feat: support tag omitzero

internal/encoder/alg/primitives.go

@@ -1,12 +1,12 @@
 /**
  * Copyright 2024 ByteDance Inc.
- * 
+ *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -19,8 +19,11 @@ package alg
 import (
 	"encoding"
 	"encoding/json"
+	"reflect"
+	"unsafe"
 
 	"github.com/bytedance/sonic/internal/encoder/vars"
+	"github.com/bytedance/sonic/internal/resolver"
 	"github.com/bytedance/sonic/internal/rt"
 )
 
@@ -92,4 +95,10 @@ func EncodeTextMarshaler(buf *[]byte, val encoding.TextMarshaler, opt uint64) er
 		return nil
 	}
 }
-
+
+func IsZero(val unsafe.Pointer, fv *resolver.FieldMeta) bool {
+	rv := reflect.NewAt(fv.Type, val).Elem()
+	b1 := fv.IsZero == nil && rv.IsZero()
+	b2 := fv.IsZero != nil && fv.IsZero(rv)
+	return  b1 || b2
+}

internal/encoder/compiler.go

@@ -440,7 +440,8 @@ func (self *Compiler) compileStructBody(p *ir.Program, sp int, vt reflect.Type)
 	p.Add(ir.OP_cond_set)
 
 	/* compile each field */
-	for _, fv := range resolver.ResolveStruct(vt) {
+	fvs := resolver.ResolveStruct(vt)
+	for i, fv := range fvs {
 		var s []int
 		var o resolver.Offset
 
@@ -463,7 +464,12 @@ func (self *Compiler) compileStructBody(p *ir.Program, sp int, vt reflect.Type)
 		/* check for "omitempty" option */
 		if fv.Type.Kind() != reflect.Struct && fv.Type.Kind() != reflect.Array && (fv.Opts&resolver.F_omitempty) != 0 {
 			s = append(s, p.PC())
-			self.compileStructFieldZero(p, fv.Type)
+			self.compileStructFieldEmpty(p, fv.Type)
+		}
+		/* check for "omitzero" option */
+		if fv.Opts&resolver.F_omitzero != 0 {
+			s = append(s, p.PC())
+			p.VField(ir.OP_is_zero, &fvs[i])
 		}
 
 		/* add the comma if not the first element */
@@ -574,7 +580,7 @@ func (self *Compiler) compileStructFieldStr(p *ir.Program, sp int, vt reflect.Ty
 	}
 }
 
-func (self *Compiler) compileStructFieldZero(p *ir.Program, vt reflect.Type) {
+func (self *Compiler) compileStructFieldEmpty(p *ir.Program, vt reflect.Type) {
 	switch vt.Kind() {
 	case reflect.Bool:
 		p.Add(ir.OP_is_zero_1)

internal/encoder/encoder_test.go

@@ -639,4 +639,4 @@ func BenchmarkEncode_Float32(b *testing.B) {
             b.Run(name, lib.test)
         }  
     }
-}
+}

internal/encoder/ir/op.go

@@ -24,6 +24,7 @@ import (
 	"unsafe"
 
 	"github.com/bytedance/sonic/internal/encoder/vars"
+	"github.com/bytedance/sonic/internal/resolver"
 	"github.com/bytedance/sonic/internal/rt"
 )
 
@@ -80,6 +81,7 @@ const (
 	OP_marshal_text_p
 	OP_cond_set
 	OP_cond_testc
+	OP_is_zero
 )
 
 const (
@@ -229,6 +231,11 @@ type typAndTab struct {
 	itab *rt.GoItab
 }
 
+type typAndField struct {
+	vt reflect.Type
+	fv *resolver.FieldMeta
+}
+
 func NewInsVtab(op Op, vt reflect.Type, itab *rt.GoItab) Instr {
 	return Instr{
 		o: op,
@@ -239,6 +246,13 @@ func NewInsVtab(op Op, vt reflect.Type, itab *rt.GoItab) Instr {
 	}
 }
 
+func NewInsField(op Op, fv *resolver.FieldMeta) Instr {
+	return Instr{
+		o: op,
+		p: unsafe.Pointer(fv),
+	}
+}
+
 func NewInsVp(op Op, vt reflect.Type, pv bool) Instr {
 	i := 0
 	if pv {
@@ -263,6 +277,10 @@ func (self Instr) Vf() uint8 {
 	return (*rt.GoType)(self.p).KindFlags
 }
 
