There are no Typecheck errors shown in StreamBase Studio for this application which uses the Protobuf output adapter. At runtime we see this error repeatedly:

 error	description=Adapter Exception: Protobuf String field cannot be set null, originalTuple={"id":100,"phones":[], "address":{"zip":"","street":""}}, operatorName=default.Tuple2ProtobufWithDesc, inputPort=0,  nodeName=sample_adapter_embedded_protobuf_protobuf.test, type=adapter-error, action=continue, time=2020-06-01 13:31:58.141-0400

 

The Protobuf specification does not accept TIBCO Streaming EventFlow 'null' values since it does not have an equivalent representation. The tuple sent into the Protobuf Output adapter must not have any fields (of any type) set to 'null'.

Specifically, the error "Protobuf String field cannot be set null" happens when the input to the Protobuf Output adapter has any string field that was missing, unset, or set explicitly to 'null'. This field will not be shown in the error message "originalTuple" field because this is a JSON string, and JSON also does not have a representation for 'null'.

If the input can contain missing/null values for some tuple fields, check the fields upstream with a Map operator and replace the null with an empty string or non-null flag value. In a Map expression this looks like (for string):   Replace, fieldA, if isnull(fieldA) then "" else fieldA

Example:

Protobuf does not support null values, so tuples with null fields are not allowed