eth2.0-specs/specs/phase1/fork-choice.md

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
  • Helpers
    • Extended LatestMessage
    • Updated update_latest_messages

Introduction

This document is the beacon chain fork choice spec for part of Ethereum 2.0 Phase 1.

Helpers

Extended LatestMessage

@dataclass(eq=True, frozen=True)
class LatestMessage(object):
    epoch: Epoch
    root: Root
    shard: Shard
    shard_root: Root

Updated update_latest_messages

def update_latest_messages(store: Store, attesting_indices: Sequence[ValidatorIndex], attestation: Attestation) -> None:
    target = attestation.data.target
    beacon_block_root = attestation.data.beacon_block_root
    # TODO: separate shard chain vote
    shard = attestation.data.shard
    for i in attesting_indices:
        if i not in store.latest_messages or target.epoch > store.latest_messages[i].epoch:
            store.latest_messages[i] = LatestMessage(
                epoch=target.epoch, root=beacon_block_root, shard=shard, shard_root=attestation.data.shard_head_root
            )