Support self referential types in zod schemas

[nicholaschiang]

What version of kubb is running?

4.1.2

What kind of platform do you use?

Linux

Your kubb.config.ts config file?

import { defineConfig } from '@kubb/core'
import { pluginOas } from '@kubb/plugin-oas'
import { pluginTs } from '@kubb/plugin-ts'
import { pluginZod } from '@kubb/plugin-zod'
import { pluginClient } from '@kubb/plugin-client'
import { pluginReactQuery } from '@kubb/plugin-react-query'
import { pluginMsw } from '@kubb/plugin-msw'
import { pluginFaker } from '@kubb/plugin-faker'

export default defineConfig({
  root: '.',
  input: {
    path: './openapi.json',
  },
  output: {
    path: './kubb',
    extension: { '.ts': '', '.tsx': '', '.js': '', '.json': '.json' },
  },
  plugins: [
    pluginOas(),
    pluginTs({
      enumType: 'enum',
      enumSuffix: '',
      unknownType: 'unknown',
    }),
    pluginZod({
      unknownType: 'unknown',
      dateType: 'stringOffset',
      output: { path: 'zod', banner: '// @ts-nocheck' },
    }),
    pluginClient({
      importPath: '../../client',
      paramsType: 'object',
      paramsCasing: 'camelcase',
      output: { path: 'clients', banner: '// @ts-nocheck' },
    }),
    pluginReactQuery({
      paramsType: 'object',
      paramsCasing: 'camelcase',
      client: {
        importPath: '../../client',
      },
      mutation: {
        importPath: '../../client',
      },
      output: { path: 'hooks', banner: '// @ts-nocheck' },
      suspense: false,
    }),
    pluginMsw(),
    pluginFaker({
      transformers: {
        name: (name) => `${name}Mock`,
      },
    }),
  ],
})

Swagger/OpenAPI file?

https://gist.github.com/nicholaschiang/625ca4b3c95c70de70af4e9e8c97067d

What version of external packages are you using(@tanstack-query, MSW, React, Vue, ...)

{
  "name": "@alation/alation-ai",
  "version": "11.1.3",
  "description": "",
  "repository": {
    "type": "git",
    "url": "https://github.com/alation/alation-ai.git"
  },
  "publishConfig": {
    "registry": "https://npm.pkg.github.com"
  },
  "type": "module",
  "scripts": {
    "generate": "rm -rf kubb && kubb generate",
    "typecheck": "tsc --noEmit --strict true --module esnext --moduleResolution bundler --lib es2022,dom --target es2022 --jsx react ./index.ts",
    "test": "vitest",
    "test:run": "vitest run",
    "test:coverage": "vitest run --coverage"
  },
  "files": [
    "kubb",
    "index.ts",
    "client.tsx"
  ],
  "exports": {
    ".": "./index.ts"
  },
  "author": "Nicholas Chiang <nicholas.chiang@alation.com>",
  "engines": {
    "node": ">=22"
  },
  "packageManager": "pnpm@10.13.1",
  "peerDependencies": {
    "react": "^18.3.1",
    "react-dom": "^18.3.1",
    "msw": "^2.6.8"
  },
  "devDependencies": {
    "@kubb/cli": "^4.1.2",
    "@kubb/core": "^4.1.2",
    "@kubb/plugin-client": "^4.1.2",
    "@kubb/plugin-faker": "^4.1.2",
    "@kubb/plugin-msw": "^4.1.2",
    "@kubb/plugin-oas": "^4.1.2",
    "@kubb/plugin-react-query": "^4.1.2",
    "@kubb/plugin-ts": "^4.1.2",
    "@kubb/plugin-zod": "^4.1.2",
    "@kubb/react": "^4.1.2",
    "@testing-library/react": "^16.3.0",
    "@types/react": "^19.2.0",
    "@vitest/coverage-v8": "^3.2.4",
    "jsdom": "^27.0.0",
    "typescript": "^5.9.3",
    "vitest": "^ref3.2.4"
  },
  "dependencies": {
    "@faker-js/faker": "^10.0.0",
    "@tanstack/react-query": "^5.90.2",
    "axios": "^1.12.2",
    "zod": "^4.1.12"
  }
}

What steps can reproduce the bug?

• Run kubb generate
• Open kubb/zod/jsonValueOutputSchema.ts

export const jsonValueOutputSchema = z.union([z.int(), z.boolean(), z.array(jsonValueOutputSchema), z.string(), z.number(), z.object({
    
    }).catchall(jsonValueOutputSchema), z.null()])

• Notice that the constant is referred to before definition
• Try importing that zod schema in your own code
• See the following error:

ReferenceError: Cannot access 'jsonValueOutputSchema' before initialization
 ❯ ../../../node_modules/@alation/alation-ai/kubb/zod/jsonValueOutputSchema.ts:9:77
      7| import { z } from "zod/v4";
      8|
      9| export const jsonValueOutputSchema = z.union([z.int(), z.boolean(), z.array(jsonValueOutputSchema), z.string(), z.number(), z.object({
       |                                                                             ^
     10|
     11|     }).catchall(jsonValueOutputSchema), z.null()])
 ❯ ../../../node_modules/@alation/alation-ai/kubb/zod/genericEvaluationCaseSchema.ts:7:1

How often does this bug happen?

Always

What is the expected behaviour?

I believe these types of issues with self referential schemas can be resolved with z.lazy (ref):

const MediaResponseSchema = z.lazy(() =>
  z.object({
    mediaId: z.number(),
    childMedias: z.array(MediaResponseSchema)
  })
);

Additional information

No response

[xeoneux]

This works in V3.18.3. I had to revert from V4.1.2 to that version because most of my schema has self refrential types

[stijnvanhulle]

@xeoneux @nicholaschiang
Kubb v4.5.1 has been released and includes a fix for your issue.
If the implementation isn’t exactly what you expected, feel free to reach out again!