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Avoid divisions by zero 

Possible fix to avoid four cases of divisions by zero:

* `return state.validator_registry[index].effective_balance // adjusted_quotient // BASE_REWARDS_PER_EPOCH`
* `rewards[index] += get_base_reward(state, index) * attesting_balance // total_balance`
* `validator.effective_balance * min(total_penalties * 3, total_balance) // total_balance`
* `rewards[index] += base_reward * attesting_balance // committee_balance`

See also #1107.
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Justin 2019-05-26 18:42:37 +03:00 committed by GitHub
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16
specs/core/0_beacon-chain.md
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@ -963,9 +963,9 @@ def bytes_to_int(data: bytes) -> int:
```python
def get_total_balance(state: BeaconState, indices: List[ValidatorIndex]) -> Gwei:
"""
Return the combined effective balance of an array of ``validators``.
Return the combined effective balance of the ``indices``. (1 Gwei minimum to avoid divisions by zero.)
"""
return sum([state.validator_registry[index].effective_balance for index in indices])
return max(sum([state.validator_registry[index].effective_balance for index in indices]), 1)
```
### `get_domain`
@ -1413,10 +1413,9 @@ def process_crosslinks(state: BeaconState) -> None:
```python
def get_base_reward(state: BeaconState, index: ValidatorIndex) -> Gwei:
adjusted_quotient = integer_squareroot(get_total_active_balance(state)) // BASE_REWARD_QUOTIENT
if adjusted_quotient == 0:
return 0
return state.validator_registry[index].effective_balance // adjusted_quotient // BASE_REWARDS_PER_EPOCH
total_balance = get_total_active_balance(state)
effective_balance = state.validator_registry[index].effective_balance
return effective_balance * BASE_REWARD_QUOTIENT // integer_squareroot(total_balance) // BASE_REWARDS_PER_EPOCH
```
```python
@ -1531,10 +1530,9 @@ def process_registry_updates(state: BeaconState) -> None:
```python
def process_slashings(state: BeaconState) -> None:
current_epoch = get_current_epoch(state)
active_validator_indices = get_active_validator_indices(state, current_epoch)
total_balance = get_total_balance(state, active_validator_indices)
total_balance = get_total_active_balance(state)
# Compute `total_penalties`
# Compute slashed balances in the current epoch
total_at_start = state.latest_slashed_balances[(current_epoch + 1) % LATEST_SLASHED_EXIT_LENGTH]
total_at_end = state.latest_slashed_balances[current_epoch % LATEST_SLASHED_EXIT_LENGTH]
total_penalties = total_at_end - total_at_start