Implement EIP-4788: Beacon block root in the EVM (#1722)

* Implement EIP-4788: Beacon block root in the EVM

* EIP-4788: Fix genesis.parentBeaconBlockRoot initialization

nimbus/beacon/beacon_engine.nim

@@ -156,6 +156,9 @@ proc generatePayload*(ben: BeaconEngineRef,
     pos.timestamp    = ethTime attrs.timestamp
     pos.feeRecipient = ethAddr attrs.suggestedFeeRecipient
     
+    if attrs.parentBeaconBlockRoot.isSome:
+      pos.parentBeaconBlockRoot = ethHash attrs.parentBeaconBlockRoot.get
+
     xp.setWithdrawals(attrs)
 
     if headBlock.blockHash != xp.head.blockHash:

nimbus/common/chain_config.nim

@@ -37,6 +37,7 @@ type
     baseFeePerGas*: Option[UInt256]
     blobGasUsed*  : Option[uint64]    # EIP-4844
     excessBlobGas*: Option[uint64]    # EIP-4844
+    parentBeaconBlockRoot*: Option[Hash256]   # EIP-4788
 
   GenesisAlloc* = Table[EthAddress, GenesisAccount]
   GenesisAccount* = object
@@ -69,6 +70,7 @@ type
     baseFeePerGas*: Option[UInt256]
     blobGasUsed*  : Option[uint64]    # EIP-4844
     excessBlobGas*: Option[uint64]    # EIP-4844
+    parentBeaconBlockRoot*: Option[Hash256]   # EIP-4788
 
 const
   CustomNet*  = 0.NetworkId

nimbus/common/genesis.nim

@@ -83,6 +83,7 @@ proc toGenesisHeader*(
   if fork >= Cancun:
     result.blobGasUsed = g.blobGasUsed
     result.excessBlobGas = g.excessBlobGas
+    result.parentBeaconBlockRoot = g.parentBeaconBlockRoot
 
 proc toGenesisHeader*(
     genesis: Genesis;

nimbus/constants.nim

@@ -1,6 +1,7 @@
 {.used.}
 
 import
+  stew/byteutils,
   eth/common/eth_types
 
 # proc default(t: typedesc): t = discard -- notused
@@ -85,4 +86,10 @@ const
   MAX_BLOB_GAS_PER_BLOCK* = 786432
   MAX_ALLOWED_BLOB* = MAX_BLOB_GAS_PER_BLOCK div GAS_PER_BLOB
 
+  # EIP-4788 addresses
+  # BeaconRootsStorageAddress is the address where historical beacon roots are stored as per EIP-4788
+  BeaconRootsStorageAddress* = hexToByteArray[20]("0xbEac00dDB15f3B6d645C48263dC93862413A222D")
+  # SystemAddress is where the system-transaction is sent from as per EIP-4788
+  SystemAddress* = hexToByteArray[20]("0xfffffffffffffffffffffffffffffffffffffffe")
+
 # End

nimbus/core/casper.nim

@@ -14,6 +14,7 @@ type
     feeRecipient : EthAddress
     timestamp    : EthTime
     prevRandao   : Hash256
+    parentBeaconBlockRoot: Hash256
 
 proc prepare*(ctx: CasperRef, header: var BlockHeader) =
   header.coinbase   = ctx.feeRecipient
@@ -40,6 +41,9 @@ func timestamp*(ctx: CasperRef): EthTime =
 func prevRandao*(ctx: CasperRef): Hash256 =
   ctx.prevRandao
 
