From d73aa31ef6d893598b942e6c67373da278bafc5c Mon Sep 17 00:00:00 2001 From: Justin Drake Date: Thu, 20 Jun 2019 11:58:05 +0100 Subject: [PATCH] Cleanups --- specs/core/0_fork-choice.md | 47 +++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 26 deletions(-) diff --git a/specs/core/0_fork-choice.md b/specs/core/0_fork-choice.md index fead7d55b..6b7e4bdbe 100644 --- a/specs/core/0_fork-choice.md +++ b/specs/core/0_fork-choice.md @@ -11,13 +11,12 @@ - [Constants](#constants) - [Time parameters](#time-parameters) - [Fork choice](#fork-choice) - - [Containers](#containers) + - [Helpers](#helpers) - [`Target`](#target) - [`Store`](#store) - - [Helpers](#helpers) - [`get_genesis_store`](#get_genesis_store) - [`get_ancestor`](#get_ancestor) - - [`get_attesting_balance_from_store`](#get_attesting_balance_from_store) + - [`get_latest_attesting_balance`](#get_latest_attesting_balance) - [`get_head`](#get_head) - [Handlers](#handlers) - [`on_tick`](#on_tick) @@ -51,9 +50,9 @@ The head block root associated with a `store` is defined as `get_head(store)`. A 1) **Leap seconds**: Slots will last `SECONDS_PER_SLOT + 1` or `SECONDS_PER_SLOT - 1` seconds around leap seconds. 2) **Honest clocks**: Honest nodes are assumed to have clocks synchronized within `SECONDS_PER_SLOT` seconds of each other. 3) **Eth1 data**: The large `ETH1_FOLLOW_DISTANCE` specified in the [honest validator document](https://github.com/ethereum/eth2.0-specs/blob/dev/specs/validator/0_beacon-chain-validator.md) should ensure that `state.latest_eth1_data` of the canonical Ethereum 2.0 chain remains consistent with the canonical Ethereum 1.0 chain. If not, emergency manual intervention will be required. -4) **Manual forks**: Manual forks may arbitrarily change the fork choice rule but are expected to be enacted at epoch transitions, with the fork details reflected in `state.fork`. +4) **Manual forks**: Manual forks may arbitrarily change the fork choice rule but are expected to be enacted at epoch transitions, with the fork details reflected in `state.fork`. -### Containers +### Helpers #### `Target` @@ -61,7 +60,7 @@ The head block root associated with a `store` is defined as `get_head(store)`. A @dataclass class Target(object): epoch: Epoch - root: Bytes32 + root: Hash ``` #### `Store` @@ -69,38 +68,36 @@ class Target(object): ```python @dataclass class Store(object): - blocks: Dict[Bytes32, BeaconBlock] = field(default_factory=dict) - states: Dict[Bytes32, BeaconState] = field(default_factory=dict) + blocks: Dict[Hash, BeaconBlock] = field(default_factory=dict) + states: Dict[Hash, BeaconState] = field(default_factory=dict) time: int = 0 latest_targets: Dict[ValidatorIndex, Target] = field(default_factory=dict) - justified_root: Bytes32 = ZERO_HASH - finalized_root: Bytes32 = ZERO_HASH + justified_root: Hash = ZERO_HASH + finalized_root: Hash = ZERO_HASH ``` -### Helpers - #### `get_genesis_store` ```python def get_genesis_store(genesis_state: BeaconState) -> Store: genesis_block = BeaconBlock(state_root=hash_tree_root(genesis_state)) root = signing_root(genesis_block) - return Store(blocks={root: genesis_block}, states={root: genesis_state}, finalized_root=root, justified_root=root) + return Store(blocks={root: genesis_block}, states={root: genesis_state}, justified_root=root, finalized_root=root) ``` #### `get_ancestor` ```python -def get_ancestor(store: Store, root: Bytes32, slot: Slot) -> Bytes32: +def get_ancestor(store: Store, root: Hash, slot: Slot) -> Hash: block = store.blocks[root] assert block.slot >= slot return root if block.slot == slot else get_ancestor(store, block.parent_root, slot) ``` -#### `get_attesting_balance_from_store` +#### `get_latest_attesting_balance` ```python -def get_attesting_balance_from_store(store: Store, root: Bytes32) -> Gwei: +def get_latest_attesting_balance(store: Store, root: Hash) -> Gwei: state = store.states[store.justified_root] active_indices = get_active_validator_indices(state.validator_registry, slot_to_epoch(state.slot)) return Gwei(sum( @@ -112,15 +109,15 @@ def get_attesting_balance_from_store(store: Store, root: Bytes32) -> Gwei: #### `get_head` ```python -def get_head(store: Store) -> Bytes32: +def get_head(store: Store) -> Hash: # Execute the LMD-GHOST fork choice head = store.justified_root while True: children = [root for root in store.blocks.keys() if store.blocks[root].parent_root == head] if len(children) == 0: return head - # Sort by attesting balance with ties broken lexicographically - head = max(children, key=lambda root: (get_attesting_balance_from_store(store, root), root)) + # Sort by latest attesting balance with ties broken lexicographically + head = max(children, key=lambda root: (get_latest_attesting_balance(store, root), root)) ``` ### Handlers @@ -147,13 +144,14 @@ def on_block(store: Store, block: BeaconBlock) -> None: state = state_transition(pre_state, block) # Add new state to the store store.states[signing_root(block)] = state - # Update justified and finalized blocks - if state.finalized_epoch > slot_to_epoch(store.blocks[store.finalized_root].slot): - store.finalized_root = state.finalized_root + # Update justified block root if state.current_justified_epoch > slot_to_epoch(store.blocks[store.justified_root].slot): store.justified_root = state.current_justified_root elif state.previous_justified_epoch > slot_to_epoch(store.blocks[store.justified_root].slot): store.justified_root = state.previous_justified_root + # Update finalized block root + if state.finalized_epoch > slot_to_epoch(store.blocks[store.finalized_root].slot): + store.finalized_root = state.finalized_root ``` #### `on_attestation` @@ -165,8 +163,5 @@ def on_attestation(store: Store, attestation: Attestation) -> None: validate_indexed_attestation(state, indexed_attestation) for i in indexed_attestation.custody_bit_0_indices + indexed_attestation.custody_bit_1_indices: if i not in store.latest_targets or attestation.data.target_epoch > store.latest_targets[i].epoch: - store.latest_targets[i] = Target( - epoch=attestation.data.target_epoch, - root=attestation.data.target_root, - ) + store.latest_targets[i] = Target(attestation.data.target_epoch, attestation.data.target_root) ```