[BUG]开启JSONWriter.Feature.ReferenceDetection进行序列化，结果却没有将重复引用替换成$ref

[BottomCoder-Ander]

问题描述

开启JSONWriter.Feature.ReferenceDetection进行序列化，结果却没有将重复引用替换成$ref

环境信息

• OS信息： Win10 4Core 3.10GHz 16 GB
• JDK信息： Openjdk 1.8.0_332
• 版本信息：Fastjson2 2.0.1~2.0.4

重现步骤

运行下面测试代码，序列化结果并没有检测引用。预期应该是序列化成$refxxx的。如果使用fastjson （1.2.78）而不是fastjson2，就不会有这个问题。

import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONWriter;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

public class Test {

    public static void main(String[] args){
        Test tt = new Test();
        tt.setTest(null);
        tt.setName("testtt");

        List<Test> list = new LinkedList<>();
        for(int i = 0; i < 4; i++) {
            Test t = new Test();
            t.setTest(tt);
            t.setName("test");
            list.add(t);
        }

        JSONWriter.Feature[] features = {
                JSONWriter.Feature.ReferenceDetection,
                //JSONWriter.Feature.FieldBased
        };
        String result = JSON.toJSONString(list,features );
        System.out.println(result);
    }

    private String name;
    private Test test;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Test getTest() {
        return test;
    }

    public void setTest(Test test) {
        this.test = test;
    }
}

预期结果

[{"name":"test","test":{"name":"testtt"}},{"name":"test","test":{"$ref":"$[0].test"}},{"name":"test","test":{"$ref":"$[0].test"}},{"name":"test","test":{"$ref":"$[0].test"}}]

实际结果

[{"name":"test","test":{"name":"testtt"}},{"name":"test","test":{"name":"testtt"}},{"name":"test","test":{"name":"testtt"}},{"name":"test","test":{"name":"testtt"}}]

[wenshao]

感谢反馈，问题已经修复，你可以用2.0.5-SNAPSHOT验证
https://oss.sonatype.org/content/repositories/snapshots/com/alibaba/fastjson2/fastjson2/2.0.5-SNAPSHOT/

[wenshao]

https://github.com/alibaba/fastjson2/releases/tag/2.0.5
问题已修复，请用新版本