IssueTracker

Component used: Room
Version used: 2.1.0
Devices/Android versions reproduced on: any device/version

When I define UUID as ids for my POJOs, and try to use @Relation, as result relation list is always empty.
Here is example:

object RoomTypeConverters {
    @TypeConverter
    @JvmStatic
    fun uuidToData(uuid: UUID?): ByteArray = ...

    @TypeConverter
    @JvmStatic
    fun dataToUUID(data: ByteArray?): UUID = ...
}

@Entity
data class Pet(
     @ PrimaryKey
     val uuid: UUID,
     val userUuid: UUID,
     val name: String
     // other fields
)

data class UserNameAndAllPets(
   val uuid: UUID,
   val name: String,
   @Relation(parentColumn = "uuid", entityColumn = "userUuid")
   lateinit var pets: List<Pet>
 )

 @Dao
interface UserPetDao {
     @Query("SELECT id, name from User")
     fun loadUserAndPets(): List<UserNameAndAllPets>
 }