feat(android): add a foss flavour without Firebase

android/build.gradle.kts

@@ -31,6 +31,14 @@ android {
         buildConfigField("boolean", "ENABLE_PUSH_NOTIFICATIONS", "$enablePush")
     }
 
+    // FCM pulls proprietary Google libraries that FOSS repos reject. The foss
+    // flavour drops them, leaving UnifiedPush as the only transport.
+    flavorDimensions += "push"
+    productFlavors {
+        create("gms")
+        create("foss")
+    }
+
     buildTypes {
         debug {
             enableUnitTestCoverage = true
@@ -78,8 +86,8 @@ dependencies {
     implementation("com.google.android.material:material:1.14.0")
     implementation("com.fasterxml.jackson.core:jackson-databind:2.22.1")
 
-    implementation(platform("com.google.firebase:firebase-bom:34.16.0"))
-    implementation("com.google.firebase:firebase-messaging-ktx:24.1.2")
+    "gmsImplementation"(platform("com.google.firebase:firebase-bom:34.16.0"))
+    "gmsImplementation"("com.google.firebase:firebase-messaging-ktx:24.1.2")
     implementation("com.squareup.okhttp3:okhttp:5.3.2")
     implementation("org.unifiedpush.android:connector:3.3.3")
     // The connector declares Tink as a runtime-only dependency, so its WebPush
@@ -89,7 +97,7 @@ dependencies {
     // classpath — `tink-android` repackages the same classes and trips AGP's
     // duplicate-class check.
     implementation("com.google.crypto.tink:tink:1.21.0")
-    implementation("org.unifiedpush.android:embedded-fcm-distributor:3.0.0")
+    "gmsImplementation"("org.unifiedpush.android:embedded-fcm-distributor:3.0.0")
     testImplementation("junit:junit:4.13.2")
     testImplementation("io.mockk:mockk-android:1.14.11")
     testImplementation("io.mockk:mockk-agent:1.14.11")

android/src/foss/java/app/tauri/notification/FcmBridge.kt

@@ -0,0 +1,15 @@
+package app.tauri.notification
+
+import android.content.Context
+
+object FcmBridge {
+  fun isConfigured(context: Context): Boolean = false
+
+  fun fetchToken(onResult: (FcmTokenResult) -> Unit) {
+    onResult(FcmTokenResult.Unavailable("FCM is not available in this build"))
+  }
+
+  fun deleteToken(onResult: (FcmDeleteResult) -> Unit) {
+    onResult(FcmDeleteResult.NotConfigured)
+  }
+}

android/src/gms/AndroidManifest.xml

@@ -0,0 +1,12 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application>
+        <!-- Firebase Cloud Messaging Service for handling push notifications -->
+        <service
+            android:name="app.tauri.notification.TauriFirebaseMessagingService"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="com.google.firebase.MESSAGING_EVENT" />
+            </intent-filter>
+        </service>
+    </application>
+</manifest>

android/src/gms/java/app/tauri/notification/FcmBridge.kt

@@ -0,0 +1,40 @@
+package app.tauri.notification
+
+import android.content.Context
+import com.google.firebase.FirebaseApp
+import com.google.firebase.messaging.FirebaseMessaging
+
+object FcmBridge {
+  fun isConfigured(context: Context): Boolean =
+    try {
+      FirebaseApp.getApps(context).isNotEmpty()
+    } catch (_: Exception) {
+      false
+    }
+
+  fun fetchToken(onResult: (FcmTokenResult) -> Unit) {
+    try {
+      FirebaseMessaging.getInstance().token.addOnCompleteListener { task ->
+        onResult(
+          if (task.isSuccessful) FcmTokenResult.Success(task.result)
+          else FcmTokenResult.Failed("Failed to get FCM token: ${task.exception?.message}")
+        )
+      }
+    } catch (error: Exception) {
+      onResult(FcmTokenResult.Unavailable(error.message ?: "Failed to get FCM token"))
+    }
+  }
+
+  fun deleteToken(onResult: (FcmDeleteResult) -> Unit) {
+    try {
+      FirebaseMessaging.getInstance().deleteToken().addOnCompleteListener { task ->
+        onResult(
+          if (task.isSuccessful) FcmDeleteResult.Deleted
+          else FcmDeleteResult.Failed("Failed to delete FCM token: ${task.exception?.message}")
+        )
+      }
+    } catch (_: Exception) {
+      onResult(FcmDeleteResult.NotConfigured)
+    }
+  }
+}

android/src/main/AndroidManifest.xml

@@ -22,15 +22,6 @@
             </intent-filter>
         </receiver>
 
-        <!-- Firebase Cloud Messaging Service for handling push notifications -->
-        <service
-            android:name="app.tauri.notification.TauriFirebaseMessagingService"
-            android:exported="false">
-            <intent-filter>
-                <action android:name="com.google.firebase.MESSAGING_EVENT" />
-            </intent-filter>
-        </service>
-
         <!-- UnifiedPush connector push service. The connector library's
              internal MessagingReceiverImpl receives distributor broadcasts
              and forwards them to this service, so no BroadcastReceiver is

