vm: copy slice in NEWARRAY/NEWSTRUCT

When performing NEWARRAY on a Struct or NEWSTRUCT on a Array,
underlying slice needs to be copied, because when it's capacity
doesn't matches it's length, underlying storage will be used
for appends even if it is already pointed at by another slice.

pkg/vm/vm.go

@@ -756,7 +756,9 @@ func (v *VM) execute(ctx *Context, op Instruction, parameter []byte) {
 		item := v.estack.Pop()
 		switch t := item.value.(type) {
 		case *StructItem:
-			v.estack.PushVal(&ArrayItem{t.value})
+			arr := make([]StackItem, len(t.value))
+			copy(arr, t.value)
+			v.estack.PushVal(&ArrayItem{arr})
 		case *ArrayItem:
 			v.estack.PushVal(t)
 		default:
@@ -772,7 +774,9 @@ func (v *VM) execute(ctx *Context, op Instruction, parameter []byte) {
 		item := v.estack.Pop()
 		switch t := item.value.(type) {
 		case *ArrayItem:
-			v.estack.PushVal(&StructItem{t.value})
+			arr := make([]StackItem, len(t.value))
+			copy(arr, t.value)
+			v.estack.PushVal(&StructItem{arr})
 		case *StructItem:
 			v.estack.PushVal(t)
 		default:

pkg/vm/vm_test.go

@@ -528,6 +528,39 @@ func TestNEWARRAYStruct(t *testing.T) {
 	assert.Equal(t, &ArrayItem{arr}, vm.estack.Pop().value)
 }
 
+func testNEWARRAYIssue437(t *testing.T, i1, i2 Instruction, appended bool) {
+	prog := makeProgram(
+		PUSH2, i1,
+		DUP, PUSH3, APPEND,
+		TOALTSTACK, DUPFROMALTSTACK, i2,
+		DUP, PUSH4, APPEND,
+		FROMALTSTACK, PUSH5, APPEND)
+	vm := load(prog)
+	vm.Run()
+
+	arr := makeArrayOfFalses(4)
+	arr[2] = makeStackItem(3)
+	arr[3] = makeStackItem(4)
+	if appended {
+		arr = append(arr, makeStackItem(5))
+	}
+
+	assert.Equal(t, false, vm.HasFailed())
+	assert.Equal(t, 1, vm.estack.Len())
+	if i2 == NEWARRAY {
+		assert.Equal(t, &ArrayItem{arr}, vm.estack.Pop().value)
+	} else {
+		assert.Equal(t, &StructItem{arr}, vm.estack.Pop().value)
+	}
+}
+
+func TestNEWARRAYIssue437(t *testing.T) {
+	t.Run("Array+Array", func(t *testing.T) { testNEWARRAYIssue437(t, NEWARRAY, NEWARRAY, true) })
+	t.Run("Struct+Struct", func(t *testing.T) { testNEWARRAYIssue437(t, NEWSTRUCT, NEWSTRUCT, true) })
+	t.Run("Array+Struct", func(t *testing.T) { testNEWARRAYIssue437(t, NEWARRAY, NEWSTRUCT, false) })
+	t.Run("Struct+Array", func(t *testing.T) { testNEWARRAYIssue437(t, NEWSTRUCT, NEWARRAY, false) })
+}
+
 func TestNEWARRAYArray(t *testing.T) {
 	prog := makeProgram(NEWARRAY)
 	vm := load(prog)
@@ -1732,6 +1765,39 @@ func TestREVERSEBadNotArray(t *testing.T) {
 	assert.Equal(t, true, vm.HasFailed())
 }
 
+func testREVERSEIssue437(t *testing.T, i1, i2 Instruction, reversed bool) {
+	prog := makeProgram(
+		PUSH0, i1,
+		DUP, PUSH1, APPEND,
+		DUP, PUSH2, APPEND,
+		DUP, i2, REVERSE)
+	vm := load(prog)
+	vm.Run()
+
+	arr := make([]StackItem, 2)
+	if reversed {
+		arr[0] = makeStackItem(2)
+		arr[1] = makeStackItem(1)
+	} else {
+		arr[0] = makeStackItem(1)
+		arr[1] = makeStackItem(2)
+	}
+	assert.Equal(t, false, vm.HasFailed())
+	assert.Equal(t, 1, vm.estack.Len())
+	if i1 == NEWARRAY {
+		assert.Equal(t, &ArrayItem{arr}, vm.estack.Pop().value)
+	} else {
+		assert.Equal(t, &StructItem{arr}, vm.estack.Pop().value)
+	}
+}
+
+func TestREVERSEIssue437(t *testing.T) {
+	t.Run("Array+Array", func(t *testing.T) { testREVERSEIssue437(t, NEWARRAY, NEWARRAY, true) })
+	t.Run("Struct+Struct", func(t *testing.T) { testREVERSEIssue437(t, NEWSTRUCT, NEWSTRUCT, true) })
+	t.Run("Array+Struct", func(t *testing.T) { testREVERSEIssue437(t, NEWARRAY, NEWSTRUCT, false) })
+	t.Run("Struct+Array", func(t *testing.T) { testREVERSEIssue437(t, NEWSTRUCT, NEWARRAY, false) })
+}
+
 func TestREVERSEGoodOneElem(t *testing.T) {
 	prog := makeProgram(DUP, REVERSE)
 	elements := []int{22}