fix(taiko-client): correct finalized and safe block hash (#18211)

Co-authored-by: David <[email protected]>

packages/taiko-client/driver/chain_syncer/beaconsync/syncer.go

@@ -5,13 +5,12 @@ import (
 	"fmt"
 	"math/big"
 
-	"github.com/taikoxyz/taiko-mono/packages/taiko-client/bindings"
-
 	"github.com/ethereum/go-ethereum/beacon/engine"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/eth/downloader"
 	"github.com/ethereum/go-ethereum/log"
 
+	"github.com/taikoxyz/taiko-mono/packages/taiko-client/bindings"
 	"github.com/taikoxyz/taiko-mono/packages/taiko-client/bindings/encoding"
 	"github.com/taikoxyz/taiko-mono/packages/taiko-client/driver/state"
 	"github.com/taikoxyz/taiko-mono/packages/taiko-client/pkg/rpc"
@@ -72,8 +71,15 @@ func (s *Syncer) TriggerBeaconSync(blockID uint64) error {
 		return fmt.Errorf("unexpected NewPayload response status: %s", status.Status)
 	}
 
+	lastVerifiedBlockHash, err := s.rpc.GetLastVerifiedBlockHash(s.ctx)
+	if err != nil {
+		return fmt.Errorf("failed to fetch the last verified block hash: %w", err)
+	}
+
 	fcRes, err := s.rpc.L2Engine.ForkchoiceUpdate(s.ctx, &engine.ForkchoiceStateV1{
-		HeadBlockHash: headPayload.BlockHash,
+		HeadBlockHash:      headPayload.BlockHash,
+		SafeBlockHash:      lastVerifiedBlockHash,
+		FinalizedBlockHash: lastVerifiedBlockHash,
 	}, nil)
 	if err != nil {
 		return err

packages/taiko-client/driver/chain_syncer/blob/syncer.go

@@ -409,7 +409,16 @@ func (s *Syncer) insertNewHead(
 		return nil, fmt.Errorf("failed to create execution payloads: %w", err)
 	}
 
-	fc := &engine.ForkchoiceStateV1{HeadBlockHash: payload.BlockHash}
+	lastVerifiedBlockHash, err := s.rpc.GetLastVerifiedBlockHash(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch the last verified block hash: %w", err)
+	}
+
+	fc := &engine.ForkchoiceStateV1{
+		HeadBlockHash:      payload.BlockHash,
+		SafeBlockHash:      lastVerifiedBlockHash,
+		FinalizedBlockHash: lastVerifiedBlockHash,
+	}
 
 	// Update the fork choice
 	fcRes, err := s.rpc.L2Engine.ForkchoiceUpdate(ctx, fc, nil)

packages/taiko-client/pkg/rpc/methods.go

@@ -510,6 +510,19 @@ func (c *Client) GetProtocolStateVariables(opts *bind.CallOpts) (*struct {
 	return GetProtocolStateVariables(c.TaikoL1, opts)
 }
 
+// GetLastVerifiedBlockHash gets the last verified block hash from TaikoL1 contract.
+func (c *Client) GetLastVerifiedBlockHash(ctx context.Context) (common.Hash, error) {
+	ctxWithTimeout, cancel := context.WithTimeout(ctx, defaultTimeout)
+	defer cancel()
+
+	b, err := c.TaikoL1.GetLastVerifiedBlock(&bind.CallOpts{Context: ctxWithTimeout})
+	if err != nil {
+		return common.Hash{}, err
+	}
+
+	return b.BlockHash, nil
+}
+
 // GetL2BlockInfo fetches the L2 block information from the protocol.
 func (c *Client) GetL2BlockInfo(ctx context.Context, blockID *big.Int) (bindings.TaikoDataBlockV2, error) {
 	ctxWithTimeout, cancel := CtxWithTimeoutOrDefault(ctx, defaultTimeout)