Memory Leak when using toHotStream

[T1m1]

Context

In our Quarkus application, we utilize the Multi.toHotStream() method on a Kafka topic that continuously publishes a large volume of data. During our load and performance testing, we observed that an ArrayList fills up with instances of BroadcastProcessor, and the references of these instances are never released. This leads to the application crashing.

It appears to be a similar issue to #1482, but in the BroadcastProcessor class. Perhaps instances that are no longer needed need to be removed from the subscribers list once the subscription has been fully processed (via onComplete or onError).

Additional details

Quarkus version: 3.7.4
Mutiny version: 2.5.7

[jponge]

Would you have a pure-Mutiny (no Kafka) reproducer that exhibits a pipeline causing a memory leak?

[jponge]

@T1m1 I have limited options to test a fix for this, can you try a local 999-SNAPSHOT build of Mutiny based on this branch? #1536

[jponge]

@T1m1 Also the current main branch of Mutiny needs tiny fixes for Quarkus and Reactive Messaging, you may check by cherry-picking the commit on top of https://github.com/smallrye/smallrye-mutiny/tree/2.5.x

[jponge]

I assume #1536 is a good fix and will proceed with merging + backporting