1.9 KiB
1.9 KiB
Ethereum 2.0 Phase 1 -- Beacon Chain Fork Choice
Notice: This document is a work-in-progress for researchers and implementers.
Table of contents
Introduction
This document is the beacon chain fork choice spec for part of Ethereum 2.0 Phase 1. The only change that we add from phase 0 is that we add a concept of "data dependencies"; a block is only eligible for consideration in the fork choice after a data availability test has been successfully completed for all dependencies. The "root" of a shard block for data dependency purposes is considered to be a DataCommitment object, which is a pair of a Kate commitment and a length.
Dependency calculation
def get_new_dependencies(state: BeaconState) -> Set[DataCommitment]:
return set(
# Already confirmed during this epoch
[c.commitment for c in state.current_epoch_pending_headers if c.confirmed] +
# Already confirmed during previous epoch
[c.commitment for c in state.previous_epoch_pending_headers if c.confirmed] +
# Confirmed in the epoch before the previous
[c for c in shard for shard in state.most_recent_confirmed_commitments if c != DataCommitment()]
)
def get_all_dependencies(store: Store, block: BeaconBlock) -> Set[DataCommitment]:
if block.slot < SHARDING_FORK_SLOT:
return set()
else:
latest = get_new_dependencies(store.block_states[hash_tree_root(block)])
older = get_all_dependencies(store, store.blocks[block.parent_root])
return latest.union(older)