Fix txPool: excessBlobGas should be calculated before entering EVM, not after (#2149)

nimbus/beacon/api_handler/api_newpayload.nim

@@ -116,9 +116,9 @@ proc newPayload*(ben: BeaconEngineRef,
     timestamp = ethTime payload.timestamp
     version = payload.version
 
-  validateVersion(com, timestamp, version, apiVersion)
   validatePayload(apiVersion, version, payload)
-
+  validateVersion(com, timestamp, version, apiVersion)
+  
   var header = blockHeader(payload, removeBlobs = true, beaconRoot = ethHash beaconRoot)
   
   if apiVersion >= Version.V3:

nimbus/core/tx_pool/tx_chain.nim

@@ -19,6 +19,7 @@ import
   ../../utils/utils,
   ../../vm_state,
   ../../vm_types,
+  ../eip4844,
   ../clique/[clique_sealer, clique_desc, clique_cfg],
   ../pow/difficulty,
   ../executor,
@@ -131,12 +132,13 @@ proc resetTxEnv(dh: TxChainRef; parent: BlockHeader; fee: Option[UInt256])
   # we don't consider PoS difficulty here
   # because that is handled in vmState
   let blockCtx = BlockContext(
-    timestamp : dh.prepHeader.timestamp,
-    gasLimit  : (if dh.maxMode: dh.limits.maxLimit else: dh.limits.trgLimit),
-    fee       : fee,
-    prevRandao: dh.prepHeader.prevRandao,
-    difficulty: dh.prepHeader.difficulty,
-    coinbase  : dh.feeRecipient,
+    timestamp    : dh.prepHeader.timestamp,
+    gasLimit     : (if dh.maxMode: dh.limits.maxLimit else: dh.limits.trgLimit),
+    fee          : fee,
+    prevRandao   : dh.prepHeader.prevRandao,
+    difficulty   : dh.prepHeader.difficulty,
+    coinbase     : dh.feeRecipient,
+    excessBlobGas: calcExcessBlobGas(parent),
   )
 
   dh.txEnv.vmState = BaseVMState.new(

nimbus/core/tx_pool/tx_tasks/tx_packer.nim

@@ -275,8 +275,7 @@ proc vmExecCommit(pst: TxPackerStateRef)
 
   if vmState.com.forkGTE(Cancun):
     # EIP-4844
-    let excessBlobGas = calcExcessBlobGas(vmState.parent)
-    xp.chain.excessBlobGas = some(excessBlobGas)
+    xp.chain.excessBlobGas = some(vmState.blockCtx.excessBlobGas)
     xp.chain.blobGasUsed = some(pst.blobGasUsed)
 
   proc balanceDelta: UInt256 =