fix: complete zod/v4 migration (supersedes #158)

package.json

@@ -40,7 +40,7 @@
   },
   "peerDependencies": {
     "@trpc/server": "^11.1.0",
-    "zod": "^4.0.0",
+    "zod": "^3.25.0 || ^4.0.0",
     "zod-openapi": "^5.0.1"
   },
   "dependencies": {

src/adapters/node-http/core.ts

@@ -5,7 +5,8 @@ import {
   type NodeHTTPResponse,
 } from '@trpc/server/adapters/node-http';
 import { getErrorShape, TRPCRequestInfo } from '@trpc/server/unstable-core-do-not-import';
-import { ZodArray, ZodError, ZodTypeAny } from 'zod';
+import { ZodArray } from 'zod/v4';
+import type { ZodError } from 'zod/v4';
 import { NodeHTTPRequest } from '../../types';
 import { generateOpenApiDocument } from '../../generator';
 import {

src/generator/index.ts

@@ -1,5 +1,5 @@
 import { ZodOpenApiObject, ZodOpenApiPathsObject, createDocument } from 'zod-openapi';
-import { ZodSchema } from 'zod';
+import type { ZodSchema } from 'zod/v4';
 
 import {
   OpenApiMeta,

src/generator/schema.ts

@@ -1,5 +1,6 @@
 import { TRPCError } from '@trpc/server';
-import { ZodObject, ZodAny, z } from 'zod';
+import { z } from 'zod/v4';
+import type { ZodObject, ZodAny } from 'zod/v4';
 import {
   ZodOpenApiContentObject,
   ZodOpenApiParameters,

src/types.ts

@@ -7,7 +7,7 @@ import type {
   RouterRecord,
 } from '@trpc/server/unstable-core-do-not-import';
 import { IncomingMessage } from 'http';
-import type { ZodObject } from 'zod';
+import type { ZodObject } from 'zod/v4';
 import type { $ZodIssue } from 'zod/v4/core';
 
 export { type OpenAPIObject, type SecuritySchemeObject } from 'openapi3-ts/oas31';

src/utils/procedure.ts

@@ -1,5 +1,6 @@
 import { TRPCProcedureType } from '@trpc/server';
-import { ZodObject, z } from 'zod';
+import { z } from 'zod/v4';
+import type { ZodObject } from 'zod/v4';
 
 import { OpenApiMeta, OpenApiProcedure, OpenApiProcedureRecord } from '../types';
 

src/utils/zod.ts

@@ -1,4 +1,5 @@
-import { ZodObject, ZodRawShape, ZodType, z } from 'zod';
+import { z } from 'zod/v4';
+import type { ZodObject, ZodRawShape, ZodType } from 'zod/v4';
 import type { $ZodType, $ZodTypes } from 'zod/v4/core';
 import type { $ZodTypeDef } from 'zod/v4/core/schemas';
 

test/adapters/express.test.ts

@@ -1,7 +1,7 @@
 import { initTRPC } from '@trpc/server';
 import express from 'express';
 import fetch from 'node-fetch';
-import { z } from 'zod';
+import { z } from 'zod/v4';
 
 import {
   CreateOpenApiExpressMiddlewareOptions,

test/adapters/fastify.test.ts

@@ -1,7 +1,7 @@
 import { initTRPC } from '@trpc/server';
 import fastify from 'fastify';
 import fetch from 'node-fetch';
-import { z } from 'zod';
+import { z } from 'zod/v4';
 
 import {
   CreateOpenApiFastifyPluginOptions,

test/adapters/fetch.test.ts

@@ -1,7 +1,7 @@
 import { TRPCError, initTRPC } from '@trpc/server';
 import fetch from 'node-fetch';
 import superjson from 'superjson';
-import { z } from 'zod';
+import { z } from 'zod/v4';
 
 import {
   CreateOpenApiFetchHandlerOptions,

test/adapters/koa.test.ts

@@ -1,7 +1,7 @@
 import { initTRPC } from '@trpc/server';
 import Koa from 'koa';
 import fetch from 'node-fetch';
-import { z } from 'zod';
+import { z } from 'zod/v4';
 
 import {
   CreateOpenApiKoaMiddlewareOptions,

test/adapters/next.test.ts

@@ -3,7 +3,7 @@ import { NextApiRequest, NextApiResponse } from 'next';
 import { IncomingHttpHeaders, IncomingMessage } from 'http';
 import { NextApiRequestCookies, NextApiRequestQuery } from 'next/dist/server/api-utils';
 import { Socket } from 'net';
-import { z } from 'zod';
+import { z } from 'zod/v4';
 
 import {
   CreateOpenApiNextHandlerOptions,

test/adapters/nuxt.test.ts

@@ -2,7 +2,7 @@
 import { initTRPC } from '@trpc/server';
 import { H3Event } from 'h3';
 import httpMocks, { RequestMethod } from 'node-mocks-http';
-import { z } from 'zod';
+import { z } from 'zod/v4';
 
 import {
   CreateOpenApiNuxtHandlerOptions,

test/adapters/standalone.test.ts

@@ -4,7 +4,7 @@ import { createHTTPHandler } from '@trpc/server/adapters/standalone';
 import { Server } from 'http';
 import fetch from 'node-fetch';
 import superjson from 'superjson';
-import { z } from 'zod';
+import { z } from 'zod/v4';
 
 import {
   CreateOpenApiHttpHandlerOptions,

test/generator.test.ts

@@ -1,6 +1,6 @@
 import { initTRPC } from '@trpc/server';
 import { observable } from '@trpc/server/observable';
-import { z } from 'zod';
+import { z } from 'zod/v4';
 
 import { GenerateOpenApiDocumentOptions, OpenApiMeta, generateOpenApiDocument } from '../src';
 import * as zodUtils from '../src/utils/zod';
@@ -3165,7 +3165,12 @@ describe('generator', () => {
         .input(
           z
             .object({ name: z.string() })
-            .meta({ examples: { Lily: { name: 'Lily' }, John: { name: 'John' } } }),
+            // zod-openapi v5 types `meta.examples` as `unknown[]`, but its runtime
+            // still accepts the v3-style named-record form used here (and emits it
+            // through to the output schema verbatim — see snapshot below).
+            .meta({
+              examples: { Lily: { name: 'Lily' }, John: { name: 'John' } } as unknown as unknown[],
+            }),
         )
         .output(z.object({ output: z.string() }))
         .mutation(({ input }) => ({