+func parentBeaconBlockRoot*(ctx: CasperRef): Hash256 =
+  ctx.parentBeaconBlockRoot
+
 # ------------------------------------------------------------------------------
 # Setters
 # ------------------------------------------------------------------------------
@@ -52,3 +56,6 @@ proc `timestamp=`*(ctx: CasperRef, val: EthTime) =
 
 proc `prevRandao=`*(ctx: CasperRef, val: Hash256) =
   ctx.prevRandao = val
+
+proc `parentBeaconBlockRoot=`*(ctx: CasperRef, val: Hash256) =
+  ctx.parentBeaconBlockRoot = val

nimbus/core/executor/process_block.nim

@@ -34,6 +34,11 @@ proc processTransactions*(vmState: BaseVMState;
     {.gcsafe, raises: [CatchableError].} =
   vmState.receipts = newSeq[Receipt](transactions.len)
   vmState.cumulativeGasUsed = 0
+
+  if header.parentBeaconBlockRoot.isSome:
+    vmState.processBeaconBlockRoot(header.parentBeaconBlockRoot.get).isOkOr:
+      return err(error)
+
   for txIndex, tx in transactions:
     var sender: EthAddress
     if not tx.getSender(sender):
@@ -58,6 +63,13 @@ proc procBlkPreamble(vmState: BaseVMState;
       blockNumber = header.blockNumber
     return false
 
+  if vmState.determineFork >= FkCancun:
+    if header.parentBeaconBlockRoot.isNone:
+      raise ValidationError.newException("Post-Cancun block header must have parentBeaconBlockRoot")
+  else:
+    if header.parentBeaconBlockRoot.isSome:
+      raise ValidationError.newException("Pre-Cancun block header must not have parentBeaconBlockRoot")
+
   if header.txRoot != EMPTY_ROOT_HASH:
     if body.transactions.len == 0:
       debug "No transactions in body",

nimbus/core/executor/process_transaction.nim

@@ -15,10 +15,12 @@ import
   ../../common/common,
   ../../db/accounts_cache,
   ../../transaction/call_evm,
+  ../../transaction/call_common,
   ../../transaction,
   ../../vm_state,
   ../../vm_types,
   ../../evm/async/operations,
+  ../../constants,
   ../validate,
   chronos,
   stew/results
@@ -129,6 +131,43 @@ proc asyncProcessTransactionImpl(
 # Public functions
 # ------------------------------------------------------------------------------
 
+proc processBeaconBlockRoot*(vmState: BaseVMState, beaconRoot: Hash256):
+                              Result[void, string] {.raises: [CatchableError].} =
+  ## processBeaconBlockRoot applies the EIP-4788 system call to the
+  ## beacon block root contract. This method is exported to be used in tests.
+  ## If EIP-4788 is enabled, we need to invoke the beaconroot storage
+  ## contract with the new root.
+  let
+    statedb = vmState.stateDB
+    call = CallParams(
+      vmState:  vmState,
+      sender:   SystemAddress,
+      gasLimit: 30_000_000.GasInt,
+      gasPrice: 0.GasInt,
+      to:       BeaconRootsStorageAddress,
+      input:    @(beaconRoot.data),
+    )
+
+  # runComputation a.k.a syscall/evm.call
+  if call.runComputation().isError:
+    return err("processBeaconBlockRoot: syscall error")
+
+  # We can choose to set SystemAddress nonce to 0
+  # like erigon or geth(their EVM have explicit nonce set)
+  # or we delete the account manually instead of let it deleted
+  # by AccountsCache.persist.
+  statedb.deleteAccount(SystemAddress)
+
+  when false:
+    # nimbus EVM automatically increase sender nonce by one
+    # for each call/create.
+    statedb.setNonce(SystemAddress, 0)
+    # statedb.persist probably not needed as each processTransaction
+    # will call it.
+    statedb.persist(clearEmptyAccount = true, clearCache = false)
+
+  ok()
+
 proc asyncProcessTransaction*(
     vmState: BaseVMState; ## Parent accounts environment for transaction
     tx:      Transaction; ## Transaction to validate

nimbus/core/tx_pool/tx_chain.nim

@@ -230,6 +230,9 @@ proc getHeader*(dh: TxChainRef): BlockHeader
   if dh.com.forkGTE(Shanghai):
     result.withdrawalsRoot = some(calcWithdrawalsRoot(dh.withdrawals))
 
