bump nim-eth, extend empty block fallback for EIP4844 (#4425)

Implements `emptyPayloadToBlockHeader` for EIP-4844.
status-im/nim-eth#570

Author: etan-status

AllTests-mainnet.md

@@ -459,10 +459,11 @@ OK: 1/1 Fail: 0/1 Skip: 0/1
 ```diff
 + build_empty_execution_payload - Bellatrix                                                  OK
 + build_empty_execution_payload - Capella                                                    OK
++ build_empty_execution_payload - EIP4844                                                    OK
 + build_proof - BeaconState                                                                  OK
 + integer_squareroot                                                                         OK
 ```
-OK: 4/4 Fail: 0/4 Skip: 0/4
+OK: 5/5 Fail: 0/5 Skip: 0/5
 ## Specific field types
 ```diff
 + root update                                                                                OK
@@ -614,4 +615,4 @@ OK: 2/2 Fail: 0/2 Skip: 0/2
 OK: 9/9 Fail: 0/9 Skip: 0/9
 
 ---TOTAL---
-OK: 343/348 Fail: 0/348 Skip: 5/348
+OK: 344/349 Fail: 0/349 Skip: 5/349

beacon_chain/spec/forks.nim

@@ -77,6 +77,11 @@ type
     Capella,
     EIP4844
 
+  ForkyExecutionPayload* =
+    bellatrix.ExecutionPayload |
+    capella.ExecutionPayload |
+    eip4844.ExecutionPayload
+
   ForkyBeaconBlockBody* =
     phase0.BeaconBlockBody |
     altair.BeaconBlockBody |
@@ -444,6 +449,7 @@ template toFork*[T:
   BeaconBlockFork.Altair
 
 template toFork*[T:
+    bellatrix.ExecutionPayload |
     bellatrix.BeaconBlock |
     bellatrix.SignedBeaconBlock |
     bellatrix.TrustedBeaconBlock |
@@ -454,6 +460,7 @@ template toFork*[T:
   BeaconBlockFork.Bellatrix
 
 template toFork*[T:
+    capella.ExecutionPayload |
     capella.BeaconBlock |
     capella.SignedBeaconBlock |
     capella.TrustedBeaconBlock |
@@ -464,6 +471,7 @@ template toFork*[T:
   BeaconBlockFork.Capella
 
 template toFork*[T:
+    eip4844.ExecutionPayload |
     eip4844.BeaconBlock |
     eip4844.SignedBeaconBlock |
     eip4844.TrustedBeaconBlock |

beacon_chain/spec/helpers.nim

@@ -19,7 +19,7 @@ import
   eth/eip1559, eth/common/[eth_types, eth_types_rlp],
   eth/rlp, eth/trie/[db, hexary],
   # Internal
-  ./datatypes/[phase0, altair, bellatrix, capella],
+  ./datatypes/[phase0, altair, bellatrix, capella, eip4844],
   "."/[eth2_merkleization, forks, ssz_codec]
 
 # TODO although eth2_merkleization already exports ssz_codec, *sometimes* code
@@ -373,7 +373,7 @@ func compute_timestamp_at_slot*(state: ForkyBeaconState, slot: Slot): uint64 =
   state.genesis_time + slots_since_genesis * SECONDS_PER_SLOT
 
 proc computeTransactionsTrieRoot*(
-    payload: bellatrix.ExecutionPayload | capella.ExecutionPayload): Hash256 =
+    payload: ForkyExecutionPayload): Hash256 =
   if payload.transactions.len == 0:
     return EMPTY_ROOT_HASH
 
@@ -392,13 +392,13 @@ func toExecutionWithdrawal*(
     withdrawal: capella.Withdrawal): ExecutionWithdrawal =
   ExecutionWithdrawal(
     index: withdrawal.index,
-    validatorIndex: withdrawal.validatorIndex,
+    validatorIndex: withdrawal.validator_index,
     address: EthAddress withdrawal.address.data,
     amount: gweiToWei withdrawal.amount)
 
 # https://eips.ethereum.org/EIPS/eip-4895
 proc computeWithdrawalsTrieRoot*(
-    payload: capella.ExecutionPayload): Hash256 =
+    payload: capella.ExecutionPayload | eip4844.ExecutionPayload): Hash256 =
   if payload.withdrawals.len == 0:
     return EMPTY_ROOT_HASH
 
@@ -411,19 +411,23 @@ proc computeWithdrawalsTrieRoot*(
   tr.rootHash()
 
 proc payloadToBlockHeader*(
-    payload: bellatrix.ExecutionPayload | capella.ExecutionPayload
-): ExecutionBlockHeader =
+    payload: ForkyExecutionPayload): ExecutionBlockHeader =
   static:  # `GasInt` is signed. We only use it for hashing.
