hello :wave: has anyone tried `value class` with ...

# jackson-kotlin

[thanksforallthefish]

hello 👋

has anyone tried value class with jackson?

fun main() {
  val string = ObjectMapper().findAndRegisterModules()
    .convertValue<Map<String, String>>(Value("any"))

  println(string)
}

@JvmInline
value class Value(val value: String)

prints {value=any} with jackson 2.12.5, but fails with jackson 2.13.0. error is

Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `java.util.LinkedHashMap` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('any')
 at [Source: UNKNOWN; byte offset: #UNKNOWN]

though https://github.com/FasterXML/jackson-module-kotlin/issues/464 makes me wonder if my expectation is wrong. my use case is the one marked as “broken”:

"broken": [ {"value":0}, {"value":0} ], though this is exactly what I want

[wrongwrong]

The policy is to serialize the value class with an unboxed value in any case.

Custom serializers configured for value class do not currently work for this use case.
https://github.com/FasterXML/jackson-module-kotlin/issues/524

An attempt to make this work properly is underway in the following PR
https://github.com/FasterXML/jackson-module-kotlin/pull/527

When this PR is merged, I believe it will be possible to make it work as expected by using a custom serializer.

Also, if there is a strong desire to serialize the`toString` form as well as the data class, an additional option may be introduced in the KotlinModule.
You can also open an issue on GitHub about this option.