+  if dh.com.forkGTE(Cancun):
+    result.parentBeaconBlockRoot = some(dh.com.pos.parentBeaconBlockRoot)
+
   dh.prepareForSeal(result)
 
 proc clearAccounts*(dh: TxChainRef)

nimbus/db/accounts_cache.nim

@@ -670,7 +670,7 @@ func witnessData(acc: RefAccount): WitnessData =
   result.storageKeys = initHashSet[UInt256]()
   update(result, acc)
 
-proc collectWitnessData*(ac: var AccountsCache) =
+proc collectWitnessData*(ac: AccountsCache) =
   # make sure all savepoint already committed
   doAssert(ac.savePoint.parentSavepoint.isNil)
   # usually witness data is collected before we call persist()
@@ -694,10 +694,10 @@ proc makeMultiKeys*(ac: AccountsCache): MultikeysRef =
     result.add(k, v.codeTouched, multiKeys(v.storageKeys))
   result.sort()
 
-proc accessList*(ac: var AccountsCache, address: EthAddress) {.inline.} =
+proc accessList*(ac: AccountsCache, address: EthAddress) {.inline.} =
   ac.savePoint.accessList.add(address)
 
-proc accessList*(ac: var AccountsCache, address: EthAddress, slot: UInt256) {.inline.} =
+proc accessList*(ac: AccountsCache, address: EthAddress, slot: UInt256) {.inline.} =
   ac.savePoint.accessList.add(address, slot)
 
 func inAccessList*(ac: AccountsCache, address: EthAddress): bool =

nimbus/graphql/ethapi.nim

@@ -1158,6 +1158,14 @@ proc blockexcessBlobGas(ud: RootRef, params: Args, parent: Node): RespResult {.a
   else:
     ok(respNull())
 
+proc blockParentBeaconBlockRoot(ud: RootRef, params: Args, parent: Node): RespResult {.apiPragma.} =
+  let h = HeaderNode(parent)
+  if h.header.parentBeaconBlockRoot.isSome:
+    resp(h.header.parentBeaconBlockRoot.get)
+  else:
+    ok(respNull())
+
+
 const blockProcs = {
   "parent": blockParent,
   "number": blockNumberImpl,
@@ -1190,7 +1198,8 @@ const blockProcs = {
   "withdrawalsRoot": blockWithdrawalsRoot,
   "withdrawals": blockWithdrawals,
   "blobGasUsed": blockBlobGasUsed,
-  "excessBlobGas": blockExcessBlobGas
+  "excessBlobGas": blockExcessBlobGas,
+  "parentBeaconBlockRoot": blockParentBeaconBlockRoot,
 }
 
 proc callResultData(ud: RootRef, params: Args, parent: Node): RespResult {.apiPragma.} =

nimbus/graphql/ethapi.ql

@@ -339,6 +339,10 @@ type Block {
   # (bounded at 0).
   excessBlobGas: Long
 
+  # EIP-4788: This root consumes 32 bytes and is exactly the hash tree root
+  # of the parent beacon block for the given execution block.
+  parentBeaconBlockRoot: Bytes32
+
   #--------------------------Extensions-------------------------------
 
   # RawHeader is the RLP encoding of the block's header.

nimbus/rpc/rpc_types.nim

@@ -78,6 +78,7 @@ type
     withdrawalsRoot*: Option[Hash256]      # EIP-4895
     blobGasUsed*: Option[HexQuantityStr]   # EIP-4844
     excessBlobGas*: Option[HexQuantityStr] # EIP-4844
+    parentBeaconBlockRoot*: Option[Hash256] # EIP-4788
 
