fix(binding): fix default tag overriding JSON values in anonymous struct

pkg/app/server/binding/binder_test.go

@@ -1747,3 +1747,77 @@ func Benchmark_Binding(b *testing.B) {
 		}
 	}
 }
+
+// TestBind_AnonymousFieldWithDefaultTag tests that default tag values don't override
+// JSON-provided values when using anonymous struct embedding with multiple tags
+func TestBind_AnonymousFieldWithDefaultTag(t *testing.T) {
+	type PageInfo struct {
+		Page  int `json:"page" form:"page" query:"page" default:"1"`
+		Limit int `json:"limit" form:"limit" query:"limit" default:"15"`
+	}
+	type Req struct {
+		Keyword string `json:"keyword"`
+		PageInfo
+	}
+
+	// Test 1: JSON values should override defaults
+	req := protocol.NewRequest("POST", "/search", nil)
+	req.SetBody([]byte(`{"keyword":"test","page":2,"limit":5}`))
+	req.Header.SetContentTypeBytes([]byte("application/json"))
+	req.Header.SetContentLength(37)
+
+	var r Req
+	err := DefaultBinder().Bind(req, &r, nil)
+	assert.Nil(t, err)
+	assert.DeepEqual(t, "test", r.Keyword)
+	assert.DeepEqual(t, 2, r.Page)  // Should use JSON value, not default
+	assert.DeepEqual(t, 5, r.Limit) // Should use JSON value, not default
+
+	// Test 2: Empty JSON should use defaults
+	req2 := protocol.NewRequest("POST", "/search", nil)
+	req2.SetBody([]byte(`{"keyword":"test"}`))
+	req2.Header.SetContentTypeBytes([]byte("application/json"))
+	req2.Header.SetContentLength(20)
+
+	var r2 Req
+	err2 := DefaultBinder().Bind(req2, &r2, nil)
+	assert.Nil(t, err2)
+	assert.DeepEqual(t, "test", r2.Keyword)
+	assert.DeepEqual(t, 1, r2.Page)   // Should use default value
+	assert.DeepEqual(t, 15, r2.Limit) // Should use default value
+
+	// Test 3: Query values should work
+	req3 := protocol.NewRequest("POST", "/search?page=3&limit=4", nil)
+	req3.Header.SetContentTypeBytes([]byte("application/x-www-form-urlencoded"))
+
+	var r3 Req
+	err3 := DefaultBinder().Bind(req3, &r3, nil)
+	assert.Nil(t, err3)
+	assert.DeepEqual(t, 3, r3.Page)  // Should use query value
+	assert.DeepEqual(t, 4, r3.Limit) // Should use query value
+
+	// Test 4: Nested anonymous structs (multi-level)
+	type BaseInfo struct {
+		Page int `json:"page" form:"page" default:"1"`
+	}
+	type ExtInfo struct {
+		BaseInfo
+		Limit int `json:"limit" form:"limit" default:"20"`
+	}
+	type Req2 struct {
+		Keyword string `json:"keyword"`
+		ExtInfo
+	}
+
+	req4 := protocol.NewRequest("POST", "/search", nil)
+	req4.SetBody([]byte(`{"keyword":"nested","page":10,"limit":30}`))
+	req4.Header.SetContentTypeBytes([]byte("application/json"))
+	req4.Header.SetContentLength(44)
+
+	var r4 Req2
+	err4 := DefaultBinder().Bind(req4, &r4, nil)
+	assert.Nil(t, err4)
+	assert.DeepEqual(t, "nested", r4.Keyword)
+	assert.DeepEqual(t, 10, r4.Page)  // Should use JSON value from nested struct
+	assert.DeepEqual(t, 30, r4.Limit) // Should use JSON value, not default
+}

pkg/app/server/binding/internal/decoder/base_type_decoder.go

@@ -67,6 +67,8 @@ func (d *baseTypeFieldTextDecoder) Decode(req *protocol.Request, params param.Pa
 	var text string
 	var exist bool
 	var defaultValue string
+	var defaultDisabled bool // Flag to prevent default value from overriding JSON-provided values
+
 	for _, tagInfo := range d.tagInfos {
 		if tagInfo.Skip || tagInfo.Key == jsonTag || tagInfo.Key == fileNameTag {
 			if tagInfo.Key == jsonTag {
@@ -77,14 +79,19 @@ func (d *baseTypeFieldTextDecoder) Decode(req *protocol.Request, params param.Pa
 				} else {
 					err = fmt.Errorf("'%s' field is a 'required' parameter, but the request body does not have this parameter '%s'", tagInfo.Value, tagInfo.JSONName)
 				}
+				// If field exists in JSON body, disable default value to prevent override
 				if len(tagInfo.Default) != 0 && keyExist(req, tagInfo) {
 					defaultValue = ""
+					defaultDisabled = true
 				}
 			}
 			continue
 		}
 		text, exist = tagInfo.Getter(req, params, tagInfo.Value)
-		defaultValue = tagInfo.Default
+		// Only set defaultValue if not disabled by JSON tag and not already set
+		if !defaultDisabled && len(defaultValue) == 0 {
+			defaultValue = tagInfo.Default
+		}
 		if exist {
 			err = nil
 			break

