`CoinbaseOutputConstraints` should always trigger `NewTemplate`+`SetNewPrevHash`

[plebhash]

similar to this bitcoin_core_sv2 design flaw: stratum-mining/sv2-apps#466 (comment)

after sv2-tp receives a CoinbaseOutputConstraints, it should return a NewTemplate+SetNewPrevHash

currently, this only happens on the initial bootstrap CoinbaseOutputConstraints, but not on subsequent ones

that causes issues on JDC fallback, because it sends a new CoinbaseOutputConstraints to sv2-tp but remains stuck waiting for the initial NewTemplate+SetNewPrevHash for a really long time, until they arrive "naturally"

[Shourya742]

I think it does. Based on that, we designed the JDC. I’m not sure if the behavior has changed recently, but as far as I know, it was sending the template and prevhash.

[Sjors]

Would be good to add a test for this. I wouldn't be surprised if we only send NewTemplate + SetNewPrevHash after the first CoinbaseOutputConstraints message. It makes sense to do it again when those constraints change.

[plebhash]

I think it does. Based on that, we designed the JDC. I’m not sure if the behavior has changed recently, but as far as I know, it was sending the template and prevhash.

maybe you misunderstood what the issue is reporting?

I'm not claiming sv2-tp never sends NewTemplate+SetNewPrevHash after CoinbaseOutputConstraints.

I'm reporting that it only does it after the first CoinbaseOutputConstraints, and but it does not on subsequent instances of this message. It's the same thing we're fixing on bitcoin_core_sv2 via stratum-mining/sv2-apps#467

[enirox001]

Opened #106 to address this