It seems that the lib does not support union types (or discriminatedUnion) on querystring

[juanmagalhaes]

I'm using it with:

import fastifySwagger from "@fastify/swagger";
import fastifySwaggerUI from "@fastify/swagger-ui";

As it is described in the documentation of this lib.

Try the following:

  app.get(
    "/",
    {
      schema: z.union([z.object({ x: 1 }), z.object({ a: 2 }) ]),
    },

I believe that z.union should be mapped to anyOf while z.discriminatedUnion should be mapped to oneOf

My complete setup is more or less the following:

import 'zod-openapi/extend';
import fastifySwagger from "@fastify/swagger";
import fastifySwaggerUI from "@fastify/swagger-ui";
import Fastify from "fastify";

import {
  type FastifyZodOpenApiTypeProvider,
  fastifyZodOpenApiPlugin,
  fastifyZodOpenApiTransform,
  fastifyZodOpenApiTransformObject,
  serializerCompiler,
  validatorCompiler,
} from 'fastify-zod-openapi';
import { type ZodOpenApiVersion } from 'zod-openapi';

import { logger } from "@/logger";


export async function buildFastifyApp() {
  const app = Fastify({
    loggerInstance: logger,
  }).withTypeProvider<FastifyZodOpenApiTypeProvider>();

  // Add schema validator and serializer
  app.setValidatorCompiler(validatorCompiler);
  app.setSerializerCompiler(serializerCompiler);

  await app.register(fastifyZodOpenApiPlugin, {
    documentOpts: {
      unionOneOf: true,
    }
  });

  await app.register(fastifySwagger, {
    openapi: {
      openapi: '3.0.3' satisfies ZodOpenApiVersion,
      info: {
        title: "My Project",
        description: "My Project API",
        version: "1.0.0",
      },
      servers: [
      ],
    },
    transform: fastifyZodOpenApiTransform,
    transformObject: fastifyZodOpenApiTransformObject,
  });

  await app.register(fastifySwaggerUI, {
    routePrefix: "/documentation",
  });

Any thoughts?

[samchungy]

Hey, openapi does not support unions for parameters. If you can find me some examples where it does I'd be happy to help you out

[samchungy]

Though, it may be possible to "flatten" the properties in the headers out into an "optional"-esque main object.

[juanmagalhaes]

I'm referring to this: https://swagger.io/docs/specification/v3_0/data-models/oneof-anyof-allof-not/

From the OpenAPI specs:

And the link to it: https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#openapi-object

Like I said

I believe that z.union should be mapped to anyOf while z.discriminatedUnion should be mapped to oneOf

Does that make sense?

[samchungy]

Yes but you mentioned query strings which are parameters which are cannot use oneOf or anyOf.

https://learn.openapis.org/specification/parameters.html

fastify-zod-openapi/src/transformer.test.ts

Line 962 in 375656f

it('should support create document options', async () => {

Here's oneOf working.