Discriminator property is missing in ADT element if it was re-registered from non-ADT context

[jakipatryk]

Suppose we have the following Scala code:

sealed trait Expression
object Expression {
   case object NullLiteral extends Expression
   case class StringLiteral(value: String) extends Expression
}

case class SomethingElse(stringLiteral: Expression.StringLiteral)

and we register it with OpenAPIModelRegistration that has RegistrationConfig#sumADTsShape == RegistrationConfig.SumADTsShape.WithDiscriminator:

openAPIModelRegistration.register[Expression]()
openAPIModelRegistration.register[SomethingElse]()

(order matters), then we get an incorrect result where StringLiteral doesn't have the discriminator property added. This happens because, while openAPIModelRegistration.register[Expression]() registered StringLiteral correctly, openAPIModelRegistration.register[SomethingElse]() then overwritten that with incorrect result, as StringLiteral is there used in "non-ADT context".

[jakipatryk]

Release Notes
Fixed missing discriminator on ADT elements that have been re-registered in non-ADT context