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v0.12 fork choice update (#1229)

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* Incomplete scraps

* Add progress on new fork choice impl

* Further progress

* First complete compiling version

* Remove chain reference

* Add new lmd_ghost crate

* Start integrating into beacon chain

* Update `milagro_bls` to new release (#1183)

* Update milagro_bls to new release

Signed-off-by: Kirk Baird <baird.k@outlook.com>

* Tidy up fake cryptos

Signed-off-by: Kirk Baird <baird.k@outlook.com>

* move SecretHash to bls and put plaintext back

Signed-off-by: Kirk Baird <baird.k@outlook.com>

* Update state processing for v0.12

* Fix EF test runners for v0.12

* Fix some tests

* Fix broken attestation verification test

* More test fixes

* Rough beacon chain impl working

* Remove fork_choice_2

* Remove checkpoint manager

* Half finished ssz impl

* Add missed file

* Add persistence

* Tidy, fix some compile errors

* Remove RwLock from ProtoArrayForkChoice

* Fix store-based compile errors

* Add comments, tidy

* Move function out of ForkChoice struct

* Start testing

* More testing

* Fix compile error

* Tidy beacon_chain::fork_choice

* Queue attestations from the current slot

* Allow fork choice to handle prior-to-genesis start

* Improve error granularity

* Test attestation dequeuing

* Process attestations during block

* Store target root in fork choice

* Move fork choice verification into new crate

* Update tests

* Consensus updates for v0.12 (#1228)

* Update state processing for v0.12

* Fix EF test runners for v0.12

* Fix some tests

* Fix broken attestation verification test

* More test fixes

* Fix typo found in review

* Add `Block` struct to ProtoArray

* Start fixing get_ancestor

* Add rough progress on testing

* Get fork choice tests working

* Progress with testing

* Fix partialeq impl

* Move slot clock from fc_store

* Improve testing

* Add testing for best justified

* Add clone back to SystemTimeSlotClock

* Add balances test

* Start adding balances cache again

* Wire-in balances cache

* Improve tests

* Remove commented-out tests

* Remove beacon_chain::ForkChoice

* Rename crates

* Update wider codebase to new fork_choice layout

* Move advance_slot in test harness

* Tidy ForkChoice::update_time

* Fix verification tests

* Fix compile error with iter::once

* Fix fork choice tests

* Ensure block attestations are processed

* Fix failing beacon_chain tests

* Add first invalid block check

* Add finalized block check

* Progress with testing, new store builder

* Add fixes to get_ancestor

* Fix old genesis justification test

* Fix remaining fork choice tests

* Change root iteration method

* Move on_verified_block

* Remove unused method

* Start adding attestation verification tests

* Add invalid ffg target test

* Add target epoch test

* Add queued attestation test

* Remove old fork choice verification tests

* Tidy, add test

* Move fork choice lock drop

* Rename BeaconForkChoiceStore

* Add comments, tidy BeaconForkChoiceStore

* Update metrics, rename fork_choice_store.rs

* Remove genesis_block_root from ForkChoice

* Tidy

* Update fork_choice comments

* Tidy, add comments

* Tidy, simplify ForkChoice, fix compile issue

* Tidy, removed dead file

* Increase http request timeout

* Fix failing rest_api test

* Set HTTP timeout back to 5s

* Apply fix to get_ancestor

* Address Michael's comments

* Fix typo

* Revert "Fix broken attestation verification test"

This reverts commit 722cdc903b.

Co-authored-by: Kirk Baird <baird.k@outlook.com>
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
This commit is contained in:
Paul Hauner
2020-06-17 11:10:22 +10:00
committed by GitHub
parent 1a4de898bc
commit 764cb2d32a
51 changed files with 2641 additions and 1376 deletions
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20
consensus/fork_choice/Cargo.toml Normal file
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[package]
name = "fork_choice"
version = "0.1.0"
authors = ["Paul Hauner <paul@paulhauner.com>"]
edition = "2018"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
types = { path = "../types" }
proto_array = { path = "../proto_array" }
eth2_ssz = { path = "../ssz" }
eth2_ssz_derive = { path = "../ssz_derive" }
[dev-dependencies]
state_processing = { path = "../../consensus/state_processing" }
beacon_chain = { path = "../../beacon_node/beacon_chain" }
store = { path = "../../beacon_node/store" }
tree_hash = { path = "../../consensus/tree_hash" }
slot_clock = { path = "../../common/slot_clock" }

