Merge pull request #39 from goccy/feature/fix-nil-marshaler

Fix nested embedded structure that has same name fields

encode.go

@@ -148,6 +148,10 @@ func (e *Encoder) encodeForMarshal(v interface{}) ([]byte, error) {
 }
 
 func (e *Encoder) encode(v interface{}) error {
+	if v == nil {
+		e.encodeNull()
+		return nil
+	}
 	header := (*interfaceHeader)(unsafe.Pointer(&v))
 	typ := header.typ
 

encode_compile.go

@@ -566,6 +566,151 @@ func (e *Encoder) structField(fieldCode *structFieldCode, valueCode *opcode, tag
 	}
 	return code
 }
+
+func (e *Encoder) isNotExistsField(head *structFieldCode) bool {
+	if head == nil {
+		return false
+	}
+	if head.op != opStructFieldAnonymousHead {
+		return false
+	}
+	if head.next == nil {
+		return false
+	}
+	if head.nextField == nil {
+		return false
+	}
+	if head.nextField.op != opStructAnonymousEnd {
+		return false
+	}
+	if head.next.op == opStructAnonymousEnd {
+		return true
+	}
+	if head.next.op.codeType() != codeStructField {
+		return false
+	}
+	return e.isNotExistsField(head.next.toStructFieldCode())
+}
+
+func (e *Encoder) optimizeAnonymousFields(head *structFieldCode) {
+	code := head
+	var prev *structFieldCode
+	for {
+		if code.op == opStructEnd || code.op == opStructEndIndent {
+			break
+		}
+		if code.op == opStructField || code.op == opStructFieldIndent {
+			codeType := code.next.op.codeType()
+			if codeType == codeStructField {
+				if e.isNotExistsField(code.next.toStructFieldCode()) {
+					code.next = code.nextField
+					linkPrevToNextField(prev, code)
+					code = prev
+				}
+			}
+		}
+		prev = code
+		code = code.nextField.toStructFieldCode()
+	}
+}
+
+type structFieldPair struct {
+	prevField   *structFieldCode
+	curField    *structFieldCode
+	isTaggedKey bool
+	linked      bool
+}
+
+func (e *Encoder) anonymousStructFieldPairMap(typ *rtype, tags structTags, valueCode *structFieldCode) map[string][]structFieldPair {
+	//fmt.Println("type = ", typ, "valueCode = ", valueCode.dump())
+	anonymousFields := map[string][]structFieldPair{}
+	f := valueCode
+	var prevAnonymousField *structFieldCode
+	for {
+		existsKey := tags.existsKey(f.displayKey)
+		op := f.op.headToAnonymousHead()
+		if op != f.op {
+			if existsKey {
+				f.op = opStructFieldAnonymousHead
+			} else {
+				f.op = op
+			}
+		} else if f.op == opStructEnd {
+			f.op = opStructAnonymousEnd
+		} else if existsKey {
+			linkPrevToNextField(prevAnonymousField, f)
+		}
+
+		if f.displayKey == "" {
+			if f.nextField == nil {
+				break
+			}
+			prevAnonymousField = f
+			f = f.nextField.toStructFieldCode()
+			continue
+		}
+
+		anonymousFields[f.displayKey] = append(anonymousFields[f.displayKey], structFieldPair{
+			prevField:   prevAnonymousField,
+			curField:    f,
+			isTaggedKey: f.isTaggedKey,
+		})
+		if f.next != nil && f.nextField != f.next && f.next.op.codeType() == codeStructField {
+			for k, v := range e.anonymousStructFieldPairMap(typ, tags, f.next.toStructFieldCode()) {
+				anonymousFields[k] = append(anonymousFields[k], v...)
+			}
+		}
+		if f.nextField == nil {
+			break
+		}
+		prevAnonymousField = f
+		f = f.nextField.toStructFieldCode()
+	}
+	return anonymousFields
