?) {
-        if analytics?.configuration.values.trackedApplicationLifecycleEvents.contains(.applicationForegrounded) == true {
-            analytics?.track(name: "Application Foregrounded")
-        }
+        // DO NOT USE THIS.
     }
 
     private func urlFrom(_ launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> String {

Tests/Segment-Tests/iOSLifecycle_Tests.swift

@@ -67,6 +67,154 @@ final class iOSLifecycle_Tests: XCTestCase {
         XCTAssertTrue(trackEvent?.event == "Application Opened")
         XCTAssertTrue(trackEvent?.type == "track")
     }
+
+    func testApplicationForegroundedOnlyFiresAfterBackground() {
+            let analytics = Analytics(configuration: Configuration(writeKey: "test")
+                .setTrackedApplicationLifecycleEvents(.all))
+            let outputReader = OutputReaderPlugin()
+            analytics.add(plugin: outputReader)
+
+            waitUntilStarted(analytics: analytics)
+
+            // Simulate: Background → Foreground
+            NotificationCenter.default.post(name: UIApplication.didEnterBackgroundNotification, object: nil)
+            NotificationCenter.default.post(name: UIApplication.willEnterForegroundNotification, object: nil)
+
+            let trackEvent: TrackEvent? = outputReader.lastEvent as? TrackEvent
+            XCTAssertEqual(trackEvent?.event, "Application Foregrounded",
+                          "Application Foregrounded should fire after coming back from background")
+        }
+
+        func testTransientInterruptionDoesNotFireForegrounded() {
+            let analytics = Analytics(configuration: Configuration(writeKey: "test")
+                .setTrackedApplicationLifecycleEvents(.all))
+            let outputReader = OutputReaderPlugin()
+            analytics.add(plugin: outputReader)
+
+            waitUntilStarted(analytics: analytics)
+
+            // Clear any startup events by capturing the current state
+            let eventsBeforeInterruption = outputReader.lastEvent
+
+            // Simulate: willResignActive → didBecomeActive (notification center, control center, etc.)
+            NotificationCenter.default.post(name: UIApplication.willResignActiveNotification, object: nil)
+            NotificationCenter.default.post(name: UIApplication.didBecomeActiveNotification, object: nil)
+
+            // lastEvent should still be the same as before (no new "Application Foregrounded")
+            let trackEvent: TrackEvent? = outputReader.lastEvent as? TrackEvent
+            if trackEvent?.event == "Application Foregrounded" {
+                XCTFail("Application Foregrounded should NOT fire for transient interruptions like notification center")
+            }
+        }
+
+        func testForegroundedNotFiredWithoutPriorBackground() {
+            let analytics = Analytics(configuration: Configuration(writeKey: "test")
+                .setTrackedApplicationLifecycleEvents(.all))
+            let outputReader = OutputReaderPlugin()
+            analytics.add(plugin: outputReader)
+
+            waitUntilStarted(analytics: analytics)
+
+            // Simulate: willEnterForeground without prior didEnterBackground
+            NotificationCenter.default.post(name: UIApplication.willEnterForegroundNotification, object: nil)
+
+            let trackEvent: TrackEvent? = outputReader.lastEvent as? TrackEvent
+            XCTAssertNotEqual(trackEvent?.event, "Application Foregrounded",
+                             "Application Foregrounded should not fire without a prior background event")
+        }
+
+        func testMultipleBackgroundForegroundCycles() {
+            let analytics = Analytics(configuration: Configuration(writeKey: "test")
+                .setTrackedApplicationLifecycleEvents(.all))
+            let outputReader = OutputReaderPlugin()
+            analytics.add(plugin: outputReader)
+
+            waitUntilStarted(analytics: analytics)
+
+            // Cycle 1: Background → Foreground
+            NotificationCenter.default.post(name: UIApplication.didEnterBackgroundNotification, object: nil)
+            NotificationCenter.default.post(name: UIApplication.willEnterForegroundNotification, object: nil)
+
+            var trackEvent: TrackEvent? = outputReader.lastEvent as? TrackEvent