884
consensus/fork_choice/src/fork_choice.rs Normal file
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use crate::ForkChoiceStore;
use proto_array::{Block as ProtoBlock, ProtoArrayForkChoice};
use ssz_derive::{Decode, Encode};
use std::marker::PhantomData;
use types::{
BeaconBlock, BeaconState, BeaconStateError, Epoch, EthSpec, Hash256, IndexedAttestation, Slot,
};
/// Defined here:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#configuration
pub const SAFE_SLOTS_TO_UPDATE_JUSTIFIED: u64 = 8;
#[derive(Debug)]
pub enum Error<T> {
InvalidAttestation(InvalidAttestation),
InvalidBlock(InvalidBlock),
ProtoArrayError(String),
InvalidProtoArrayBytes(String),
MissingProtoArrayBlock(Hash256),
UnknownAncestor {
ancestor_slot: Slot,
descendant_root: Hash256,
},
InconsistentOnTick {
previous_slot: Slot,
time: Slot,
},
BeaconStateError(BeaconStateError),
AttemptToRevertJustification {
store: Slot,
state: Slot,
},
ForkChoiceStoreError(T),
UnableToSetJustifiedCheckpoint(T),
AfterBlockFailed(T),
}
impl<T> From<InvalidAttestation> for Error<T> {
fn from(e: InvalidAttestation) -> Self {
Error::InvalidAttestation(e)
}
}
#[derive(Debug)]
pub enum InvalidBlock {
UnknownParent(Hash256),
FutureSlot {
current_slot: Slot,
block_slot: Slot,
},
FinalizedSlot {
finalized_slot: Slot,
block_slot: Slot,
},
NotFinalizedDescendant {
finalized_root: Hash256,
block_ancestor: Option<Hash256>,
},
}
#[derive(Debug)]
pub enum InvalidAttestation {
/// The attestations aggregation bits were empty when they shouldn't be.
EmptyAggregationBitfield,
/// The `attestation.data.beacon_block_root` block is unknown.
UnknownHeadBlock { beacon_block_root: Hash256 },
/// The `attestation.data.slot` is not from the same epoch as `data.target.epoch` and therefore
/// the attestation is invalid.
BadTargetEpoch { target: Epoch, slot: Slot },
/// The target root of the attestation points to a block that we have not verified.
UnknownTargetRoot(Hash256),
/// The attestation is for an epoch in the future (with respect to the gossip clock disparity).
FutureEpoch {
attestation_epoch: Epoch,
current_epoch: Epoch,
},
/// The attestation is for an epoch in the past (with respect to the gossip clock disparity).
PastEpoch {
attestation_epoch: Epoch,
current_epoch: Epoch,
},
/// The attestation references a target root that does not match what is stored in our
/// database.
InvalidTarget {
attestation: Hash256,
local: Hash256,
},
/// The attestation is attesting to a state that is later than itself. (Viz., attesting to the
/// future).
AttestsToFutureBlock { block: Slot, attestation: Slot },
}
impl<T> From<String> for Error<T> {
fn from(e: String) -> Self {
Error::ProtoArrayError(e)
}
}
/// Calculate how far `slot` lies from the start of its epoch.
///
/// ## Specification
///
/// Equivalent to:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#compute_slots_since_epoch_start
pub fn compute_slots_since_epoch_start<E: EthSpec>(slot: Slot) -> Slot {
slot - slot
.epoch(E::slots_per_epoch())
.start_slot(E::slots_per_epoch())
}
/// Calculate the first slot in `epoch`.
///
/// ## Specification
///
/// Equivalent to:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/beacon-chain.md#compute_start_slot_at_epoch
fn compute_start_slot_at_epoch<E: EthSpec>(epoch: Epoch) -> Slot {
epoch.start_slot(E::slots_per_epoch())
}
/// Called whenever the current time increases.
///
/// ## Specification
///
/// Equivalent to:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#on_tick
fn on_tick<T, E>(store: &mut T, time: Slot) -> Result<(), Error<T::Error>>
where
T: ForkChoiceStore<E>,
E: EthSpec,
{
let previous_slot = store.get_current_slot();
if time > previous_slot + 1 {
return Err(Error::InconsistentOnTick {
previous_slot,
time,
});
}
// Update store time.
store.set_current_slot(time);
let current_slot = store.get_current_slot();
if !(current_slot > previous_slot && compute_slots_since_epoch_start::<E>(current_slot) == 0) {
return Ok(());
}
if store.best_justified_checkpoint().epoch > store.justified_checkpoint().epoch {
store
.set_justified_checkpoint(*store.best_justified_checkpoint())
.map_err(Error::ForkChoiceStoreError)?;
}
Ok(())
}
/// Used for queuing attestations from the current slot. Only contains the minimum necessary
/// information about the attestation.
#[derive(Clone, PartialEq, Encode, Decode)]
pub struct QueuedAttestation {
slot: Slot,
attesting_indices: Vec<u64>,
block_root: Hash256,
target_epoch: Epoch,
}
impl<E: EthSpec> From<&IndexedAttestation<E>> for QueuedAttestation {
fn from(a: &IndexedAttestation<E>) -> Self {
Self {
slot: a.data.slot,
attesting_indices: a.attesting_indices[..].to_vec(),
block_root: a.data.beacon_block_root,
target_epoch: a.data.target.epoch,
}
}
}
/// Returns all values in `self.queued_attestations` that have a slot that is earlier than the
/// current slot. Also removes those values from `self.queued_attestations`.
fn dequeue_attestations(
current_slot: Slot,
queued_attestations: &mut Vec<QueuedAttestation>,
) -> Vec<QueuedAttestation> {
let remaining = queued_attestations.split_off(
queued_attestations
.iter()
.position(|a| a.slot >= current_slot)
.unwrap_or(queued_attestations.len()),
);
std::mem::replace(queued_attestations, remaining)
}
/// Provides an implementation of "Ethereum 2.0 Phase 0 -- Beacon Chain Fork Choice":
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#ethereum-20-phase-0----beacon-chain-fork-choice
///
/// ## Detail
///
/// This struct wraps `ProtoArrayForkChoice` and provides:
///
/// - Management of the justified state and caching of balances.
/// - Queuing of attestations from the current slot.
pub struct ForkChoice<T, E> {
/// Storage for `ForkChoice`, modelled off the spec `Store` object.
fc_store: T,
/// The underlying representation of the block DAG.
proto_array: ProtoArrayForkChoice,
/// Attestations that arrived at the current slot and must be queued for later processing.
queued_attestations: Vec<QueuedAttestation>,
_phantom: PhantomData<E>,
}
impl<T, E> PartialEq for ForkChoice<T, E>
where
T: ForkChoiceStore<E> + PartialEq,
E: EthSpec,
{
fn eq(&self, other: &Self) -> bool {
self.fc_store == other.fc_store
&& self.proto_array == other.proto_array
&& self.queued_attestations == other.queued_attestations
}
}
impl<T, E> ForkChoice<T, E>
where
T: ForkChoiceStore<E>,
E: EthSpec,
{
/// Instantiates `Self` from the genesis parameters.
pub fn from_genesis(
fc_store: T,
genesis_block: &BeaconBlock<E>,
) -> Result<Self, Error<T::Error>> {
let finalized_block_slot = genesis_block.slot;
let finalized_block_state_root = genesis_block.state_root;
let proto_array = ProtoArrayForkChoice::new(
finalized_block_slot,
finalized_block_state_root,
fc_store.justified_checkpoint().epoch,
fc_store.finalized_checkpoint().epoch,
fc_store.finalized_checkpoint().root,
)?;
Ok(Self {
fc_store,
proto_array,
queued_attestations: vec![],
_phantom: PhantomData,
})
}
/// Instantiates `Self` from some existing components.
///
/// This is useful if the existing components have been loaded from disk after a process
/// restart.
pub fn from_components(
fc_store: T,
proto_array: ProtoArrayForkChoice,
queued_attestations: Vec<QueuedAttestation>,
) -> Self {
Self {
fc_store,
proto_array,
queued_attestations,
_phantom: PhantomData,
}
}
/// Returns the block root of an ancestor of `block_root` at the given `slot`. (Note: `slot` refers
/// to the block that is *returned*, not the one that is supplied.)
///
/// The result may be `Ok(None)` if the block does not descend from the finalized block. This
/// is an artifact of proto-array, sometimes it contains descendants of blocks that have been
/// pruned.
///
/// ## Specification
///
/// Equivalent to:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#get_ancestor
fn get_ancestor(
&self,
block_root: Hash256,
ancestor_slot: Slot,
) -> Result<Option<Hash256>, Error<T::Error>>
where
T: ForkChoiceStore<E>,
E: EthSpec,
{
let block = self
.proto_array
.get_block(&block_root)
.ok_or_else(|| Error::MissingProtoArrayBlock(block_root))?;
if block.slot > ancestor_slot {
Ok(self
.proto_array
.core_proto_array()
.iter_block_roots(&block_root)
// Search for a slot that is **less than or equal to** the target slot. We check
// for lower slots to account for skip slots.
.find(|(_, slot)| *slot <= ancestor_slot)
.map(|(root, _)| root))
} else if block.slot == ancestor_slot {
Ok(Some(block_root))
} else {
// Root is older than queried slot, thus a skip slot. Return most recent root prior to
// slot.
