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David Jacot commented on KAFKA-15869: ------------------------------------- [~antonagestam-aiven] No, it is not a mistake. We had a KIP for this: [https://cwiki.apache.org/confluence/display/KAFKA/KIP-893%3A+The+Kafka+protocol+should+support+nullable+structs.] However, I agree that we should update the protocol guide. We can use this Jira for this purpose. > Document semantics of nullable nested API entities > -------------------------------------------------- > > Key: KAFKA-15869 > URL: https://issues.apache.org/jira/browse/KAFKA-15869 > Project: Kafka > Issue Type: Wish > Reporter: Anton Agestam > Priority: Minor > > The initial version of ConsumerGroupHeartbeatResponse [introduced the first > field across the protocol that is a nullable nested > entity|https://github.com/dajac/kafka/blob/3acd87a3e82e1d2fd4c07218d362e7665b99c547/clients/src/main/resources/common/message/ConsumerGroupHeartbeatResponse.json#L48]. > As the implementor of a third-party schema parser it is not clear how to > handle this field, where such fields are allowed, and how null is represented > for such fields. > As far as I can tell, the [protocol > guide|https://kafka.apache.org/protocol.html#The_Messages_ConsumerGroupHeartbeat] > does not mention the nullability at all. > The reason I ask where such fields are allowed is because if the answer to > how null is represented here is just omitting writing any bytes, then I > suspect the only unambiguous place for such field to appear would be as the > last field of a top-level entity. Even then, how is it discriminated from > tagged fields? > Is it possible this field was made nullable by mistake? > -- This message was sent by Atlassian Jira (v8.20.10#820010)