   TransactionObject* = object       # A transaction object, or null when no transaction was found:
     # Returned to user

nimbus/rpc/rpc_utils.nim

@@ -244,6 +244,8 @@ proc populateBlockObject*(header: BlockHeader, chain: CoreDbRef, fullTx: bool, i
   if header.excessBlobGas.isSome:
     result.excessBlobGas = some(encodeQuantity(header.excessBlobGas.get))
 
+  result.parentBeaconBlockRoot = header.parentBeaconBlockRoot
+
 proc populateReceipt*(receipt: Receipt, gasUsed: GasInt, tx: Transaction,
                       txIndex: int, header: BlockHeader): ReceiptObject
     {.gcsafe, raises: [ValidationError].} =

tools/evmstate/helpers.nim

@@ -115,7 +115,8 @@ proc parseHeader*(n: JsonNode): BlockHeader =
     mixDigest  : omitZero(Hash256, "currentRandom"),
     fee        : optional(UInt256, "currentBaseFee"),
     excessBlobGas: optional(uint64, "excessBlobGas"),
-    blobGasUsed: optional(uint64, "blobGasUsed")
+    blobGasUsed: optional(uint64, "blobGasUsed"),
+    parentBeaconBlockRoot: optional(Hash256, "parentBeaconBlockRoot"),
   )
 
 proc parseTx*(n: JsonNode, dataIndex, gasIndex, valueIndex: int): Transaction =

tools/t8n/helpers.nim

@@ -183,6 +183,7 @@ proc parseEnv*(ctx: var TransContext, n: JsonNode) =
   optional(ctx.env, uint64, currentExcessBlobGas)
   optional(ctx.env, uint64, parentBlobGasUsed)
   optional(ctx.env, uint64, parentExcessBlobGas)
+  optional(ctx.env, Hash256, parentBeaconBlockRoot)
 
   if n.hasKey("blockHashes"):
     let w = n["blockHashes"]
@@ -442,7 +443,7 @@ proc `@@`*(x: ExecutionResult): JsonNode =
     result["currentBaseFee"] = @@(x.currentBaseFee)
   if x.withdrawalsRoot.isSome:
     result["withdrawalsRoot"] = @@(x.withdrawalsRoot)
-  if x.blobGasUsed.isSome:
+  if x.currentBlobGasUsed.isSome:
-    result["blobGasUsed"] = @@(x.blobGasUsed)
+    result["currentBlobGasUsed"] = @@(x.currentBlobGasUsed)
-  if x.excessBlobGas.isSome:
+  if x.currentExcessBlobGas.isSome:
-    result["excessBlobGas"] = @@(x.excessBlobGas)
+    result["currentExcessBlobGas"] = @@(x.currentExcessBlobGas)

tools/t8n/t8n_test.nim

@@ -524,6 +524,24 @@ const
       output: T8nOutput(trace: true, result: true),
       expOut: "exp.txt",
     ),
+    TestSpec(
+      name  : "Cancun tests",
+      base  : "testdata/28",
+      input : t8nInput(
+        "alloc.json", "txs.rlp", "env.json", "Cancun", "",
+      ),
+      output: T8nOutput(alloc: true, result: true),
+      expOut: "exp.json",
+    ),
+    TestSpec(
+      name  : "More cancun tests",
+      base  : "/testdata/29",
+      input : t8nInput(
+        "alloc.json", "txs.json", "env.json", "Cancun", "",
+      ),
+      output: T8nOutput(alloc: true, result: true),
+      expOut: "exp.json",
+    ),
   ]
 
 proc main() =

tools/t8n/testdata/00-517/env.json

@@ -15,5 +15,6 @@
     }
   ],
   "parentBlobGasUsed": "0x100",
-  "parentExcessBlobGas": "0x100"
+  "parentExcessBlobGas": "0x100",
+  "parentBeaconBlockRoot" : "0x5e20a0453cecd065ea59c37ac63e079ee08998b6045136a8ce6635c7912ec0b6",
 }