+func (self Instr) VField() (*resolver.FieldMeta) {
+	return (*resolver.FieldMeta)(self.p)
+}
+
 func (self Instr) Vs() (v string) {
 	(*rt.GoString)(unsafe.Pointer(&v)).Ptr = self.p
 	(*rt.GoString)(unsafe.Pointer(&v)).Len = self.Vi()
@@ -442,6 +460,10 @@ func (self *Program) Vtab(op Op, vt reflect.Type, itab *rt.GoItab) {
 	*self = append(*self, NewInsVtab(op, vt, itab))
 }
 
+func (self *Program) VField(op Op, fv *resolver.FieldMeta) {
+	*self = append(*self, NewInsField(op, fv))
+}
+
 func (self Program) Disassemble() string {
 	nb := len(self)
 	tab := make([]bool, nb+1)

internal/encoder/omitzero_test.go

@@ -0,0 +1,216 @@
+//go:build go1.24
+
+/**
+ * Copyright 2025 ByteDance Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package encoder
+
+import (
+    "testing"
+	"time"
+    "fmt"
+	"strings"
+)
+
+type NonZeroStruct struct{}
+
+func (nzs NonZeroStruct) IsZero() bool {
+	return false
+}
+
+type NoPanicStruct struct {
+	Int int `json:"int,omitzero"`
+}
+
+func (nps *NoPanicStruct) IsZero() bool {
+	return nps.Int != 0
+}
+
+type isZeroer interface {
+	IsZero() bool
+}
+
+type OptionalsZero struct {
+	Sr string `json:"sr"`
+	So string `json:"so,omitzero"`
+	Sw string `json:"-"`
+
+	Ir int `json:"omitzero"` // actually named omitzero, not an option
+	Io int `json:"io,omitzero"`
+
+	Slr       []string `json:"slr,random"`
+	Slo       []string `json:"slo,omitzero"`
+	SloNonNil []string `json:"slononnil,omitzero"`
+
+	Mr  map[string]interface{} `json:"mr"`
+	Mo  map[string]interface{} `json:",omitzero"`
+	Moo map[string]interface{} `json:"moo,omitzero"`
+
+	Fr   float64    `json:"fr"`
+	Fo   float64    `json:"fo,omitzero"`
+	Foo  float64    `json:"foo,omitzero"`
+	Foo2 [2]float64 `json:"foo2,omitzero"`
+
+	Br bool `json:"br"`
+	Bo bool `json:"bo,omitzero"`
+
+	Ur uint `json:"ur"`
+	Uo uint `json:"uo,omitzero"`
+
+	Str struct{} `json:"str"`
+	Sto struct{} `json:"sto,omitzero"`
+
+	Time      time.Time     `json:"time,omitzero"`
+	TimeLocal time.Time     `json:"timelocal,omitzero"`
+	Nzs       NonZeroStruct `json:"nzs,omitzero"`
+
+	NilIsZeroer    isZeroer       `json:"niliszeroer,omitzero"`    // nil interface
+	NonNilIsZeroer isZeroer       `json:"nonniliszeroer,omitzero"` // non-nil interface
+	NoPanicStruct0 isZeroer       `json:"nps0,omitzero"`           // non-nil interface with nil pointer
+	NoPanicStruct1 isZeroer       `json:"nps1,omitzero"`           // non-nil interface with non-nil pointer
+	NoPanicStruct2 *NoPanicStruct `json:"nps2,omitzero"`           // nil pointer
+	NoPanicStruct3 *NoPanicStruct `json:"nps3,omitzero"`           // non-nil pointer
+	NoPanicStruct4 NoPanicStruct  `json:"nps4,omitzero"`           // concrete type
+}
+
+func TestOmitZero(t *testing.T) {
+    // ForceUseVM()
+	const want = `{
+ "sr": "",
+ "omitzero": 0,
+ "slr": null,
+ "slononnil": [],
+ "mr": {},
+ "Mo": {},
+ "fr": 0,
+ "br": false,
+ "ur": 0,
+ "str": {},
+ "nzs": {},
+ "nps1": {},
+ "nps3": {},
+ "nps4": {}
+}`
+	var o OptionalsZero