pkg/app/server/binding/internal/decoder/decoder.go

@@ -183,7 +183,11 @@ func getFieldDecoder(pInfo parentInfos, field reflect.StructField, index int, by
 			idxes = append(idxes, index)
 			pInfo.Indexes = idxes
 			pInfo.Types = append(pInfo.Types, el)
-			pInfo.JSONName = newParentJSONName
+			// For anonymous embedded structs, keep the parent JSONName at the same level
+			// because Go's JSON marshaling flattens anonymous struct fields to the parent level
+			if !field.Anonymous {
+				pInfo.JSONName = newParentJSONName
+			}
 			dec, err := getFieldDecoder(pInfo, el.Field(i), i, byTag, config)
 			if err != nil {
 				return nil, err

pkg/app/server/binding/internal/decoder/map_type_decoder.go

@@ -59,6 +59,8 @@ func (d *mapTypeFieldTextDecoder) Decode(req *protocol.Request, params param.Par
 	var text string
 	var exist bool
 	var defaultValue string
+	var defaultDisabled bool // Flag to prevent default value from overriding JSON-provided values
+
 	for _, tagInfo := range d.tagInfos {
 		if tagInfo.Skip || tagInfo.Key == jsonTag || tagInfo.Key == fileNameTag {
 			if tagInfo.Key == jsonTag {
@@ -69,14 +71,19 @@ func (d *mapTypeFieldTextDecoder) Decode(req *protocol.Request, params param.Par
 				} else {
 					err = fmt.Errorf("'%s' field is a 'required' parameter, but the request does not have this parameter", tagInfo.Value)
 				}
+				// If field exists in JSON body, disable default value to prevent override
 				if len(tagInfo.Default) != 0 && keyExist(req, tagInfo) {
 					defaultValue = ""
+					defaultDisabled = true
 				}
 			}
 			continue
 		}
 		text, exist = tagInfo.Getter(req, params, tagInfo.Value)
-		defaultValue = tagInfo.Default
+		// Only set defaultValue if not disabled by JSON tag and not already set
+		if !defaultDisabled && len(defaultValue) == 0 {
+			defaultValue = tagInfo.Default
+		}
 		if exist {
 			err = nil
 			break

pkg/app/server/binding/internal/decoder/slice_type_decoder.go

@@ -62,6 +62,8 @@ func (d *sliceTypeFieldTextDecoder) Decode(req *protocol.Request, params param.P
 	var defaultValue string
 	var bindRawBody bool
 	var isDefault bool
+	var defaultDisabled bool // Flag to prevent default value from overriding JSON-provided values
+
 	for _, tagInfo := range d.tagInfos {
 		if tagInfo.Skip || tagInfo.Key == jsonTag || tagInfo.Key == fileNameTag {
 			if tagInfo.Key == jsonTag {
@@ -72,8 +74,10 @@ func (d *sliceTypeFieldTextDecoder) Decode(req *protocol.Request, params param.P
 				} else {
 					err = fmt.Errorf("'%s' field is a 'required' parameter, but the request does not have this parameter", tagInfo.Value)
 				}
-				if len(tagInfo.Default) != 0 && keyExist(req, tagInfo) { //
+				// If field exists in JSON body, disable default value to prevent override
+				if len(tagInfo.Default) != 0 && keyExist(req, tagInfo) {
 					defaultValue = ""
+					defaultDisabled = true
 				}
 			}
 			continue
@@ -82,7 +86,10 @@ func (d *sliceTypeFieldTextDecoder) Decode(req *protocol.Request, params param.P
 			bindRawBody = true
 		}
 		texts = tagInfo.SliceGetter(req, params, tagInfo.Value)
-		defaultValue = tagInfo.Default
+		// Only set defaultValue if not disabled by JSON tag and not already set
+		if !defaultDisabled && len(defaultValue) == 0 {
+			defaultValue = tagInfo.Default
+		}
 		if len(texts) != 0 {
 			err = nil
 			break

pkg/app/server/binding/internal/decoder/struct_type_decoder.go

@@ -36,6 +36,8 @@ func (d *structTypeFieldTextDecoder) Decode(req *protocol.Request, params param.
 	var text string
 	var exist bool
 	var defaultValue string
+	var defaultDisabled bool // Flag to prevent default value from overriding JSON-provided values
+
 	for _, tagInfo := range d.tagInfos {
 		if tagInfo.Skip || tagInfo.Key == jsonTag || tagInfo.Key == fileNameTag {
 			if tagInfo.Key == jsonTag {
@@ -46,14 +48,19 @@ func (d *structTypeFieldTextDecoder) Decode(req *protocol.Request, params param.
 				} else {
 					err = fmt.Errorf("'%s' field is a 'required' parameter, but the request does not have this parameter", tagInfo.Value)
 				}
+				// If field exists in JSON body, disable default value to prevent override
 				if len(tagInfo.Default) != 0 && keyExist(req, tagInfo) {
 					defaultValue = ""
+					defaultDisabled = true
 				}
 			}
 			continue
 		}
 		text, exist = tagInfo.Getter(req, params, tagInfo.Value)
-		defaultValue = tagInfo.Default
+		// Only set defaultValue if not disabled by JSON tag and not already set
+		if !defaultDisabled && len(defaultValue) == 0 {
+			defaultValue = tagInfo.Default
+		}
 		if exist {
 			err = nil
 			break