Bug in AvroConverter:Unable to convert data with null values.

[Sumanth B]

AvroConverter is throwing error when trying to convert avro data with null values for the fields whose schema is ["null","string"].It works fine for null data if the schema is  ["null","int"].To elaborate more 

I have the following avro schema:

{
    "namespace": "xxx",
    "type": "record",
    "name": "yyy",
    "fields": [
      {"name": "key","type": ["null", "int"]},
      {"name": "from_state","type": ["null", "string"]},
      {"name": "to_state","type": ["null", "string"]}
    ]
  }

Avro Converter is working fine for the following messages in kafka

{
      "key":190057,
      "from_state":"dsds" ,
      "to_state":"dfd"
}

{
      "key":null,
      "from_state":"dsds" ,
      "to_state":"dfd"
}

But it is failing for 
{
      "key":190057,
      "from_state":null ,
      "to_state":"dfd"
}

Following is the error :ERROR Thread WorkerSinkTask-local-file-sink-0 exiting with uncaught exception:  (org.apache.kafka.connect.util.ShutdownableThread:84)
java.lang.NullPointerException
	at io.confluent.connect.avro.AvroData.toConnectData(AvroData.java:863)
	at io.confluent.connect.avro.AvroData.toConnectData(AvroData.java:946)
	at io.confluent.connect.avro.AvroData.toConnectData(AvroData.java:751)
	at io.confluent.connect.avro.AvroConverter.toConnectData(AvroConverter.java:103)
	at org.apache.kafka.connect.runtime.WorkerSinkTask.convertMessages(WorkerSinkTask.java:273)
	at org.apache.kafka.connect.runtime.WorkerSinkTask.poll(WorkerSinkTask.java:175)
	at org.apache.kafka.connect.runtime.WorkerSinkTaskThread.iteration(WorkerSinkTaskThread.java:90)
	at org.apache.kafka.connect.runtime.WorkerSinkTaskThread.execute(WorkerSinkTaskThread.java:58)
	at org.apache.kafka.connect.util.ShutdownableThread.run(ShutdownableThread.java:82)


I got this error when I'm trying to use connect-file-sink to consume data from kafka.

[Steven Deutscher-Kobayashi]

Hey Sumanth,

This bug should be fixed in 3.x (https://github.com/confluentinc/schema-registry/pull/280)

There is also a backport for 2.x (https://github.com/confluentinc/schema-registry/pull/326)

Cheers,

Steven