+}
+
+func (e *Encoder) optimizeConflictAnonymousFields(anonymousFields map[string][]structFieldPair) {
+	for _, fieldPairs := range anonymousFields {
+		if len(fieldPairs) == 1 {
+			continue
+		}
+		// conflict anonymous fields
+		taggedPairs := []structFieldPair{}
+		for _, fieldPair := range fieldPairs {
+			if fieldPair.isTaggedKey {
+				taggedPairs = append(taggedPairs, fieldPair)
+			} else {
+				if !fieldPair.linked {
+					if fieldPair.prevField == nil {
+						// head operation
+						fieldPair.curField.op = opStructFieldAnonymousHead
+					} else {
+						linkPrevToNextField(fieldPair.prevField, fieldPair.curField)
+					}
+					fieldPair.linked = true
+				}
+			}
+		}
+		if len(taggedPairs) > 1 {
+			for _, fieldPair := range taggedPairs {
+				if !fieldPair.linked {
+					if fieldPair.prevField == nil {
+						// head operation
+						fieldPair.curField.op = opStructFieldAnonymousHead
+					} else {
+						linkPrevToNextField(fieldPair.prevField, fieldPair.curField)
+					}
+					fieldPair.linked = true
+				}
+			}
+		} else {
+			for _, fieldPair := range taggedPairs {
+				fieldPair.curField.isTaggedKey = false
+			}
+		}
+	}
+}
+
 func (e *Encoder) compileStruct(typ *rtype, isPtr, root, withIndent bool) (*opcode, error) {
 	if code := e.compiledCode(typ, withIndent); code != nil {
 		return code, nil
@@ -588,12 +733,17 @@ func (e *Encoder) compileStruct(typ *rtype, isPtr, root, withIndent bool) (*opco
 		prevField *structFieldCode
 	)
 	e.indent++
+	tags := structTags{}
+	anonymousFields := map[string][]structFieldPair{}
 	for i := 0; i < fieldNum; i++ {
 		field := typ.Field(i)
 		if isIgnoredStructField(field) {
 			continue
 		}
-		tag := structTagFromField(field)
+		tags = append(tags, structTagFromField(field))
+	}
+	for i, tag := range tags {
+		field := tag.field
 		fieldType := type2rtype(field.Type)
 		if isPtr && i == 0 {
 			// head field of pointer structure at top level
@@ -609,16 +759,8 @@ func (e *Encoder) compileStruct(typ *rtype, isPtr, root, withIndent bool) (*opco
 			return nil, err
 		}
 		if field.Anonymous {
-			f := valueCode.toStructFieldCode()
-			for {
-				f.op = f.op.headToAnonymousHead()
-				if f.op == opStructEnd {
-					f.op = opStructAnonymousEnd
-				}
-				if f.nextField == nil {
-					break
-				}
-				f = f.nextField.toStructFieldCode()
+			for k, v := range e.anonymousStructFieldPairMap(typ, tags, valueCode.toStructFieldCode()) {
+				anonymousFields[k] = append(anonymousFields[k], v...)
 			}
 		}
 		if fieldNum == 1 && valueCode.op == opPtr {
@@ -640,6 +782,8 @@ func (e *Encoder) compileStruct(typ *rtype, isPtr, root, withIndent bool) (*opco
 			},
 			anonymousKey: field.Anonymous,
 			key:          []byte(key),
+			isTaggedKey:  tag.isTaggedKey,
+			displayKey:   tag.key,
 			offset:       field.Offset,
 		}
 		if fieldIdx == 0 {
@@ -690,6 +834,10 @@ func (e *Encoder) compileStruct(typ *rtype, isPtr, root, withIndent bool) (*opco
 	}
 	head.end = structEndCode
 	code.next = structEndCode
+
+	e.optimizeConflictAnonymousFields(anonymousFields)
+	e.optimizeAnonymousFields(head)
+
 	ret := (*opcode)(unsafe.Pointer(head))
 	compiled.code = ret
 

