not cross compatible scala 2.12.13 with scala 2.11.12

[DimaGolomozy]

bytes that were serialized in scala 2.11.12 are not deserialzed in scala 2.12.13
specially a nested class with option field.

in scala 2.11.12:

case class A(s: String, b: B)
case class B(s: String, option: Option[String])

val object = A("test", B("test", Some("option")))

val kryoSerializer = ...
val scala211Bytes = kryoSerializer.toBInary(object)

now print the bytes and use them in a variable:
in scala 2.12.13:

// the bytes from val scala211Bytes
val bytesFromScala211 = Array[Byte](1,0,99,111,109,46,115,101,99,102,117,108,46,103,97,116,101,119,97,121,99,111,110,116,114,111,108,108,101,114,46,-63,1,2,-126,98,-126,115,76,1,1,99,111,109,46,115,101,99,102,117,108,46,103,97,116,101,119,97,121,99,111,110,116,114,111,108,108,101,114,46,-62,1,2,111,112,116,105,111,-18,-126,115,25,1,2,115,99,97,108,97,46,83,111,109,-27,1,1,-126,120,7,1,111,112,116,105,111,-18,0,0,5,1,116,101,115,-12,0,0,1,6,0)

val kryoSerializer = ...

kryoSerialzer.fromBInary(bytesFromScala211).   <-- throws exception

Exception:

java.lang.IndexOutOfBoundsException: Index: 4, Size: 4
Serialization trace:
s (com.secful.gatewaycontroller.A)
com.esotericsoftware.kryo.KryoException: java.lang.IndexOutOfBoundsException: Index: 4, Size: 4
Serialization trace:
s (com.secful.gatewaycontroller.A)
	at com.esotericsoftware.kryo.serializers.ObjectField.read(ObjectField.java:144)
	at com.esotericsoftware.kryo.serializers.CompatibleFieldSerializer.read(CompatibleFieldSerializer.java:110)
	at com.secful.common.akka.serialization.OptionAwareCompatibleFieldSerializer.read(OptionAwareCompatibleFieldSerializer.scala:12)
	at com.esotericsoftware.kryo.Kryo.readClassAndObject(Kryo.java:790)
	at io.altoo.akka.serialization.kryo.KryoSerializerBackend.fromBinary(KryoSerializerBackend.scala:42)
	at io.altoo.akka.serialization.kryo.KryoSerializer.fromBinary(KryoSerializer.scala:188)
	at akka.serialization.Serializer.fromBinary(Serializer.scala:66)
	at akka.serialization.Serializer.fromBinary$(Serializer.scala:66)
	at io.altoo.akka.serialization.kryo.KryoSerializer.fromBinary(KryoSerializer.scala:72)

[nvollmar]

Hi,

Kryo does high performance binary serialization. As there is no binary compatibility guaranteed between minor Scala versions this is bound to fail.

For such use cases a serializer with an independent serialization format like JSON would be more suitable.

[DimaGolomozy]

cool.. thats for the quick response..
strange that it happens only for "nested Option".. like all other types work :\

[nvollmar]

Which version do you use? 2.0.0 used Kryo 5.0.0 which had generic optimizations enabled but had a bug that manifested itself in the same way (nested Option).

[DimaGolomozy]

ohhh.. we use kryo-shaded 3.0.3

[nvollmar]

so you might be in the wrong project and be looking for https://github.com/EsotericSoftware/kryo?

[DimaGolomozy]

ill have a look.. thanks for the help
closing this one