     doAssert sizeof(GasInt) == sizeof(payload.gas_limit)
     doAssert sizeof(GasInt) == sizeof(payload.gas_used)
 
   let
     txRoot = payload.computeTransactionsTrieRoot()
     withdrawalsRoot =
-      when payload is bellatrix.ExecutionPayload:
+      when typeof(payload).toFork >= BeaconBlockFork.Capella:
+        some payload.computeWithdrawalsTrieRoot()
+      else:
         none(Hash256)
+    excessDataGas =
+      when typeof(payload).toFork >= BeaconBlockFork.EIP4844:
+        some payload.excess_data_gas
       else:
-        some payload.computeWithdrawalsTrieRoot()
+        none(UInt256)
 
   ExecutionBlockHeader(
     parentHash     : payload.parent_hash,
@@ -442,11 +446,11 @@ proc payloadToBlockHeader*(
     mixDigest      : payload.prev_randao, # EIP-4399 `mixDigest` -> `prevRandao`
     nonce          : default(BlockNonce),
     fee            : some payload.base_fee_per_gas,
-    withdrawalsRoot: withdrawalsRoot)
+    withdrawalsRoot: withdrawalsRoot,
+    excessDataGas  : excessDataGas)
 
 proc compute_execution_block_hash*(
-    payload: bellatrix.ExecutionPayload | capella.ExecutionPayload
-): Eth2Digest =
+    payload: ForkyExecutionPayload): Eth2Digest =
   rlpHash payloadToBlockHeader(payload)
 
 proc build_empty_execution_payload*(
@@ -481,7 +485,8 @@ proc build_empty_execution_payload*(
 proc build_empty_execution_payload*(
     state: capella.BeaconState,
     feeRecipient: Eth1Address,
-    expectedWithdrawals = newSeq[capella.Withdrawal](0)): capella.ExecutionPayload =
+    expectedWithdrawals = newSeq[capella.Withdrawal](0)
+): capella.ExecutionPayload =
   ## Assuming a pre-state of the same slot, build a valid ExecutionPayload
   ## without any transactions.
   let
@@ -509,3 +514,52 @@ proc build_empty_execution_payload*(
   payload.block_hash = payload.compute_execution_block_hash()
 
   payload
+
+# https://eips.ethereum.org/EIPS/eip-4844#parameters
+const
+  TARGET_DATA_GAS_PER_BLOCK* = 1.u256 shl 18
+  DATA_GAS_PER_BLOB* = 1.u256 shl 17
+
+# https://eips.ethereum.org/EIPS/eip-4844#header-extension
+func calc_excess_data_gas*(
+    parent: eip4844.ExecutionPayloadHeader, new_blobs: uint): UInt256 =
+  let consumed_data_gas = new_blobs.u256 * DATA_GAS_PER_BLOB
+  return
+    if parent.excess_data_gas + consumed_data_gas < TARGET_DATA_GAS_PER_BLOCK:
+      0.u256
+    else:
+      parent.excess_data_gas + consumed_data_gas - TARGET_DATA_GAS_PER_BLOCK
+
+proc build_empty_execution_payload*(
+    state: eip4844.BeaconState,
+    feeRecipient: Eth1Address,
+    expectedWithdrawals = newSeq[capella.Withdrawal](0)
+): eip4844.ExecutionPayload =
+  ## Assuming a pre-state of the same slot, build a valid ExecutionPayload
+  ## without any transactions.