+	o.Sw = "something"
+	o.SloNonNil = make([]string, 0)
+	o.Mr = map[string]interface{}{}
+	o.Mo = map[string]interface{}{}
+
+	o.Foo = -0
+	o.Foo2 = [2]float64{+0, -0}
+
+	o.TimeLocal = time.Time{}.Local()
+
+	o.NonNilIsZeroer = time.Time{}
+	o.NoPanicStruct0 = (*NoPanicStruct)(nil)
+	o.NoPanicStruct1 = &NoPanicStruct{}
+	o.NoPanicStruct3 = &NoPanicStruct{}
+
+	got, err := EncodeIndented(&o, "", " ", 0)
+	if err != nil {
+		t.Fatalf("MarshalIndent error: %v", err)
+	}
+	if got := string(got); got != want {
+		t.Errorf("MarshalIndent:\n\tgot:  %s\n\twant: %s\n", indentNewlines(got), indentNewlines(want))
+	}
+}
+
+func TestOmitZeroMap(t *testing.T) {
+	const want = `{
+ "foo": {
+  "sr": "",
+  "omitzero": 0,
+  "slr": null,
+  "mr": null,
+  "fr": 0,
+  "br": false,
+  "ur": 0,
+  "str": {},
+  "nzs": {},
+  "nps4": {}
+ }
+}`
+	m := map[string]OptionalsZero{"foo": {}}
+	got, err := EncodeIndented(m, "", " ", 0)
+	if err != nil {
+		t.Fatalf("MarshalIndent error: %v", err)
+	}
+	if got := string(got); got != want {
+		fmt.Println(got)
+		t.Errorf("MarshalIndent:\n\tgot:  %s\n\twant: %s\n", indentNewlines(got), indentNewlines(want))
+	}
+}
+
+type OptionalsEmptyZero struct {
+	Sr string `json:"sr"`
+	So string `json:"so,omitempty,omitzero"`
+	Sw string `json:"-"`
+
+	Io int `json:"io,omitempty,omitzero"`
+
+	Slr       []string `json:"slr,random"`
+	Slo       []string `json:"slo,omitempty,omitzero"`
+	SloNonNil []string `json:"slononnil,omitempty,omitzero"`
+
+	Mr map[string]interface{} `json:"mr"`
+	Mo map[string]interface{} `json:",omitempty,omitzero"`
+
+	Fr float64 `json:"fr"`
+	Fo float64 `json:"fo,omitempty,omitzero"`
+
+	Br bool `json:"br"`
+	Bo bool `json:"bo,omitempty,omitzero"`
+
+	Ur uint `json:"ur"`
+	Uo uint `json:"uo,omitempty,omitzero"`
+
+	Str struct{} `json:"str"`
+	Sto struct{} `json:"sto,omitempty,omitzero"`
+
+	Time time.Time     `json:"time,omitempty,omitzero"`
+	Nzs  NonZeroStruct `json:"nzs,omitempty,omitzero"`
+}
+
+func TestOmitEmptyZero(t *testing.T) {
+	const want = `{
+ "sr": "",
+ "slr": null,
+ "mr": {},
+ "fr": 0,
+ "br": false,
+ "ur": 0,
+ "str": {},
+ "nzs": {}
+}`
+	var o OptionalsEmptyZero
+	o.Sw = "something"
+	o.SloNonNil = make([]string, 0)
+	o.Mr = map[string]interface{}{}
+	o.Mo = map[string]interface{}{}
+
+	got, err := EncodeIndented(&o, "", " ", 0)
+	if err != nil {
+		t.Fatalf("MarshalIndent error: %v", err)
+	}
+	if got := string(got); got != want {
+		t.Errorf("MarshalIndent:\n\tgot:  %s\n\twant: %s\n", indentNewlines(got), indentNewlines(want))
+	}
+}
+
+func indentNewlines(s string) string {
+	return strings.Join(strings.Split(s, "\n"), "\n\t")
+}

internal/encoder/vm/vm.go

@@ -283,6 +283,12 @@ func Execute(b *[]byte, p unsafe.Pointer, s *vars.Stack, flags uint64, prog *ir.
 				pc = ins.Vi()
 				continue
 			}
+		case ir.OP_is_zero:
+			fv := ins.VField()
+			if alg.IsZero(p, fv) {
+				pc = ins.Vi()
+				continue
+			}
 		case ir.OP_is_zero_1:
 			if *(*uint8)(p) == 0 {
 				pc = ins.Vi()