Different creator parameter null behavior for 2.17.3 and 2.18.2

[hykilpikonna]

Search before asking

• I searched in the issues and found nothing similar.
• I have confirmed that the same problem is not reproduced if I exclude the KotlinModule.
• I searched in the issues of databind and other modules used and found nothing similar.
• I have confirmed that the problem does not reproduce in Java and only occurs when using Kotlin and KotlinModule.

Describe the bug

After upgrading from jackson 2.17.3 to 2.18.1, the following error occurs when trying to deserialize null into an inherited field with a default value that also has a required constructor.

Exception in thread "main" com.fasterxml.jackson.module.kotlin.MissingKotlinParameterException: Instantiation of [simple type, class icu.samnyan.aqua.sega.chusan.model.userdata.UserActivity] value failed for JSON property user due to missing (therefore NULL) value for creator parameter user which is a non-nullable type
 at [Source: REDACTED (`StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION` disabled); line: 1, column: 76] (through reference chain: icu.samnyan.aqua.sega.chusan.model.userdata.UserActivity["user"])
	at com.fasterxml.jackson.module.kotlin.KotlinValueInstantiator.createFromObjectWith(KotlinValueInstantiator.kt:97)
	at com.fasterxml.jackson.databind.deser.impl.PropertyBasedCreator.build(PropertyBasedCreator.java:214)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeUsingPropertyBased(BeanDeserializer.java:541)
	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1497)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:348)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:185)
	at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:342)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4917)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3860)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3843)
	at test.JsonTestKt.main(JsonTest.kt:25)

To Reproduce

Here are my model definitions. Note that the user field in the parent has a default value, but the UserActivity class also has a constructor parameter user that doesn't have a default value.

@MappedSuperclass
open class BaseEntity(
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @JsonIgnore
    open var id: Long = 0
)

@MappedSuperclass
open class Chu3UserEntity : BaseEntity(), IUserEntity<Chu3UserData> {
    @JsonIgnore
    @ManyToOne
    @JoinColumn(name = "user_id")
    public override var user: Chu3UserData = Chu3UserData()
}

@Entity(name = "ChusanUserActivity")
@Table(name = "chusan_user_activity")
class UserActivity(user: Chu3UserData) : Chu3UserEntity() {
    init { this.user = user }

    var kind = 0
    @JsonProperty("id")
    @Column(name = "activity_id")
    var activityId = 0
    var sortNumber = 0
}

The following code will run successfully on Jackson (+kotlin module) 2.15 but fail on 2.18:

fun main(args: Array<String>) {
    val mapper = jacksonObjectMapper().apply {
        configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
        configure(SerializationFeature.WRITE_ENUMS_USING_INDEX, true)
        findAndRegisterModules()
    }
    val json = mapper.writeValueAsString(UserActivity(Chu3UserData()))
    mapper.readValue<UserActivity>(json)
}

Expected behavior

I do not expect null-handling behavior to subtly change when upgrading between minor versions of jackson-module-kotlin.

Versions

Kotlin: 2.1.0
Jackson-module-kotlin: 2.18.2
Jackson-databind: 2.18.2

Additional context

No response

[hykilpikonna]

Just tested that 2.17.3 does not have this issue.

[k163377]

@hykilpikonna
Would it be possible for you to test the same in 2.18.2?

[hykilpikonna]

Would it be possible for you to test the same in 2.18.2?

2.18.2 has the same issue as 2.18.1

[k163377]

@hykilpikonna
The code you attached seems incomplete.
At least the definition of Chu3UserData is missing.

Also, if you resubmit the code, I would appreciate the following

1. Remove as much of the code other than Jackson as possible, such as annotations
2. Remove as much code as possible that registers anything other than kotlin-module, to the extent that the problem can be reproduced.
3. Attach the import correctly as well.

---

In 2.18, databind has been modified to handle single argument constructors.
If that is the cause, adding @JsonCreator(mode = Mode.DELEGATING) to the constructor may improve it.