fix searching for tx hash in block for ArbitrumLegacyTx

Author: magicxyyz

core/rawdb/accessors_indexes.go

@@ -162,11 +162,17 @@ func findTxInBlockBody(blockbody rlp.RawValue, target common.Hash) (*types.Trans
 		if kind == rlp.List { // Legacy transaction
 			txHashPayload = txRLP
 		}
-		if crypto.Keccak256Hash(txHashPayload) == target {
-			var tx types.Transaction
-			if err := rlp.DecodeBytes(txRLP, &tx); err != nil {
-				return nil, 0, err
+		// arbitrum: decode txRLP to check tx type and support HashOverride in case of ArbitrumLegacyTx (happens in (*Transaction)Hash)
+		var tx types.Transaction
+		if err := rlp.DecodeBytes(txRLP, &tx); err != nil {
+			return nil, 0, err
+		}
+		// arbitrum: only use Hash() method for ArbitrumLegacyTxType, otherwise use the optimised path that does not involve encoding the RLP again
+		if tx.Type() == types.ArbitrumLegacyTxType {
+			if tx.Hash() == target {
+				return &tx, txIndex, nil
 			}
+		} else if crypto.Keccak256Hash(txHashPayload) == target {
 			return &tx, txIndex, nil
 		}
 		txIndex++

core/rawdb/accessors_indexes_test.go

@@ -130,6 +130,10 @@ func TestFindTxInBlockBody(t *testing.T) {
 		Value:    big.NewInt(5),
 		Data:     []byte{0x11, 0x11, 0x11},
 	})
+	arbitrumLegacyTx, err := types.NewArbitrumLegacyTx(tx1, common.HexToHash("0xdeadbeef"), 0, 0, new(common.Address))
+	if err != nil {
+		t.Fatalf("Failed to create ArbitrumLegacyTx, err: %v", err)
+	}
 	tx2 := types.NewTx(&types.AccessListTx{
 		Nonce:    1,
 		GasPrice: big.NewInt(1),
@@ -198,7 +202,7 @@ func TestFindTxInBlockBody(t *testing.T) {
 		},
 	})
 
-	txs := []*types.Transaction{tx1, tx2, tx3, tx4, tx5}
+	txs := []*types.Transaction{tx1, arbitrumLegacyTx, tx2, tx3, tx4, tx5}
 
 	block := types.NewBlock(&types.Header{Number: big.NewInt(314)}, &types.Body{Transactions: txs}, nil, newTestHasher())
 	db := NewMemoryDatabase()