Ok(Some(block_root))
}
}
/// Run the fork choice rule to determine the head.
///
/// ## Specification
///
/// Is equivalent to:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#get_head
pub fn get_head(&mut self, current_slot: Slot) -> Result<Hash256, Error<T::Error>> {
self.update_time(current_slot)?;
let store = &mut self.fc_store;
let result = self
.proto_array
.find_head(
store.justified_checkpoint().epoch,
store.justified_checkpoint().root,
store.finalized_checkpoint().epoch,
store.justified_balances(),
)
.map_err(Into::into);
result
}
/// Returns `true` if the given `store` should be updated to set
/// `state.current_justified_checkpoint` its `justified_checkpoint`.
///
/// ## Specification
///
/// Is equivalent to:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#should_update_justified_checkpoint
fn should_update_justified_checkpoint(
&mut self,
current_slot: Slot,
state: &BeaconState<E>,
) -> Result<bool, Error<T::Error>> {
self.update_time(current_slot)?;
let new_justified_checkpoint = &state.current_justified_checkpoint;
if compute_slots_since_epoch_start::<E>(self.fc_store.get_current_slot())
< SAFE_SLOTS_TO_UPDATE_JUSTIFIED
{
return Ok(true);
}
let justified_slot =
compute_start_slot_at_epoch::<E>(self.fc_store.justified_checkpoint().epoch);
// This sanity check is not in the spec, but the invariant is implied.
if justified_slot >= state.slot {
return Err(Error::AttemptToRevertJustification {
store: justified_slot,
state: state.slot,
});
}
// We know that the slot for `new_justified_checkpoint.root` is not greater than
// `state.slot`, since a state cannot justify its own slot.
//
// We know that `new_justified_checkpoint.root` is an ancestor of `state`, since a `state`
// only ever justifies ancestors.
//
// A prior `if` statement protects against a justified_slot that is greater than
// `state.slot`
let justified_ancestor =
self.get_ancestor(new_justified_checkpoint.root, justified_slot)?;
if justified_ancestor != Some(self.fc_store.justified_checkpoint().root) {
return Ok(false);
}
Ok(true)
}
/// Add `block` to the fork choice DAG.
///
/// - `block_root` is the root of `block.
/// - The root of `state` matches `block.state_root`.
///
/// ## Specification
///
/// Approximates:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#on_block
///
/// It only approximates the specification since it does not run the `state_transition` check.
/// That should have already been called upstream and it's too expensive to call again.
///
/// ## Notes:
///
/// The supplied block **must** pass the `state_transition` function as it will not be run
/// here.
pub fn on_block(
&mut self,
current_slot: Slot,
block: &BeaconBlock<E>,
block_root: Hash256,
state: &BeaconState<E>,
) -> Result<(), Error<T::Error>> {
let current_slot = self.update_time(current_slot)?;
// Parent block must be known.
if !self.proto_array.contains_block(&block.parent_root) {
return Err(Error::InvalidBlock(InvalidBlock::UnknownParent(
block.parent_root,
)));
}
// Blocks cannot be in the future. If they are, their consideration must be delayed until
// the are in the past.
//
// Note: presently, we do not delay consideration. We just drop the block.
if block.slot > current_slot {
return Err(Error::InvalidBlock(InvalidBlock::FutureSlot {
current_slot,
block_slot: block.slot,
}));
}
// Check that block is later than the finalized epoch slot (optimization to reduce calls to
// get_ancestor).
let finalized_slot =
compute_start_slot_at_epoch::<E>(self.fc_store.finalized_checkpoint().epoch);
if block.slot <= finalized_slot {
return Err(Error::InvalidBlock(InvalidBlock::FinalizedSlot {
finalized_slot,
block_slot: block.slot,
}));
}
// Check block is a descendant of the finalized block at the checkpoint finalized slot.
//
// Note: the specification uses `hash_tree_root(block)` instead of `block.parent_root` for
// the start of this search. I claim that since `block.slot > finalized_slot` it is
// equivalent to use the parent root for this search. Doing so reduces a single lookup
// (trivial), but more importantly, it means we don't need to have added `block` to
// `self.proto_array` to do this search. See:
//
// https://github.com/ethereum/eth2.0-specs/pull/1884
let block_ancestor = self.get_ancestor(block.parent_root, finalized_slot)?;
let finalized_root = self.fc_store.finalized_checkpoint().root;
if block_ancestor != Some(finalized_root) {
return Err(Error::InvalidBlock(InvalidBlock::NotFinalizedDescendant {
finalized_root,
block_ancestor,
}));
}
// Update justified checkpoint.
if state.current_justified_checkpoint.epoch > self.fc_store.justified_checkpoint().epoch {
if state.current_justified_checkpoint.epoch
> self.fc_store.best_justified_checkpoint().epoch
{
self.fc_store
.set_best_justified_checkpoint(state.current_justified_checkpoint);
}
if self.should_update_justified_checkpoint(current_slot, state)? {
self.fc_store
.set_justified_checkpoint(state.current_justified_checkpoint)
.map_err(Error::UnableToSetJustifiedCheckpoint)?;
}
}
// Update finalized checkpoint.
if state.finalized_checkpoint.epoch > self.fc_store.finalized_checkpoint().epoch {
self.fc_store
.set_finalized_checkpoint(state.finalized_checkpoint);
let finalized_slot =
compute_start_slot_at_epoch::<E>(self.fc_store.finalized_checkpoint().epoch);
// Note: the `if` statement here is not part of the specification, but I claim that it
// is an optimization and equivalent to the specification. See this PR for more
// information:
//
// https://github.com/ethereum/eth2.0-specs/pull/1880
if *self.fc_store.justified_checkpoint() != state.current_justified_checkpoint {
if state.current_justified_checkpoint.epoch
> self.fc_store.justified_checkpoint().epoch
|| self
.get_ancestor(self.fc_store.justified_checkpoint().root, finalized_slot)?
!= Some(self.fc_store.finalized_checkpoint().root)
{
self.fc_store
.set_justified_checkpoint(state.current_justified_checkpoint)
.map_err(Error::UnableToSetJustifiedCheckpoint)?;
}
}
}
let target_slot = block
.slot
.epoch(E::slots_per_epoch())
.start_slot(E::slots_per_epoch());
let target_root = if block.slot == target_slot {
block_root
} else {
*state
.get_block_root(target_slot)
.map_err(Error::BeaconStateError)?
};
self.fc_store
.on_verified_block(block, block_root, state)
.map_err(Error::AfterBlockFailed)?;
// This does not apply a vote to the block, it just makes fork choice aware of the block so
// it can still be identified as the head even if it doesn't have any votes.
self.proto_array.process_block(ProtoBlock {
slot: block.slot,
root: block_root,
parent_root: Some(block.parent_root),
target_root,
state_root: block.state_root,
justified_epoch: state.current_justified_checkpoint.epoch,
finalized_epoch: state.finalized_checkpoint.epoch,
})?;
Ok(())
}
/// Validates the `indexed_attestation` for application to fork choice.
///
/// ## Specification
///
/// Equivalent to:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.1/specs/phase0/fork-choice.md#validate_on_attestation
fn validate_on_attestation(
&self,
indexed_attestation: &IndexedAttestation<E>,
) -> Result<(), InvalidAttestation> {
// There is no point in processing an attestation with an empty bitfield. Reject
// it immediately.
//
// This is not in the specification, however it should be transparent to other nodes. We
// return early here to avoid wasting precious resources verifying the rest of it.
if indexed_attestation.attesting_indices.len() == 0 {
return Err(InvalidAttestation::EmptyAggregationBitfield);
}
let slot_now = self.fc_store.get_current_slot();
let epoch_now = slot_now.epoch(E::slots_per_epoch());
let target = indexed_attestation.data.target.clone();
// Attestation must be from the current or previous epoch.
if target.epoch > epoch_now {
return Err(InvalidAttestation::FutureEpoch {
attestation_epoch: target.epoch,
current_epoch: epoch_now,
});
} else if target.epoch + 1 < epoch_now {
return Err(InvalidAttestation::PastEpoch {
attestation_epoch: target.epoch,
current_epoch: epoch_now,
});
}
if target.epoch != indexed_attestation.data.slot.epoch(E::slots_per_epoch()) {
return Err(InvalidAttestation::BadTargetEpoch {
target: target.epoch,
slot: indexed_attestation.data.slot,
});
}
// Attestation target must be for a known block.
//
// We do not delay the block for later processing to reduce complexity and DoS attack
// surface.
if !self.proto_array.contains_block(&target.root) {
return Err(InvalidAttestation::UnknownTargetRoot(target.root));
}
