4.8 KiB
Capella -- Fork Logic
Table of contents
Introduction
This document describes the process of the Capella upgrade.
Configuration
Warning: this configuration is not definitive.
| Name | Value |
|---|---|
CAPELLA_FORK_VERSION |
Version('0x03000000') |
CAPELLA_FORK_EPOCH |
Epoch(18446744073709551615) TBD |
Helper functions
Misc
Modified compute_fork_version
def compute_fork_version(epoch: Epoch) -> Version:
"""
Return the fork version at the given ``epoch``.
"""
if epoch >= CAPELLA_FORK_EPOCH:
return CAPELLA_FORK_VERSION
if epoch >= BELLATRIX_FORK_EPOCH:
return BELLATRIX_FORK_VERSION
if epoch >= ALTAIR_FORK_EPOCH:
return ALTAIR_FORK_VERSION
return GENESIS_FORK_VERSION
Fork to Capella
Fork trigger
The fork is triggered at epoch CAPELLA_FORK_EPOCH.
Note that for the pure Capella networks, we don't apply upgrade_to_capella since it starts with Capella version logic.
Upgrading the state
If state.slot % SLOTS_PER_EPOCH == 0 and compute_epoch_at_slot(state.slot) == CAPELLA_FORK_EPOCH,
an irregular state change is made to upgrade to Capella.
The upgrade occurs after the completion of the inner loop of process_slots that sets state.slot equal to CAPELLA_FORK_EPOCH * SLOTS_PER_EPOCH.
Care must be taken when transitioning through the fork boundary as implementations will need a modified state transition function that deviates from the Phase 0 document.
In particular, the outer state_transition function defined in the Phase 0 document will not expose the precise fork slot to execute the upgrade in the presence of skipped slots at the fork boundary. Instead the logic must be within process_slots.
def upgrade_to_capella(pre: bellatrix.BeaconState) -> BeaconState:
epoch = bellatrix.get_current_epoch(pre)
post = BeaconState(
# Versioning
genesis_time=pre.genesis_time,
genesis_validators_root=pre.genesis_validators_root,
slot=pre.slot,
fork=Fork(
previous_version=pre.fork.current_version,
current_version=CAPELLA_FORK_VERSION,
epoch=epoch,
),
# History
latest_block_header=pre.latest_block_header,
block_roots=pre.block_roots,
state_roots=pre.state_roots,
historical_roots=pre.historical_roots,
# Eth1
eth1_data=pre.eth1_data,
eth1_data_votes=pre.eth1_data_votes,
eth1_deposit_index=pre.eth1_deposit_index,
# Registry
validators=[],
balances=pre.balances,
# Randomness
randao_mixes=pre.randao_mixes,
# Slashings
slashings=pre.slashings,
# Participation
previous_epoch_participation=pre.previous_epoch_participation,
current_epoch_participation=pre.current_epoch_participation,
# Finality
justification_bits=pre.justification_bits,
previous_justified_checkpoint=pre.previous_justified_checkpoint,
current_justified_checkpoint=pre.current_justified_checkpoint,
finalized_checkpoint=pre.finalized_checkpoint,
# Inactivity
inactivity_scores=pre.inactivity_scores,
# Sync
current_sync_committee=pre.current_sync_committee,
next_sync_committee=pre.next_sync_committee,
# Execution-layer
latest_execution_payload_header=pre.latest_execution_payload_header,
# Withdrawals
withdrawal_queue=[],
next_withdrawal_index=WithdrawalIndex(0),
next_partial_withdrawal_validator_index=ValidatorIndex(0),
)
for pre_validator in pre.validators:
post_validator = Validator(
pubkey=pre_validator.pubkey,
withdrawal_credentials=pre_validator.withdrawal_credentials,
effective_balance=pre_validator.effective_balance,
slashed=pre_validator.slashed,
activation_eligibility_epoch=pre_validator.activation_eligibility_epoch,
activation_epoch=pre_validator.activation_epoch,
exit_epoch=pre_validator.exit_epoch,
withdrawable_epoch=pre_validator.withdrawable_epoch,
fully_withdrawn_epoch=FAR_FUTURE_EPOCH,
)
post.validators.append(post_validator)
return post