From ff3c370fa67e42039cc71f0c98d5b04eaec62a7c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20Negovanovi=C4=87?= <stefan@ethernal.tech>
Date: Mon, 7 Aug 2023 15:18:28 +0200
Subject: [PATCH] Prevent marshaling gas price in case of dynamic fee
 transactions

---
 structs_marshal.go                 | 20 +++++++++++---------
 structs_unmarshal.go               | 22 +++++++++++-----------
 testsuite/transaction-eip1159.json |  3 +--
 3 files changed, 23 insertions(+), 22 deletions(-)

diff --git a/structs_marshal.go b/structs_marshal.go
index c058c682..b88e079e 100644
--- a/structs_marshal.go
+++ b/structs_marshal.go
@@ -117,18 +117,20 @@ func (t *Transaction) marshalJSON(a *fastjson.Arena) *fastjson.Value {
 	if t.Value != nil {
 		o.Set("value", a.NewString(fmt.Sprintf("0x%x", t.Value)))
 	}
-	o.Set("gasPrice", a.NewString(fmt.Sprintf("0x%x", t.GasPrice)))
-
+	if t.Type == TransactionDynamicFee {
+		if t.MaxPriorityFeePerGas != nil {
+			o.Set("maxPriorityFeePerGas", a.NewString(fmt.Sprintf("0x%x", t.MaxPriorityFeePerGas)))
+		}
+		if t.MaxFeePerGas != nil {
+			o.Set("maxFeePerGas", a.NewString(fmt.Sprintf("0x%x", t.MaxFeePerGas)))
+		}
+	} else {
+		o.Set("gasPrice", a.NewString(fmt.Sprintf("0x%x", t.GasPrice)))
+	}
 	// gas limit fields
 	if t.Gas != 0 {
 		o.Set("gas", a.NewString(fmt.Sprintf("0x%x", t.Gas)))
 	}
-	if t.MaxPriorityFeePerGas != nil {
-		o.Set("maxPriorityFeePerGas", a.NewString(fmt.Sprintf("0x%x", t.MaxPriorityFeePerGas)))
-	}
-	if t.MaxFeePerGas != nil {
-		o.Set("maxFeePerGas", a.NewString(fmt.Sprintf("0x%x", t.MaxFeePerGas)))
-	}
 
 	if t.Nonce != 0 {
 		// we can remove this once we include support for custom nonces
@@ -298,4 +300,4 @@ func (s StateOverride) MarshalJSON() ([]byte, error) {
 	defaultArena.Put(a)
 
 	return res, nil
-} 
+}
diff --git a/structs_unmarshal.go b/structs_unmarshal.go
index 4b7ef4eb..a3f28c0b 100644
--- a/structs_unmarshal.go
+++ b/structs_unmarshal.go
@@ -156,8 +156,17 @@ func (t *Transaction) unmarshalJSON(v *fastjson.Value) error {
 	if err = decodeAddr(&t.From, v, "from"); err != nil {
 		return err
 	}
-	if t.GasPrice, err = decodeUint(v, "gasPrice"); err != nil {
-		return err
+	if typ == TransactionDynamicFee {
+		if t.MaxPriorityFeePerGas, err = decodeBigInt(t.MaxPriorityFeePerGas, v, "maxPriorityFeePerGas"); err != nil {
+			return err
+		}
+		if t.MaxFeePerGas, err = decodeBigInt(t.MaxFeePerGas, v, "maxFeePerGas"); err != nil {
+			return err
+		}
+	} else {
+		if t.GasPrice, err = decodeUint(v, "gasPrice"); err != nil {
+			return err
+		}
 	}
 	if t.Input, err = decodeBytes(t.Input[:0], v, "input"); err != nil {
 		return err
@@ -207,15 +216,6 @@ func (t *Transaction) unmarshalJSON(v *fastjson.Value) error {
 		return err
 	}
 
-	if typ == TransactionDynamicFee {
-		if t.MaxPriorityFeePerGas, err = decodeBigInt(t.MaxPriorityFeePerGas, v, "maxPriorityFeePerGas"); err != nil {
-			return err
-		}
-		if t.MaxFeePerGas, err = decodeBigInt(t.MaxFeePerGas, v, "maxFeePerGas"); err != nil {
-			return err
-		}
-	}
-
 	// Check if the block hash field is set
 	// If it's not -> the transaction is a pending txn, so these fields should be omitted
 	// If it is -> the transaction is a sealed txn, so these fields should be included
diff --git a/testsuite/transaction-eip1159.json b/testsuite/transaction-eip1159.json
index 534ebe36..bad0eb94 100644
--- a/testsuite/transaction-eip1159.json
+++ b/testsuite/transaction-eip1159.json
@@ -3,10 +3,9 @@
     "from": "0x0000000000000000000000000000000000000001",
     "input": "0x00",
     "value": "0x0",
-    "gasPrice": "0x0",
-    "gas": "0x10",
     "maxPriorityFeePerGas": "0x10",
     "maxFeePerGas": "0x10",
+    "gas": "0x10",
     "nonce": "0x10",
     "to": null,
     "v":"0x25",