KotlinModule is not registered in jackson3

[rsobies]

Basic information

When switching from jackson to jackson3 serialization start working diffrently for kotlin, KotlinModule is not registrer in JsonMapper
this lead to serialization:

val isTrueFalse: Boolean -> "trueFalse"

• Axon Framework version: 4.13.1

Expected behaviour

val isTrueFalse:Boolen -> "isTrueFalse"

Description

In the class JacksonSerializer objectMapper is passed from spring context to builder, so when KotlinModule is alredy registered in spring, serialization works correctly
but class Jackson3Serializer doesn't accept objectMapper from spring like it is in JacksonSerializer. It create new instance of JsonMapper so user has to add KotlinModule manually via Jackson3SerializerCustomizer despite it is registered in spring objectMapper

Solution

Allow passing objectMapper parameter to Jackson3Serializer

[smcvb]

The Jackson3Serializer is a new class. As such, it's not a regression, although it's worded as such.
Thus, I have switched the type from bug to enhancement.

Secondly, to the predicament at hand, how are you currently setting the KotlinModule for your ObjectMapper?
Assuming it's a dependency you set, I think the Jackson3Serializer would be solved with a JsonMapper.Builder#findAndAddModules, or by adding a Jackson3SerializerCustomizer bean whenever more modules are found instead.

Lastly, nudging @hjohn, as he made the choice to deviate from being able to set the ObjectMapper.
Perhaps there was some additional valid reasoning that I am missing in my suggestions.

[rsobies]

In my application KotlinModule is added automatically by spring

[hjohn]

Jackson3 ObjectMappers are immutable, so if we wanted to keep the same builder pattern we used for Jackson2, we couldn't start from an ObjectMapper.

[rsobies]

I think we could do it this way:

protected Jackson3Serializer(Builder builder) {
   ..
  JsonMapper.Builder jmb = JsonMapper.builder();
  builder.objectMapper.registeredModules().forEach(module -> jmb.addModule(module));
  ...

[smcvb]

That seems like a doable enhancement, @rsobies. Are you up for a PR perchance?

[rsobies]

@smcvb
I can take care of it. Should I start from 4.13 branch?