BUG: nullable schema

[ssssota]

Hi! I think this project is useful and so interesting.

I have a question. Why do generator use interface for schema definition?

I think type alias is more useful.

e.g.

https://swagger.io/specification/#:~:text=A%20true%20value%20adds%20%22null%22%20to%20the%20allowed%20type%20specified%20by%20the%20type%20keyword%2C%20only%20if%20type%20is%20explicitly%20defined%20within%20the%20same%20Schema%20Object.

schema:
  type: object
  nullable: true
  properties:
    foo:
      type: integer

type schema = { foo: number } | null;

[Himenon]

It does not matter whether it is a Type Alias or an interface. I believe the essence of the issue is whether the problem is solved or not.

By the way, do you mean that there is a problem with specifying nullable in the case that @ssssota wrote about? Could you please provide some more details?

[Himenon]

When defined in components/schemas, nullable will not work, but will work elsewhere. It would be difficult to define a nullable schema in components/schema, but you want to use it here? In that case, it would probably be more convenient to use oneOf, but is it a situation where the schema cannot be changed?

openapi: 3.0.3
info:
  version: 1.0.0

components:
  schemas:
    Author:
      type: object
      nullable: true # Not works
      properties:
        name:
          type: string
    NullableAuthor:
      oneOf:
        - $ref: "#/components/schemas/Author"
        - type: "null"
  responses:
    Books:
      description: Get Books
      content:
        application/json:
          schema:
            type: object
            nullable: true # This works
            properties:
              author:
                type: object
                nullable: true # This works
                properties:
                  name:
                    type: string
              authorRef:
                $ref: "#/components/schemas/Author"
              author2:
                oneOf:
                  - $ref: "#/components/schemas/Author"
                  - type: "null"
              nullableAuthorRef:
                $ref: "#/components/schemas/NullableAuthor"

paths:
  /get/books:
    get:
      operationId: getBooks
      responses:
        200:
          $ref: "#/components/responses/Books"

You can check the operation in Playground (https://openapi-typescript-code-generator.netlify.app/v0.19.1/index.html).

[Himenon]

And this is not what we talk about in the topic of Type Alias or Interface. What you really want to do with the issue is to put it in the title. Otherwise, I will close this issue.

@ssssota

[ssssota]

I believe the essence of the issue is whether the problem is solved or not.

I think so too.

---

I'm using OpenAPITools/openapi-generator to generate types and client. And I am considering where to migrate to.

I have schemas like follows:

components:
  schemas:
    member:
      type: object
      additionalProperties: false
      required:
        - child
      properties:
        child:
          $ref: "#/components/schemas/child"
    child:
      type: object
      nullable: true
      additionalProperties: false
      required:
        - name
      properties:
        name:
          type: string

https://github.com/ssssota/openapi-typescript-code-generator/blob/e1b63b408604def8686187698316eead3f8f5d1b/test/nullable.schema.domain/index.yml#L18-L36

This generator generates like follows:

    export interface member {
        child: Schemas.child;
    }
    export interface child {
        name: string;
    }

https://github.com/ssssota/openapi-typescript-code-generator/blob/6b3e5f573102dfcd9f0ffed4582f56df7719756f/test/__tests__/__snapshots__/nullable-schema-domain-test.ts.snap#L13-L18

I think it is not correct.
So, I patched with type-alias and generate like follows:

    export type member = {
        child: Schemas.child;
    };
    export type child = {
        name: string;
    } | null;

https://github.com/ssssota/openapi-typescript-code-generator/blob/e1b63b408604def8686187698316eead3f8f5d1b/test/__tests__/__snapshots__/nullable-schema-domain-test.ts.snap#L14-L19

This is why I asked the previous question.

And this is not what we talk about in the topic of Type Alias or Interface. What you really want to do with the issue is to put it in the title. Otherwise, I will close this issue.

OK. I'll change title.

[ssssota]

is it a situation where the schema cannot be changed?

Maybe no.
However, I don't want to take that workaround.

[Himenon]

I published v0.19.2. Thanks your bug report !

And, I could align everything to type alias, but that would be a disruptive change to existing users and I need to provide options to minimize that. However, I do not have the time to provide that option, so I will only release a patch to allow nullable.

@ssssota