// Load the block for `attestation.data.beacon_block_root`.
//
// This indirectly checks to see if the `attestation.data.beacon_block_root` is in our fork
// choice. Any known, non-finalized block should be in fork choice, so this check
// immediately filters out attestations that attest to a block that has not been processed.
//
// Attestations must be for a known block. If the block is unknown, we simply drop the
// attestation and do not delay consideration for later.
let block = self
.proto_array
.get_block(&indexed_attestation.data.beacon_block_root)
.ok_or_else(|| InvalidAttestation::UnknownHeadBlock {
beacon_block_root: indexed_attestation.data.beacon_block_root,
})?;
if block.target_root != target.root {
return Err(InvalidAttestation::InvalidTarget {
attestation: target.root,
local: block.target_root,
});
}
// Attestations must not be for blocks in the future. If this is the case, the attestation
// should not be considered.
if block.slot > indexed_attestation.data.slot {
return Err(InvalidAttestation::AttestsToFutureBlock {
block: block.slot,
attestation: indexed_attestation.data.slot,
});
}
Ok(())
}
/// Register `attestation` with the fork choice DAG so that it may influence future calls to
/// `Self::get_head`.
///
/// ## Specification
///
/// Approximates:
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#on_attestation
///
/// It only approximates the specification since it does not perform
/// `is_valid_indexed_attestation` since that should already have been called upstream and it's
/// too expensive to call again.
///
/// ## Notes:
///
/// The supplied `attestation` **must** pass the `in_valid_indexed_attestation` function as it
/// will not be run here.
pub fn on_attestation(
&mut self,
current_slot: Slot,
attestation: &IndexedAttestation<E>,
) -> Result<(), Error<T::Error>> {
// Ensure the store is up-to-date.
self.update_time(current_slot)?;
// Ignore any attestations to the zero hash.
//
// This is an edge case that results from the spec aliasing the zero hash to the genesis
// block. Attesters may attest to the zero hash if they have never seen a block.
//
// We have two options here:
//
// 1. Apply all zero-hash attestations to the genesis block.
// 2. Ignore all attestations to the zero hash.
//
// (1) becomes weird once we hit finality and fork choice drops the genesis block. (2) is
// fine because votes to the genesis block are not useful; all validators implicitly attest
// to genesis just by being present in the chain.
if attestation.data.beacon_block_root == Hash256::zero() {
return Ok(());
}
self.validate_on_attestation(attestation)?;
if attestation.data.slot < self.fc_store.get_current_slot() {
for validator_index in attestation.attesting_indices.iter() {
self.proto_array.process_attestation(
*validator_index as usize,
attestation.data.beacon_block_root,
attestation.data.target.epoch,
)?;
}
} else {
// The spec declares:
//
// ```
// Attestations can only affect the fork choice of subsequent slots.
// Delay consideration in the fork choice until their slot is in the past.
// ```
self.queued_attestations
.push(QueuedAttestation::from(attestation));
}
Ok(())
}
/// Call `on_tick` for all slots between `fc_store.get_current_slot()` and the provided
/// `current_slot`. Returns the value of `self.fc_store.get_current_slot`.
pub fn update_time(&mut self, current_slot: Slot) -> Result<Slot, Error<T::Error>> {
while self.fc_store.get_current_slot() < current_slot {
let previous_slot = self.fc_store.get_current_slot();
// Note: we are relying upon `on_tick` to update `fc_store.time` to ensure we don't
// get stuck in a loop.
on_tick(&mut self.fc_store, previous_slot + 1)?
}
// Process any attestations that might now be eligible.
self.process_attestation_queue()?;
Ok(self.fc_store.get_current_slot())
}
/// Processes and removes from the queue any queued attestations which may now be eligible for
/// processing due to the slot clock incrementing.
fn process_attestation_queue(&mut self) -> Result<(), Error<T::Error>> {
for attestation in dequeue_attestations(
self.fc_store.get_current_slot(),
&mut self.queued_attestations,
) {
for validator_index in attestation.attesting_indices.iter() {
self.proto_array.process_attestation(
*validator_index as usize,
attestation.block_root,
attestation.target_epoch,
)?;
}
}
Ok(())
}
/// Returns `true` if the block is known.
pub fn contains_block(&self, block_root: &Hash256) -> bool {
self.proto_array.contains_block(block_root)
}
/// Returns a `ProtoBlock` if the block is known.
pub fn get_block(&self, block_root: &Hash256) -> Option<ProtoBlock> {
self.proto_array.get_block(block_root)
}
/// Returns the latest message for a given validator, if any.
///
/// Returns `(block_root, block_slot)`.
///
/// ## Notes
///
/// It may be prudent to call `Self::update_time` before calling this function,
/// since some attestations might be queued and awaiting processing.
pub fn latest_message(&self, validator_index: usize) -> Option<(Hash256, Epoch)> {
self.proto_array.latest_message(validator_index)
}
/// Returns a reference to the underlying fork choice DAG.
pub fn proto_array(&self) -> &ProtoArrayForkChoice {
&self.proto_array
}
/// Returns a reference to the underlying `fc_store`.
pub fn fc_store(&self) -> &T {
&self.fc_store
}
/// Returns a reference to the currently queued attestations.
pub fn queued_attestations(&self) -> &[QueuedAttestation] {
&self.queued_attestations
}
/// Prunes the underlying fork choice DAG.
pub fn prune(&mut self) -> Result<(), Error<T::Error>> {
let finalized_root = self.fc_store.finalized_checkpoint().root;
self.proto_array
.maybe_prune(finalized_root)
.map_err(Into::into)
}
/// Instantiate `Self` from some `PersistedForkChoice` generated by a earlier call to
/// `Self::to_persisted`.
pub fn from_persisted(
persisted: PersistedForkChoice,
fc_store: T,
) -> Result<Self, Error<T::Error>> {
let proto_array = ProtoArrayForkChoice::from_bytes(&persisted.proto_array_bytes)
.map_err(Error::InvalidProtoArrayBytes)?;
Ok(Self {
fc_store,
proto_array,
queued_attestations: persisted.queued_attestations,
_phantom: PhantomData,
})
}
/// Takes a snapshot of `Self` and stores it in `PersistedForkChoice`, allowing this struct to
/// be instantiated again later.
pub fn to_persisted(&self) -> PersistedForkChoice {
PersistedForkChoice {
proto_array_bytes: self.proto_array().as_bytes(),
queued_attestations: self.queued_attestations().to_vec(),
}
}
}
/// Helper struct that is used to encode/decode the state of the `ForkChoice` as SSZ bytes.
///
/// This is used when persisting the state of the fork choice to disk.
#[derive(Encode, Decode, Clone)]
pub struct PersistedForkChoice {
proto_array_bytes: Vec<u8>,
queued_attestations: Vec<QueuedAttestation>,
}
#[cfg(test)]
mod tests {
use super::*;
use types::{EthSpec, MainnetEthSpec};
type E = MainnetEthSpec;
#[test]
fn slots_since_epoch_start() {
for epoch in 0..3 {
for slot in 0..E::slots_per_epoch() {
let input = epoch * E::slots_per_epoch() + slot;
assert_eq!(compute_slots_since_epoch_start::<E>(Slot::new(input)), slot)
}
}
}
#[test]
fn start_slot_at_epoch() {
for epoch in 0..3 {
assert_eq!(
compute_start_slot_at_epoch::<E>(Epoch::new(epoch)),
epoch * E::slots_per_epoch()
)
}
}
fn get_queued_attestations() -> Vec<QueuedAttestation> {
(1..4)
.into_iter()
.map(|i| QueuedAttestation {
slot: Slot::new(i),
attesting_indices: vec![],
block_root: Hash256::zero(),
target_epoch: Epoch::new(0),
})
.collect()
}
fn get_slots(queued_attestations: &[QueuedAttestation]) -> Vec<u64> {
queued_attestations.iter().map(|a| a.slot.into()).collect()
}
fn test_queued_attestations(current_time: Slot) -> (Vec<u64>, Vec<u64>) {
let mut queued = get_queued_attestations();
let dequeued = dequeue_attestations(current_time, &mut queued);
(get_slots(&queued), get_slots(&dequeued))
}
#[test]
fn dequeing_attestations() {
let (queued, dequeued) = test_queued_attestations(Slot::new(0));
assert_eq!(queued, vec![1, 2, 3]);
assert!(dequeued.is_empty());
let (queued, dequeued) = test_queued_attestations(Slot::new(1));
assert_eq!(queued, vec![1, 2, 3]);
assert!(dequeued.is_empty());
let (queued, dequeued) = test_queued_attestations(Slot::new(2));
assert_eq!(queued, vec![2, 3]);
assert_eq!(dequeued, vec![1]);
let (queued, dequeued) = test_queued_attestations(Slot::new(3));
assert_eq!(queued, vec![3]);
assert_eq!(dequeued, vec![1, 2]);
let (queued, dequeued) = test_queued_attestations(Slot::new(4));
assert!(queued.is_empty());
assert_eq!(dequeued, vec![1, 2, 3]);
}
}

