refactor: read firebase-messaging version from native module at prebuild time

Instead of hardcoding the firebase-messaging version, read it from the
native module's android/build.gradle so the app dependency stays in
sync automatically when the SDK is updated.

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

Author: Rosie-Kennelly-1

__tests__/withAndroidPushNotifications.test.ts

@@ -42,7 +42,14 @@ describe('withAndroidPushNotifications', () => {
   let writeFileSyncSpy: jest.SpyInstance;
   let readFileSyncSpy: jest.SpyInstance;
 
-  const fakeBuildGradle = `
+  const fakeNativeBuildGradle = `
+dependencies {
+    implementation "com.google.firebase:firebase-messaging:24.1.2"
+    implementation 'io.intercom.android:intercom-sdk:17.4.5'
+}
+`;
+
+  const fakeAppBuildGradle = `
 android {
     compileSdkVersion 34
 }
@@ -59,7 +66,13 @@ dependencies {
       .mockReturnValue(undefined);
     readFileSyncSpy = jest
       .spyOn(fs, 'readFileSync')
-      .mockReturnValue(fakeBuildGradle);
+      .mockImplementation((filePath: any) => {
+        const p = String(filePath);
+        if (p.includes(path.join('app', 'build.gradle'))) {
+          return fakeAppBuildGradle;
+        }
+        return fakeNativeBuildGradle;
+      });
   });
 
   afterEach(() => {
@@ -154,21 +167,25 @@ dependencies {
   });
 
   describe('Gradle dependency', () => {
-    test('adds firebase-messaging when not present', () => {
+    test('adds firebase-messaging with version from native module', () => {
       const config = createMockConfig('com.example.myapp');
       withAndroidPushNotifications(config as any, {} as any);
 
       const gradleWriteCall = writeFileSyncSpy.mock.calls.find((call: any[]) =>
         (call[0] as string).includes('build.gradle')
       );
       expect(gradleWriteCall).toBeDefined();
-      expect(gradleWriteCall[1]).toContain('firebase-messaging');
+      expect(gradleWriteCall[1]).toContain('firebase-messaging:24.1.2');
     });
 
     test('skips adding firebase-messaging when already present', () => {
-      readFileSyncSpy.mockReturnValue(
-        'dependencies {\n    implementation("com.google.firebase:firebase-messaging:23.0.0")\n}'
-      );
+      readFileSyncSpy.mockImplementation((filePath: any) => {
+        const p = String(filePath);
+        if (p.includes(path.join('app', 'build.gradle'))) {
+          return 'dependencies {\n    implementation("com.google.firebase:firebase-messaging:23.0.0")\n}';
+        }
+        return fakeNativeBuildGradle;
+      });
       const config = createMockConfig('com.example.myapp');
       withAndroidPushNotifications(config as any, {} as any);
 

src/expo-plugins/withAndroidPushNotifications.ts

@@ -77,7 +77,19 @@ const writeFirebaseService: ConfigPlugin<IntercomPluginProps> = (_config) =>
       // The native module declares firebase-messaging as an `implementation`
       // dependency, which keeps it private to the library. Since our generated
       // service lives in the app module, we need firebase-messaging on the
-      // app's compile classpath too.
+      // app's compile classpath too. We read the version from the native
+      // module's build.gradle so it stays in sync automatically.
+      const nativeBuildGradle = fs.readFileSync(
+        path.join(__dirname, '..', '..', 'android', 'build.gradle'),
+        'utf-8'
+      );
+      const versionMatch = nativeBuildGradle.match(
+        /com\.google\.firebase:firebase-messaging:([\d.]+)/
+      );
+      const firebaseMessagingVersion = versionMatch
+        ? versionMatch[1]
+        : '24.1.2';
+
       const buildGradlePath = path.join(
         projectRoot,
         'android',
@@ -88,7 +100,7 @@ const writeFirebaseService: ConfigPlugin<IntercomPluginProps> = (_config) =>
       if (!buildGradle.includes('firebase-messaging')) {
         const updatedBuildGradle = buildGradle.replace(
           /dependencies\s*\{/,
-          `dependencies {\n    implementation("com.google.firebase:firebase-messaging:24.1.2")`
+          `dependencies {\n    implementation("com.google.firebase:firebase-messaging:${firebaseMessagingVersion}")`
         );
         fs.writeFileSync(buildGradlePath, updatedBuildGradle, 'utf-8');
       }