From 2ed7c99ee1090bc3bb01621b7132c959bdac33c6 Mon Sep 17 00:00:00 2001
From: lmittmann <3458786+lmittmann@users.noreply.github.com>
Date: Thu, 8 Aug 2024 18:32:41 +0200
Subject: [PATCH] w3types: fix merge of account with empty code (#176)

* added test: merge empty code

* fixed account deep copy

---------

Co-authored-by: lmittmann <lmittmann@users.noreply.github.com>
---
 w3types/state.go      |  2 +-
 w3types/state_test.go | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/w3types/state.go b/w3types/state.go
index ae8747e9..d7a22c22 100644
--- a/w3types/state.go
+++ b/w3types/state.go
@@ -66,7 +66,7 @@ func (acc *Account) deepCopy() *Account {
 	if acc.Balance != nil {
 		newAcc.Balance = new(big.Int).Set(acc.Balance)
 	}
-	if len(acc.Code) > 0 {
+	if acc.Code != nil {
 		newAcc.Code = bytes.Clone(acc.Code)
 	}
 	if len(acc.Storage) > 0 {
diff --git a/w3types/state_test.go b/w3types/state_test.go
index 6123edde..8824287d 100644
--- a/w3types/state_test.go
+++ b/w3types/state_test.go
@@ -64,6 +64,24 @@ func TestStateMerge(t *testing.T) {
 			StateSrc: w3types.State{common.Address{}: {Storage: w3types.Storage{common.Hash{}: common.Hash{0x02}}}},
 			Want:     w3types.State{common.Address{}: {Storage: w3types.Storage{common.Hash{}: common.Hash{0x02}}}},
 		},
+
+		// https://github.com/lmittmann/w3/pull/176
+		{
+			Name:     "empty-code",
+			StateDst: w3types.State{common.Address{}: {Code: []byte{}}},
+			StateSrc: w3types.State{},
+			Want: w3types.State{
+				common.Address{}: {Code: []byte{}},
+			},
+		},
+		{
+			Name:     "empty-code2",
+			StateDst: w3types.State{},
+			StateSrc: w3types.State{common.Address{}: {Code: []byte{}}},
+			Want: w3types.State{
+				common.Address{}: {Code: []byte{}},
+			},
+		},
 	}
 
 	for _, test := range tests {