cerc-io/lighthouse
16
0
Fork 0
Code Issues 1 Pull Requests Packages Projects Releases Wiki Activity

Fix bug with fork choice, tidy

Browse Source
This commit is contained in:
Paul Hauner 2019-08-09 11:54:35 +10:00
parent 284166c7f8
commit 76bb671084
No known key found for this signature in database
GPG Key ID: 5E2CFF9B75FA63DF
6 changed files with 70 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

63
beacon_node/beacon_chain/src/beacon_chain.rs
View File

@ -524,7 +524,13 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
// If it turns out that the attestation was made using the head state, then there
// is no need to load a state from the database to process the attestation.
if state.current_epoch() == attestation_head_block.epoch()
//
// Note: use the epoch of the target because it indicates which epoch the
// attestation was created in. You cannot use the epoch of the head block, because
// the block doesn't necessarily need to be in the same epoch as the attestation
// (e.g., if there are skip slots between the epoch the block was created in and
// the epoch for the attestation).
if state.current_epoch() == attestation.data.target.epoch
&& (state
.get_block_root(attestation_head_block.slot)
.map(|root| *root == attestation.data.beacon_block_root)
@ -546,7 +552,11 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
if let Some(outcome) = optional_outcome {
outcome
} else {
// The state required to verify this attestation must be loaded from the database.
// Use the `data.beacon_block_root` to load the state from the latest non-skipped
// slot preceding the attestations creation.
//
// This state is guaranteed to be in the same chain as the attestation, but it's
// not guaranteed to be from the same slot or epoch as the attestation.
let mut state: BeaconState<T::EthSpec> = self
.store
.get(&attestation_head_block.state_root)?
@ -554,7 +564,21 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
// Ensure the state loaded from the database matches the state of the attestation
// head block.
for _ in state.slot.as_u64()..attestation_head_block.slot.as_u64() {
//
// The state needs to be advanced from the current slot through to the epoch in
// which the attestation was created in. It would be an error to try and use
// `state.get_attestation_data_slot(..)` because the state matching the
// `data.beacon_block_root` isn't necessarily in a nearby epoch to the attestation
// (e.g., if there were lots of skip slots since the head of the chain and the
// epoch creation epoch).
for _ in state.slot.as_u64()
..attestation
.data
.target
.epoch
.start_slot(T::EthSpec::slots_per_epoch())
.as_u64()
{
per_slot_processing(&mut state, &self.spec)?;
}
@ -639,36 +663,6 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
timer.observe_duration();
result
/*
if self
.fork_choice
.should_process_attestation(state, &attestation)?
{
// TODO: check validation.
let indexed_attestation = common::get_indexed_attestation(state, &attestation)?;
per_block_processing::is_valid_indexed_attestation(
state,
&indexed_attestation,
&self.spec,
)?;
self.fork_choice.process_attestation(&state, &attestation)?;
}
let result = self
.op_pool
.insert_attestation(attestation, state, &self.spec);
timer.observe_duration();
if result.is_ok() {
self.metrics.attestation_processing_successes.inc();
}
result
.map(|_| AttestationProcessingOutcome::Processed)
.map_err(|e| Error::AttestationValidationError(e))
*/
}
/// Accept some deposit and queue it for inclusion in an appropriate block.
@ -735,7 +729,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
return Ok(BlockProcessingOutcome::GenesisBlock);
}
let block_root = block.block_header().canonical_root();
let block_root = block.canonical_root();
if block_root == self.genesis_block_root {
return Ok(BlockProcessingOutcome::GenesisBlock);
@ -781,6 +775,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
per_slot_processing(&mut state, &self.spec)?;
}
state.build_committee_cache(RelativeEpoch::Previous, &self.spec)?;
state.build_committee_cache(RelativeEpoch::Current, &self.spec)?;
// Apply the received block to its parent state (which has been transitioned into this

