naive-withdrawer-exits-beacon-spec.py

MAX_WITHDRAWER_EXITS = 2**4


class WithdrawerExit(Container):
    validator_index: ValidatorIndex
    withdrawer_address: ExecutionAddress


class BeaconBlockBody(Container):
    # ...
    deposits: List[Deposit, MAX_DEPOSITS]
    voluntary_exits: List[SignedVoluntaryExit, MAX_VOLUNTARY_EXITS]
    withdrawer_exits: List[WithdrawerExit, MAX_WITHDRAWER_EXITS]


def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
    # ...
    for_ops(body.deposits, process_deposit)
    for_ops(body.voluntary_exits, process_voluntary_exit)
    for_ops(body.withdrawer_exits, process_withdrawer_exit)


def is_withdrawer_exit_valid(state: BeaconState, withdrawer_exit: WithdrawerExit) -> bool:
    validator = state.validators[withdrawer_exit.validator_index]
    # Verify the validator is active
    assert is_active_validator(validator, get_current_epoch(state))
    # Verify exit has not been initiated
    assert validator.exit_epoch == FAR_FUTURE_EPOCH
    # Verify the validator has been active long enough
    assert get_current_epoch(state) >= validator.activation_epoch + SHARD_COMMITTEE_PERIOD

    # Check withdrawer_exit was indeed initiated by withdrawal credentials
    return withdrawer_exit.withdrawer_address == validator.withdrawal_credentials


def process_withdrawer_exit(state: BeaconState, withdrawer_exit: WithdrawerExit) -> None:
    if is_withdrawer_exit_valid(state, withdrawer_exit):
        initiate_validator_exit(state, withdrawer_exit.validator_index)