def _get_fork_choice_context(self) -> LMDGHOSTContext:
try:
fork_choice_context_data = self.chain_db.get_fork_choice_context_data_for(
self.fork)
except MissingForkChoiceContext:
# NOTE: ``MissingForkChoiceContext`` here implies that we are missing the
# fork choice context for this fork, which happens to be the genesis fork.
# In this situation (possibly uniquely), we want to build a new
# fork choice context from the genesis data.
genesis_root = self.chain_db.get_genesis_block_root()
genesis_block = self.chain_db.get_block_by_root(
genesis_root, self.block_class)
genesis_state = self.chain_db.get_state_by_root(
genesis_block.message.state_root, self.state_class)
return LMDGHOSTContext.from_genesis(genesis_state, genesis_block)
else:
return LMDGHOSTContext.from_bytes(fork_choice_context_data)
def genesis_fork_choice_context(genesis_state, genesis_block):
return LMDGHOSTContext.from_genesis(genesis_state, genesis_block)
def test_lmd_ghost_fork_choice_scoring(
sample_beacon_block_params,
chaindb_at_genesis,
# see note below on how this is used
fork_choice_scoring,
forking_descriptor,
forking_asymmetry,
genesis_state,
genesis_block,
config,
):
"""
Given some blocks and some attestations, can we score them correctly?
"""
chain_db = chaindb_at_genesis
root_block = chain_db.get_canonical_head(SignedBeaconBlock)
some_epoch = 3
some_slot_offset = 10
state = genesis_state.mset(
"slot",
compute_start_slot_at_epoch(some_epoch, config.SLOTS_PER_EPOCH) +
some_slot_offset,
"current_justified_checkpoint",
Checkpoint.create(epoch=some_epoch,
root=root_block.message.hash_tree_root),
)
assert some_epoch >= state.current_justified_checkpoint.epoch
# NOTE: the attestations have to be aligned to the blocks which start from ``base_slot``.
base_slot = compute_start_slot_at_epoch(some_epoch,
config.SLOTS_PER_EPOCH) + 1
block_tree = _build_block_tree(
sample_beacon_block_params,
root_block,
base_slot,
forking_descriptor,
forking_asymmetry,
config,
)
slot_count = len(forking_descriptor)
committee_sampling_fraction = 1
committees_by_slot = tuple(
_get_committees(state, base_slot +
slot_offset, config, committee_sampling_fraction)
for slot_offset in range(slot_count))
_attach_committees_to_block_tree(state, block_tree, committees_by_slot,
config, forking_asymmetry)
_attach_attestations_to_block_tree_with_committees(block_tree, config)
context = Context.from_genesis(genesis_state, genesis_block)
store = Store(chain_db, SignedBeaconBlock, config, context)
score_index = _build_score_index_from_decorated_block_tree(
block_tree, store, state, config)
for block in _iter_block_tree_by_block(block_tree):
# NOTE: we use the ``fork_choice_scoring`` fixture, it doesn't matter for this test
chain_db.persist_block(block, SignedBeaconBlock, fork_choice_scoring)
for block in _iter_block_tree_by_block(block_tree):
score = store.scoring(block)
expected_score = score_index[block.message.hash_tree_root]
assert score == expected_score
def test_store_get_latest_attestation(genesis_state, genesis_block, config,
collisions_from_another_epoch):
"""
Given some attestations across the various sources, can we
find the latest ones for each validator?
"""
some_epoch = 3
state = genesis_state.set(
"slot", compute_start_slot_at_epoch(some_epoch,
config.SLOTS_PER_EPOCH))
some_time = (_compute_seconds_since_genesis_for_epoch(some_epoch, config) +
state.genesis_time)
previous_epoch = state.previous_epoch(config.SLOTS_PER_EPOCH,
config.GENESIS_EPOCH)
previous_epoch_committee_count = _get_committee_count(
state, previous_epoch, config)
current_epoch = state.current_epoch(config.SLOTS_PER_EPOCH)
current_epoch_committee_count = _get_committee_count(
state, current_epoch, config)
number_of_committee_samples = 4
assert number_of_committee_samples <= previous_epoch_committee_count
assert number_of_committee_samples <= current_epoch_committee_count
block_producer = _mk_block_at_slot(genesis_block)
# prepare samples from previous epoch
previous_epoch_attestations_by_index = _mk_attestations_for_epoch_by_count(
number_of_committee_samples, previous_epoch, block_producer, state,
config)
previous_epoch_attestations = _extract_attestations_from_index_keying(
previous_epoch_attestations_by_index.values())
# prepare samples from current epoch
current_epoch_attestations_by_index = _mk_attestations_for_epoch_by_count(
number_of_committee_samples, current_epoch, block_producer, state,
config)
current_epoch_attestations_by_index = keyfilter(
lambda index: index not in previous_epoch_attestations_by_index,
current_epoch_attestations_by_index,
)
current_epoch_attestations = _extract_attestations_from_index_keying(
current_epoch_attestations_by_index.values())
pool_attestations_by_index = _mk_attestations_for_epoch_by_count(
number_of_committee_samples, current_epoch, block_producer, state,
config)
pool_attestations_by_index = keyfilter(
lambda index: (index not in previous_epoch_attestations_by_index or
index not in current_epoch_attestations_by_index),
pool_attestations_by_index,
)
pool_attestations = _extract_attestations_from_index_keying(
pool_attestations_by_index.values())
all_attestations_by_index = (
previous_epoch_attestations_by_index,
current_epoch_attestations_by_index,
pool_attestations_by_index,
)
if collisions_from_another_epoch:
(
previous_epoch_attestations_by_index,
current_epoch_attestations_by_index,
pool_attestations_by_index,
) = _introduce_collisions(all_attestations_by_index, block_producer,
state, config)
previous_epoch_attestations = _extract_attestations_from_index_keying(
previous_epoch_attestations_by_index.values())
current_epoch_attestations = _extract_attestations_from_index_keying(
current_epoch_attestations_by_index.values())
pool_attestations = _extract_attestations_from_index_keying(
pool_attestations_by_index.values())
# build expected results
expected_index = merge_with(
_keep_by_latest_slot,
previous_epoch_attestations_by_index,
current_epoch_attestations_by_index,
pool_attestations_by_index,
)
chain_db = None # not relevant for this test
context = Context.from_genesis(genesis_state, genesis_block)
context.time = some_time
store = Store(chain_db, SignedBeaconBlock, config, context)
for attestations in (
previous_epoch_attestations,
current_epoch_attestations,
pool_attestations,
):
for attestation in attestations:
# NOTE: we need to synchronize the context w/ chain data used to construct
# attestations above; this synchronization takes advantage of some of the
# internals of ``on_attestation`` to shortcut constructing the complete network
# state needed to test the function of the ``Store``.
block = block_producer(attestation.data.slot)
context.blocks[block.message.hash_tree_root] = block
context.block_states[block.message.hash_tree_root] = genesis_state
store.on_attestation(attestation, validate_signature=False)
# sanity check
assert expected_index.keys() == store._context.latest_messages.keys()
for validator_index in range(len(state.validators)):
expected_attestation_data = expected_index.get(validator_index, None)
target = expected_attestation_data.target
expected_message = LatestMessage(epoch=target.epoch, root=target.root)
stored_message = store._context.latest_messages.get(
validator_index, None)
assert expected_message == stored_message