diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index b621f83c0..cad7507e9 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -57,6 +57,7 @@ - [Beacon chain fork choice rule](#beacon-chain-fork-choice-rule) - [Beacon chain state transition function](#beacon-chain-state-transition-function) - [Helper functions](#helper-functions) + - [`is_active_validator`](#is_active_validator) - [`get_active_validator_indices`](#get_active_validator_indices) - [`shuffle`](#shuffle) - [`split`](#split) @@ -86,6 +87,7 @@ - [Attestations](#attestations-1) - [Deposits](#deposits-1) - [Exits](#exits-1) + - [Ejections](#ejections) - [Per-epoch processing](#per-epoch-processing) - [Helpers](#helpers) - [Receipt roots](#receipt-roots) @@ -143,7 +145,7 @@ Unless otherwise indicated, code appearing in `this style` is to be interpreted | - | - | :-: | | `SHARD_COUNT` | `2**10` (= 1,024) | shards | | `TARGET_COMMITTEE_SIZE` | `2**8` (= 256) | [validators](#dfn-validator) | -| `MIN_BALANCE` | `2**4` (= 16) | ETH | +| `EJECTION_BALANCE` | `2**4` (= 16) | ETH | | `MAX_BALANCE_CHURN_QUOTIENT` | `2**5` (= 32) | - | | `GWEI_PER_ETH` | `10**9` | Gwei/ETH | | `BEACON_CHAIN_SHARD_NUMBER` | `2**64 - 1` | - | @@ -701,6 +703,15 @@ The per-slot transitions generally focus on verifying aggregate signatures and s Note: The definitions below are for specification purposes and are not necessarily optimal implementations. +#### `is_active_validator` + ```python +def is_active_validator(validator: ValidatorRecord) -> bool: + """ + Checks if ``validator`` is active. + """ + return validator.status in [ACTIVE, ACTIVE_PENDING_EXIT] +``` + #### `get_active_validator_indices` ```python @@ -708,7 +719,7 @@ def get_active_validator_indices(validators: [ValidatorRecord]) -> List[int]: """ Gets indices of active validators from ``validators``. """ - return [i for i, v in enumerate(validators) if v.status in [ACTIVE, ACTIVE_PENDING_EXIT]] + return [i for i, v in enumerate(validators) if is_active_validator(v)] ``` #### `shuffle` @@ -895,7 +906,7 @@ def get_updated_ancestor_hashes(latest_block: BeaconBlock, #### `get_attestation_participants` ```python -def get_attestation_participants(state: State, +def get_attestation_participants(state: BeaconState, attestation_data: AttestationData, participation_bitfield: bytes) -> List[int]: """ @@ -963,7 +974,7 @@ def get_domain(fork_data: ForkData, #### `verify_casper_votes` ```python -def verify_casper_votes(state: State, votes: SlashableVoteData) -> bool: +def verify_casper_votes(state: BeaconState, votes: SlashableVoteData) -> bool: if len(votes.aggregate_signature_poc_0_indices) + len(votes.aggregate_signature_poc_1_indices) > MAX_CASPER_VOTES: return False @@ -1032,8 +1043,8 @@ def on_startup(initial_validator_entries: List[Any], proof_of_possession=proof_of_possession, withdrawal_credentials=withdrawal_credentials, randao_commitment=randao_commitment, - current_slot=INITIAL_SLOT_NUMBER, status=ACTIVE, + current_slot=INITIAL_SLOT_NUMBER, ) # Setup state @@ -1166,8 +1177,7 @@ def process_deposit(state: BeaconState, proof_of_possession: bytes, withdrawal_credentials: Hash32, randao_commitment: Hash32, - status: int, - current_slot: int) -> int: + status: int) -> int: """ Process a deposit from Ethereum 1.0. Note that this function mutates ``state``. @@ -1185,7 +1195,7 @@ def process_deposit(state: BeaconState, withdrawal_credentials=withdrawal_credentials, randao_commitment=randao_commitment, status=status, - current_slot=current_slot, + current_slot=state.slot, ) return index @@ -1196,8 +1206,7 @@ def process_deposit(state: BeaconState, ```python def exit_validator(index: int, state: BeaconState, - penalize: bool, - current_slot: int) -> None: + new_status: bool) -> None: """ Exit the validator with the given ``index``. Note that this function mutates ``state``. @@ -1205,7 +1214,8 @@ def exit_validator(index: int, state.validator_registry_exit_count += 1 validator = state.validator_registry[index] - validator.latest_status_change_slot = current_slot + validator.status = new_status + validator.latest_status_change_slot = state.slot validator.exit_count = state.validator_registry_exit_count # Remove validator from persistent committees @@ -1215,16 +1225,13 @@ def exit_validator(index: int, committee.pop(i) break - if penalize: - validator.status = EXITED_WITH_PENALTY - state.latest_penalized_exit_balances[current_slot // COLLECTIVE_PENALTY_CALCULATION_PERIOD] += get_effective_balance(validator) + if new_status == EXITED_WITH_PENALTY: + state.latest_penalized_exit_balances[state.slot // COLLECTIVE_PENALTY_CALCULATION_PERIOD] += get_effective_balance(validator) - whistleblower = state.validator_registry[get_beacon_proposer_index(state, current_slot)] + whistleblower = state.validator_registry[get_beacon_proposer_index(state, state.slot)] whistleblower_reward = validator.balance // WHISTLEBLOWER_REWARD_QUOTIENT whistleblower.balance += whistleblower_reward