fix(android): Improve warm start detection with API 35+ support

- Add support for ApplicationStartInfo API on Android 15+ (API 35) for more accurate cold/warm start detection
- Add null safety check for ActivityManager service
- Fix detection logic to prevent legacy methods from running when API 35+ already determined start type
- Set app start type to WARM when app moves to background (process stays alive)
- Add comprehensive test coverage with notification-triggered start scenarios

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: markushi

sentry-android-core/src/main/java/io/sentry/android/core/performance/AppStartMetrics.java

@@ -1,8 +1,11 @@
 package io.sentry.android.core.performance;
 
 import android.app.Activity;
+import android.app.ActivityManager;
 import android.app.Application;
+import android.app.ApplicationStartInfo;
 import android.content.ContentProvider;
+import android.content.Context;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
@@ -335,7 +338,25 @@ public void registerLifecycleCallbacks(final @NotNull Application application) {
     appLaunchedInForeground.resetValue();
     application.registerActivityLifecycleCallbacks(instance);
 
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+    final @Nullable ActivityManager activityManager =
+        (ActivityManager) application.getSystemService(Context.ACTIVITY_SERVICE);
+
+    if (activityManager != null && Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM) {
+      final List<ApplicationStartInfo> historicalProcessStartReasons =
+          activityManager.getHistoricalProcessStartReasons(1);
+      if (!historicalProcessStartReasons.isEmpty()) {
+        final @NotNull ApplicationStartInfo info = historicalProcessStartReasons.get(0);
+        if (info.getStartupState() == ApplicationStartInfo.STARTUP_STATE_STARTED) {
+          if (info.getStartType() == ApplicationStartInfo.START_TYPE_COLD) {
+            appStartType = AppStartType.COLD;
+          } else {
+            appStartType = AppStartType.WARM;
+          }
+        }
+      }
+    }
+
+    if (appStartType == AppStartType.UNKNOWN && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
       Looper.getMainLooper()
           .getQueue()
           .addIdleHandler(
@@ -347,7 +368,7 @@ public boolean queueIdle() {
                   return false;
                 }
               });
-    } else {
+    } else if (appStartType == AppStartType.UNKNOWN) {
       // We post on the main thread a task to post a check on the main thread. On Pixel devices
       // (possibly others) the first task posted on the main thread is called before the
       // Activity.onCreate callback. This is a workaround for that, so that the Activity.onCreate
@@ -402,12 +423,15 @@ public void onActivityCreated(@NonNull Activity activity, @Nullable Bundle saved
         CLASS_LOADED_UPTIME_MS = activityCreatedUptimeMillis;
         contentProviderOnCreates.clear();
         applicationOnCreate.reset();
-      } else if (savedInstanceState != null) {
-        appStartType = AppStartType.WARM;
-      } else if (firstIdle != -1 && activityCreatedUptimeMillis > firstIdle) {
-        appStartType = AppStartType.WARM;
-      } else {
-        appStartType = AppStartType.COLD;
+      } else if (appStartType == AppStartType.UNKNOWN) {
+        // pre API 35 handling
+        if (savedInstanceState != null) {
+          appStartType = AppStartType.WARM;
+        } else if (firstIdle != -1 && activityCreatedUptimeMillis > firstIdle) {
+          appStartType = AppStartType.WARM;
+        } else {
+          appStartType = AppStartType.COLD;
+        }
       }
     }
     appLaunchedInForeground.setValue(true);
@@ -451,6 +475,7 @@ public void onActivityDestroyed(@NonNull Activity activity) {
     // if the app is moving into background
     // as the next onActivityCreated will treat it as a new warm app start
     if (remainingActivities == 0 && !activity.isChangingConfigurations()) {
+      appStartType = AppStartType.WARM;
       appLaunchedInForeground.setValue(true);
       shouldSendStartMeasurements = true;
       firstDrawDone.set(false);

sentry-android-integration-tests/sentry-uitest-android-critical/maestro/appStart.yaml

@@ -16,7 +16,38 @@ name: App Launch Tests
     stopApp: false
 - assertVisible: "App Start Type: WARM"
 
-# Test 3: Launch app after a broadcast receiver already created the application
+# Test 3: Notification (WARM start)
+- launchApp:
+    stopApp: true
+    permissions:
+      all: allow
+- assertVisible: "Welcome!"
+- tapOn: "Trigger Notification"
+- tapOn: "Finish Activity"
+- assertNotVisible: "Welcome!"
+- swipe:
+    start: 50%, 0%
+    end: 50%, 50%
+- tapOn: "Sentry Test Notification"
+- assertVisible: "App Start Type: WARM"
+
+
+# Test 4: Notification (COLD start)
+- launchApp:
+    stopApp: true
+    permissions:
+      all: allow
+- assertVisible: "Welcome!"
+- tapOn: "Trigger Notification"
+- killApp
+- swipe:
+    start: 50%, 0%
+    end: 50%, 50%
+- tapOn: "Sentry Test Notification"
+- assertVisible: "App Start Type: COLD"
+
+
+# Test 5: Launch app after a broadcast receiver already created the application
 # Uncomment once https://github.com/mobile-dev-inc/Maestro/pull/2925 is merged
 # - killApp
 # - sendBroadcast:

sentry-android-integration-tests/sentry-uitest-android-critical/src/main/AndroidManifest.xml

