diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index f95cb29e8..f3f66ce41 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1041,7 +1041,7 @@ def verify_merkle_branch(leaf: Bytes32, proof: List[Bytes32], depth: int, index: ```python def get_crosslink_committee_for_attestation(state: BeaconState, - attestation_data: AttestationData) -> List[ValidatorIndex]: + attestation_data: AttestationData) -> List[ValidatorIndex]: # Find the committee in the list with the desired shard crosslink_committees = get_crosslink_committees_at_slot(state, attestation_data.slot) @@ -1766,10 +1766,7 @@ def get_winning_root_and_participants(state: BeaconState, slot: Slot, shard: Sha attestations = state.current_epoch_attestations if slot_to_epoch(slot) == get_current_epoch(state) else state.previous_epoch_attestations crosslinks = state.current_crosslinks if slot_to_epoch(slot) == get_current_epoch(state) else state.previous_crosslinks - valid_attestations = [ - a for a in attestations - if a.data.previous_crosslink == crosslinks[shard] and a.data.shard == shard - ] + valid_attestations = [a for a in attestations if a.data.shard == shard] all_roots = [a.data.crosslink_data_root for a in valid_attestations] # handle when no attestations for shard available diff --git a/tests/phase0/epoch_processing/test_process_crosslinks.py b/tests/phase0/epoch_processing/test_process_crosslinks.py new file mode 100644 index 000000000..a69950f21 --- /dev/null +++ b/tests/phase0/epoch_processing/test_process_crosslinks.py @@ -0,0 +1,92 @@ +from copy import deepcopy +import pytest + +import build.phase0.spec as spec + +from build.phase0.state_transition import ( + state_transition, +) +from build.phase0.spec import ( + ZERO_HASH, + cache_state, + get_crosslink_committee_for_attestation, + get_current_epoch, + process_crosslinks, + slot_to_epoch, +) +from tests.phase0.helpers import ( + add_attestation_to_state, + build_empty_block_for_next_slot, + fill_aggregate_attestation, + get_valid_attestation, + next_epoch, + set_bitfield_bit, +) + + +# mark entire file as 'crosslinks' +pytestmark = pytest.mark.crosslinks + + +def run_process_crosslinks(state, valid=True): + post_state = deepcopy(state) + + # transition state to slot before state transition + slot = state.slot + (spec.SLOTS_PER_EPOCH - state.slot % spec.SLOTS_PER_EPOCH) - 1 + block = build_empty_block_for_next_slot(state) + block.slot = slot + state_transition(state, block) + + # cache state before epoch transition + cache_state(state) + + process_crosslinks(post_state) + + return state, post_state + + +def test_no_attestations(state): + pre_state, post_state = run_process_crosslinks(state) + + for shard in range(spec.SHARD_COUNT): + assert post_state.previous_crosslinks[shard] == post_state.current_crosslinks[shard] + + return pre_state, post_state + + +def test_single_crosslink_update_from_current_epoch(state): + next_epoch(state) + + attestation = get_valid_attestation(state) + + fill_aggregate_attestation(state, attestation) + add_attestation_to_state(state, attestation, state.slot + spec.MIN_ATTESTATION_INCLUSION_DELAY) + + assert len(state.current_epoch_attestations) == 1 + + pre_state, post_state = run_process_crosslinks(state) + + shard = attestation.data.shard + assert post_state.previous_crosslinks[shard] != post_state.current_crosslinks[shard] + assert pre_state.current_crosslinks[shard] != post_state.current_crosslinks[shard] + + return pre_state, post_state + + +def test_single_crosslink_update_from_previous_epoch(state): + next_epoch(state) + + attestation = get_valid_attestation(state) + + fill_aggregate_attestation(state, attestation) + add_attestation_to_state(state, attestation, state.slot + spec.SLOTS_PER_EPOCH) + + assert len(state.previous_epoch_attestations) == 1 + + pre_state, post_state = run_process_crosslinks(state) + + shard = attestation.data.shard + assert post_state.previous_crosslinks[shard] != post_state.current_crosslinks[shard] + assert pre_state.current_crosslinks[shard] != post_state.current_crosslinks[shard] + + return pre_state, post_state diff --git a/tests/phase0/helpers.py b/tests/phase0/helpers.py index 0fd7bab73..ead0a0489 100644 --- a/tests/phase0/helpers.py +++ b/tests/phase0/helpers.py @@ -4,6 +4,9 @@ from py_ecc import bls import build.phase0.spec as spec from build.phase0.utils.minimal_ssz import signed_root +from build.phase0.state_transition import ( + state_transition, +) from build.phase0.spec import ( # constants EMPTY_SIGNATURE, @@ -47,6 +50,19 @@ pubkeys = [bls.privtopub(privkey) for privkey in privkeys] pubkey_to_privkey = {pubkey: privkey for privkey, pubkey in zip(privkeys, pubkeys)} +def set_bitfield_bit(bitfield, i): + """ + Set the bit in ``bitfield`` at position ``i`` to ``1``. + """ + byte_index = i // 8 + bit_index = i % 8 + return ( + bitfield[:byte_index] + + bytes([bitfield[byte_index] | (1 << bit_index)]) + + bitfield[byte_index+1:] + ) + + def create_mock_genesis_validator_deposits(num_validators, deposit_data_leaves=None): if not deposit_data_leaves: deposit_data_leaves = [] @@ -140,7 +156,7 @@ def build_attestation_data(state, slot, shard): if epoch_start_slot == slot: epoch_boundary_root = block_root else: - get_block_root(state, epoch_start_slot) + epoch_boundary_root = get_block_root(state, epoch_start_slot) if slot < epoch_start_slot: justified_block_root = state.previous_justified_root @@ -257,7 +273,7 @@ def get_valid_attester_slashing(state): def get_valid_attestation(state, slot=None): if slot is None: slot = state.slot - shard = state.latest_start_shard + shard = state.latest_start_shard + slot % spec.SLOTS_PER_EPOCH attestation_data = build_attestation_data(state, slot, shard) crosslink_committee = get_crosslink_committee_for_attestation(state, attestation_data) @@ -309,3 +325,22 @@ def get_attestation_signature(state, attestation_data, privkey, custody_bit=0b0) domain_type=spec.DOMAIN_ATTESTATION, ) ) + + +def fill_aggregate_attestation(state, attestation): + crosslink_committee = get_crosslink_committee_for_attestation(state, attestation.data) + for i in range(len(crosslink_committee)): + attestation.aggregation_bitfield = set_bitfield_bit(attestation.aggregation_bitfield, i) + + +def add_attestation_to_state(state, attestation, slot): + block = build_empty_block_for_next_slot(state) + block.slot = slot + block.body.attestations.append(attestation) + state_transition(state, block) + + +def next_epoch(state): + block = build_empty_block_for_next_slot(state) + block.slot += spec.SLOTS_PER_EPOCH - (state.slot % spec.SLOTS_PER_EPOCH) + state_transition(state, block)