def test_get_current_and_previous_epoch_attestations(random,
sample_state,
genesis_epoch,
epoch_length,
sample_attestation_data_params,
sample_attestation_params):
num_previous_epoch_attestation, num_current_epoch_attestation = random.sample(
range(epoch_length),
2,
)
previous_epoch_attestion_slots = random.sample(
range(epoch_length),
num_previous_epoch_attestation,
)
current_epoch_attestion_slots = random.sample(
range(epoch_length, epoch_length * 2),
num_current_epoch_attestation,
)
previous_epoch_attestations = []
for slot in previous_epoch_attestion_slots:
previous_epoch_attestations.append(
Attestation(**sample_attestation_params).copy(
data=AttestationData(**sample_attestation_data_params).copy(
slot=slot,
),
)
)
current_epoch_attestations = []
for slot in current_epoch_attestion_slots:
current_epoch_attestations.append(
Attestation(**sample_attestation_params).copy(
data=AttestationData(**sample_attestation_data_params).copy(
slot=slot,
),
)
)
state = sample_state.copy(
slot=(epoch_length * 2 - 1),
latest_attestations=(previous_epoch_attestations + current_epoch_attestations),
)
assert set(previous_epoch_attestations) == set(
get_previous_epoch_attestations(state, epoch_length, genesis_epoch))
assert set(current_epoch_attestations) == set(
get_current_epoch_attestations(state, epoch_length))
def process_crosslinks(state: BeaconState, config: BeaconConfig) -> BeaconState:
"""
Implement 'per-epoch-processing.crosslinks' portion of Phase 0 spec:
https://github.com/ethereum/eth2.0-specs/blob/master/specs/core/0_beacon-chain.md#crosslinks
For each shard from the past two epochs, find the shard block
root that has been attested to by the most stake.
If enough(>= 2/3 total stake) attesting stake, update the crosslink record of that shard.
Return resulting ``state``
"""
latest_crosslinks = state.latest_crosslinks
previous_epoch_attestations = get_previous_epoch_attestations(
state,
config.EPOCH_LENGTH,
config.GENESIS_EPOCH,
)
current_epoch_attestations = get_current_epoch_attestations(state, config.EPOCH_LENGTH)
prev_epoch_start_slot = get_epoch_start_slot(
state.previous_epoch(config.EPOCH_LENGTH, config.GENESIS_EPOCH),
config.EPOCH_LENGTH,
)
next_epoch_start_slot = get_epoch_start_slot(
state.next_epoch(config.EPOCH_LENGTH),
config.EPOCH_LENGTH,
)
for slot in range(prev_epoch_start_slot, next_epoch_start_slot):
crosslink_committees_at_slot = get_crosslink_committees_at_slot(
state,
slot,
CommitteeConfig(config),
)
for crosslink_committee, shard in crosslink_committees_at_slot:
try:
winning_root, total_attesting_balance = get_winning_root(
state=state,
shard=shard,
# Use `_filter_attestations_by_shard` to filter out attestations
# not attesting to this shard so we don't need to going over
# irrelevent attestations over and over again.
attestations=_filter_attestations_by_shard(
previous_epoch_attestations + current_epoch_attestations,
shard,
),
max_deposit_amount=config.MAX_DEPOSIT_AMOUNT,
committee_config=CommitteeConfig(config),
)
except NoWinningRootError:
# No winning shard block root found for this shard.
pass
else:
total_balance = sum(
get_effective_balance(state.validator_balances, i, config.MAX_DEPOSIT_AMOUNT)
for i in crosslink_committee
)
if 3 * total_attesting_balance >= 2 * total_balance:
latest_crosslinks = update_tuple_item(
latest_crosslinks,
shard,
CrosslinkRecord(
epoch=state.current_epoch(config.EPOCH_LENGTH),
shard_block_root=winning_root,
),
)
else:
# Don't update the crosslink of this shard
pass
state = state.copy(
latest_crosslinks=latest_crosslinks,
)
return state
def _process_rewards_and_penalties_for_crosslinks(
state: BeaconState, config: BeaconConfig,
previous_epoch_attestations: Iterable[PendingAttestationRecord],
effective_balances: Dict[ValidatorIndex,
Gwei], base_rewards: Dict[ValidatorIndex, Gwei],
old_rewards_received: Dict[ValidatorIndex, SignedGwei]
) -> Dict[ValidatorIndex, SignedGwei]:
rewards_received = old_rewards_received.copy()
previous_epoch_start_slot = get_epoch_start_slot(
state.previous_epoch(config.SLOTS_PER_EPOCH, config.GENESIS_EPOCH),
config.SLOTS_PER_EPOCH,
)
current_epoch_start_slot = get_epoch_start_slot(
state.current_epoch(config.SLOTS_PER_EPOCH),
config.SLOTS_PER_EPOCH,
)
# Also need current epoch attestations to compute the winning root.
current_epoch_attestations = get_current_epoch_attestations(
state, config.SLOTS_PER_EPOCH)
for slot in range(previous_epoch_start_slot, current_epoch_start_slot):
crosslink_committees_at_slot = get_crosslink_committees_at_slot(
state,
slot,
CommitteeConfig(config),
)
for crosslink_committee, shard in crosslink_committees_at_slot:
filtered_attestations = _filter_attestations_by_shard(
previous_epoch_attestations + current_epoch_attestations,
shard,
)
try:
winning_root, total_attesting_balance = get_winning_root(
state=state,
shard=shard,
attestations=filtered_attestations,
max_deposit_amount=config.MAX_DEPOSIT_AMOUNT,
committee_config=CommitteeConfig(config),
)
except NoWinningRootError:
# No winning shard block root found for this shard.
# Hence no one is counted as attesting validator.
attesting_validator_indices: Iterable[ValidatorIndex] = set()
else:
attesting_validator_indices = get_attester_indices_from_attesttion(
state=state,
attestations=(a for a in filtered_attestations
if a.data.shard == shard and
a.data.crosslink_data_root == winning_root),
committee_config=CommitteeConfig(config),
)
total_balance = get_total_balance_from_effective_balances(
effective_balances,
crosslink_committee,
)
for index in attesting_validator_indices:
reward = base_rewards[
index] * total_attesting_balance // total_balance
rewards_received[index] = SignedGwei(rewards_received[index] +
reward)
for index in set(crosslink_committee).difference(
attesting_validator_indices):
penalty = base_rewards[index]
rewards_received[index] = SignedGwei(rewards_received[index] -
penalty)
return rewards_received