From 22a207ffa8a6d8c1d88da7545607f989e3976d05 Mon Sep 17 00:00:00 2001 From: Josh King Date: Thu, 30 Apr 2026 15:26:20 +0200 Subject: [PATCH] fix: fallback to empty genesis block for external genesis states --- beacon_node/beacon_chain/src/builder.rs | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/beacon_node/beacon_chain/src/builder.rs b/beacon_node/beacon_chain/src/builder.rs index d70561db9b..5fb572d15c 100644 --- a/beacon_node/beacon_chain/src/builder.rs +++ b/beacon_node/beacon_chain/src/builder.rs @@ -46,8 +46,8 @@ use tracing::{debug, error, info, warn}; use tree_hash::TreeHash; use types::data::CustodyIndex; use types::{ - BeaconState, BlobSidecarList, ChainSpec, ColumnIndex, DataColumnSidecarList, Epoch, EthSpec, - Hash256, SignedBeaconBlock, Slot, + BeaconBlock, BeaconState, BlobSidecarList, ChainSpec, ColumnIndex, DataColumnSidecarList, + Epoch, EthSpec, Hash256, SignedBeaconBlock, Slot, }; /// An empty struct used to "witness" all the `BeaconChainTypes` traits. It has no user-facing @@ -1177,9 +1177,19 @@ fn make_genesis_block( genesis_state: &mut BeaconState, spec: &ChainSpec, ) -> Result, String> { + // For Gloas, genesis_block() populates the bid in the block body. However, if + // the genesis state was produced by an external tool (e.g. ethereum-genesis-generator), + // its latest_block_header.body_root may correspond to an empty block. In that case, + // use an empty block so the stored block root matches what fork choice derives from + // the state's latest_block_header. let mut block = genesis_block(genesis_state, spec) .map_err(|e| format!("Error building genesis block: {:?}", e))?; + let state_body_root = genesis_state.latest_block_header().body_root; + if state_body_root != block.body_root() { + block = BeaconBlock::empty(spec); + } + *block.state_root_mut() = genesis_state .update_tree_hash_cache() .map_err(|e| format!("Error hashing genesis state: {:?}", e))?;