61
consensus/fork_choice/src/fork_choice_store.rs Normal file
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@@ -0,0 +1,61 @@
use types::{BeaconBlock, BeaconState, Checkpoint, EthSpec, Hash256, Slot};
/// Approximates the `Store` in "Ethereum 2.0 Phase 0 -- Beacon Chain Fork Choice":
///
/// https://github.com/ethereum/eth2.0-specs/blob/v0.12.0/specs/phase0/fork-choice.md#store
///
/// ## Detail
///
/// This is only an approximation for two reasons:
///
/// - This crate stores the actual block DAG in `ProtoArrayForkChoice`.
/// - `time` is represented using `Slot` instead of UNIX epoch `u64`.
///
/// ## Motiviation
///
/// The primary motivation for defining this as a trait to be implemented upstream rather than a
/// concrete struct is to allow this crate to be free from "impure" on-disk database logic,
/// hopefully making auditing easier.
pub trait ForkChoiceStore<T: EthSpec>: Sized {
type Error;
/// Returns the last value passed to `Self::update_time`.
fn get_current_slot(&self) -> Slot;
/// Set the value to be returned by `Self::get_current_slot`.
///
/// ## Notes
///
/// This should only ever be called from within `ForkChoice::on_tick`.
fn set_current_slot(&mut self, slot: Slot);
/// Called whenever `ForkChoice::on_block` has verified a block, but not yet added it to fork
/// choice. Allows the implementer to performing caching or other housekeeping duties.
fn on_verified_block(
&mut self,
block: &BeaconBlock<T>,
block_root: Hash256,
state: &BeaconState<T>,
) -> Result<(), Self::Error>;
/// Returns the `justified_checkpoint`.
fn justified_checkpoint(&self) -> &Checkpoint;
/// Returns balances from the `state` identified by `justified_checkpoint.root`.
fn justified_balances(&self) -> &[u64];
/// Returns the `best_justified_checkpoint`.
fn best_justified_checkpoint(&self) -> &Checkpoint;
/// Returns the `finalized_checkpoint`.
fn finalized_checkpoint(&self) -> &Checkpoint;
/// Sets `finalized_checkpoint`.
fn set_finalized_checkpoint(&mut self, checkpoint: Checkpoint);
/// Sets the `justified_checkpoint`.
fn set_justified_checkpoint(&mut self, checkpoint: Checkpoint) -> Result<(), Self::Error>;
/// Sets the `best_justified_checkpoint`.
fn set_best_justified_checkpoint(&mut self, checkpoint: Checkpoint);
}

