Kafka: What happens to message with null key when log compaction is enabled?

In current version what happens is this:

"Currently when a user sends a null key to a log compacted topic, the broker returns CorruptRecordException, which is a retriable exception. As such, the producer keeps retrying until retries are exhausted or request.timeout.ms expires and eventually throws a TimeoutException."

As reported in Jira KIP-135 this is a bit confusing.

In the future if the cleaner solution from KIP-135 (still under discussion as @Ran Lupvoich pointed out) get accepted another behavior should be the following:

When you try to produce null key to log compacted topic, Kafka should return a new error type INVALID_KEY