zod-openapi outputting invalid OpenAPI specs when using 'nullable'

[sebpowell]

Hello,

I've just started using this library and have come across the following issue. Consider the following:

import { extendApi } from '@anatine/zod-openapi';
import { object, string, z } from 'zod';

export const GetItems = extendApi(
  z.object({
    skus: object({
      test: string().nullable(),
    }),
  }),
);

The Swagger UI looks like this:

And the JSON / Yaml it generates looks like this:

schemas:
    GetItemsDto:
      type: object
      properties:
        items:
          type: object
          properties:
            test:
              type: 'null'
          required:
            - test
      required:
        - items

Not sure if this is a known bug, or whether I'm somehow doing something wrong?

In case it's relevant, I am using this within a Nest.js application, so the Swagger docs are being generated as per the documentation:

import { NestFactory } from '@nestjs/core';
import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
import { AppModule } from './app.module';
import { ValidationPipe } from '@nestjs/common';
import { ResponseInterceptor } from 'src/interceptors/response.interceptor';
import { ZodValidationPipe } from '@anatine/zod-nestjs';

import { patchNestjsSwagger } from '@anatine/zod-nestjs';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);

  app.useGlobalPipes(
    new ValidationPipe({ whitelist: true, forbidNonWhitelisted: true }),
  );

  app.useGlobalPipes(new ZodValidationPipe());

  app.useGlobalInterceptors(new ResponseInterceptor());

  const options = new DocumentBuilder()
    .setVersion('1.0')
    .addBearerAuth()
    .build();

  patchNestjsSwagger();

  const document = SwaggerModule.createDocument(app, options);

  SwaggerModule.setup('api', app, document);

  app.enableCors();

  // app.useLogger(app.get(Logger));

  await app.listen(3000);
}
bootstrap();

Thank you in advance.

[briangottfried]

We've gotten around this by doing .or(z.null()).

[Xayrulloh]

Same with me. Another way is .union([z.string(), z.null(), etc..]). But when you wanna edit that schema by calling it and to set that property to required it doesn't change anything it'd be still like string | null | etc

[benyap]

We've reverted to @anatine/[email protected] as an alternative solution until this is fixed.

Changing all of our schemas which had .nullable() to .or(z.null()) wasn't an ideal workaround as it also changed the output OpenAPI spec.

v2.2.1 with .nullable()

{
  "field": {
    "type": "boolean",
    "nullable": true
  }
}

v2.2.6 after changing to .or(z.null())

{
  "field": {
    "oneOf": [
      {
        "type": "boolean"
      },
      {
        "type": "null"
      }
    ]
  }
}

[alex-statsig]

This is related to #211 and #221