8
consensus/fork_choice/src/lib.rs Normal file
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@@ -0,0 +1,8 @@
mod fork_choice;
mod fork_choice_store;
pub use crate::fork_choice::{
Error, ForkChoice, InvalidAttestation, InvalidBlock, PersistedForkChoice, QueuedAttestation,
SAFE_SLOTS_TO_UPDATE_JUSTIFIED,
};
pub use fork_choice_store::ForkChoiceStore;

802
consensus/fork_choice/tests/tests.rs Normal file
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@@ -0,0 +1,802 @@
#![cfg(not(debug_assertions))]
use beacon_chain::{
test_utils::{AttestationStrategy, BeaconChainHarness, BlockStrategy, HarnessType},
BeaconChain, BeaconChainError, BeaconForkChoiceStore, ForkChoiceError,
};
use fork_choice::{
ForkChoiceStore, InvalidAttestation, InvalidBlock, QueuedAttestation,
SAFE_SLOTS_TO_UPDATE_JUSTIFIED,
};
use std::sync::Mutex;
use store::{MemoryStore, Store};
use types::{
test_utils::{generate_deterministic_keypair, generate_deterministic_keypairs},
Epoch, EthSpec, IndexedAttestation, MainnetEthSpec, Slot,
};
use types::{BeaconBlock, BeaconState, Hash256, SignedBeaconBlock};
pub type E = MainnetEthSpec;
pub const VALIDATOR_COUNT: usize = 16;
/// Defines some delay between when an attestation is created and when it is mutated.
pub enum MutationDelay {
/// No delay between creation and mutation.
NoDelay,
/// Create `n` blocks before mutating the attestation.
Blocks(usize),
}
/// A helper struct to make testing fork choice more ergonomic and less repetitive.
struct ForkChoiceTest {
harness: BeaconChainHarness<HarnessType<E>>,
}
impl ForkChoiceTest {
/// Creates a new tester.
pub fn new() -> Self {
let harness = BeaconChainHarness::new_with_target_aggregators(
MainnetEthSpec,
generate_deterministic_keypairs(VALIDATOR_COUNT),
// Ensure we always have an aggregator for each slot.
u64::max_value(),
);
Self { harness }
}
/// Get a value from the `ForkChoice` instantiation.
fn get<T, U>(&self, func: T) -> U
where
T: Fn(&BeaconForkChoiceStore<MemoryStore<E>, E>) -> U,
{
func(&self.harness.chain.fork_choice.read().fc_store())
}
/// Assert the epochs match.
pub fn assert_finalized_epoch(self, epoch: u64) -> Self {
assert_eq!(
self.get(|fc_store| fc_store.finalized_checkpoint().epoch),
Epoch::new(epoch),
"finalized_epoch"
);
self
}
/// Assert the epochs match.
pub fn assert_justified_epoch(self, epoch: u64) -> Self {
assert_eq!(
self.get(|fc_store| fc_store.justified_checkpoint().epoch),
Epoch::new(epoch),
"justified_epoch"
);
self
}
/// Assert the epochs match.
pub fn assert_best_justified_epoch(self, epoch: u64) -> Self {
assert_eq!(
self.get(|fc_store| fc_store.best_justified_checkpoint().epoch),
Epoch::new(epoch),
"best_justified_epoch"
);
self
}
/// Inspect the queued attestations in fork choice.
pub fn inspect_queued_attestations<F>(self, mut func: F) -> Self
where
F: FnMut(&[QueuedAttestation]),
{
self.harness
.chain
.fork_choice
.write()
.update_time(self.harness.chain.slot().unwrap())
.unwrap();
func(self.harness.chain.fork_choice.read().queued_attestations());
self
}
/// Skip a slot, without producing a block.
pub fn skip_slot(self) -> Self {
self.harness.advance_slot();
self
}
/// Build the chain whilst `predicate` returns `true`.
pub fn apply_blocks_while<F>(self, mut predicate: F) -> Self
where
F: FnMut(&BeaconBlock<E>, &BeaconState<E>) -> bool,
{
self.harness.advance_slot();
self.harness.extend_chain_while(
|block, state| predicate(&block.message, state),
BlockStrategy::OnCanonicalHead,
AttestationStrategy::AllValidators,
);
self
}
/// Apply `count` blocks to the chain (with attestations).
pub fn apply_blocks(self, count: usize) -> Self {
self.harness.advance_slot();
self.harness.extend_chain(
count,
BlockStrategy::OnCanonicalHead,
AttestationStrategy::AllValidators,
);
self
}
/// Apply `count` blocks to the chain (without attestations).
pub fn apply_blocks_without_new_attestations(self, count: usize) -> Self {
self.harness.advance_slot();
self.harness.extend_chain(
count,
BlockStrategy::OnCanonicalHead,
AttestationStrategy::SomeValidators(vec![]),
);
self
}
/// Moves to the next slot that is *outside* the `SAFE_SLOTS_TO_UPDATE_JUSTIFIED` range.
///
/// If the chain is presently in an unsafe period, transition through it and the following safe
/// period.
pub fn move_to_next_unsafe_period(self) -> Self {
self.move_inside_safe_to_update()
.move_outside_safe_to_update()
}
/// Moves to the next slot that is *outside* the `SAFE_SLOTS_TO_UPDATE_JUSTIFIED` range.
pub fn move_outside_safe_to_update(self) -> Self {
while is_safe_to_update(self.harness.chain.slot().unwrap()) {
self.harness.advance_slot()
}
self
}
/// Moves to the next slot that is *inside* the `SAFE_SLOTS_TO_UPDATE_JUSTIFIED` range.
pub fn move_inside_safe_to_update(self) -> Self {
while !is_safe_to_update(self.harness.chain.slot().unwrap()) {
self.harness.advance_slot()
}
self
}
/// Applies a block directly to fork choice, bypassing the beacon chain.
///
/// Asserts the block was applied successfully.
pub fn apply_block_directly_to_fork_choice<F>(self, mut func: F) -> Self
where
F: FnMut(&mut BeaconBlock<E>, &mut BeaconState<E>),
{
let (mut block, mut state) = self.harness.get_block();
func(&mut block.message, &mut state);
let current_slot = self.harness.chain.slot().unwrap();
self.harness
.chain
.fork_choice
.write()
.on_block(current_slot, &block.message, block.canonical_root(), &state)
.unwrap();
self
}
/// Applies a block directly to fork choice, bypassing the beacon chain.
///
/// Asserts that an error occurred and allows inspecting it via `comparison_func`.
pub fn apply_invalid_block_directly_to_fork_choice<F, G>(
self,
mut mutation_func: F,
mut comparison_func: G,
) -> Self
where
F: FnMut(&mut BeaconBlock<E>, &mut BeaconState<E>),
G: FnMut(ForkChoiceError),
{
let (mut block, mut state) = self.harness.get_block();
mutation_func(&mut block.message, &mut state);
let current_slot = self.harness.chain.slot().unwrap();
let err = self
.harness
.chain
.fork_choice
.write()
.on_block(current_slot, &block.message, block.canonical_root(), &state)
.err()
.expect("on_block did not return an error");
comparison_func(err);
self
}
/// Compares the justified balances in the `ForkChoiceStore` verses a direct lookup from the
/// database.
fn check_justified_balances(&self) {
let harness = &self.harness;
let fc = self.harness.chain.fork_choice.read();
let state_root = harness
.chain
.store
.get_item::<SignedBeaconBlock<E>>(&fc.fc_store().justified_checkpoint().root)
.unwrap()
.unwrap()
.message
.state_root;
let state = harness
.chain
.store
.get_state(&state_root, None)
.unwrap()
.unwrap();
let balances = state
.validators
.into_iter()
.map(|v| {
if v.is_active_at(state.current_epoch()) {
v.effective_balance
} else {
0
}
})
.collect::<Vec<_>>();
assert_eq!(
&balances[..],
fc.fc_store().justified_balances(),
"balances should match"
)
}
/// Returns an attestation that is valid for some slot in the given `chain`.
///
/// Also returns some info about who created it.
fn apply_attestation_to_chain<F, G>(
self,
delay: MutationDelay,
mut mutation_func: F,
mut comparison_func: G,
) -> Self
where
