# Deneb Light Client -- Full Node **Notice**: This document is a work-in-progress for researchers and implementers. ## Table of contents - [Introduction](#introduction) - [Helper functions](#helper-functions) - [Modified `block_to_light_client_header`](#modified-block_to_light_client_header) ## Introduction This upgrade adds information about the execution payload to light client data as part of the Deneb upgrade. ## Helper functions ### Modified `block_to_light_client_header` ```python def block_to_light_client_header(block: SignedBeaconBlock) -> LightClientHeader: epoch = compute_epoch_at_slot(block.message.slot) if epoch >= CAPELLA_FORK_EPOCH: payload = block.message.body.execution_payload execution_header = ExecutionPayloadHeader( parent_hash=payload.parent_hash, fee_recipient=payload.fee_recipient, state_root=payload.state_root, receipts_root=payload.receipts_root, logs_bloom=payload.logs_bloom, prev_randao=payload.prev_randao, block_number=payload.block_number, gas_limit=payload.gas_limit, gas_used=payload.gas_used, timestamp=payload.timestamp, extra_data=payload.extra_data, base_fee_per_gas=payload.base_fee_per_gas, block_hash=payload.block_hash, transactions_root=hash_tree_root(payload.transactions), withdrawals_root=hash_tree_root(payload.withdrawals), ) # [New in Deneb] if epoch >= DENEB_FORK_EPOCH: execution_header.data_gas_used = payload.data_gas_used execution_header.excess_data_gas = payload.excess_data_gas execution_branch = compute_merkle_proof_for_block_body(block.message.body, EXECUTION_PAYLOAD_INDEX) else: # Note that during fork transitions, `finalized_header` may still point to earlier forks. # While Bellatrix blocks also contain an `ExecutionPayload` (minus `withdrawals_root`), # it was not included in the corresponding light client data. To ensure compatibility # with legacy data going through `upgrade_lc_header_to_capella`, leave out execution data. execution_header = ExecutionPayloadHeader() execution_branch = [Bytes32() for _ in range(floorlog2(EXECUTION_PAYLOAD_INDEX))] return LightClientHeader( beacon=BeaconBlockHeader( slot=block.message.slot, proposer_index=block.message.proposer_index, parent_root=block.message.parent_root, state_root=block.message.state_root, body_root=hash_tree_root(block.message.body), ), execution=execution_header, execution_branch=execution_branch, ) ```