Android: protobuf-java conflicts with Firebase (protobuf-javalite) causing DuplicateClass and VerifyError

Description

When using mobile-payments-sdk-react-native alongside Firebase (Firestore/Auth/Crashlytics) on Android, the build fails with DuplicateClass errors and/or the app crashes at runtime with VerifyError.

The root cause is a dependency conflict between the two SDKs:

• Square Mobile Payments SDK (all versions 2.3.0–2.5.0) depends on com.google.protobuf:protobuf-java (full runtime)
• Firebase Android SDKs depend on com.google.protobuf:protobuf-javalite (lite runtime)

These two protobuf variants have incompatible class hierarchies. For example, com.google.protobuf.Timestamp extends GeneratedMessage in protobuf-java but extends GeneratedMessageLite in protobuf-javalite. Firebase's compiled bytecode contains casts like (GeneratedMessageLite) Timestamp, which fail at runtime with VerifyError when protobuf-java is on the classpath.

There is no Gradle exclusion workaround that resolves this:

• Excluding protobuf-java fixes the dex DuplicateClass build error, but Square SDK may fail if it relies on full-protobuf APIs at runtime.
• Excluding protobuf-javalite causes a new DuplicateClass (from protolite-well-known-types) and then VerifyError at runtime because Firebase's bytecode was compiled against GeneratedMessageLite, not GeneratedMessage.

Steps to reproduce

1. Create a React Native project using mobile-payments-sdk-react-native
2. Add Firebase to Android: @react-native-firebase/app, @react-native-firebase/firestore, @react-native-firebase/auth, @react-native-firebase/crashlytics
3. Run ./gradlew assembleDebug

Expected behavior

Build succeeds and app runs without crash. Both Square SDK and Firebase coexist on Android.

Actual behavior

Build-time error (DuplicateClass):

DuplicateClass com.google.protobuf.AbstractMessageLite found in modules
  protobuf-java-3.25.3.jar (com.google.protobuf:protobuf-java:3.25.3)
  protobuf-javalite-3.25.1.jar (com.google.protobuf:protobuf-javalite:3.25.1)

Runtime error if protobuf-java is excluded (VerifyError):

java.lang.VerifyError: Verifier rejected class com.google.firebase.firestore.proto.WriteResponse
  because: com.google.protobuf.Timestamp is not instance of
  com.google.protobuf.GeneratedMessageLite (declaration of
  'com.google.firestore.v1.WriteResponse' appears in
  /data/app/.../base.apk)

Environment

• mobile-payments-sdk-react-native: 2025.12.1 (native SDK 2.3.1–2.5.0, all affected)
• @react-native-firebase/app: 21.x
• React Native: 0.79.x
• Android: minSdk 28, compileSdk 35

Workaround

Exclude the Square SDK from Android autolinking (react-native.config.js) and provide a no-op JS stub for Android via platform-specific files (.android.ts). This means Square card payments are unavailable on Android.

Request

Please consider migrating the native Android SDK's protobuf dependency from protobuf-java to protobuf-javalite. Firebase and most modern Android libraries use javalite, and it is Google's recommended protobuf variant for Android. This would allow Square SDK and Firebase to coexist without conflicts.