ToOne Object is Null

[SimonHaenle]

Issue Basics

• ObjectBox version 2.5.1
• Reproducibility: [always]

Hi, I am getting this error everytime I want to load my Object even though on saving I checked in the debugger and see that the relation target is not null and everything is saved correctly.

I am having those trhee entity classes

@Entity
data class NetflixCache (
    val results: List<NetflixSearchResult>,
    @Id var objectBoxId: Long?
) {
   var searchParams: ToOne<SearchParams> = ToOne<SearchParams>(this, NetflixCache_.searchParams)
}

@Entity
data class SearchParams(val genrelist: String, 
                        val type: String,
                        val imdbRatingMin: String,
                        val countryId: String,
                        val startYear: Int,
                        val endYear: Int,
                        val offset: Int? = 0,
                        val timeStamp: Long,
                        @Id var id: Long? = null)

@Entity
data class NetflixSearchResult (
    val vtype: String?,
    val img: String?,
    val nfid: Long?,
    val imdbid: String?,
    val title: String?,
    val clist: String?,
    val poster: String?,
    val imdbrating: Double?,
    val synopsis: String?,
    val titledate: Date?,
    val year: Int?,
    var id: Long,
    @Id var objectBoxId: Long?
)

Using this code to save:

val cacheBox = LetsFlixApplication.boxStore.boxFor(NetflixCache::class.java)
val netflixCache = NetflixCache(searchResults, null)
netflixCache.searchParams.target = searchParams
cacheBox.put(netflixCache)

And this code to load:

val cachedResult = cacheBox.all //<-Exception is thrown here

As you can see in debugger when saving, ToOne Object is NOT null:
https://ibb.co/s3tdhqP

This is the exact exception message I am getting:
ToOne object is null inside com.haenles.letsflix.domain.NetflixCache

[greenrobot-team]

@SimonHaenle Thanks for reporting. Do you have a full stack trace for the exception? Otherwise it's hard to pinpoint the issue.

My first guess is that the data classes are missing default values as recommended in the docs. Hence no default constructor is available and the ToOne can't be properly restored.
https://docs.objectbox.io/getting-started#entity-classes

[greenrobot-team]

Closing this issue due to inactivity. 💤 Please re-open with more details or submit a new issue.