NATS source's consumer.ack_policy defaults to "None" - JS redelivering every message

[almostintuitive]

Describe the bug

It looks like from the documentation that NATS source's consumer.ack_policy property is optional but it defaults to None, which essentially breaks Jetstream durable consumers - the messages are redelivered on every occasion, essentially grinding Risingwave to a halt with duplicate messages.

Error message/log

To Reproduce

No response

Expected behavior

No response

How did you deploy RisingWave?

No response

The version of RisingWave

No response

Additional context

No response

[tabVersion]

Hi @almostintuitive

Thanks for the bug report.

consumer.ack_policy is optional in RisingWave, and RisingWave’s checkpoint ACK task selection treats an omitted value as AckPolicy::None. However, the actual async-nats pull consumer default is AckPolicy::Explicit. This mismatch means JetStream expects ACKs while RisingWave does not send them, causing redelivery after AckWait.

We will fix it.