writeObject throws IllegalArgumentException with oneof label ------------------------------------------------------------ Key: IPROTO-63 URL: https://issues.jboss.org/browse/IPROTO-63 Project: Infinispan ProtoStream Issue Type: Bug Reporter: Ryan Emerson Assignee: Nistor Adrian Priority: Major Fix For: 4.3.0.Alpha14, 4.3.1.Final The below schema results in the following exception: Schema: {code:java} message EntryVersion { oneof version { NumericVersion numeric = 1; ClusteredVersion clustered = 2; } // optional NumericVersion numeric = 1; // optional ClusteredVersion clustered = 2; } message NumericVersion { required int64 version = 1; } message ClusteredVersion { required int64 version = 1; required int32 topology = 2; } {code} Exception: {code:java} java.lang.IllegalArgumentException: Declared field type is not a message or an enum : numeric {code} It seems this is caused because the type for the field "numeric" is null in the associated FieldDescriptor object that is retrieved in the [writeObject impl|https://github.com/infinispan/protostream/blob/master/core/src/main/...]. If the oneof label is replaced with the commented optional fields, the marshallers work as expected.