@@ -2,6 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools">
 
+  <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+
   <application
     android:name=".App"
     android:label="Sentry UI Tests Critical"

sentry-android-integration-tests/sentry-uitest-android-critical/src/main/java/io/sentry/uitest/android/critical/MainActivity.kt

@@ -1,9 +1,13 @@
 package io.sentry.uitest.android.critical
 
 import android.content.Intent
+import android.os.Build
 import android.os.Bundle
+import android.widget.Toast
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.activity.result.ActivityResultLauncher
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
@@ -20,15 +24,30 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
 import io.sentry.Sentry
 import io.sentry.android.core.performance.AppStartMetrics
+import io.sentry.uitest.android.critical.NotificationHelper.showNotification
 import java.io.File
 import kotlinx.coroutines.delay
 
 class MainActivity : ComponentActivity() {
+  private lateinit var requestPermissionLauncher: ActivityResultLauncher<String?>
+
   override fun onCreate(savedInstanceState: Bundle?) {
+    setTheme(android.R.style.Theme_DeviceDefault_NoActionBar)
+
     super.onCreate(savedInstanceState)
     val outboxPath =
       Sentry.getCurrentHub().options.outboxPath ?: throw RuntimeException("Outbox path is not set.")
 
+    requestPermissionLauncher =
+      registerForActivityResult(ActivityResultContracts.RequestPermission()) { isGranted: Boolean ->
+        if (isGranted) {
+          // Permission granted, show notification
+          postNotification()
+        } else {
+          // Permission denied, handle accordingly
+          Toast.makeText(this, "Notification permission denied", Toast.LENGTH_SHORT).show()
+        }
+      }
     setContent {
       var appStartType by remember { mutableStateOf("") }
 
@@ -39,7 +58,7 @@ class MainActivity : ComponentActivity() {
 
       MaterialTheme {
         Surface {
-          Column(modifier = Modifier.fillMaxSize().padding(20.dp)) {
+          Column(modifier = Modifier.fillMaxSize().padding(24.dp)) {
             Text(text = "Welcome!")
             Text(text = "App Start Type: $appStartType")
 
@@ -61,6 +80,17 @@ class MainActivity : ComponentActivity() {
               Text("Write Corrupted Envelope")
             }
             Button(onClick = { finish() }) { Text("Finish Activity") }
+            Button(
+              onClick = {
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+                  requestPermissionLauncher.launch(android.Manifest.permission.POST_NOTIFICATIONS)
+                } else {
+                  postNotification()
+                }
+              }
+            ) {
+              Text("Trigger Notification")
+            }
             Button(
               onClick = {
                 startActivity(
@@ -81,4 +111,12 @@ class MainActivity : ComponentActivity() {
       }
     }
   }
+
+  fun postNotification() {
+    NotificationHelper.showNotification(
+      this@MainActivity,
+      "Sentry Test Notification",
+      "This is a test notification.",
+    )
+  }
 }

sentry-android-integration-tests/sentry-uitest-android-critical/src/main/java/io/sentry/uitest/android/critical/NotificationHelper.kt

@@ -0,0 +1,52 @@
+package io.sentry.uitest.android.critical
+
+import android.R
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.content.Context
+import android.content.Intent
+import android.os.Build
+import androidx.core.app.NotificationCompat
+
+object NotificationHelper {
+
+  private const val CHANNEL_ID = "channel_id"
+  private const val NOTIFICATION_ID = 1
+
+  fun showNotification(context: Context, title: String?, message: String?) {
+    val notificationManager =
+      context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+
+    // Create notification channel for Android 8.0+ (API 26+)
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+      val channel =
+        NotificationChannel(CHANNEL_ID, "Notifications", NotificationManager.IMPORTANCE_DEFAULT)
+      channel.description = "description"
+      notificationManager.createNotificationChannel(channel)
+    }
+
+    // Intent to open when notification is tapped
+    val intent = Intent(context, MainActivity::class.java)
+    val pendingIntent =
+      PendingIntent.getActivity(
+        context,
+        0,
+        intent,
+        PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+      )
+
+    // Build the notification
+    val builder =
+      NotificationCompat.Builder(context, CHANNEL_ID)
+        .setSmallIcon(R.drawable.ic_dialog_info)
+        .setContentTitle(title)
+        .setContentText(message)
+        .setPriority(NotificationCompat.PRIORITY_DEFAULT)
+        .setContentIntent(pendingIntent)
+        .setAutoCancel(true) // Dismiss when tapped
+
+    // Show the notification
+    notificationManager.notify(NOTIFICATION_ID, builder.build())
+  }
+}