From ade7515c812e96467dce51da39af346aa27df575 Mon Sep 17 00:00:00 2001
From: Matthieu Vachon <matt@streamingfast.io>
Date: Wed, 24 Apr 2024 01:58:05 -0400
Subject: [PATCH] eth, eth/tracers: process beacon root before transactions
 (#29402)

The beacon root when applied in `state_processor.go` is performed right before executing transaction. That means that contract reliying on this value would query the same value found in the block header.

In that spirit, it means that any tracing/operation relying on state data which touches transaction must have updated the beacon root before any transaction processing.
---
 eth/state_accessor.go |  6 ++++++
 eth/tracers/api.go    | 22 +++++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/eth/state_accessor.go b/eth/state_accessor.go
index 770532cbfe..372c76f496 100644
--- a/eth/state_accessor.go
+++ b/eth/state_accessor.go
@@ -233,6 +233,12 @@ func (eth *Ethereum) stateAtTransaction(ctx context.Context, block *types.Block,
 	if err != nil {
 		return nil, vm.BlockContext{}, nil, nil, err
 	}
+	// Insert parent beacon block root in the state as per EIP-4788.
+	if beaconRoot := block.BeaconRoot(); beaconRoot != nil {
+		context := core.NewEVMBlockContext(block.Header(), eth.blockchain, nil)
+		vmenv := vm.NewEVM(context, vm.TxContext{}, statedb, eth.blockchain.Config(), vm.Config{})
+		core.ProcessBeaconBlockRoot(*beaconRoot, vmenv, statedb)
+	}
 	if txIndex == 0 && len(block.Transactions()) == 0 {
 		return nil, vm.BlockContext{}, statedb, release, nil
 	}
diff --git a/eth/tracers/api.go b/eth/tracers/api.go
index 7a7c5e48d9..d99531d48f 100644
--- a/eth/tracers/api.go
+++ b/eth/tracers/api.go
@@ -376,6 +376,13 @@ func (api *API) traceChain(start, end *types.Block, config *TraceConfig, closed
 				failed = err
 				break
 			}
+			// Insert block's parent beacon block root in the state
+			// as per EIP-4788.
+			if beaconRoot := next.BeaconRoot(); beaconRoot != nil {
+				context := core.NewEVMBlockContext(next.Header(), api.chainContext(ctx), nil)
+				vmenv := vm.NewEVM(context, vm.TxContext{}, statedb, api.backend.ChainConfig(), vm.Config{})
+				core.ProcessBeaconBlockRoot(*beaconRoot, vmenv, statedb)
+			}
 			// Clean out any pending release functions of trace state. Note this
 			// step must be done after constructing tracing state, because the
 			// tracing state of block next depends on the parent state and construction
@@ -517,7 +524,6 @@ func (api *API) IntermediateRoots(ctx context.Context, hash common.Hash, config
 		return nil, err
 	}
 	defer release()
-
 	var (
 		roots              []common.Hash
 		signer             = types.MakeSigner(api.backend.ChainConfig(), block.Number(), block.Time())
@@ -525,6 +531,10 @@ func (api *API) IntermediateRoots(ctx context.Context, hash common.Hash, config
 		vmctx              = core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
 		deleteEmptyObjects = chainConfig.IsEIP158(block.Number())
 	)
+	if beaconRoot := block.BeaconRoot(); beaconRoot != nil {
+		vmenv := vm.NewEVM(vmctx, vm.TxContext{}, statedb, chainConfig, vm.Config{})
+		core.ProcessBeaconBlockRoot(*beaconRoot, vmenv, statedb)
+	}
 	for i, tx := range block.Transactions() {
 		if err := ctx.Err(); err != nil {
 			return nil, err
@@ -584,7 +594,6 @@ func (api *API) traceBlock(ctx context.Context, block *types.Block, config *Trac
 		return nil, err
 	}
 	defer release()
-
 	// JS tracers have high overhead. In this case run a parallel
 	// process that generates states in one thread and traces txes
 	// in separate worker threads.
@@ -601,6 +610,10 @@ func (api *API) traceBlock(ctx context.Context, block *types.Block, config *Trac
 		signer    = types.MakeSigner(api.backend.ChainConfig(), block.Number(), block.Time())
 		results   = make([]*txTraceResult, len(txs))
 	)
+	if beaconRoot := block.BeaconRoot(); beaconRoot != nil {
+		vmenv := vm.NewEVM(blockCtx, vm.TxContext{}, statedb, api.backend.ChainConfig(), vm.Config{})
+		core.ProcessBeaconBlockRoot(*beaconRoot, vmenv, statedb)
+	}
 	for i, tx := range txs {
 		// Generate the next state snapshot fast without tracing
 		msg, _ := core.TransactionToMessage(tx, signer, block.BaseFee())
@@ -727,7 +740,6 @@ func (api *API) standardTraceBlockToFile(ctx context.Context, block *types.Block
 		return nil, err
 	}
 	defer release()
-
 	// Retrieve the tracing configurations, or use default values
 	var (
 		logConfig logger.Config
@@ -756,6 +768,10 @@ func (api *API) standardTraceBlockToFile(ctx context.Context, block *types.Block
 		// Note: This copies the config, to not screw up the main config
 		chainConfig, canon = overrideConfig(chainConfig, config.Overrides)
 	}
+	if beaconRoot := block.BeaconRoot(); beaconRoot != nil {
+		vmenv := vm.NewEVM(vmctx, vm.TxContext{}, statedb, chainConfig, vm.Config{})
+		core.ProcessBeaconBlockRoot(*beaconRoot, vmenv, statedb)
+	}
 	for i, tx := range block.Transactions() {
 		// Prepare the transaction for un-traced execution
 		var (