encode_opcode.go

@@ -53,12 +53,12 @@ func (c *opcode) beforeLastCode() *opcode {
 	code := c
 	for {
 		var nextCode *opcode
-		switch code.op {
-		case opArrayElem, opArrayElemIndent:
+		switch code.op.codeType() {
+		case codeArrayElem:
 			nextCode = code.toArrayElemCode().end
-		case opSliceElem, opSliceElemIndent, opRootSliceElemIndent:
+		case codeSliceElem:
 			nextCode = code.toSliceElemCode().end
-		case opMapKey, opMapKeyIndent, opRootMapKeyIndent:
+		case codeMapKey:
 			nextCode = code.toMapKeyCode().end
 		default:
 			nextCode = code.next
@@ -112,13 +112,13 @@ func (c *opcode) dump() string {
 	codes := []string{}
 	for code := c; code.op != opEnd; {
 		indent := strings.Repeat(" ", code.indent)
-		codes = append(codes, fmt.Sprintf("%s%s", indent, code.op))
-		switch code.op {
-		case opArrayElem, opArrayElemIndent:
+		codes = append(codes, fmt.Sprintf("%s%s ( %p )", indent, code.op, unsafe.Pointer(code)))
+		switch code.op.codeType() {
+		case codeArrayElem:
 			code = code.toArrayElemCode().end
-		case opSliceElem, opSliceElemIndent, opRootSliceElemIndent:
+		case codeSliceElem:
 			code = code.toSliceElemCode().end
-		case opMapKey, opMapKeyIndent, opRootMapKeyIndent:
+		case codeMapKey:
 			code = code.toMapKeyCode().end
 		default:
 			code = code.next
@@ -305,12 +305,44 @@ func (c *arrayElemCode) copy(codeMap map[uintptr]*opcode) *opcode {
 type structFieldCode struct {
 	*opcodeHeader
 	key          []byte
+	displayKey   string
+	isTaggedKey  bool
 	offset       uintptr
 	anonymousKey bool
 	nextField    *opcode
 	end          *opcode
 }
 
+func linkPrevToNextField(prev, cur *structFieldCode) {
+	prev.nextField = cur.nextField
+	code := prev.toOpcode()
+	fcode := cur.toOpcode()
+	for {
+		var nextCode *opcode
+		switch code.op.codeType() {
+		case codeArrayElem:
+			nextCode = code.toArrayElemCode().end
+		case codeSliceElem:
+			nextCode = code.toSliceElemCode().end
+		case codeMapKey:
+			nextCode = code.toMapKeyCode().end
+		default:
+			nextCode = code.next
+		}
+		if nextCode == fcode {
+			code.next = fcode.next
+			break
+		} else if nextCode.op == opEnd {
+			break
+		}
+		code = nextCode
+	}
+}
+
+func (c *structFieldCode) toOpcode() *opcode {
+	return (*opcode)(unsafe.Pointer(c))
+}
+
 func (c *structFieldCode) copy(codeMap map[uintptr]*opcode) *opcode {
 	if c == nil {
 		return nil
@@ -321,6 +353,8 @@ func (c *structFieldCode) copy(codeMap map[uintptr]*opcode) *opcode {
 	}
 	field := &structFieldCode{
 		key:          c.key,
+		isTaggedKey:  c.isTaggedKey,
+		displayKey:   c.displayKey,
 		anonymousKey: c.anonymousKey,
 		offset:       c.offset,
 	}

