Updated firebase dependency and got duplicated protobuf classes error

Question

I'm getting this error after updating one of my firebase SDKs

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:checkDebugDuplicateClasses'.
> 1 exception was raised by workers:
  java.lang.RuntimeException: Duplicate class com.google.protobuf.AbstractMessageLite found in modules jetified-protobuf-javalite-3.11.0.jar (com.google.protobuf:protobuf-javalite:3.11.0) and jetified-protobuf-lite-3.0.1.jar (com.google.protobuf:protobuf-lite:3.0.1)
  Duplicate class com.google.protobuf.AbstractMessageLite$Builder found in modules jetified-protobuf-javalite-3.11.0.jar (com.google.protobuf:protobuf-javalite:3.11.0) and jetified-protobuf-lite-3.0.1.jar (com.google.protobuf:protobuf-lite:3.0.1)
  Duplicate class com.google.protobuf.AbstractMessageLite$Builder$LimitedInputStream found in modules jetified-protobuf-javalite-3.11.0.jar (com.google.protobuf:protobuf-javalite:3.11.0) and jetified-protobuf-lite-3.0.1.jar (com.google.protobuf:protobuf-lite:3.0.1)
  Duplicate class com.google.protobuf.AbstractParser found in modules jetified-protobuf-javalite-3.11.0.jar (com.google.protobuf:protobuf-javalite:3.11.0) and jetified-protobuf-lite-3.0.1.jar (com.google.protobuf:protobuf-lite:3.0.1)
  Duplicate class com.google.protobuf.AbstractProtobufList found in modules jetified-protobuf-javalite-3.11.0.jar (com.google.protobuf:protobuf-javalite:3.11.0) and jetified-protobuf-lite-3.0.1.jar (com.google.protobuf:protobuf-lite:3.0.1)
  Duplicate class com.google.protobuf.BooleanArrayList found in modules jetified-protobuf-javalite-3.11.0.jar (com.google.protobuf:protobuf-javalite:3.11.0) and jetified-protobuf-lite-3.0.1.jar (com.google.protobuf:protobuf-lite:3.0.1)
  Duplicate class com.google.protobuf.ByteBufferWriter found in modules jetified-protobuf-javalite-3.11.0.jar (com.google.protobuf:protobuf-javalite:3.11.0) and jetified-protobuf-lite-3.0.1.jar (com.google.protobuf:protobuf-lite:3.0.1)
...

My app now depends on protobuf-lite and protobuf-javalite, which triggers the duplicate class error.

Answer 1

Recently, Firebase Android has migrated from depending on the old protobuf-lite to depend on protobuf-javalite (github issue | PR implementing the change).

You need to update all the firebase SDKs affected by this change together, otherwise the old SDKs will pull the wrong dependency into your app.

Here is the list of affected SDKs and their versions supporting protobuf-javalite

- com.google.firebase:firebase-firestore:21.5.0
- com.google.firebase:firebase-inappmessaging:19.1.0
- com.google.firebase:firebase-inappmessaging-display:19.1.0
- com.google.firebase:firebase-config:19.2.0
- com.google.firebase:firebase-abt:19.1.0
- com.google.firebase:firebase-perf:19.0.8

EDIT: Added firebase-perf to the list, as it transitively depends on config and also needs to be updated.

Answer 2

In my case the problem was androidx.security:security-crypto:1.0.0-alpha02 library that depends on protobuf-lite which conflicts with protobuf-java-lite being used by Firebase. Updating this library helped.

You can check if other libraries depend on conflicting protobuf-lite by calling ./gradlew app:dependencies in Terminal. Then cmd+f and search for proto.