Incompatible encoding behavior for the object with MarshalJSON

[denverdino]

If the result byte array of MarshalJSON has some special char, e.g. \n or char need escape, the jsoniter Encode() will have incompatible behavior to impl of "encoding/json"

A simple test case is as following

package test

import (
	"bytes"
	"encoding/json"
	"github.com/json-iterator/go"
	"testing"
)


type Foo struct {
	Bar interface{}
}

func (f Foo) MarshalJSON() ([]byte, error) {
	var buf bytes.Buffer
	err := json.NewEncoder(&buf).Encode(f.Bar)
	return buf.Bytes(), err
}


// Standard Encoder has trailing newline.
func TestEncode(t *testing.T) {

	foo := Foo {
		Bar: 123,
	}

	var buf, stdbuf bytes.Buffer
	enc := jsoniter.ConfigCompatibleWithStandardLibrary.NewEncoder(&buf)
	enc.Encode(foo)
	stdenc := json.NewEncoder(&stdbuf)
	stdenc.Encode(foo)
	t.Logf("%q", string(buf.Bytes()))
	t.Logf("%q", string(stdbuf.Bytes()))
}

In Kubernetes project, there are several PRs are blocking on that. E.g. kubernetes/kubernetes#70574

E.g. in kubernetes/staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/unstructured/unstructured.go, its impl of MarshalJSON() will trigger this problem

// MarshalJSON ensures that the unstructured object produces proper
// JSON when passed to Go's standard JSON library.
func (u *Unstructured) MarshalJSON() ([]byte, error) {
	var buf bytes.Buffer
	err := UnstructuredJSONScheme.Encode(u, &buf)
	return buf.Bytes(), err
}