tools/t8n/testdata/00-517/exp.json

@@ -16,7 +16,7 @@
     "gasUsed": "0x0",
     "currentBaseFee": "0x500",
     "withdrawalsRoot": "0x4921c0162c359755b2ae714a0978a1dad2eb8edce7ff9b38b9b6fc4cbc547eb5",
-    "blobGasUsed": "0x0",
+    "currentBlobGasUsed": "0x0",
-    "excessBlobGas": "0x0"
+    "currentExcessBlobGas": "0x0"
   }
 }

tools/t8n/testdata/00-518/env.json

@@ -8,6 +8,6 @@
   "currentTimestamp" : "0x03e8",
   "parentBlobGasUsed" : "0x2000",
   "parentExcessBlobGas" : "0x1000",
-  "previousHash" : "0x5e20a0453cecd065ea59c37ac63e079ee08998b6045136a8ce6635c7912ec0b6",
+  "parentBeaconBlockRoot" : "0x5e20a0453cecd065ea59c37ac63e079ee08998b6045136a8ce6635c7912ec0b6",
   "withdrawals": []
 }

tools/t8n/testdata/28/alloc.json

@@ -0,0 +1,16 @@
+{
+  "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b" : {
+    "balance" : "0x016345785d8a0000",
+    "code" : "0x",
+    "nonce" : "0x00",
+    "storage" : {
+    }
+  },
+  "0xb94f5374fce5edbc8e2a8697c15331677e6ebf0b" : {
+    "balance" : "0x016345785d8a0000",
+    "code" : "0x60004960015500",
+    "nonce" : "0x00",
+    "storage" : {
+    }
+  }
+}

tools/t8n/testdata/28/env.json

@@ -0,0 +1,23 @@
+{
+    "currentCoinbase" : "0x2adc25665018aa1fe0e6bc666dac8fc2697ff9ba",
+    "currentNumber" : "0x01",
+    "currentTimestamp" : "0x079e",
+    "currentGasLimit" : "0x7fffffffffffffff",
+    "previousHash" : "0x3a9b485972e7353edd9152712492f0c58d89ef80623686b6bf947a4a6dce6cb6",
+    "currentBlobGasUsed" : "0x00",
+    "parentTimestamp" : "0x03b6",
+    "parentDifficulty" : "0x00",
+    "parentUncleHash" : "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "currentRandom" : "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "withdrawals" : [
+    ],
+    "parentBaseFee" : "0x0a",
+    "parentGasUsed" : "0x00",
+    "parentGasLimit" : "0x7fffffffffffffff",
+    "parentExcessBlobGas" : "0x00",
+    "parentBlobGasUsed" : "0x00",
+    "blockHashes" : {
+        "0" : "0x3a9b485972e7353edd9152712492f0c58d89ef80623686b6bf947a4a6dce6cb6"
+    },
+    "parentBeaconBlockRoot": "0x0000beac00beac00beac00beac00beac00beac00beac00beac00beac00beac00"
+}