F: FnMut(&mut IndexedAttestation<E>, &BeaconChain<HarnessType<E>>),
G: FnMut(Result<(), BeaconChainError>),
{
let chain = &self.harness.chain;
let head = chain.head().expect("should get head");
let current_slot = chain.slot().expect("should get slot");
let mut attestation = chain
.produce_unaggregated_attestation(current_slot, 0)
.expect("should not error while producing attestation");
let validator_committee_index = 0;
let validator_index = *head
.beacon_state
.get_beacon_committee(current_slot, attestation.data.index)
.expect("should get committees")
.committee
.get(validator_committee_index)
.expect("there should be an attesting validator");
let validator_sk = generate_deterministic_keypair(validator_index).sk;
attestation
.sign(
&validator_sk,
validator_committee_index,
&head.beacon_state.fork,
chain.genesis_validators_root,
&chain.spec,
)
.expect("should sign attestation");
let mut verified_attestation = chain
.verify_unaggregated_attestation_for_gossip(attestation)
.expect("precondition: should gossip verify attestation");
if let MutationDelay::Blocks(slots) = delay {
self.harness.advance_slot();
self.harness.extend_chain(
slots,
BlockStrategy::OnCanonicalHead,
AttestationStrategy::SomeValidators(vec![]),
);
}
mutation_func(verified_attestation.__indexed_attestation_mut(), chain);
let result = chain.apply_attestation_to_fork_choice(&verified_attestation);
comparison_func(result);
self
}
}
fn is_safe_to_update(slot: Slot) -> bool {
slot % E::slots_per_epoch() < SAFE_SLOTS_TO_UPDATE_JUSTIFIED
}
/// - The new justified checkpoint descends from the current.
/// - Current slot is within `SAFE_SLOTS_TO_UPDATE_JUSTIFIED`
#[test]
fn justified_checkpoint_updates_with_descendent_inside_safe_slots() {
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.current_justified_checkpoint.epoch == 0)
.move_inside_safe_to_update()
.assert_justified_epoch(0)
.apply_blocks(1)
.assert_justified_epoch(2);
}
/// - The new justified checkpoint descends from the current.
/// - Current slot is **not** within `SAFE_SLOTS_TO_UPDATE_JUSTIFIED`
/// - This is **not** the first justification since genesis
#[test]
fn justified_checkpoint_updates_with_descendent_outside_safe_slots() {
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.current_justified_checkpoint.epoch <= 2)
.move_outside_safe_to_update()
.assert_justified_epoch(2)
.assert_best_justified_epoch(2)
.apply_blocks(1)
.assert_justified_epoch(3);
}
/// - The new justified checkpoint descends from the current.
/// - Current slot is **not** within `SAFE_SLOTS_TO_UPDATE_JUSTIFIED`
/// - This is the first justification since genesis
#[test]
fn justified_checkpoint_updates_first_justification_outside_safe_to_update() {
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.current_justified_checkpoint.epoch == 0)
.move_to_next_unsafe_period()
.assert_justified_epoch(0)
.assert_best_justified_epoch(0)
.apply_blocks(1)
.assert_justified_epoch(2)
.assert_best_justified_epoch(2);
}
/// - The new justified checkpoint **does not** descend from the current.
/// - Current slot is within `SAFE_SLOTS_TO_UPDATE_JUSTIFIED`
/// - Finalized epoch has **not** increased.
#[test]
fn justified_checkpoint_updates_with_non_descendent_inside_safe_slots_without_finality() {
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.current_justified_checkpoint.epoch == 0)
.apply_blocks(1)
.move_inside_safe_to_update()
.assert_justified_epoch(2)
.apply_block_directly_to_fork_choice(|_, state| {
// The finalized checkpoint should not change.
state.finalized_checkpoint.epoch = Epoch::new(0);
// The justified checkpoint has changed.
state.current_justified_checkpoint.epoch = Epoch::new(3);
// The new block should **not** include the current justified block as an ancestor.
state.current_justified_checkpoint.root = *state
.get_block_root(Epoch::new(1).start_slot(E::slots_per_epoch()))
.unwrap();
})
.assert_justified_epoch(3)
.assert_best_justified_epoch(3);
}
/// - The new justified checkpoint **does not** descend from the current.
/// - Current slot is **not** within `SAFE_SLOTS_TO_UPDATE_JUSTIFIED`.
/// - Finalized epoch has **not** increased.
#[test]
fn justified_checkpoint_updates_with_non_descendent_outside_safe_slots_without_finality() {
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.current_justified_checkpoint.epoch == 0)
.apply_blocks(1)
.move_to_next_unsafe_period()
.assert_justified_epoch(2)
.apply_block_directly_to_fork_choice(|_, state| {
// The finalized checkpoint should not change.
state.finalized_checkpoint.epoch = Epoch::new(0);
// The justified checkpoint has changed.
state.current_justified_checkpoint.epoch = Epoch::new(3);
// The new block should **not** include the current justified block as an ancestor.
state.current_justified_checkpoint.root = *state
.get_block_root(Epoch::new(1).start_slot(E::slots_per_epoch()))
.unwrap();
})
.assert_justified_epoch(2)
.assert_best_justified_epoch(3);
}
/// - The new justified checkpoint **does not** descend from the current.
/// - Current slot is **not** within `SAFE_SLOTS_TO_UPDATE_JUSTIFIED`
/// - Finalized epoch has increased.
#[test]
fn justified_checkpoint_updates_with_non_descendent_outside_safe_slots_with_finality() {
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.current_justified_checkpoint.epoch == 0)
.apply_blocks(1)
.move_to_next_unsafe_period()
.assert_justified_epoch(2)
.apply_block_directly_to_fork_choice(|_, state| {
// The finalized checkpoint should change.
state.finalized_checkpoint.epoch = Epoch::new(1);
// The justified checkpoint has changed.
state.current_justified_checkpoint.epoch = Epoch::new(3);
// The new block should **not** include the current justified block as an ancestor.
state.current_justified_checkpoint.root = *state
.get_block_root(Epoch::new(1).start_slot(E::slots_per_epoch()))
.unwrap();
})
.assert_justified_epoch(3)
.assert_best_justified_epoch(3);
}
/// Check that the balances are obtained correctly.
#[test]
fn justified_balances() {
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.current_justified_checkpoint.epoch == 0)
.apply_blocks(1)
.assert_justified_epoch(2)
.check_justified_balances()
}
macro_rules! assert_invalid_block {
($err: tt, $($error: pat) |+ $( if $guard: expr )?) => {
assert!(
matches!(
$err,
$( ForkChoiceError::InvalidBlock($error) ) |+ $( if $guard )?
),
);
};
}
/// Specification v0.12.1
///
/// assert block.parent_root in store.block_states
#[test]
fn invalid_block_unknown_parent() {
let junk = Hash256::from_low_u64_be(42);
ForkChoiceTest::new()
.apply_blocks(2)
.apply_invalid_block_directly_to_fork_choice(
|block, _| {
block.parent_root = junk;
},
|err| {
assert_invalid_block!(
err,
InvalidBlock::UnknownParent(parent)
if parent == junk
)
},
);
}
/// Specification v0.12.1
///
/// assert get_current_slot(store) >= block.slot
#[test]
fn invalid_block_future_slot() {
ForkChoiceTest::new()
.apply_blocks(2)
.apply_invalid_block_directly_to_fork_choice(
|block, _| {
block.slot = block.slot + 1;
},
|err| {
assert_invalid_block!(
err,
InvalidBlock::FutureSlot { .. }
)
},
);
}
/// Specification v0.12.1