+  let
+    latest = state.latest_execution_payload_header
+    timestamp = compute_timestamp_at_slot(state, state.slot)
+    randao_mix = get_randao_mix(state, get_current_epoch(state))
+    base_fee = calcEip1599BaseFee(GasInt.saturate latest.gas_limit,
+                                  GasInt.saturate latest.gas_used,
+                                  latest.base_fee_per_gas)
+
+  var payload = eip4844.ExecutionPayload(
+    parent_hash: latest.block_hash,
+    fee_recipient: bellatrix.ExecutionAddress(data: distinctBase(feeRecipient)),
+    state_root: latest.state_root, # no changes to the state
+    receipts_root: EMPTY_ROOT_HASH,
+    block_number: latest.block_number + 1,
+    prev_randao: randao_mix,
+    gas_limit: latest.gas_limit, # retain same limit
+    gas_used: 0, # empty block, 0 gas
+    timestamp: timestamp,
+    base_fee_per_gas: base_fee,
+    excess_data_gas: latest.calc_excess_data_gas(new_blobs = 0))
+  for withdrawal in expectedWithdrawals:
+    doAssert payload.withdrawals.add withdrawal
+
+  payload.block_hash = payload.compute_execution_block_hash()
+
+  payload

beacon_chain/validators/validator_duties.nim

@@ -332,6 +332,7 @@ proc getFeeRecipient(node: BeaconNode,
 
 from web3/engine_api_types import PayloadExecutionStatus
 from ../spec/datatypes/capella import BeaconBlock, ExecutionPayload
+from ../spec/datatypes/eip4844 import BeaconBlock, ExecutionPayload
 
 proc getExecutionPayload[T](
     node: BeaconNode, proposalState: ref ForkedHashedBeaconState,
@@ -351,7 +352,9 @@ proc getExecutionPayload[T](
     # transmit this information through the Forked types, so this has to
     # be re-proven here.
     withState(proposalState[]):
-      when (stateFork == BeaconStateFork.Capella and
+      when (stateFork == BeaconStateFork.EIP4844 and
+            T is eip4844.ExecutionPayload) or
+           (stateFork == BeaconStateFork.Capella and
             T is capella.ExecutionPayload) or
            (stateFork == BeaconStateFork.Bellatrix and
             T is bellatrix.ExecutionPayload):

tests/test_helpers.nim

@@ -126,3 +126,29 @@ suite "Spec helpers":
         validatorIndex: 2,
         address: bellatrix.ExecutionAddress(data: distinctBase(recipient)),
         amount: 2.Gwei)]
+
+  test "build_empty_execution_payload - EIP4844":
+    var cfg = defaultRuntimeConfig
+    cfg.ALTAIR_FORK_EPOCH = GENESIS_EPOCH
+    cfg.BELLATRIX_FORK_EPOCH = GENESIS_EPOCH
+    cfg.CAPELLA_FORK_EPOCH = GENESIS_EPOCH
+    cfg.EIP4844_FORK_EPOCH = GENESIS_EPOCH
+
+    let
+      state = newClone(initGenesisState(cfg = cfg).eip4844Data)
+      recipient = Eth1Address.fromHex(
+        "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b")
+      withdrawals = @[
+        capella.Withdrawal(
+          index: 42,
+          validatorIndex: 1337,
+          address: bellatrix.ExecutionAddress(data: distinctBase(recipient)),
+          amount: 25.Gwei)]
+
+      payload = build_empty_execution_payload(
+        state[].data, recipient, withdrawals)
+    check:
+      payload.fee_recipient ==
+        bellatrix.ExecutionAddress(data: distinctBase(recipient))
+      payload.withdrawals[0] == withdrawals[0]
+      payload.excess_data_gas == 0.u256