[BUG] The subclass field does not overwrite the parent class

[qq31715879]

package com.kael.test.dto;

import com.fasterxml.jackson.annotation.JsonIgnore;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.experimental.SuperBuilder;


@Setter
@Getter
@SuperBuilder
@AllArgsConstructor
@NoArgsConstructor
public class TestParentDTO {

    @JsonIgnore
    private String demo;
    private String ddd;
}

package com.kael.test.dto;

import com.jugg.agile.framework.core.util.io.serialize.json.JaJson;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.experimental.SuperBuilder;


@Setter
@Getter
@SuperBuilder
@AllArgsConstructor
@NoArgsConstructor
public class TestChildrenDTO extends TestParentDTO {

    private String demo;

    public static void main(String[] args) {
        TestChildrenDTO testChildrenDTO = new TestChildrenDTO();
        testChildrenDTO.setDemo("ddemo");
        testChildrenDTO.setDdd("ddd");

        System.out.println(JaJson.toString(testChildrenDTO));
    }
}

Subclass fields have removed annotations @JsonIgnore

---

version 1.8.12 can runsuccess

---

but High version failed to run

[janrieke]

Things probably changed when Lombok started copying certain annotation to the setter with 1.18.16, including @JsonIgnore. Jackson can sometimes be confusing when it comes to detecting which annotations belong to a property, because it builds a combination of annotations on the field and its corresponding setters and getters.

With 1.18.12, the @JsonIgnore annotation was only on the field of the superclass, and Jackson correctly ignores only the field from the superclass. However, once Lombok copies it to the setter, I suspect that Jackson considers this setter method as if it belongs to the property defined in the subclass.

I tend towards "this is a Jackson bug", although you could argue that the setter method is overridden and thus it's the same method. On the other hand, @JsonIgnore is not inheritable (in a JLS sense), so Jackson should not consider it for the subclass property. But there is some indication in the JavaDoc of @JsonIgnore (last paragraph) that Jackson in fact considers it as inheritable.

From a lombok POV, this is another example why it's a bad idea to copy those Jackson annotations in the first place. (Except, of course, for builders, because Jackson does not combine the builder's setter methods with the property.)

[qq31715879]

@janrieke
I looked at the class, and in higher versions of Lombok, @ JsonIgnore will be added to the setDemo method of the parent class
I'm not sure if it's a bug with Lombok or Jackson either, but I'm curious why higher versions of Lombok add @ JsonIgnore to the set method

[qq31715879]

If @ JsonIgnore must be added to the method, should both the get and set methods be added; However, I personally feel that @ JsonIgnore should not be added to the method. The historical code encountered problems and now I want to upgrade to a higher version of Lombok, but I cannot do it

[janrieke]

You should be able to mitigate by adding @JsonIgnore(false) to the field in the subclass.

[qq31715879]

It's a bit awkward, the historical code is that the parent class defaults to @ JsonIgnore, and some special subclasses need to remove @ JsonIgnore

[Rawi01]

You can always add a custom setter without annotation to the parent class.

I agree with @janrieke that this is probably a jackson bug/issue.