[BUG] R generator handles enums in response payloads incorrectly

[jlorince]

Bug Report Checklist

• [X] Have you provided a full/minimal spec to reproduce the issue?
• [X] Have you validated the input using an OpenAPI validator (example)?
• [ ] Have you tested with the latest master to confirm the issue still exists?
• [X] Have you searched for related issues/PRs?
• [X] What's the actual output vs expected output?
• [ ] [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When a response payload contains an enum value, the R generator seems to produce unusable code.

The code to generate response payload from JSON ends up looking like this:

    fromJSON = function(input_json) {
      this_object <- jsonlite::fromJSON(input_json)
      ...
      if (!is.null(this_object$`status`)) {
        status_object <- ProjectRunStatus$new()
        status_object$fromJSON(jsonlite::toJSON(this_object$status, auto_unbox = TRUE, digits = NA))
        self$`status` <- status_object
      }
      ...

However, the line status_object <- ProjectRunStatus$new() fails because the class for the enumerated value cannot be initialized without a value:

    initialize = function(...) {
      local.optional.var <- list(...)
      val <- unlist(local.optional.var)
      enumvec <- .parse_ProjectRunStatus()
      stopifnot(length(val) == 1L)

      if (!val %in% enumvec)
          stop("Use one of the valid values: ",
              paste0(enumvec, collapse = ", "))
      private$value <- val
    },

openapi-generator version

6.1.0

Generation Details

yarn run openapi-generator-cli generate -i ./generated/openapi.json -o ../../r-sdk --package-name hexApi -g r

Steps to reproduce

See Above

Related issues/PRs

Suggest a fix

I'm not too familiar with classes in R, so I'm not certain, but somehow the code should somehow be updated to not try to instantiate an empty enum class.

[wing328]

can you please provide a spec to reproduce the issue?