def attest_proposed_block(cls, post_crystallized_state: CrystallizedState,
post_active_state: ActiveState,
block_proposal: 'BlockProposal',
chaindb: BaseBeaconChainDB,
private_key: int) -> 'AttestationRecord':
"""
Return the initial attestation by the block proposer.
The proposer broadcasts their attestation with the proposed block.
"""
block_committees_info = get_block_committees_info(
block_proposal.block,
post_crystallized_state,
cls.config.CYCLE_LENGTH,
)
# Vote
attester_bitfield = set_voted(
get_empty_bitfield(block_committees_info.proposer_committee_size),
block_committees_info.proposer_index_in_committee,
)
# Get justified_slot and justified_block_hash
justified_slot = post_crystallized_state.last_justified_slot
justified_block_hash = chaindb.get_canonical_block_hash_by_slot(
justified_slot)
# Get signing message and sign it
parent_hashes = get_hashes_to_sign(
post_active_state.recent_block_hashes,
block_proposal.block,
cls.config.CYCLE_LENGTH,
)
message = create_signing_message(
block_proposal.block.slot_number,
parent_hashes,
block_proposal.shard_id,
block_proposal.shard_block_hash,
justified_slot,
)
sig = bls.sign(
message,
private_key,
)
return cls.get_attestation_record_class()(
slot=block_proposal.block.slot_number,
shard_id=block_proposal.shard_id,
oblique_parent_hashes=(),
shard_block_hash=block_proposal.shard_block_hash,
attester_bitfield=attester_bitfield,
justified_slot=justified_slot,
justified_block_hash=justified_block_hash,
aggregate_sig=sig,
)
def test_get_hashes_to_sign(genesis_block, beacon_config):
cycle_length = beacon_config.cycle_length
current_block_slot_number = 1
blocks, recent_block_hashes = generate_mock_recent_block_hashes(
genesis_block,
current_block_slot_number,
cycle_length,
)
block = blocks[current_block_slot_number]
result = get_hashes_to_sign(
recent_block_hashes,
block,
cycle_length,
)
assert len(result) == cycle_length
assert result[-1] == blake(block.hash)