tools/t8n/testdata/28/exp.json

@@ -0,0 +1,46 @@
+{
+  "alloc": {
+    "0x2adc25665018aa1fe0e6bc666dac8fc2697ff9ba": {
+      "balance": "0x150ca"
+    },
+    "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
+      "balance": "0x16345785d80c3a9",
+      "nonce": "0x1"
+    },
+    "0xb94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
+      "code": "0x60004960015500",
+      "storage": {
+        "0x0000000000000000000000000000000000000000000000000000000000000001": "0x01a915e4d060149eb4365960e6a7a45f334393093061116b197e3240065ff2d8"
+      },
+      "balance": "0x16345785d8a0000"
+    }
+  },
+  "result": {
+    "stateRoot": "0xa40cb3fab01848e922a48bd24191815df9f721ad4b60376edac75161517663e8",
+    "txRoot": "0x4409cc4b699384ba5f8248d92b784713610c5ff9c1de51e9239da0dac76de9ce",
+    "receiptsRoot": "0xbff643da765981266133094092d98c81d2ac8e9a83a7bbda46c3d736f1f874ac",
+    "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "receipts": [
+      {
+        "type": "0x3",
+        "root": "0x",
+        "status": "0x1",
+        "cumulativeGasUsed": "0xa865",
+        "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "logs": null,
+        "transactionHash": "0x7508d7139d002a4b3a26a4f12dec0d87cb46075c78bf77a38b569a133b509262",
+        "contractAddress": "0x0000000000000000000000000000000000000000",
+        "gasUsed": "0xa865",
+        "blockHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+        "transactionIndex": "0x0"
+      }
+    ],
+    "currentDifficulty": null,
+    "gasUsed": "0xa865",
+    "currentBaseFee": "0x9",
+    "withdrawalsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "currentExcessBlobGas": "0x0",
+    "currentBlobGasUsed": "0x20000"
+  }
+}

tools/t8n/testdata/28/txs.rlp

@@ -0,0 +1 @@
+"0xf88bb88903f8860180026483061a8094b94f5374fce5edbc8e2a8697c15331677e6ebf0b8080c00ae1a001a915e4d060149eb4365960e6a7a45f334393093061116b197e3240065ff2d801a025e16bb498552165016751911c3608d79000ab89dc3100776e729e6ea13091c7a03acacff7fc0cff6eda8a927dec93ca17765e1ee6cbc06c5954ce102e097c01d2"

tools/t8n/testdata/29/alloc.json

@@ -0,0 +1,16 @@
+{
+  "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b" : {
+    "balance" : "0x016345785d8a0000",
+    "code" : "0x",
+    "nonce" : "0x00",
+    "storage" : {
+    }
+  },
+  "0xbEac00dDB15f3B6d645C48263dC93862413A222D" : {
+    "balance" : "0x1",
+    "code" : "0x3373fffffffffffffffffffffffffffffffffffffffe14604457602036146024575f5ffd5b620180005f350680545f35146037575f5ffd5b6201800001545f5260205ff35b6201800042064281555f359062018000015500",
+    "nonce" : "0x00",
+    "storage" : {
+    }
+  }
+}

tools/t8n/testdata/29/env.json

@@ -0,0 +1,20 @@
+{
+    "currentCoinbase" : "0x2adc25665018aa1fe0e6bc666dac8fc2697ff9ba",
+    "currentNumber" : "0x01",
+    "currentTimestamp" : "0x079e",
+    "currentGasLimit" : "0x7fffffffffffffff",
+    "previousHash" : "0x3a9b485972e7353edd9152712492f0c58d89ef80623686b6bf947a4a6dce6cb6",
+    "currentBlobGasUsed" : "0x00",
+    "parentTimestamp" : "0x03b6",
+    "parentDifficulty" : "0x00",
+    "parentUncleHash" : "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "currentRandom" : "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "withdrawals" : [
+    ],
+    "parentBaseFee" : "0x0a",
+    "parentGasUsed" : "0x00",
+    "parentGasLimit" : "0x7fffffffffffffff",
+    "parentExcessBlobGas" : "0x00",
+    "parentBlobGasUsed" : "0x00",
+    "parentBeaconBlockRoot": "0x0000beac00beac00beac00beac00beac00beac00beac00beac00beac00beac00"
+}

