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Assimilated #697
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@vbuterin
vbuterin committed Mar 3, 2019
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Showing 1 changed file with 15 additions and 23 deletions.
38 changes: 15 additions & 23 deletions specs/core/0_beacon-chain.md
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Original file line number Diff line number Diff line change
Expand Up @@ -533,6 +533,8 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git
'current_shuffling_seed': 'bytes32',

# Finality
'previous_epoch_attestations': [PendingAttestation],
'current_epoch_attestations': [PendingAttestation],
'previous_justified_epoch': 'uint64',
'justified_epoch': 'uint64',
'justification_bitfield': 'uint64',
Expand All @@ -543,7 +545,6 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git
'latest_block_roots': ['bytes32'],
'latest_active_index_roots': ['bytes32'],
'latest_slashed_balances': ['uint64'], # Balances slashed at every withdrawal period
'latest_attestations': [PendingAttestation],
'batched_block_roots': ['bytes32'],

# Ethereum 1.0 chain data
Expand Down Expand Up @@ -1461,6 +1462,8 @@ def get_genesis_beacon_state(genesis_validator_deposits: List[Deposit],
current_shuffling_seed=ZERO_HASH,

# Finality
previous_epoch_attestations=[],
current_epoch_attestations=[],
previous_justified_epoch=GENESIS_EPOCH,
justified_epoch=GENESIS_EPOCH,
justification_bitfield=0,
Expand All @@ -1471,7 +1474,6 @@ def get_genesis_beacon_state(genesis_validator_deposits: List[Deposit],
latest_block_roots=[ZERO_HASH for _ in range(LATEST_BLOCK_ROOTS_LENGTH)],
latest_active_index_roots=[ZERO_HASH for _ in range(LATEST_ACTIVE_INDEX_ROOTS_LENGTH)],
latest_slashed_balances=[0 for _ in range(LATEST_SLASHED_EXIT_LENGTH)],
latest_attestations=[],
batched_block_roots=[],

# Ethereum 1.0 chain data
Expand Down Expand Up @@ -1702,7 +1704,9 @@ For each `attestation` in `block.body.attestations`:
```

* [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.crosslink_data_root == ZERO_HASH`.
* Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, custody_bitfield=attestation.custody_bitfield, inclusion_slot=state.slot)` to `state.latest_attestations`.
* Let `pending_attestation = PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, custody_bitfield=attestation.custody_bitfield, inclusion_slot=state.slot)`.
* Append `pending_attestation` to `state.previous_epoch_attestations` if `slot_to_epoch(attestation.data.slot) == get_previous_epoch(state)`.
* Append `pending_attestation` to `state.current_epoch_attestations` if `slot_to_epoch(attestation.data.slot) == get_current_epoch(state)`.

##### Deposits

Expand Down Expand Up @@ -1777,11 +1781,6 @@ The steps below happen when `(state.slot + 1) % SLOTS_PER_EPOCH == 0`.

We define some helper functions:

```python
def get_current_attestations(state: BeaconState) -> List[PendingAttestation]:
return [a for a in state.latest_attestations if get_current_epoch(state) == slot_to_epoch(a.data.slot)]
```

```python
def get_current_total_balance(state: BeaconState) -> Gwei:
return get_total_balance(state, get_active_validator_indices(state.validator_registry, get_current_epoch(state)))
Expand All @@ -1792,11 +1791,6 @@ def get_previous_total_balance(state: BeaconState) -> Gwei:
return get_total_balance(state, get_active_validator_indices(state.validator_registry, get_previous_epoch(state)))
```

```python
def get_previous_attestations(state: BeaconState) -> List[PendingAttestation]:
return [a for a in state.latest_attestations if get_previous_epoch(state) == slot_to_epoch(a.data.slot)]
```

```python
def get_attesting_indices(state: BeaconState, attestations: List[PendingAttestation]) -> List[ValidatorIndex]:
output = set({})
Expand All @@ -1813,23 +1807,23 @@ def get_attesting_balance(state: BeaconState, attestations: List[PendingAttestat
```python
def get_current_epoch_boundary_attestations(state: BeaconState) -> List[PendingAttestation]:
return [
a for a in get_current_attestations(state) if
a for a in state.current_epoch_attestations if
a.data.epoch_boundary_root == get_block_root(state, get_epoch_start_slot(get_current_epoch(state)))
]
```

```python
def get_previous_epoch_boundary_attestations(state: BeaconState) -> List[PendingAttestation]:
return [
a for a in get_previous_attestations(state) if
a for a in state.previous_epoch_attestations if
a.data.epoch_boundary_root == get_block_root(state, get_epoch_start_slot(get_previous_epoch(state)))
]
```

```python
def get_previous_epoch_matching_head_attestations(state: BeaconState) -> List[PendingAttestation]:
return [
a for a in get_previous_epoch_attestations(state) if
a for a in state.previous_epoch_attestations if
a.data.beacon_block_root == get_block_root(state, a.data.slot)
]
```
Expand All @@ -1838,7 +1832,7 @@ def get_previous_epoch_matching_head_attestations(state: BeaconState) -> List[Pe

```python
def get_winning_root_and_participants(state: BeaconState, shard: Shard) -> Tuple[Bytes32, List[ValidatorIndex]]:
all_attestations = get_current_attestations(state) + get_previous_attestations(state)
all_attestations = state.current_epoch_attestations + state.previous_epoch_attestations
valid_attestations = [
a for a in all_attestations if a.data.latest_crosslink == state.latest_crosslinks[shard]
]
Expand Down Expand Up @@ -1989,7 +1983,7 @@ def compute_normal_justification_and_finalization_deltas(state: BeaconState) ->
# Process rewards or penalties for all validators
for index in get_active_validator_indices(state.validator_registry, previous_epoch):
# Expected FFG source
if index in get_attesting_indices(get_previous_attestations(state)):
if index in get_attesting_indices(state.previous_epoch_attestations):
deltas[index] += get_base_reward(state, index) * total_attesting_balance // total_balance
# Inclusion speed bonus
deltas[index] += (
Expand Down Expand Up @@ -2258,11 +2252,9 @@ def finish_epoch_update(state: BeaconState) -> None:
)
# Set randao mix
state.latest_randao_mixes[next_epoch % LATEST_RANDAO_MIXES_LENGTH] = get_randao_mix(state, current_epoch)
# Remove previous epoch attestations
state.latest_attestations = [
a for a in state.latest_attestations if
slot_to_epoch(attestation.data.slot) == current_epoch
]
# Rotate current/previous epoch attestations
state.previous_epoch_attestations = state.current_epoch_attestations
state.current_epoch_attestations = []
```

### State root verification
Expand Down

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