fix: fixed an issue that could not set the correct NextField for fiel…

…ds in the embedded structure (#438)

fix #391

encode_test.go

@@ -2630,6 +2630,40 @@ func TestCustomMarshalForMapKey(t *testing.T) {
  assertEq(t, "custom map key", string(expected), string(got))
 }
 
+func TestIssue391(t *testing.T) {
+ type A struct {
+ X string `json:"x,omitempty"`
+ }
+ type B struct {
+ A
+ }
+ type C struct {
+ X []int `json:"x,omitempty"`
+ }
+ for _, tc := range []struct {
+ name string
+ in interface{}
+ out string
+ }{
+ {in: struct{ B }{}, out: "{}"},
+ {in: struct {
+ B
+ Y string `json:"y"`
+ }{}, out: `{"y":""}`},
+ {in: struct {
+ Y string `json:"y"`
+ B
+ }{}, out: `{"y":""}`},
+ {in: struct{ C }{}, out: "{}"},
+ } {
+ t.Run(tc.name, func(t *testing.T) {
+ b, err := json.Marshal(tc.in)
+ assertErr(t, err)
+ assertEq(t, "unexpected result", tc.out, string(b))
+ })
+ }
+}
+
 func TestIssue417(t *testing.T) {
  x := map[string]string{
  "b": "b",

internal/encoder/code.go

@@ -397,7 +397,10 @@ func (c *StructCode) lastFieldCode(field *StructFieldCode, firstField *Opcode) *
 func (c *StructCode) lastAnonymousFieldCode(firstField *Opcode) *Opcode {
  // firstField is special StructHead operation for anonymous structure.
  // So, StructHead's next operation is truly struct head operation.
- lastField := firstField.Next
+ for firstField.Op == OpStructHead {
+ firstField = firstField.Next
+ }
+ lastField := firstField
  for lastField.NextField != nil {
  lastField = lastField.NextField
  }
@@ -437,11 +440,6 @@ func (c *StructCode) ToOpcode(ctx *compileContext) Opcodes {
  }
  if isEndField {
  endField := fieldCodes.Last()
- if isEmbeddedStruct(field) {
- firstField.End = endField
- lastField := c.lastAnonymousFieldCode(firstField)
- lastField.NextField = endField
- }
  if len(codes) > 0 {
  codes.First().End = endField
  } else {
@@ -698,7 +696,15 @@ func (c *StructFieldCode) addStructEndCode(ctx *compileContext, codes Opcodes) O
  Indent: ctx.indent,
  }
  codes.Last().Next = end
- codes.First().NextField = end
+ code := codes.First()
+ for code.Op == OpStructField || code.Op == OpStructHead {
+ code = code.Next
+ }
+ for code.NextField != nil {
+ code = code.NextField
+ }
+ code.NextField = end
+
  codes = codes.Add(end)
  ctx.incOpcodeIndex()
  return codes