Kafka Avro Classloading Issue in Quarkustest - SerializationException

[bmgkp]

Bug description

In testing trying to consume data for 2 different Avro schemata leads to an exception.

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We are using

QuarkusCamel: 3.27.0

but got this bug also in 3.20.3

Currently we are using confluenct registry, using apicurio did not change the behavior.

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Trying to consume data for 2 different Avro schemata leads to an exception:

org.apache.kafka.common.errors.SerializationException: Could not find class RestCallTrace specified in writer's schema whilst finding reader's schema for a SpecificRecord.

The Route is built up like:

		from("direct:kafka")
				.routeId("FromDirect")
				.process(Routes::transformToRestCallTraceOne)
				.to(getKafkaFirst())
				.process(Routes::transformToRestCallTraceTwo)
				.to(getKafkaSecond());

using 2 Kafka Topics and a total of 2 Avro Schemata involved. One Schema is used in a topic exclusively.

Tests are failing consuming data from the second kafka topic.

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Seems that the

org.apache.avro.specific.SpecificData#classCache

in

org.apache.avro.specific.SpecificData#getClass

is filled using the wrong classloader while writing the data.

In following consuming cached entry is faulty and the consuming fails.

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A reproducer is attached.

avro-reproducer.zip

[jamesnetherton]

If you force a flat test classpath, it'll work:

quarkus.test.flat-class-path=true

Might be better to create this issue over in the Quarkus project. I don't think there's anything specific about Camel Kafka that would cause these issues.