Inheritance in openApi code generation incorrect.

[AlexBrad1ey]

Swagger Inheritance & Polymorphism is not generating correctly from the OpenApi definition. this is directly related to #1940. But i am recording this as a seperate issue because it references a different case but is most probably a related error in the code.

I have striped down the situation as to not clutter the issue.
When a openApi schema has an Entity base type and a subtype called Project, and is defined simply as Project -> allOf -> Entity with no descriminators or anything just a simple inheritance the Project entity is not correctly generated.

RTK Generator produces the following type output:

export type Entity= {
  id?: string | null;
  name?: string | null;
  description?: string | null;
  status?: string | null;
};
export type Project = Entity

This is incorrect and seems to have 2 mistakes:

1. all additional properties on a subtype are lost due to the Project = Entity.
2. the missing properties are caused because the code gen creates types not interfaces which cannot be extended.

[phryneas]

We use https://github.com/cellular/oazapfts for the type generation - I would assume that this is not a problem in the codegen, but in the upstream library - but I could go wrong. Either way, could you create a small reproduction? I can take a look and even if I come to the conclusion that you have to ask there, they will need that too.

[msutkowski]

If you could provide the swagger schema, that'd be great. I can confirm that this is an upstream issue have made a repro here: https://github.com/msutkowski/oazapfts-typesecript-codegen-repro.

I'm going to spend a little time investigating this and seeing if we can easily issue a patch for oazapfts, and if not, what our other options are.

[msutkowski]

@AlexBrad1ey can you try installing the local build of the linked PR in #2004?

Any of these should work depending on your package manager.

# yarn 1
yarn add https://pkg.csb.dev/reduxjs/redux-toolkit/commit/9100477b/@rtk-query/codegen-openapi
# yarn 2, 3
yarn add @rtk-query/codegen-openapi@https://pkg.csb.dev/reduxjs/redux-toolkit/commit/9100477b/@rtk-query/codegen-openapi/_pkg.tgz
# npm
npm i https://pkg.csb.dev/reduxjs/redux-toolkit/commit/9100477b/@rtk-query/codegen-openapi

Thanks!

[Elewyth]

@msutkowski I just tested the PR with npm i https://pkg.csb.dev/reduxjs/redux-toolkit/commit/9100477b/@rtk-query/codegen-openapi and for my case it successfully generates the following:

Spec:

    TokenResponseDto:
      allOf:
        - $ref: '#/components/schemas/TokenPatchDto'
      properties:
        id:
          type: number
      required:
        - id
        - type # <- This is a property from TokenPatchDto

TokenApi.ts:

export type TokenResponseDto = TokenPatchDto & {
  id: number
}

Thank you for this fix :).

However, there is one further detail, that is not covered correctly:
In my TokenResponseDto (the one inheriting the properties) I specify some of the inherited properties as required (i.e. non-nullable in TypeScript). Since the generated type simply references the TokenPatchDto where all properties are nullable, the fields in the final TokenResponseDto type are still all nullable (except for the id which is declared directly on the type).

Maybe a possible approach would be to include the required properties explicitly again in the type? So:

export type TokenResponseDto = TokenPatchDto & {
  id: number
  type: string // this overrides the "type?: string" from TokenPatchDto
}

[msutkowski]

@Elewyth Sorry about resurrecting this so many months later! I was just doing some experimenting before we release a new version, and I'm unable to reproduce what you're describing. If I use a schema that requires properties on a response, they are generated correctly. If you're able to share your open API spec, I can test specifically against that. If you can't share that publicly, you can find me on Twitter/Discord and share privately - or just provide me with a minimal repro schema with obfuscated things.