tools/t8n/testdata/29/exp.json

@@ -0,0 +1,44 @@
+{
+  "alloc": {
+    "0xbeac00ddb15f3b6d645c48263dc93862413a222d": {
+      "code": "0x3373fffffffffffffffffffffffffffffffffffffffe14604457602036146024575f5ffd5b620180005f350680545f35146037575f5ffd5b6201800001545f5260205ff35b6201800042064281555f359062018000015500",
+      "storage": {
+        "0x000000000000000000000000000000000000000000000000000000000000079e": "0x000000000000000000000000000000000000000000000000000000000000079e",
+        "0x000000000000000000000000000000000000000000000000000000000001879e": "0x0000beac00beac00beac00beac00beac00beac00beac00beac00beac00beac00"
+      },
+      "balance": "0x1"
+    },
+    "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
+      "balance": "0x16345785d871db8",
+      "nonce": "0x1"
+    }
+  },
+  "result": {
+    "stateRoot": "0x2db9f6bc233e8fd0af2d8023404493a19b37d9d69ace71f4e73158851fced574",
+    "txRoot": "0x248074fabe112f7d93917f292b64932394f835bb98da91f21501574d58ec92ab",
+    "receiptsRoot": "0xf78dfb743fbd92ade140711c8bbc542b5e307f0ab7984eff35d751969fe57efa",
+    "logsHash": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
+    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "receipts": [
+      {
+        "type": "0x2",
+        "root": "0x",
+        "status": "0x1",
+        "cumulativeGasUsed": "0x5208",
+        "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "logs": null,
+        "transactionHash": "0x84f70aba406a55628a0620f26d260f90aeb6ccc55fed6ec2ac13dd4f727032ed",
+        "contractAddress": "0x0000000000000000000000000000000000000000",
+        "gasUsed": "0x5208",
+        "blockHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
+        "transactionIndex": "0x0"
+      }
+    ],
+    "currentDifficulty": null,
+    "gasUsed": "0x5208",
+    "currentBaseFee": "0x9",
+    "withdrawalsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+    "currentExcessBlobGas": "0x0",
+    "currentBlobGasUsed": "0x0"
+  }
+}

tools/t8n/testdata/29/readme.md

@@ -0,0 +1,29 @@
+## EIP 4788
+
+This test contains testcases for EIP-4788. The 4788-contract is 
+located at address `0xbeac00ddb15f3b6d645c48263dc93862413a222d`, and this test executes a simple transaction. It also
+implicitly invokes the system tx, which sets calls the contract and sets the 
+storage values
+```
+$ dir=./testdata/29/ && go run . t8n --state.fork=Cancun  --input.alloc=$dir/alloc.json --input.txs=$dir/txs.json --input.env=$dir/env.json --output.alloc=stdout
+INFO [08-15|20:07:56.335] Trie dumping started                     root=ecde45..2af8a7
+INFO [08-15|20:07:56.335] Trie dumping complete                    accounts=2 elapsed="225.848µs"
+INFO [08-15|20:07:56.335] Wrote file                               file=result.json
+{
+  "alloc": {
+    "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
+      "balance": "0x16345785d871db8",
+      "nonce": "0x1"
+    },
+    "0xbeac00541d49391ed88abf392bfc1f4dea8c4143": {
+      "code": "0x3373fffffffffffffffffffffffffffffffffffffffe14604457602036146024575f5ffd5b620180005f350680545f35146037575f5ffd5b6201800001545f5260205ff35b6201800042064281555f359062018000015500",
+      "storage": {
+        "0x000000000000000000000000000000000000000000000000000000000000079e": "0x000000000000000000000000000000000000000000000000000000000000079e",
+        "0x000000000000000000000000000000000000000000000000000000000001879e": "0x0000beac00beac00beac00beac00beac00beac00beac00beac00beac00beac00"
+      },
+      "balance": "0x
+    }
+  }
+}
+
+```

tools/t8n/testdata/29/txs.json

@@ -0,0 +1,19 @@
+[
+  {
+    "input" : "0x",
+    "gas" : "0x10000000",
+    "nonce" : "0x0",
+    "to" : "0x1111111111111111111111111111111111111111",
+    "value" : "0x0",
+    "secretKey" : "0x45a915e4d060149eb4365960e6a7a45f334393093061116b197e3240065ff2d8",
+    "chainId" : "0x1",
+    "type" : "0x2",
+    "v": "0x0",
+    "r": "0x0",
+    "s": "0x0",
+    "maxFeePerGas" : "0xfa0",
+    "maxPriorityFeePerGas" : "0x0",
+    "accessList" : [
+    ]
+  }
+]