validator.balance -= whistleblower_reward - else: - validator.status = ACTIVE_PENDING_EXIT state.validator_registry_delta_chain_tip = get_new_validator_registry_delta_chain_tip( validator_registry_delta_chain_tip=state.validator_registry_delta_chain_tip, @@ -1244,11 +1251,13 @@ Below are the processing steps that happen at every slot. * Set `state.latest_block_hashes = state.latest_block_hashes + [latest_hash]`. (The output of `get_block_hash` should not change, except that it will no longer throw for `state.slot - 1`). If there is a block from the proposer for `state.slot`, we process that incoming block: + * Let `block` be that associated incoming block. * Verify that `block.slot == state.slot` * Verify that `block.ancestor_hashes` equals `get_updated_ancestor_hashes(latest_block, latest_hash)`. If there is no block from the proposer at state.slot: + * Set `state.validator_registry[get_beacon_proposer_index(state, state.slot)].randao_skips += 1`. * Skip all other per-slot processing. Move directly to [per-epoch processing](#per-epoch-processing). @@ -1287,7 +1296,7 @@ For each `proposer_slashing` in `block.body.proposer_slashings`: * Verify that `proposer_slashing.proposal_data_1.shard == proposer_slashing.proposal_data_2.shard`. * Verify that `proposer_slashing.proposal_data_1.block_hash != proposer_slashing.proposal_data_2.block_hash`. * Verify that `proposer.status != EXITED_WITH_PENALTY`. -* Run `exit_validator(proposer_slashing.proposer_index, state, penalize=True, current_slot=state.slot)`. +* Run `exit_validator(proposer_slashing.proposer_index, state, new_status=EXITED_WITH_PENALTY)`. #### Casper slashings @@ -1302,7 +1311,7 @@ For each `casper_slashing` in `block.body.casper_slashings`: * Let `intersection = [x for x in indices(casper_slashing.votes_1) if x in indices(casper_slashing.votes_2)]`. * Verify that `len(intersection) >= 1`. * Verify that `casper_slashing.votes_1.data.justified_slot + 1 < casper_slashing.votes_2.data.justified_slot + 1 == casper_slashing.votes_2.data.slot < casper_slashing.votes_1.data.slot` or `casper_slashing.votes_1.data.slot == casper_slashing.votes_2.data.slot`. -* For each [validator](#dfn-validator) index `i` in `intersection`, if `state.validator_registry[i].status` does not equal `EXITED_WITH_PENALTY`, then run `exit_validator(i, state, penalize=True, current_slot=state.slot)` +* For each [validator](#dfn-validator) index `i` in `intersection`, if `state.validator_registry[i].status` does not equal `EXITED_WITH_PENALTY`, then run `exit_validator(i, state, new_status=EXITED_WITH_PENALTY)` #### Attestations @@ -1353,8 +1362,7 @@ process_deposit( proof_of_possession=deposit.deposit_data.deposit_parameters.proof_of_possession, withdrawal_credentials=deposit.deposit_data.deposit_parameters.withdrawal_credentials, randao_commitment=deposit.deposit_data.deposit_parameters.randao_commitment, - status=PENDING_ACTIVATION, - current_slot=state.slot + status=PENDING_ACTIVATION ) ``` @@ -1369,7 +1377,22 @@ For each `exit` in `block.body.exits`: * Verify that `validator.status == ACTIVE`. * Verify that `state.slot >= exit.slot`. * Verify that `state.slot >= validator.latest_status_change_slot + SHARD_PERSISTENT_COMMITTEE_CHANGE_PERIOD`. -* Run `exit_validator(validator_index, state, penalize=False, current_slot=state.slot)`. +* Run `exit_validator(validator_index, state, new_status=ACTIVE_PENDING_EXIT)`. + +### Ejections + +* Run `process_ejections(state)`. + + ```python +def process_ejections(state: BeaconState) -> None: + """ + Iterate through the validator registry + and eject active validators with balance below ``EJECTION_BALANCE``. + """ + for i, v in enumerate(state.validator_registry): + if is_active_validator(v) and v.balance < EJECTION_BALANCE: + exit_validator(i, state, new_status=EXITED_WITHOUT_PENALTY) +``` ## Per-epoch processing @@ -1437,6 +1460,7 @@ If `state.slot % POW_RECEIPT_ROOT_VOTING_PERIOD == 0`: ### Finalization Set `state.finalized_slot = state.previous_justified_slot` if any of the following are true: + * `state.previous_justified_slot == state.slot - 2 * EPOCH_LENGTH and state.justification_bitfield % 4 == 3` * `state.previous_justified_slot == state.slot - 3 * EPOCH_LENGTH and state.justification_bitfield % 8 == 7` * `state.previous_justified_slot == state.slot - 4 * EPOCH_LENGTH and state.justification_bitfield % 16 in (15, 14)` @@ -1620,7 +1644,6 @@ while len(state.persistent_committee_reassignments) > 0 and state.persistent_com ### Final updates * Remove any `attestation` in `state.latest_attestations` such that `attestation.data.slot < state.slot - EPOCH_LENGTH`. -* Run `exit_validator(i, state, penalize=False, current_slot=state.slot)` for indices `i` such that `state.validator_registry[i].status == ACTIVE and state.validator_registry[i].balance < MIN_BALANCE`. * Set `state.latest_block_hashes = state.latest_block_hashes[EPOCH_LENGTH:]`. ## State root processing