[BUG] Missing type value when using @JSONType with seeAlso

[sunnyguan]

问题描述

When using @JSONType(typeKey = ..., seeAlso = {...}), if typeKey is not the first key in the json, the value is deserialized properly; however if typeKey is the first key, its value is ignored and null is stored instead.

From some debugging it seems like this line causes the issue - if I manually run jsonReader.reset(savePoint) here when i == 0 and continue the debugger, the test passes successfully. But there could be other reasons for this line that I'm not aware of.

环境信息

请填写以下信息：

• JDK信息： 21.0.2
• 版本信息：Fastjson2 2.0.57

重现步骤

import static org.junit.jupiter.api.Assertions.assertEquals;

import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.annotation.JSONType;
import org.junit.jupiter.api.Test;

class TestAutoType {
    @JSONType(typeKey = "type", seeAlso = {Cat.class})
    interface Animal {}

    @JSONType(typeName = "cat")
    record Cat(String type, int age) implements Animal {}

    @Test
    void cat() {
        String s1 = "{\"age\": 20, \"type\": \"cat\"}";  // type comes second
        Cat c1 = (Cat) JSON.parseObject(s1, Animal.class);
        assertEquals("cat", c1.type);  // succeeds

        String s2 = "{\"type\": \"cat\", \"age\": 20}";  // type comes first
        Cat c2 = (Cat) JSON.parseObject(s2, Animal.class);
        assertEquals("cat", c2.type);  // fails
    }
}

期待的正确结果

Test should pass

附加信息

Related - ideally I can do something like this:

@JSONType(typeKey = "type")
sealed interface Animal permits Cat {}

instead of

@JSONType(typeKey = "type", seeAlso = {Cat.class})
interface Animal {}

i.e. no need to specify seeAlso for a sealed interface as theoretically we should know all possible subclasses already. This didn't seem to work so I had to add in the seeAlso.

[wenshao]

https://oss.sonatype.org/content/repositories/snapshots/com/alibaba/fastjson2/fastjson2/2.0.57-SNAPSHOT/
问题已经修复，请帮忙用2.0.57-SNAPSHOT版本验证，预计2.0.57在3月底前发布。

[wenshao]

https://github.com/alibaba/fastjson2/releases/tag/2.0.57
问题已修复，请用新版本