Neon node mining error

[obycode]

I observed this situation on testnet:

• Miner M1 mines block B1 and submits its block commit
• Miner M2 mines block B2 and submits its block commit
• Miner M3 has not yet received block B2, so it mines block B2', containing 4 transactions, and submits its block commit
• Miner M3 receives block B2, so it mines block B3, containing 2 transactions
• Miner M3 does not RBF its previous block commit with this new block B3, because B3 has less transactions than B2'

So basically miner M3 is intentionally reorging block B2 -- risking its block getting reorged (which it does) just to get a couple more transactions included in the block. This is not the best default strategy and was likely a mistake in the code. It should only prefer the block with more transactions if they are at the same height.

It hits this case and does not resubmit a new block commit, though the change should likely be made inside get_mine_attempt.

https://github.com/stacks-network/stacks-core/blob/1c5315606ae0cd006b27617302223b164b6f362f/testnet/stacks-node/src/neon_node.rs#L2634-L2639

Note: this problem is not present after epoch 3.0.