Serialization of value class kotlin.time.Duration does not work

Trying to use the value class Duration with kotlin 1.5 and serialization 1.2 states

    kotlinx.serialization.SerializationException: Serializer for class 'Duration' is not found.
    Mark the class as @Serializable or provide the serializer explicitly.

My expectation is that value classes would “simply work”. The Duration class is not owned by me but the kotlin platform so attaching a @Serializable annotation is not possible.

To Reproduce

@Serializable
data class MyObject(
  val time: Duration = Duration.ZERO
)

Expected behavior Serialize.

Environment

• Kotlin version: 1.5.0
• Library version: 1.2.0
• Kotlin platforms: JVM
• Gradle version: 7.x

[sandwwraith]

Thanks for reminder, we’ll update the priority

[guness]

Edit:

Wrong alarm. I was using java time. Keeping original post below the line.

---

are we sure if this is deployed? On my end, Duration is not still serializable by default.

version.kotlinx.serialization=1.4.1
version.kotlin=1.7.20