CoroutineCollection#save doesn't use specified Serializer (kotlinx.serialization)

[emmaboecker]

I have this data class in my Project:

@Serializable
data class DBPlayer(
    @SerialName("_id") val uuid: SerializableUUID,
    @Contextual val team: Id<DBTeam>?
)

SerializableUUID is a typealias for UUID with my own Serializer:

typealias SerializableUUID = @Serializable(UUIDSerializer::class) UUID

object UUIDSerializer : KSerializer<UUID> {
    override val descriptor: SerialDescriptor =
        PrimitiveSerialDescriptor("UUID", PrimitiveKind.STRING)

    override fun deserialize(decoder: Decoder): UUID {
        return UUID.fromString(decoder.decodeString())
    }

    override fun serialize(encoder: Encoder, value: UUID) {
        encoder.encodeString(value.toString())
    }
}

When I now try to save an instance of DBPlayer like this, playerCollection being a CoroutineCollection

val player = DBPlayer(owner, team.teamId)
playerCollection.save(player)

It will use the internal UUIDSerializer of KMongo and not the one that I specified.

But when I use insertOne this is not the case:

val player = DBPlayer(owner, team.teamId)
database.playerCollection.insertOne(player)

Furthermore, I'm having to call UUID#toString because it would otherwise try to use the internal Serializer again and not be able to find the right document

val player = DBPlayer(owner, team.teamId)
plugin.database.playerCollection.updateOneById(owner.toString(), player)

Is this intentional behavior, or is this a bug? Because it seems rather inconsistent.

[zigzago]

The typealias trick will not work. The way to go is to use registerSerializer, but I think it will not work for built-in type below. I will provide a fix in next kmongo release.

    private val serializersMap: Map<KClass<*>, KSerializer<*>> = mapOf(
        ObjectId::class to ObjectIdSerializer,
        BigDecimal::class to BigDecimalSerializer,
        ByteArray::class to ByteArraySerializer,
        Date::class to DateSerializer,
        Calendar::class to CalendarSerializer,
        GregorianCalendar::class to CalendarSerializer,
        Instant::class to InstantSerializer,
        ZonedDateTime::class to ZonedDateTimeSerializer,
        OffsetDateTime::class to OffsetDateTimeSerializer,
        LocalDate::class to LocalDateSerializer,
        LocalDateTime::class to LocalDateTimeSerializer,
        LocalTime::class to LocalTimeSerializer,
        OffsetTime::class to OffsetTimeSerializer,
        BsonTimestamp::class to BsonTimestampSerializer,
        Locale::class to LocaleSerializer,
        Binary::class to BinarySerializer,
        Id::class to IdSerializer(false),
        StringId::class to IdSerializer(true),
        WrappedObjectId::class to IdSerializer(false),
        Pattern::class to PatternSerializer,
        Regex::class to RegexSerializer,
        UUID::class to UUIDSerializer
    )