Jackson produces invalid field names from Kotlin value classes

[kevinstembridge]

This may well be an issue on the Kotlin side, but when a Kotlin class has a property that is one of the new @JvmInline value classes, Jackson converts it to JSON with a weird suffix on the field name.

e.g.

@JvmInline
value class ModelName(val value: String)

data class MyDto(val modelName: ModelName)

Jackson will produce JSON that looks like this:

{
    "modelName-11MJ8YI": "Some Model Name"
}

I've tried adding a @JsonProperty("modelName") annotation but it doesn't make a difference.

UPDATE: I found this comment on a previous issue:
#413 (comment)

Using @get:JsonProperty instead of @JsonProperty fixes (or works around) this issue.

I'll leave this issue open in case you think there is something that can be done on the Jackson side to handle these inline field names without having to use the extra annotation.

[dinomite]

Ahh yes, it seems we have some work to do around value classes. That postfix (-11MJ8YI) is generated by the Kotlin compiler. I think in this case they act as bridge methods to the true accessors, which means the annotations aren't present and we'll have to infer (read: guess at) the base method to find annotations or just what the method should be, sans postfix.

Could you make a minimal reproduction example? You could make a PR against 2.13 and add a test which would help us get this fixed.

[kevinstembridge]

My apologies. I've wasted your time. I was using an older version of Jackson.

I forked and started creating a test but came across an existing test for this exact problem.

This issue was fixed in #356.

Sorry for the trouble.

[dinomite]

Thanks for the update, that's a great outcome for us all!