Support for default schema values

The GraphQL spec allows for arguments to have default values:

• https://graphql.org/learn/schema/#arguments

Kotlin allows specifying default values:

• https://kotlinlang.org/docs/reference/functions.html#default-arguments

This information is not available on reflection though due to the way Kotlin compiles to the JVM:

• https://discuss.kotlinlang.org/t/kotlin-reflection-and-default-values/2254
• https://discuss.kotlinlang.org/t/retrieve-default-parameter-value-via-reflection/7314

We could solve this issue by adding a new annotation @GraphQLDefaultValue. This would require developers to duplicate some information but I think it would be worth it until we have a better way of extracting the info

fun getWidget(id: Int, @GraphQLDefaultValue(WidgetType.UNICORN) type: WidgetType = WidgetType.UNICORN) {
    return database.getWidgetByIdAndType(id, type)
}

[smyrick]

@keerthi4308 Feel free to propose a solution or provide a PR! This is not being worked on by someone today so you can assign yourself if you would like.

As you can see from the previous discussion there is a bit of complexity on the best way to solve it

[Keerthi4308]

I’m wondering if this issue is taken care by anyone? I would like to contribute to this repo.