tools/t8n/transition.nim

@@ -101,7 +101,7 @@ proc envToHeader(env: EnvStruct): BlockHeader =
     fee        : env.currentBaseFee,
     withdrawalsRoot: env.withdrawals.calcWithdrawalsRoot(),
     blobGasUsed: env.currentBlobGasUsed,
-    excessBlobGas: env.currentExcessBlobGas
+    excessBlobGas: env.currentExcessBlobGas,
   )
 
 proc postState(db: AccountsCache, alloc: var GenesisAlloc) =
@@ -217,6 +217,10 @@ proc exec(ctx: var TransContext,
   vmState.receipts = newSeqOfCap[Receipt](txList.len)
   vmState.cumulativeGasUsed = 0
 
+  if ctx.env.parentBeaconBlockRoot.isSome:
+    vmState.processBeaconBlockRoot(ctx.env.parentBeaconBlockRoot.get).isOkOr:
+      raise newError(ErrorConfig, error)
+
   var blobGasUsed = 0'u64
   for txIndex, txRes in txList:
     if txRes.isErr:
@@ -306,8 +310,8 @@ proc exec(ctx: var TransContext,
   )
 
   if fork >= FkCancun:
-    result.result.blobGasUsed = some blobGasUsed
+    result.result.currentBlobGasUsed = some blobGasUsed
-    result.result.excessBlobGas = some calcExcessBlobGas(vmState.parent)
+    result.result.currentExcessBlobGas = some calcExcessBlobGas(vmState.parent)
 
 template wrapException(body: untyped) =
   when wrapExceptionEnabled:
@@ -413,7 +417,7 @@ proc transitionAction*(ctx: var TransContext, conf: T8NConf) =
       ommersHash: uncleHash,
       blockNumber: ctx.env.currentNumber - 1.toBlockNumber,
       blobGasUsed: ctx.env.parentBlobGasUsed,
-      excessBlobGas: ctx.env.parentExcessBlobGas
+      excessBlobGas: ctx.env.parentExcessBlobGas,
     )
 
     # Sanity check, to not `panic` in state_transition
@@ -436,9 +440,15 @@ proc transitionAction*(ctx: var TransContext, conf: T8NConf) =
       if ctx.env.parentExcessBlobGas.isNone:
         raise newError(ErrorConfig, "Cancun config but missing 'parentExcessBlobGas' in env section")
 
+      if ctx.env.parentBeaconBlockRoot.isNone:
+        raise newError(ErrorConfig, "Cancun config but missing 'parentBeaconBlockRoot' in env section")
+
       let res = loadKzgTrustedSetup()
       if res.isErr:
         raise newError(ErrorConfig, res.error)
+    else:
+      # un-set it if it has been set too early
+      ctx.env.parentBeaconBlockRoot = none(Hash256)
 
     if com.forkGTE(MergeFork):
       if ctx.env.currentRandom.isNone:

tools/t8n/types.nim

@@ -48,6 +48,7 @@ type
     currentExcessBlobGas*: Option[uint64]
     parentBlobGasUsed*: Option[uint64]
     parentExcessBlobGas*: Option[uint64]
+    parentBeaconBlockRoot*: Option[Hash256]
 
   TxsType* = enum
     TxsNone
@@ -96,8 +97,8 @@ type
     gasUsed*: GasInt
     currentBaseFee*: Option[UInt256]
     withdrawalsRoot*: Option[Hash256]
-    blobGasUsed*: Option[uint64]
+    currentBlobGasUsed*: Option[uint64]
-    excessBlobGas*: Option[uint64]
+    currentExcessBlobGas*: Option[uint64]
 
 const
   ErrorEVM*              = 2.T8NExitCode