From cd2c443b56becc83b9c5af505bee8e6e6fff05a5 Mon Sep 17 00:00:00 2001
From: MariusVanDerWijden <m.vanderwijden@live.de>
Date: Fri, 1 May 2026 01:42:54 +0200
Subject: [PATCH] core: add better debug logging

---
 core/blockchain.go | 12 ++++++++++++
 eth/tracers/api.go | 37 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/core/blockchain.go b/core/blockchain.go
index f26501dd88..15f79f5cdf 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -2861,6 +2861,18 @@ func (bc *BlockChain) reportBadBlock(block *types.Block, res *ProcessResult, err
 	}
 	rawdb.WriteBadBlock(bc.db, block)
 	log.Error(summarizeBadBlock(block, receipts, bc.Config(), err))
+
+	// Post-Amsterdam, dump the remote and locally-computed BALs to aid diagnosis
+	// of any mismatch between what the network produced and what we computed.
+	if bc.Config().IsAmsterdam(block.Number(), block.Time()) {
+		if remote := block.AccessList(); remote != nil {
+			log.Error("Bad block: remote BAL", "number", block.Number(), "hash", block.Hash(), "bal", remote.JSONString())
+		}
+		if res != nil && res.AccessList != nil {
+			local := res.AccessList.ToEncodingObj()
+			log.Error("Bad block: local BAL", "number", block.Number(), "hash", block.Hash(), "bal", local.JSONString())
+		}
+	}
 }
 
 // logForkReadiness will write a log when a future fork is scheduled, but not
diff --git a/eth/tracers/api.go b/eth/tracers/api.go
index 1b30472d89..8c0eb5c65c 100644
--- a/eth/tracers/api.go
+++ b/eth/tracers/api.go
@@ -35,6 +35,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/types/bal"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/eth/tracers/logger"
 	"github.com/ethereum/go-ethereum/ethdb"
@@ -555,15 +556,49 @@ func (api *API) IntermediateRoots(ctx context.Context, hash common.Hash, config
 
 // StandardTraceBadBlockToFile dumps the structured logs created during the
 // execution of EVM against a block pulled from the pool of bad ones to the
-// local file system and returns a list of files to the caller.
+// local file system and returns a list of files to the caller. After Amsterdam,
+// the block (header + body + access list) is also RLP-dumped to a temporary
+// file to allow offline post-mortem of BAL mismatches.
 func (api *API) StandardTraceBadBlockToFile(ctx context.Context, hash common.Hash, config *StdTraceConfig) ([]string, error) {
 	block := rawdb.ReadBadBlock(api.backend.ChainDb(), hash)
 	if block == nil {
 		return nil, fmt.Errorf("bad block %#x not found", hash)
 	}
+	if api.backend.ChainConfig().IsAmsterdam(block.Number(), block.Time()) {
+		if name, err := dumpBadBlockWithBAL(block); err != nil {
+			log.Warn("Failed to dump bad block with BAL", "hash", block.Hash(), "err", err)
+		} else {
+			log.Info("Dumped bad block (header+body+BAL)", "hash", block.Hash(), "file", name)
+		}
+	}
 	return api.standardTraceBlockToFile(ctx, block, config)
 }
 
+// dumpBadBlockWithBAL writes an RLP encoding of the block header, body, and
+// (if attached) the block access list to a temporary file. This is intended
+// for post-mortem analysis of BAL mismatches.
+func dumpBadBlockWithBAL(block *types.Block) (string, error) {
+	prefix := fmt.Sprintf("badblock_%d_%#x-", block.NumberU64(), block.Hash().Bytes()[:4])
+	f, err := os.CreateTemp(os.TempDir(), prefix+"*.rlp")
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+	payload := struct {
+		Header     *types.Header
+		Body       *types.Body
+		AccessList *bal.BlockAccessList `rlp:"optional"`
+	}{
+		Header:     block.Header(),
+		Body:       block.Body(),
+		AccessList: block.AccessList(),
+	}
+	if err := rlp.Encode(f, &payload); err != nil {
+		return "", err
+	}
+	return f.Name(), nil
+}
+
 // traceBlock configures a new tracer according to the provided configuration, and
 // executes all the transactions contained within. The return value will be one item
 // per transaction, dependent on the requested tracer.