14
beacon_node/beacon_chain/src/fork_choice.rs
View File

@ -19,6 +19,7 @@ pub enum Error {
}
pub struct ForkChoice<T: BeaconChainTypes> {
store: Arc<T::Store>,
backend: T::LmdGhost,
/// Used for resolving the `0x00..00` alias back to genesis.
///
@ -38,6 +39,7 @@ impl<T: BeaconChainTypes> ForkChoice<T> {
genesis_block_root: Hash256,
) -> Self {
Self {
store: store.clone(),
backend: T::LmdGhost::new(store, genesis_block, genesis_block_root),
genesis_block_root,
}
@ -117,9 +119,19 @@ impl<T: BeaconChainTypes> ForkChoice<T> {
//
// https://github.com/ethereum/eth2.0-specs/blob/v0.7.0/specs/core/0_fork-choice.md
for attestation in &block.body.attestations {
self.process_attestation(state, attestation, block)?;
let block = self
.store
.get::<BeaconBlock<T::EthSpec>>(&attestation.data.beacon_block_root)?
.ok_or_else(|| Error::MissingBlock(attestation.data.beacon_block_root))?;
self.process_attestation(state, attestation, &block)?;
}
// 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.
//
// A case where a block without any votes can be the head is where it is the only child of
// a block that has the majority of votes applied to it.
self.backend.process_block(block, block_root)?;
Ok(())

6
beacon_node/beacon_chain/src/test_utils.rs
View File

@ -349,14 +349,12 @@ where
agg_sig
};
let attestation = Attestation {
vec.push(Attestation {
aggregation_bits,
data,
custody_bits,
signature,
};
vec.push(attestation)
})
}
}
});

22
beacon_node/beacon_chain/tests/tests.rs
View File

@ -342,27 +342,29 @@ fn free_attestations_added_to_fork_choice_some_none() {
let state = &harness.chain.head().beacon_state;
let fork_choice = &harness.chain.fork_choice;
let validators: Vec<usize> = (0..VALIDATOR_COUNT).collect();
let slots: Vec<Slot> = validators
.iter()
.map(|&v| {
state
.get_attestation_duties(v, RelativeEpoch::Current)
let validator_slots: Vec<(usize, Slot)> = (0..VALIDATOR_COUNT)
.into_iter()
.map(|validator_index| {
let slot = state
.get_attestation_duties(validator_index, RelativeEpoch::Current)
.expect("should get attester duties")
.unwrap()
.slot
.slot;
(validator_index, slot)
})
.collect();
let validator_slots: Vec<(&usize, Slot)> = validators.iter().zip(slots).collect();
for (validator, slot) in validator_slots.clone() {
let latest_message = fork_choice.latest_message(*validator);
let latest_message = fork_choice.latest_message(validator);
if slot <= num_blocks_produced && slot != 0 {
assert_eq!(
latest_message.unwrap().1,
slot,
"Latest message slot should be equal to attester duty."
"Latest message slot for {} should be equal to slot {}.",
validator,
slot
)
} else {
assert!(

3
eth2/state_processing/src/per_block_processing/errors.rs
View File

@ -136,6 +136,9 @@ pub enum AttestationInvalid {
delay: u64,
attestation: Slot,
},
/// The attestation is attesting to a state that is later than itself. (Viz., attesting to the
/// future).
AttestsToFutureState { state: Slot, attestation: Slot },
/// Attestation slot is too far in the past to be included in a block.
IncludedTooLate { state: Slot, attestation: Slot },
/// Attestation target epoch does not match the current or previous epoch.

11
eth2/state_processing/src/per_block_processing/verify_attestation.rs
View File

@ -62,6 +62,17 @@ pub fn verify_attestation_for_state<T: EthSpec>(
Invalid::BadShard
);
let attestation_slot = state.get_attestation_data_slot(&data)?;
// An attestation cannot attest to a state that is later than itself.
verify!(
attestation_slot <= state.slot,
Invalid::AttestsToFutureState {
state: state.slot,
attestation: attestation_slot
}
);
// Verify the Casper FFG vote and crosslink data.
let parent_crosslink = verify_casper_ffg_vote(attestation, state)?;