encode_test.go

@@ -2,6 +2,7 @@ package json_test
 
 import (
 	"bytes"
+	"encoding"
 	"errors"
 	"fmt"
 	"log"
@@ -1233,3 +1234,161 @@ func TestHTMLEscape(t *testing.T) {
 		t.Errorf("HTMLEscape(&b, []byte(m)) = %s; want %s", b.Bytes(), want.Bytes())
 	}
 }
+
+type BugA struct {
+	S string
+}
+
+type BugB struct {
+	BugA
+	S string
+}
+
+type BugC struct {
+	S string
+}
+
+// Legal Go: We never use the repeated embedded field (S).
+type BugX struct {
+	A int
+	BugA
+	BugB
+}
+
+// golang.org/issue/16042.
+// Even if a nil interface value is passed in, as long as
+// it implements Marshaler, it should be marshaled.
+type nilJSONMarshaler string
+
+func (nm *nilJSONMarshaler) MarshalJSON() ([]byte, error) {
+	if nm == nil {
+		return json.Marshal("0zenil0")
+	}
+	return json.Marshal("zenil:" + string(*nm))
+}
+
+// golang.org/issue/34235.
+// Even if a nil interface value is passed in, as long as
+// it implements encoding.TextMarshaler, it should be marshaled.
+type nilTextMarshaler string
+
+func (nm *nilTextMarshaler) MarshalText() ([]byte, error) {
+	if nm == nil {
+		return []byte("0zenil0"), nil
+	}
+	return []byte("zenil:" + string(*nm)), nil
+}
+
+// See golang.org/issue/16042 and golang.org/issue/34235.
+func TestNilMarshal(t *testing.T) {
+	testCases := []struct {
+		v    interface{}
+		want string
+	}{
+		{v: nil, want: `null`},
+		{v: new(float64), want: `0`},
+		{v: []interface{}(nil), want: `null`},
+		{v: []string(nil), want: `null`},
+		{v: map[string]string(nil), want: `null`},
+		{v: []byte(nil), want: `null`},
+		{v: struct{ M string }{"gopher"}, want: `{"M":"gopher"}`},
+		{v: struct{ M json.Marshaler }{}, want: `{"M":null}`},
+		{v: struct{ M json.Marshaler }{(*nilJSONMarshaler)(nil)}, want: `{"M":"0zenil0"}`},
+		{v: struct{ M interface{} }{(*nilJSONMarshaler)(nil)}, want: `{"M":"0zenil0"}`}, // doesn't compatible with encoding/json
+		{v: struct{ M encoding.TextMarshaler }{}, want: `{"M":null}`},
+		{v: struct{ M encoding.TextMarshaler }{(*nilTextMarshaler)(nil)}, want: `{"M":"0zenil0"}`},
+		{v: struct{ M interface{} }{(*nilTextMarshaler)(nil)}, want: `{"M":null}`},
+	}
+
+	for i, tt := range testCases {
+		out, err := json.Marshal(tt.v)
+		if err != nil || string(out) != tt.want {
+			t.Errorf("%d: Marshal(%#v) = %#q, %#v, want %#q, nil", i, tt.v, out, err, tt.want)
+			continue
+		}
+	}
+}
+
+// Issue 5245.
+func TestEmbeddedBug(t *testing.T) {
+	v := BugB{
+		BugA{"A"},
+		"B",
+	}
+	b, err := json.Marshal(v)
+	if err != nil {
+		t.Fatal("Marshal:", err)
+	}
+	want := `{"S":"B"}`
+	got := string(b)
+	if got != want {
+		t.Fatalf("Marshal: got %s want %s", got, want)
+	}
+	// Now check that the duplicate field, S, does not appear.
+	x := BugX{
+		A: 23,
+	}
+	b, err = json.Marshal(x)
+	if err != nil {
+		t.Fatal("Marshal:", err)
+	}
+	want = `{"A":23}`
+	got = string(b)
+	if got != want {
+		t.Fatalf("Marshal: got %s want %s", got, want)
+	}
+}
+
+type BugD struct { // Same as BugA after tagging.
+	XXX string `json:"S"`
+}
+
+// BugD's tagged S field should dominate BugA's.
+type BugY struct {
+	BugA
+	BugD
+}
+
+// Test that a field with a tag dominates untagged fields.
+func TestTaggedFieldDominates(t *testing.T) {
+	v := BugY{
+		BugA{"BugA"},
+		BugD{"BugD"},
+	}
+	b, err := json.Marshal(v)
+	if err != nil {
+		t.Fatal("Marshal:", err)
+	}
+	want := `{"S":"BugD"}`
+	got := string(b)
+	if got != want {
+		t.Fatalf("Marshal: got %s want %s", got, want)
+	}
+}
+
+// There are no tags here, so S should not appear.
+type BugZ struct {
+	BugA
+	BugC
+	BugY // Contains a tagged S field through BugD; should not dominate.
+}
+
+func TestDuplicatedFieldDisappears(t *testing.T) {
+	v := BugZ{
+		BugA{"BugA"},
+		BugC{"BugC"},
+		BugY{
+			BugA{"nested BugA"},
+			BugD{"nested BugD"},
+		},
+	}
+	b, err := json.Marshal(v)
+	if err != nil {
+		t.Fatal("Marshal:", err)
+	}
+	want := `{}`
+	got := string(b)
+	if got != want {
+		t.Fatalf("Marshal: got %s want %s", got, want)
+	}
+}

