GeneratedValue annotation doesn't update kotlin data class while insert

@MappedEntity
data class Model(@Id @GeneratedValue val id: Long, val name: String)

@JdbcRepository(dialect = Dialect.H2)
interface Repository {
    fun save(model: Model): Single<Model>
}

val savedModel = repository.save(Model(id = 0, name = "Test")).blockingGet()

savedModel.id is always 0. Changing val id: Long to var id: Long or even var id: Long? doesn’t work. I have to move id parameter to mutable id field:

@MappedEntity
data class Model(val name: String) {
    @Id @GeneratedValue var id: Long = 0
}

[piotrwalkusz1]

I forgot to write that I added JPA plugin too:

plugins {
  id "org.jetbrains.kotlin.plugin.jpa" version "1.3.50"
}

Decompilation of Kotlin class shows that no-arg constructor was generated. After more investigation, I found out that code:

@Entity
data class Model(@Id @GeneratedValue val id: Long, val name: String)

compiles to:

public final class Model {
   @GeneratedValue
   private final long id;
   ...
   public Model(@Id long id, @NotNull String name) {
      ...
   }
   ...
   public Model() {
   }

and code:

@Entity
data class Model(val name: String) {
    @Id
    @GeneratedValue
    var id: Long = 0
}

compiles to:

public final class Model {
   @Id
   @GeneratedValue
   private long id;
   ...
   public Model(@NotNull String name) {
      ...
   }
   ...
   public Model() {
   }

In the first case, annotations @Id and @GeneratedValue are on the field and the argument, in the second case, both annotations are on the field.

Workaround

The correct workaround that works for me is:

@Entity
data class Model(@field:Id @GeneratedValue var id: Long? = null, val name: String)

Please notice @field:Id instead of @Id. But still id field has to be mutable…

[stale[bot]]

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