Question: assumptions around ProduceResponse → ProducerBatch matching

[shan305]

While reading through Sender.handleProduceResponse, I wanted to double-check my understanding of how produce responses are matched back to ProducerBatch instances.

From what I can tell, the matching logic prefers topicId when present (v13+), and otherwise falls back to topic name + partition, using a topic-name snapshot captured before the request is sent.

This makes sense, but I wanted to confirm the intended guarantees here, especially since metadata can change while a produce request is in flight (for example: topic recreation or leadership changes).

In particular, I’m trying to understand:

• Whether we rely on the pre-send topic snapshot to always resolve a non-zero topicId in the response
• Whether a batch == null case is considered impossible by design, or treated as a deliberate hard failure

No behavior change proposed yet — opening this mainly to confirm assumptions before going any deeper.

[shan305]

Keeping this as a draft for now since this is primarily a design / behavior question.
Happy to follow up with a concrete change (or tests) once assumptions are confirmed.