Drop the include_dummy_extranonce branch from the OP_0 padding
condition in CreateNewBlock(), so that the dummy extraNonce is
only appended when consensus actually requires it (heights <= 16,
where the BIP34 height push alone would yield a 1-byte scriptSig
and trigger bad-cb-length).
The include_dummy_extranonce option struct field is now unused by
the miner and is removed in the next commit. Callers still set it,
so that this commit compiles.
Regenerate the hardcoded coinbase / block hashes throughout the
unit and functional test suites and update the regtest assumeutxo
snapshot in chainparams.
Additional side-effects:
- Without the dummy extranonce, coinbase scriptSigs are 1 byte
shorter at heights > 16, making every block 1 byte smaller.
This shifts where block files wrap and therefore where pruning
boundaries land.
- feature_assumeutxo malleation cases:
- case 1: error message changes due to UTXO reordering, similar
to 8f2078af6a
- case 4: the corruption byte is swapped from \x82 to \x83
because \x82 happened to be the actual value at that
offset in the new snapshot.