NullPointerException if field in schema not present in value

Given a message:

{
   "schema":{
      "type":"struct",
      "fields":[
         {
            "type":"string",
            "optional":true,
            "field":"abc"
         }
      ],
      "optional":false,
      "name":"foobar"
   },
   "payload":{
   }
}

I would expect, given the field is optional, for the JsonConverter to still process this value.

What happens is I get a null pointer exception, the stacktrace points to this line: https://github.com/apache/kafka/blob/2.1/connect/json/src/main/java/org/apache/kafka/connect/json/JsonConverter.java#L701 called by https://github.com/apache/kafka/blob/2.1/connect/json/src/main/java/org/apache/kafka/connect/json/JsonConverter.java#L181

Issue seems to be that we need to check and see if the jsonValue is null before checking if the jsonValue has a null value.