encode_vm.go

@@ -69,10 +69,16 @@ func (e *Encoder) run(code *opcode) error {
 			e.encodeBool(e.ptrToBool(code.ptr))
 			code = code.next
 		case opBytes:
-			s := base64.StdEncoding.EncodeToString(e.ptrToBytes(code.ptr))
-			e.encodeByte('"')
-			e.encodeBytes(*(*[]byte)(unsafe.Pointer(&s)))
-			e.encodeByte('"')
+			ptr := code.ptr
+			header := (*reflect.SliceHeader)(unsafe.Pointer(ptr))
+			if ptr == 0 || header.Data == 0 {
+				e.encodeNull()
+			} else {
+				s := base64.StdEncoding.EncodeToString(e.ptrToBytes(code.ptr))
+				e.encodeByte('"')
+				e.encodeBytes(*(*[]byte)(unsafe.Pointer(&s)))
+				e.encodeByte('"')
+			}
 			code = code.next
 		case opInterface:
 			ifaceCode := code.toInterfaceCode()
@@ -148,7 +154,9 @@ func (e *Encoder) run(code *opcode) error {
 			ptr := code.ptr
 			isPtr := code.typ.Kind() == reflect.Ptr
 			p := unsafe.Pointer(ptr)
-			if isPtr && *(*unsafe.Pointer)(p) == nil {
+			if p == nil {
+				e.encodeNull()
+			} else if isPtr && *(*unsafe.Pointer)(p) == nil {
 				e.encodeBytes([]byte{'"', '"'})
 			} else {
 				if isPtr && code.typ.Elem().Implements(marshalTextType) {
@@ -172,12 +180,12 @@ func (e *Encoder) run(code *opcode) error {
 		case opSliceHead:
 			p := code.ptr
 			headerCode := code.toSliceHeaderCode()
-			if p == 0 {
+			header := (*reflect.SliceHeader)(unsafe.Pointer(p))
+			if p == 0 || header.Data == 0 {
 				e.encodeNull()
 				code = headerCode.end.next
 			} else {
 				e.encodeByte('[')
-				header := (*reflect.SliceHeader)(unsafe.Pointer(p))
 				headerCode.elem.set(header)
 				if header.Len > 0 {
 					code = code.next
@@ -541,6 +549,16 @@ func (e *Encoder) run(code *opcode) error {
 				code.ptr = ptr
 				field.nextField.ptr = ptr
 			}
+		case opStructFieldAnonymousHead:
+			field := code.toStructFieldCode()
+			ptr := field.ptr
+			if ptr == 0 {
+				code = field.end.next
+			} else {
+				code = field.next
+				code.ptr = ptr
+				field.nextField.ptr = ptr
+			}
 		case opStructFieldPtrHeadInt:
 			code.ptr = e.ptrToPtr(code.ptr)
 			fallthrough
@@ -1027,7 +1045,13 @@ func (e *Encoder) run(code *opcode) error {
 					typ: code.typ,
 					ptr: unsafe.Pointer(ptr),
 				}))
-				b, err := v.(Marshaler).MarshalJSON()
+				rv := reflect.ValueOf(v)
+				if rv.Type().Kind() == reflect.Interface && rv.IsNil() {
+					e.encodeNull()
+					code = field.end
+					break
+				}
+				b, err := rv.Interface().(Marshaler).MarshalJSON()
 				if err != nil {
 					return &MarshalerError{
 						Type: rtype2type(code.typ),
@@ -1062,7 +1086,13 @@ func (e *Encoder) run(code *opcode) error {
