Kaspad providing invalid templates to miner

[michaelsutton]

A user on discord reported that at some point, all blocks mined by his miner got the following messages:

[2021-12-15T22:05:51Z INFO  kaspa_miner::miner] Found a block: ddd33dbcac02779d7911d1031db6f39bf9d24e53723438e8b97060366b219385
[2021-12-15T22:05:51Z WARN  kaspa_miner::client] Failed submitting block: RpcError { message: "Block rejected. Reason: block is violating bounded merge depth: ErrViolatingBoundedMergeDepth" }

This indicates that the template builder within kaspad is providing a template which kaspad itself rejects during validation, due to finality violation.

Seems like the virtual block is probably in invalid state due to a bug.

[michaelsutton]

(this is a rare event, and must be related to the fact that in recent days there appears to be a miner mining more than a day back)

[someone235]

It seems there's a bug in the virtual parent selection algorithm that makes the block builder generate an invalid template