Invalid type files are generated with Null-only enum or Empty enum

[bigen1925]

What are the steps to reproduce this issue?

1. input this

# openapi.yaml
openapi: 3.0.0
info:
  title: title
components:
  schemas:
    NullOnlyStringEnum:
      type: string
      nullable: true
      enum:
        - null
    NullOnlyNumberEnum:
      type: number
      nullable: true
      enum:
        - null
    EmptyStringEnum:
      type: string
      enum: []
    EmptyNumberEnum:
      type: number
      enum: []

2. generate
   npx orval --input ./openapi.yaml --output out.ts
3. output

/**
 * Generated by orval v6.19.1 🍺
 * Do not edit manually.
 * title
 */
export type EmptyNumberEnum = typeof EmptyNumberEnum[keyof typeof EmptyNumberEnum];


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const EmptyNumberEnum = {
  '': , // invalid typescript
} as const;

export type EmptyStringEnum = typeof EmptyStringEnum[keyof typeof EmptyStringEnum];


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const EmptyStringEnum = {
  '': '', // valid typescript, but not appropriate
} as const;

export type NullOnlyNumberEnum = typeof NullOnlyNumberEnum[keyof typeof NullOnlyNumberEnum];


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyNumberEnum = {
  '': , // invalid typescript
  null: null,
} as const;

export type NullOnlyStringEnum = typeof NullOnlyStringEnum[keyof typeof NullOnlyStringEnum];


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyStringEnum = {
  '': '', // valid typescript, but not appropriate
  null: null,
} as const;

What happens?

An empty enum item not included in spec is generated.
In case of number, a const value is empty and it's invalid typescript.

What were you expecting to happen?

output

/**
 * Generated by orval v6.19.1 🍺
 * Do not edit manually.
 * title
 */
export type EmptyNumberEnum = typeof EmptyNumberEnum[keyof typeof EmptyNumberEnum]; // or, never


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const EmptyNumberEnum = {} as const;

export type EmptyStringEnum = typeof EmptyStringEnum[keyof typeof EmptyStringEnum]; // or, never


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const EmptyStringEnum = {} as const;

export type NullOnlyNumberEnum = typeof NullOnlyNumberEnum[keyof typeof NullOnlyNumberEnum];


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyNumberEnum = {
  null: null,
} as const;

export type NullOnlyStringEnum = typeof NullOnlyStringEnum[keyof typeof NullOnlyStringEnum];


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyStringEnum = {
  null: null,
} as const;

Any logs, error output, etc?

No information logs involving the behavior.

🍻 Start orval v6.19.1 - A swagger client generator for typescript
⚠️  SyntaxError: /Users/mitsurukasai/Documents/exercise/orval-ref-decode/openapi.yaml is not a valid Openapi API definition
🎉 title - Your OpenAPI spec has been converted into ready to use orval!

Any other comments?

Thanks for developing and maintaining this awesome package! :D

I try to make PR about this issue.

What versions are you using?

Operating System: MacOS 13.0
Package Version: 6.19.1
Browser Version: N/A

[melloware]

Interesting this was just fixed: #1010

Why are your enums totally null that is not really an enum right?

[melloware]

Oh and yes PR is welcome

[bigen1925]

@melloware
Thank you for your comment!
I'm sorry in advance for my poor english.

Interesting this was just fixed: #1010

I tried with latest master (sha 7a9587, #1010 was merged) , and output was like bellow.
Type representation of null is improved, and still there are empty items.

export type NullOnlyNumberEnum = typeof NullOnlyNumberEnum[keyof typeof NullOnlyNumberEnum] | null;


// eslint-disable-next-line @typescript-eslint/no-redeclare
export const NullOnlyNumberEnum = {
  '': ,
  // `null : null` is removed, but `'': ,` is still there 
} as const;

Why are your enums totally null that is not really an enum right?

My API have schemas of objects that have exact null property, like

schemas:
  result:
    anyOf:
        -  type: object
           properties:
             data: ...
             error: # exact null
        -  type: object
           properties:
             data: # exact null
             error: ...

There are not null type in openapi 3.0.x, (added in 3.1.0) and the only way to represent exact null value is with nullable and enum

type: object # any type is ok
nullable: true
enum: 
  - null

[bigen1925]

FYI, by Release Note of Openapi, enum is SHOULD NOT empty (means not recommended but valid) in 3.0.
It is MUST NOT (means invalid) in 3.1.

[melloware]

Cc @lenwhite please review