2.0.5版本，双向链表向Json序列化可用，但是序列化产生的数据反序列化节点存在问题

[javalipf]

@Data
@NoArgsConstructor
@AllArgsConstructor
public class ApproveConfigJson implements Serializable {
    private String postId;

    private boolean hasPreNode = false;

    private ApproveConfigJson preNode;

    private boolean hasNextNode = false;

    private ApproveConfigJson nextNode;

    private int sort;

    public ApproveConfigJson(String postId, int sort) {
        this.postId = postId;
        this.sort = sort;
    }
}
public static void main(String[] args) {
        List<ApproveConfigJson> approveConfigJsons = new ArrayList<>();
        approveConfigJsons.add(new ApproveConfigJson("1",1));
        approveConfigJsons.add(new ApproveConfigJson("2",2));
        approveConfigJsons.add(new ApproveConfigJson("3",3));
        String s = list2LinkedJson2(approveConfigJsons);
        ApproveConfigJson approveConfigJson = JSON.parseObject(s, ApproveConfigJson.class);
        System.err.println(approveConfigJson.getNextNode().getPreNode().getPostId());
    }

    public static String list2LinkedJson2(List<ApproveConfigJson> approveConfigJsons) {
        approveConfigJsons = approveConfigJsons.stream().sorted(Comparator.comparing(ApproveConfigJson::getSort)).collect(Collectors.toList());
        ApproveConfigJson approveUtil = null;
        Iterator<ApproveConfigJson> iterator = approveConfigJsons.iterator();
        ApproveConfigJson local = new ApproveConfigJson();
        while (iterator.hasNext()) {
            ApproveConfigJson next = iterator.next();
            if (approveUtil == null) {
                approveUtil = next;
                local = next;
            } else {
                approveUtil.setHasNextNode(true);
                approveUtil.setNextNode(next);
                next.setHasPreNode(true);
                next.setPreNode(local);
                local = next;
                approveUtil = approveUtil.getNextNode();
                approveUtil.setNextNode(null);
            }
        }

        ApproveConfigJson finalNode = approveUtil;
        while (finalNode.isHasPreNode()) {
            finalNode = finalNode.getPreNode();
        }
        return JSON.toJSONString(finalNode);
    }

按照sort排序，链表首节点为postId = 1，序列化的json串正常，但是反序列化后链表的首节点为postId = 2，且获取下级节点后再获取上级节点会出现java.lang.NullPointerException
在 ApproveConfigJson approveConfigJson = JSON.parseObject(s, ApproveConfigJson.class);方法中

[wenshao]

https://oss.sonatype.org/content/repositories/snapshots/com/alibaba/fastjson2/fastjson2/2.0.6-SNAPSHOT/

感谢反馈了JSON格式支持引用的BUG，问题已修复，请用2.0.6-SNAPSHOT版本验证。2.0.6正式版本预计6月5日前发布。

[wenshao]

https://github.com/alibaba/fastjson2/releases/tag/2.0.6
问题已经修复，请用新版本