Notify Sessions when a fatal crash occurs

Author: mrober

firebase-crashlytics/src/main/java/com/google/firebase/crashlytics/internal/common/CrashlyticsController.java

@@ -43,6 +43,7 @@
 import com.google.firebase.crashlytics.internal.persistence.FileStore;
 import com.google.firebase.crashlytics.internal.settings.Settings;
 import com.google.firebase.crashlytics.internal.settings.SettingsProvider;
+import com.google.firebase.sessions.api.CrashEventReceiver;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FilenameFilter;
@@ -216,6 +217,11 @@ public Task<Void> call() throws Exception {
                 doCloseSessions(settingsProvider);
                 doOpenSession(new CLSUUID().getSessionId(), isOnDemand);
 
+                // Notify the Firebase Sessions SDK that a fatal crash has occurred.
+                if (!isOnDemand) {
+                  CrashEventReceiver.notifyCrashOccurred();
+                }
+
                 // If automatic data collection is disabled, we'll need to wait until the next run
                 // of the app.
                 if (!dataCollectionArbiter.isAutomaticDataCollectionEnabled()) {

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/FirebaseSessionsComponent.kt

@@ -70,6 +70,7 @@ internal interface FirebaseSessionsComponent {
   val sessionFirelogPublisher: SessionFirelogPublisher
   val sessionGenerator: SessionGenerator
   val sessionsSettings: SessionsSettings
+  val sharedSessionRepository: SharedSessionRepository
 
   @Component.Builder
   interface Builder {

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/SharedSessionRepository.kt

@@ -18,7 +18,9 @@ package com.google.firebase.sessions
 
 import android.util.Log
 import androidx.datastore.core.DataStore
+import com.google.firebase.Firebase
 import com.google.firebase.annotations.concurrent.Background
+import com.google.firebase.app
 import com.google.firebase.sessions.FirebaseSessions.Companion.TAG
 import com.google.firebase.sessions.api.FirebaseSessionsDependencies
 import com.google.firebase.sessions.api.SessionSubscriber
@@ -35,6 +37,11 @@ internal interface SharedSessionRepository {
   fun appBackground()
 
   fun appForeground()
+
+  companion object {
+    val instance: SharedSessionRepository
+      get() = Firebase.app[FirebaseSessionsComponent::class.java].sharedSessionRepository
+  }
 }
 
 @Singleton

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/api/CrashEventReceiver.kt

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.sessions.api
+
+import com.google.firebase.sessions.SharedSessionRepository
+
+/**
+ * Internal API used by Firebase Crashlytics to notify the Firebase Sessions SDK of fatal crashes.
+ *
+ * This object provides a static-like entry point that Crashlytics calls to inform Sessions a fatal
+ * crash has occurred.
+ */
+object CrashEventReceiver {
+
+  /**
+   * Notifies the Firebase Sessions SDK that a fatal crash has occurred.
+   *
+   * This method should be called by Firebase Crashlytics as soon as it detects a fatal crash. It
+   * safely processes the crash notification, treating the crash as a background event, to ensure
+   * that the session state is updated correctly.
+   *
+   * @see SharedSessionRepository.appBackground
+   */
+  @JvmStatic
+  fun notifyCrashOccurred() {
+    try {
+      // Treat the crash as if the app went to the background, and update session state.
+      SharedSessionRepository.instance.appBackground()
+    } catch (_: Exception) {
+      // Catch and suppress any exception to avoid crashing during crash handling.
+      // This can occur if Firebase or the SDK are in an unexpected state (e.g. FirebaseApp deleted)
+      // No action needed, avoid interfering with the crash reporting process.
+    }
+  }
+}

firebase-sessions/test-app/src/main/kotlin/com/google/firebase/testing/sessions/MyServiceA.kt

@@ -29,7 +29,7 @@ class MyServiceA : Service() {
     Log.i(TAG, "Service A action: ${intent?.action} on process: $myProcessName")
 
     // Send actions from adb shell this way, so it can start the process if needed:
-    // am startservice -n com.google.firebase.testing.sessions/.MyServiceA -a PING
+    // am startservice --user 0 -n com.google.firebase.testing.sessions/.MyServiceA -a PING
     when (intent?.action) {
       "PING" -> ping()
       "CRASH" -> crash()