jooby-apt: kotlin: should generates a code with !! null operator for nullable types

[jonaskahn]

I will go straight to the problem. I make a controller with return type is nullable, but it will make generate source error because the generate source somehow think return type is always not null

• Source:

    @POST("/secure/org/info")
    fun info(request: OrgInfoRequest): OrgDto? {
        BeanValidator.validate(request)
        return orgService.info(request)
    }

• Generated source

    fun info(ctx: io.jooby.Context): io.github.jonaskahn.services.org.dto.OrgDto {
      val c = this.factory.apply(ctx)
      return c.info(ctx.body(io.github.jonaskahn.controllers.org.OrgInfoRequest::class.java))
    }

I think it could be a bug?

[jknack]

What will be the output if your controller returns null?

If we make the mapping function to returns a nullable response, a new error is generated:

    @Throws(Exception::class)
    override fun install(app: io.jooby.Jooby) {
      /** See [Controller.nullable] */
      app.get("/", this::nullable)
                    ^^^^^^^^^^^^^ problem is here
        .setReturnType(String::class.java)
        .setMvcMethod(Controller::class.java.getMethod("nullable"))
    }

    fun nullable(ctx: io.jooby.Context): String? {
      val c = this.factory.apply(ctx)
      return c.nullable()
    }

 ERROR: Inapplicable candidate(s): fun nullable(ctx: Context): String?

One solution could be:

fun nullable(ctx: io.jooby.Context): String {
      val c = this.factory.apply(ctx)
      return c.nullable()!!
}