///
/// assert block.slot > finalized_slot
#[test]
fn invalid_block_finalized_slot() {
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.finalized_checkpoint.epoch == 0)
.apply_blocks(1)
.apply_invalid_block_directly_to_fork_choice(
|block, _| {
block.slot = Epoch::new(2).start_slot(E::slots_per_epoch()) - 1;
},
|err| {
assert_invalid_block!(
err,
InvalidBlock::FinalizedSlot { finalized_slot, .. }
if finalized_slot == Epoch::new(2).start_slot(E::slots_per_epoch())
)
},
);
}
/// Specification v0.12.1
///
/// assert get_ancestor(store, hash_tree_root(block), finalized_slot) ==
/// store.finalized_checkpoint.root
///
/// Note: we technically don't do this exact check, but an equivalent check. Reference:
///
/// https://github.com/ethereum/eth2.0-specs/pull/1884
#[test]
fn invalid_block_finalized_descendant() {
let invalid_ancestor = Mutex::new(Hash256::zero());
ForkChoiceTest::new()
.apply_blocks_while(|_, state| state.finalized_checkpoint.epoch == 0)
.apply_blocks(1)
.assert_finalized_epoch(2)
.apply_invalid_block_directly_to_fork_choice(
|block, state| {
block.parent_root = *state
.get_block_root(Epoch::new(1).start_slot(E::slots_per_epoch()))
.unwrap();
*invalid_ancestor.lock().unwrap() = block.parent_root;
},
|err| {
assert_invalid_block!(
err,
InvalidBlock::NotFinalizedDescendant { block_ancestor, .. }
if block_ancestor == Some(*invalid_ancestor.lock().unwrap())
)
},
);
}
macro_rules! assert_invalid_attestation {
($err: tt, $($error: pat) |+ $( if $guard: expr )?) => {
assert!(
matches!(
$err,
$( Err(BeaconChainError::ForkChoiceError(ForkChoiceError::InvalidAttestation($error))) ) |+ $( if $guard )?
),
"{:?}",
$err
);
};
}
/// Ensure we can process a valid attestation.
#[test]
fn valid_attestation() {
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(1)
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|_, _| {},
|result| assert_eq!(result.unwrap(), ()),
);
}
/// This test is not in the specification, however we reject an attestation with an empty
/// aggregation bitfield since it has no purpose beyond wasting our time.
#[test]
fn invalid_attestation_empty_bitfield() {
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(1)
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|attestation, _| {
attestation.attesting_indices = vec![].into();
},
|result| {
assert_invalid_attestation!(result, InvalidAttestation::EmptyAggregationBitfield)
},
);
}
/// Specification v0.12.1:
///
/// assert target.epoch in [expected_current_epoch, previous_epoch]
///
/// (tests epoch after current epoch)
#[test]
fn invalid_attestation_future_epoch() {
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(1)
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|attestation, _| {
attestation.data.target.epoch = Epoch::new(2);
},
|result| {
assert_invalid_attestation!(
result,
InvalidAttestation::FutureEpoch { attestation_epoch, current_epoch }
if attestation_epoch == Epoch::new(2) && current_epoch == Epoch::new(0)
)
},
);
}
/// Specification v0.12.1:
///
/// assert target.epoch in [expected_current_epoch, previous_epoch]
///
/// (tests epoch prior to previous epoch)
#[test]
fn invalid_attestation_past_epoch() {
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(E::slots_per_epoch() as usize * 3 + 1)
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|attestation, _| {
attestation.data.target.epoch = Epoch::new(0);
},
|result| {
assert_invalid_attestation!(
result,
InvalidAttestation::PastEpoch { attestation_epoch, current_epoch }
if attestation_epoch == Epoch::new(0) && current_epoch == Epoch::new(3)
)
},
);
}
/// Specification v0.12.1:
///
/// assert target.epoch == compute_epoch_at_slot(attestation.data.slot)
#[test]
fn invalid_attestation_target_epoch() {
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(E::slots_per_epoch() as usize + 1)
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|attestation, _| {
attestation.data.slot = Slot::new(1);
},
|result| {
assert_invalid_attestation!(
result,
InvalidAttestation::BadTargetEpoch { target, slot }
if target == Epoch::new(1) && slot == Slot::new(1)
)
},
);
}
/// Specification v0.12.1:
///
/// assert target.root in store.blocks
#[test]
fn invalid_attestation_unknown_target_root() {
let junk = Hash256::from_low_u64_be(42);
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(1)
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|attestation, _| {
attestation.data.target.root = junk;
},
|result| {
assert_invalid_attestation!(
result,
InvalidAttestation::UnknownTargetRoot(root)
if root == junk
)
},
);
}
/// Specification v0.12.1:
///
/// assert attestation.data.beacon_block_root in store.blocks
#[test]
fn invalid_attestation_unknown_beacon_block_root() {
let junk = Hash256::from_low_u64_be(42);
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(1)
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|attestation, _| {
attestation.data.beacon_block_root = junk;
},
|result| {
assert_invalid_attestation!(
result,
InvalidAttestation::UnknownHeadBlock { beacon_block_root }
if beacon_block_root == junk
)
},
);
}
/// Specification v0.12.1:
///
/// assert store.blocks[attestation.data.beacon_block_root].slot <= attestation.data.slot
#[test]
fn invalid_attestation_future_block() {
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(1)
.apply_attestation_to_chain(
MutationDelay::Blocks(1),
|attestation, chain| {
attestation.data.beacon_block_root = chain
.block_at_slot(chain.slot().unwrap())
.unwrap()
.unwrap()
.canonical_root();
},
|result| {
assert_invalid_attestation!(
result,
InvalidAttestation::AttestsToFutureBlock { block, attestation }
if block == 2 && attestation == 1
)
},
);
}
/// Specification v0.12.1:
///
/// assert target.root == get_ancestor(store, attestation.data.beacon_block_root, target_slot)
#[test]
fn invalid_attestation_inconsistent_ffg_vote() {
let local_opt = Mutex::new(None);
let attestation_opt = Mutex::new(None);
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(1)
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|attestation, chain| {
attestation.data.target.root = chain
.block_at_slot(Slot::new(1))
.unwrap()
.unwrap()
.canonical_root();
*attestation_opt.lock().unwrap() = Some(attestation.data.target.root);
*local_opt.lock().unwrap() = Some(
chain
.block_at_slot(Slot::new(0))
.unwrap()
.unwrap()
.canonical_root(),
);
},
|result| {
assert_invalid_attestation!(
result,
InvalidAttestation::InvalidTarget { attestation, local }
if attestation == attestation_opt.lock().unwrap().unwrap()
&& local == local_opt.lock().unwrap().unwrap()
)
},
);
}
/// Specification v0.12.1:
///
/// assert get_current_slot(store) >= attestation.data.slot + 1
#[test]
fn invalid_attestation_delayed_slot() {
ForkChoiceTest::new()
.apply_blocks_without_new_attestations(1)
.inspect_queued_attestations(|queue| assert_eq!(queue.len(), 0))
.apply_attestation_to_chain(
MutationDelay::NoDelay,
|_, _| {},
|result| assert_eq!(result.unwrap(), ()),
)
.inspect_queued_attestations(|queue| assert_eq!(queue.len(), 1))
.skip_slot()
.inspect_queued_attestations(|queue| assert_eq!(queue.len(), 0));
}