+            XCTAssertEqual(trackEvent?.event, "Application Foregrounded",
+                          "First foreground cycle should fire Application Foregrounded")
+
+            // Cycle 2: Background → Foreground
+            NotificationCenter.default.post(name: UIApplication.didEnterBackgroundNotification, object: nil)
+            NotificationCenter.default.post(name: UIApplication.willEnterForegroundNotification, object: nil)
+
+            trackEvent = outputReader.lastEvent as? TrackEvent
+            XCTAssertEqual(trackEvent?.event, "Application Foregrounded",
+                          "Second foreground cycle should also fire Application Foregrounded")
+        }
+
+        func testBackgroundAlwaysFires() {
+            let analytics = Analytics(configuration: Configuration(writeKey: "test")
+                .setTrackedApplicationLifecycleEvents(.all))
+            let outputReader = OutputReaderPlugin()
+            analytics.add(plugin: outputReader)
+
+            waitUntilStarted(analytics: analytics)
+
+            // Simulate: Background
+            NotificationCenter.default.post(name: UIApplication.didEnterBackgroundNotification, object: nil)
+
+            let trackEvent: TrackEvent? = outputReader.lastEvent as? TrackEvent
+            XCTAssertEqual(trackEvent?.event, "Application Backgrounded",
+                          "Application Backgrounded should always fire when app enters background")
+        }
+
+        func testComplexLifecycleSequence() {
+            let analytics = Analytics(configuration: Configuration(writeKey: "test")
+                .setTrackedApplicationLifecycleEvents(.all))
+            let outputReader = OutputReaderPlugin()
+            analytics.add(plugin: outputReader)
+
+            waitUntilStarted(analytics: analytics)
+
+            // Simulate realistic user behavior:
+            // 1. Background the app
+            NotificationCenter.default.post(name: UIApplication.didEnterBackgroundNotification, object: nil)
+            var trackEvent: TrackEvent? = outputReader.lastEvent as? TrackEvent
+            XCTAssertEqual(trackEvent?.event, "Application Backgrounded")
+
+            // 2. Foreground the app
+            NotificationCenter.default.post(name: UIApplication.willEnterForegroundNotification, object: nil)
+            trackEvent = outputReader.lastEvent as? TrackEvent
+            XCTAssertEqual(trackEvent?.event, "Application Foregrounded")
+
+            // 3. Pull down notification center (transient interruption)
+            NotificationCenter.default.post(name: UIApplication.willResignActiveNotification, object: nil)
+            NotificationCenter.default.post(name: UIApplication.didBecomeActiveNotification, object: nil)
+
+            // Last event should still be "Application Foregrounded" from step 2
+            trackEvent = outputReader.lastEvent as? TrackEvent
+            XCTAssertEqual(trackEvent?.event, "Application Foregrounded",
+                          "Transient interruption should not create new events")
+
+            // 4. Background again
+            NotificationCenter.default.post(name: UIApplication.didEnterBackgroundNotification, object: nil)
+            trackEvent = outputReader.lastEvent as? TrackEvent
+            XCTAssertEqual(trackEvent?.event, "Application Backgrounded")
+        }
+
+        func testDidBecomeActiveDoesNotFireForegrounded() {
+            let analytics = Analytics(configuration: Configuration(writeKey: "test")
+                .setTrackedApplicationLifecycleEvents(.all))
+            let outputReader = OutputReaderPlugin()
+            analytics.add(plugin: outputReader)
+
+            waitUntilStarted(analytics: analytics)
+
+            // Simulate: didBecomeActive (should not fire anything anymore)
+            NotificationCenter.default.post(name: UIApplication.didBecomeActiveNotification, object: nil)
+
+            // Verify no new event was created
+            let trackEvent: TrackEvent? = outputReader.lastEvent as? TrackEvent
+            if trackEvent?.event == "Application Foregrounded" {
+                XCTFail("didBecomeActive should not fire Application Foregrounded anymore")
+            }
+        }
 }
 
 #endif