Ability to generate open Kotlin classes

[l3r8yJ]

@paulbakker I'm implementing a reach error type via GraphQL type, represented in code as a parent class. Error codes section

GraphQL type

type Error {
    msg: String!
}

Current Generated Kotlin code

public class Error(
  message: () -> String = messageDefault,
) {
  
  private val _message: () -> String = message
  
  // etc...
}

Usage

sealed class ValidationError(
    message: () -> String,
) : Error( // Inheriting from generated Error
    message = message,
) {

    class DuplicateTitle(fields: () -> List<String>) : ValidationError(message = { "some error msg" })

Problem

The generated Error class isn't open, making it impossible to extend.

Solution

Property for generator

I see it like property for plugin generateKotlinAllOpenClasses

generateJava {
  generateKotlinAllOpenClasses = true
}

Custom derictive

In case when making all generated classes is redundant, we can add new directive @open, which I see in two ways:

type Error @open {
  message: String!
}

or

type @open Error {
  message: String!
}

Can we modify the generator to make the Error class open? If so, I'd like to implement some solution.

Thanks!

[l3r8yJ]

I can move discussion into generator repo, if needed