 					typ: code.typ,
 					ptr: unsafe.Pointer(ptr),
 				}))
-				b, err := v.(Marshaler).MarshalJSON()
+				rv := reflect.ValueOf(v)
+				if rv.Type().Kind() == reflect.Interface && rv.IsNil() {
+					e.encodeNull()
+					code = field.end
+					break
+				}
+				b, err := rv.Interface().(Marshaler).MarshalJSON()
 				if err != nil {
 					return &MarshalerError{
 						Type: rtype2type(code.typ),
@@ -1099,7 +1129,13 @@ func (e *Encoder) run(code *opcode) error {
 					typ: code.typ,
 					ptr: unsafe.Pointer(ptr),
 				}))
-				bytes, err := v.(encoding.TextMarshaler).MarshalText()
+				rv := reflect.ValueOf(v)
+				if rv.Type().Kind() == reflect.Interface && rv.IsNil() {
+					e.encodeNull()
+					code = field.end
+					break
+				}
+				bytes, err := rv.Interface().(encoding.TextMarshaler).MarshalText()
 				if err != nil {
 					return &MarshalerError{
 						Type: rtype2type(code.typ),
@@ -1124,7 +1160,13 @@ func (e *Encoder) run(code *opcode) error {
 					typ: code.typ,
 					ptr: unsafe.Pointer(ptr),
 				}))
-				bytes, err := v.(encoding.TextMarshaler).MarshalText()
+				rv := reflect.ValueOf(v)
+				if rv.Type().Kind() == reflect.Interface && rv.IsNil() {
+					e.encodeNull()
+					code = field.end
+					break
+				}
+				bytes, err := rv.Interface().(encoding.TextMarshaler).MarshalText()
 				if err != nil {
 					return &MarshalerError{
 						Type: rtype2type(code.typ),
@@ -3840,7 +3882,9 @@ func (e *Encoder) run(code *opcode) error {
 				e.encodeByte(',')
 			}
 			c := code.toStructFieldCode()
-			e.encodeBytes(c.key)
+			if !c.anonymousKey {
+				e.encodeBytes(c.key)
+			}
 			code = code.next
 			code.ptr = c.ptr + c.offset
 			c.nextField.ptr = c.ptr

struct_field.go

@@ -23,20 +23,35 @@ func isIgnoredStructField(field reflect.StructField) bool {
 
 type structTag struct {
 	key         string
+	isTaggedKey bool
 	isOmitEmpty bool
 	isString    bool
+	field       reflect.StructField
+}
+
+type structTags []*structTag
+
+func (t structTags) existsKey(key string) bool {
+	for _, tt := range t {
+		if tt.key == key {
+			return true
+		}
+	}
+	return false
 }
 
 func structTagFromField(field reflect.StructField) *structTag {
 	keyName := field.Name
 	tag := getTag(field)
+	st := &structTag{field: field}
 	opts := strings.Split(tag, ",")
 	if len(opts) > 0 {
 		if opts[0] != "" {
 			keyName = opts[0]
+			st.isTaggedKey = true
 		}
 	}
-	st := &structTag{key: keyName}
+	st.key = keyName
 	if len(opts) > 1 {
 		st.isOmitEmpty = opts[1] == "omitempty"
 		st.isString = opts[1] == "string"