From 7d0a6191edade473053cec49ce560ea253a220fd Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Mon, 6 May 2019 09:09:37 -0600 Subject: [PATCH] simplify justificatio/finality notes at genesis --- specs/core/0_fork-choice.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_fork-choice.md b/specs/core/0_fork-choice.md index cb11ea860..8ec0a604c 100644 --- a/specs/core/0_fork-choice.md +++ b/specs/core/0_fork-choice.md @@ -106,4 +106,4 @@ def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) ### Justification and finality at genesis -Clients may choose to refer to the justification and finality data in a given `BeaconState` to determine the finalized/justified head. During the early epochs right after genesis, the justification and finality data are not stored in the `BeaconState`. In their place are "empty" values; for example, the 32-byte zero value as the `finalized_root`. Clients wishing to compute the fork choice in these early epochs should work around this fact of the `BeaconState` to recognize that the genesis epoch and root of the genesis block are _both_ the finalized and justified heads until updated via the state transition function defined in [Phase 0 -- The Beacon Chain](./0_beacon-chain.md). Solutions will be language-specific but one possibility is to treat the zero-value hash as an exceptional case that references the genesis block/epoch. +During genesis, justification and finality root fields within the `BeaconState` reference `ZERO_HASH` rather than a known block. `ZERO_HASH` in `previous_justified_root`, `current_justified_root`, and `finalized_root` should be considered as an alias to the root of the genesis block.