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(state: BeaconState,
config: BeaconConfig) -> BeaconState:
# Compute previous epoch active validator indices and the total balance they account for
# for later use.
previous_epoch_active_validator_indices = set(
get_active_validator_indices(
state.validator_registry,
state.previous_epoch(config.SLOTS_PER_EPOCH,
config.GENESIS_EPOCH)))
previous_total_balance: Gwei = get_total_balance(
state.validator_balances,
tuple(previous_epoch_active_validator_indices),
config.MAX_DEPOSIT_AMOUNT,
)
# Compute previous epoch attester indices and the total balance they account for
# for later use.
previous_epoch_attestations = get_previous_epoch_attestations(
state,
config.SLOTS_PER_EPOCH,
config.GENESIS_EPOCH,
)
previous_epoch_attester_indices = get_attester_indices_from_attesttion(
state=state,
attestations=previous_epoch_attestations,
committee_config=CommitteeConfig(config),
)
# Compute inclusion slot/distance of previous attestations for later use.
inclusion_infos = get_inclusion_infos(
state=state,
attestations=previous_epoch_attestations,
committee_config=CommitteeConfig(config),
)
# Compute effective balance of each previous epoch active validator for later use
effective_balances = {
index: get_effective_balance(
state.validator_balances,
index,
config.MAX_DEPOSIT_AMOUNT,
)
for index in previous_epoch_active_validator_indices
}
# Compute base reward of each previous epoch active validator for later use
_base_reward_quotient = (integer_squareroot(previous_total_balance) //
config.BASE_REWARD_QUOTIENT)
base_rewards = {
index: get_base_reward(
state=state,
index=index,
base_reward_quotient=_base_reward_quotient,
max_deposit_amount=config.MAX_DEPOSIT_AMOUNT,
)
for index in previous_epoch_active_validator_indices
}
# Initialize the reward (validator) received map
rewards_received = {
index: SignedGwei(0)
for index in previous_epoch_active_validator_indices
}
# 1. Process rewards and penalties for justification and finalization
rewards_received = pipe(
rewards_received,
_process_rewards_and_penalties_for_finality(
state,
config,
previous_epoch_active_validator_indices,
previous_total_balance,
previous_epoch_attestations,
previous_epoch_attester_indices,
inclusion_infos,
effective_balances,
base_rewards,
),
_process_rewards_and_penalties_for_attestation_inclusion(
state,
config,
previous_epoch_attester_indices,
inclusion_infos,
base_rewards,
),
_process_rewards_and_penalties_for_crosslinks(
state,
config,
previous_epoch_attestations,
effective_balances,
base_rewards,
))
# Apply the overall rewards/penalties
for index in previous_epoch_active_validator_indices:
state = state.update_validator_balance(
index,
# Prevent validator balance under flow
max(state.validator_balances[index] + rewards_received[index], 0),
)
return state