android/src/main/java/app/tauri/notification/FcmResult.kt

@@ -0,0 +1,19 @@
+package app.tauri.notification
+
+sealed class FcmTokenResult {
+  data class Success(val token: String) : FcmTokenResult()
+
+  /** The request ran and failed. Unlike [Unavailable], this triggers `push-error`. */
+  data class Failed(val message: String) : FcmTokenResult()
+
+  /** Firebase is absent or threw before the request ran. */
+  data class Unavailable(val message: String) : FcmTokenResult()
+}
+
+sealed class FcmDeleteResult {
+  object Deleted : FcmDeleteResult()
+  data class Failed(val message: String) : FcmDeleteResult()
+
+  /** No default FirebaseApp, so there was nothing to delete. */
+  object NotConfigured : FcmDeleteResult()
+}

android/src/main/java/app/tauri/notification/NotificationPlugin.kt

@@ -24,8 +24,6 @@ import app.tauri.plugin.Invoke
 import app.tauri.plugin.JSArray
 import app.tauri.plugin.JSObject
 import app.tauri.plugin.Plugin
-import com.google.firebase.FirebaseApp
-import com.google.firebase.messaging.FirebaseMessaging
 import org.unifiedpush.android.connector.UnifiedPush
 import java.util.ArrayDeque
 
@@ -634,12 +632,7 @@ class NotificationPlugin(private val activity: Activity): Plugin(activity) {
     getFirebaseToken(registration)
   }
 
-  private fun fcmConfigured(): Boolean =
-    try {
-      FirebaseApp.getApps(activity).isNotEmpty()
-    } catch (_: Exception) {
-      false
-    }
+  private fun fcmConfigured(): Boolean = FcmBridge.isConfigured(activity)
 
   /** Returns false when no gateway is configured, leaving the caller to report why. */
   private fun startEmbeddedPushRegistration(registration: PushRegistration): Boolean {
@@ -734,18 +727,11 @@ class NotificationPlugin(private val activity: Activity): Plugin(activity) {
       return
     }
 
-    try {
-      FirebaseMessaging.getInstance().deleteToken().addOnCompleteListener { task ->
-        if (!task.isSuccessful) {
-          invoke.reject("Failed to delete FCM token: ${task.exception?.message}")
-          return@addOnCompleteListener
-        }
-        fcmToken = null
-        if (unifiedPushState.activeProvider == "fcm") unifiedPushState.activeProvider = null
-        invoke.resolve()
+    FcmBridge.deleteToken { result ->
+      if (result is FcmDeleteResult.Failed) {
+        invoke.reject(result.message)
+        return@deleteToken
       }
-    } catch (error: Exception) {
-      // No default FirebaseApp (embedded-FCM/VAPID, no google-services.json): nothing to delete.
       fcmToken = null
       if (unifiedPushState.activeProvider == "fcm") unifiedPushState.activeProvider = null
       invoke.resolve()
@@ -923,29 +909,28 @@ class NotificationPlugin(private val activity: Activity): Plugin(activity) {
       return
     }
 
-    try {
-      FirebaseMessaging.getInstance().token.addOnCompleteListener { task ->
-        if (pendingPushRegistration !== registration || registration.phase != PushRegistrationPhase.FCM) {
-          return@addOnCompleteListener
-        }
-        if (!task.isSuccessful) {
-          val errorMessage = "Failed to get FCM token: ${task.exception?.message}"
-          val errorData = JSObject()
-          errorData.put("message", errorMessage)
-          trigger("push-error", errorData)
-          finishPushRegistrationError(errorMessage)
-          return@addOnCompleteListener
-        }
-
-        val token = task.result
-        fcmToken = token
+    FcmBridge.fetchToken { outcome ->
+      if (outcome is FcmTokenResult.Unavailable) {
+        finishPushRegistrationError(outcome.message)
+        return@fetchToken
+      }
+      if (pendingPushRegistration !== registration || registration.phase != PushRegistrationPhase.FCM) {
+        return@fetchToken
+      }
+      if (outcome is FcmTokenResult.Failed) {
+        val errorData = JSObject()
+        errorData.put("message", outcome.message)
+        trigger("push-error", errorData)
+        finishPushRegistrationError(outcome.message)
+        return@fetchToken
+      }
+      if (outcome is FcmTokenResult.Success) {
+        fcmToken = outcome.token
         unifiedPushState.activeProvider = "fcm"
         val result = JSObject()
-        result.put("deviceToken", token)
+        result.put("deviceToken", outcome.token)
         finishPushRegistrationSuccess(result)
       }
-    } catch (error: Exception) {
-      finishPushRegistrationError(error.message ?: "Failed to get FCM token")
     }
   }