[jira] [Created] (AVRO-1915) AvroTypeException decoding from earlier schema version

["NPE (JIRA)" <ji...@apache.org>]

NPE created AVRO-1915:
-------------------------

             Summary: AvroTypeException decoding from earlier schema version
                 Key: AVRO-1915
                 URL: https://issues.apache.org/jira/browse/AVRO-1915
             Project: Avro
          Issue Type: Bug
          Components: java
    Affects Versions: 1.7.7
            Reporter: NPE


We have two services which communicate with one another by sending JSON-encoded Avro-based messages over Kafka.  We want to update the schema for messages sent from service A to service B by adding an additional string field with a default value of "" (empty string).  We have tested by initially adding the updated schema to service B (the reader) and continuing to send messages in the older format from service A (the writer).

Simplified example of old schema (some fields omitted):
{code}
{
	"type": "record",
	"name": "Envelope",
	"fields": [{
		"name": "appId",
		"type": "string"
	}, {
		"name": "time",
		"type": "long"
	}, {
		"name": "type",
		"type": "string"
	}, {
		"name": "payload",
		"type": [{
			"type": "record",
			"name": "MessagePayload",
			"fields": [{
				"name": "context",
				"type": {
					"type": "record",
					"name": "PayloadContext",
					"fields": [{
						"name": "source",
						"type": "string"
					}, {
						"name": "requestId",
						"type": "string"
					}]
				}
			}, {
				"name": "content",
				"type": "string"
			}, {
				"name": "contentType",
				"type": "string"
			}]
		}]
	}]
}
{code}

Simplified example of new schema (some fields omitted):
{code}
{
	"type": "record",
	"name": "Envelope",
	"fields": [{
		"name": "appId",
		"type": "string"
	}, {
		"name": "time",
		"type": "long"
	}, {
		"name": "type",
		"type": "string"
	}, {
		"name": "payload",
		"type": [{
			"type": "record",
			"name": "MessagePayload",
			"fields": [{
				"name": "context",
				"type": {
					"type": "record",
					"name": "PayloadContext",
					"fields": [{
						"name": "source",
						"type": "string"
					}, {
						"name": "requestId",
						"type": "string"
					}, {
						"name": "newField",
						"type": "string",
						"default": ""
					}]
				}
			}, {
				"name": "content",
				"type": "string"
			}, {
				"name": "contentType",
				"type": "string"
			}]
		}]
	}]
}
{code}

Our understanding was that the reader, with the newer schema, should be able to parse messages sent with the older given the default value for the missing field; however, we are getting the following exception:
{code}
org.apache.avro.AvroTypeException: Expected string. Got END_OBJECT
{code}

Are we missing something here?



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