feat: skip service registration when existing FCM service detected

If a developer already has a FirebaseMessagingService registered (from
manual setup or another SDK), adding a second one would cause
unpredictable FCM routing. The plugin now detects this and skips
registration with a warning explaining how to route Intercom pushes
manually.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Rosie-Kennelly-1

__tests__/withAndroidPushNotifications.test.ts

@@ -199,6 +199,40 @@ describe('withAndroidPushNotifications', () => {
       const services = config.modResults.manifest.application[0].service;
       expect(services).toHaveLength(1);
     });
+
+    test('skips registration and warns when another FCM service exists', () => {
+      const config = createMockConfig('com.example.myapp');
+      const warnSpy = jest.spyOn(console, 'warn').mockImplementation();
+
+      config.modResults.manifest.application[0].service.push({
+        $: {
+          'android:name': '.ExistingFcmService',
+          'android:exported': 'true',
+        },
+        'intent-filter': [
+          {
+            action: [
+              {
+                $: {
+                  'android:name': 'com.google.firebase.MESSAGING_EVENT',
+                },
+              },
+            ],
+          },
+        ],
+      } as any);
+
+      withAndroidPushNotifications(config as any, {} as any);
+
+      const services = config.modResults.manifest.application[0].service;
+      expect(services).toHaveLength(1);
+      expect(services[0].$['android:name']).toBe('.ExistingFcmService');
+      expect(warnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('existing FirebaseMessagingService')
+      );
+
+      warnSpy.mockRestore();
+    });
   });
 
   describe('error handling', () => {

src/expo-plugins/withAndroidPushNotifications.ts

@@ -102,6 +102,26 @@ const registerServiceInManifest: ConfigPlugin<IntercomPluginProps> = (
       (s) => s.$?.['android:name'] === serviceName
     );
 
+    const hasExistingFcmService = mainApplication.service?.some(
+      (s) =>
+        s.$?.['android:name'] !== serviceName &&
+        s['intent-filter']?.some((f: any) =>
+          f.action?.some(
+            (a: any) =>
+              a.$?.['android:name'] === 'com.google.firebase.MESSAGING_EVENT'
+          )
+        )
+    );
+
+    if (hasExistingFcmService) {
+      console.warn(
+        '@intercom/intercom-react-native: An existing FirebaseMessagingService was found in AndroidManifest.xml. ' +
+          'Skipping automatic Intercom service registration to avoid conflicts. ' +
+          'You will need to route Intercom pushes manually using IntercomModule.isIntercomPush() and IntercomModule.handleRemotePushMessage().'
+      );
+      return config;
+    }
+
     if (!existingService) {
       if (!mainApplication.service) {
         mainApplication.service = [];