feat(zod-openapi): support Zod v4 (#1223)

* feat(zod-openapi): support Zod v4

* update `peerDependencies`

* add changeset

* fixed type error

* update dependencies

.changeset/young-cats-shop.md

@@ -0,0 +1,9 @@
+---
+'@hono/zod-openapi': major
+---
+
+feat: support Zod v4
+
+Zod OpenAPI has been migrated the Zod version from v3 to v4. As a result, the `zod` in `peerDependencies` has been updated to 4.0.0 or higher.
+
+Although this is not a breaking change, it is a major change, so it is considered a major version upgrade.

packages/zod-openapi/package.json

@@ -41,7 +41,7 @@
   "homepage": "https://github.com/honojs/middleware",
   "peerDependencies": {
     "hono": ">=4.3.6",
-    "zod": ">=3.0.0"
+    "zod": "^4.0.0"
   },
   "devDependencies": {
     "@arethetypeswrong/cli": "^0.17.4",
@@ -51,10 +51,10 @@
     "typescript": "^5.8.2",
     "vitest": "^3.2.4",
     "yaml": "^2.4.3",
-    "zod": "^3.22.1"
+    "zod": "^4.0.5"
   },
   "dependencies": {
-    "@asteasolutions/zod-to-openapi": "^7.3.0",
+    "@asteasolutions/zod-to-openapi": "^8.0.0",
     "@hono/zod-validator": "workspace:^",
     "openapi3-ts": "^4.5.0"
   },

packages/zod-openapi/src/index.test-d.ts

@@ -240,7 +240,7 @@ describe('coerce', () => {
     type Actual = ExtractSchema<typeof routes>['/api/users/:id']['$get']['input']
     type Expected = {
       param: {
-        id: number
+        id: unknown
       }
     }
     type verify = Expect<Equal<Expected, Actual>>

packages/zod-openapi/src/index.ts

@@ -11,6 +11,7 @@ import {
   OpenApiGeneratorV3,
   OpenApiGeneratorV31,
   extendZodWithOpenApi,
+  getOpenApiMetadata,
 } from '@asteasolutions/zod-to-openapi'
 import { zValidator } from '@hono/zod-validator'
 import { Hono } from 'hono'
@@ -38,8 +39,8 @@ import type { JSONParsed, JSONValue, RemoveBlankRecord, SimplifyDeepArray } from
 import { mergePath } from 'hono/utils/url'
 import type { OpenAPIObject } from 'openapi3-ts/oas30'
 import type { OpenAPIObject as OpenAPIV31bject } from 'openapi3-ts/oas31'
-import type { ZodError, ZodSchema } from 'zod'
-import { ZodType, z } from 'zod'
+import { ZodType, z } from 'zod/v4'
+import type { ZodError } from 'zod/v4'
 
 type MaybePromise<T> = Promise<T> | T
 
@@ -128,7 +129,7 @@ type InputTypeJson<R extends RouteConfig> = R['request'] extends RequestTypes
         ? {}
         : R['request']['body']['content'][keyof R['request']['body']['content']] extends Record<
               'schema',
-              ZodSchema<any>
+              ZodType<any>
             >
           ? {
               in: {
@@ -154,7 +155,7 @@ type InputTypeForm<R extends RouteConfig> = R['request'] extends RequestTypes
         ? {}
         : R['request']['body']['content'][keyof R['request']['body']['content']] extends Record<
               'schema',
-              ZodSchema<any>
+              ZodType<any>
             >
           ? {
               in: {
@@ -181,7 +182,7 @@ type InputTypeCookie<R extends RouteConfig> = InputTypeBase<R, 'cookies', 'cooki
 type ExtractContent<T> = T extends {
   [K in keyof T]: infer A
 }
-  ? A extends Record<'schema', ZodSchema>
+  ? A extends Record<'schema', ZodType>
     ? z.infer<A['schema']>
     : never
   : never
@@ -659,11 +660,14 @@ export class OpenAPIHono<
         }
 
         case 'schema':
-          return this.openAPIRegistry.register(def.schema._def.openapi._internal.refId, def.schema)
+          return this.openAPIRegistry.register(
+            getOpenApiMetadata(def.schema)._internal?.refId,
+            def.schema
+          )
 
         case 'parameter':
           return this.openAPIRegistry.registerParameter(
-            def.schema._def.openapi._internal.refId,
+            getOpenApiMetadata(def.schema)._internal?.refId,
             def.schema
           )
 

yarn.lock

@@ -99,14 +99,14 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@asteasolutions/zod-to-openapi@npm:^7.3.0":
-  version: 7.3.0
-  resolution: "@asteasolutions/zod-to-openapi@npm:7.3.0"
+"@asteasolutions/zod-to-openapi@npm:^8.0.0":
+  version: 8.0.0
+  resolution: "@asteasolutions/zod-to-openapi@npm:8.0.0"
   dependencies:
     openapi3-ts: "npm:^4.1.2"
   peerDependencies:
-    zod: ^3.20.2
-  checksum: 10c0/f0a68a89929cdeaa3e21d2027489689f982824d676a9332c680e119f60881dd39b571324b24ad4837fda49bf6fe7c3e2af2199268b281bf1aec923d7a7cbfc40
+    zod: ^4.0.0
+  checksum: 10c0/b522d074832fb137dca724c8bd4bb134c7b4d4cad12c247ed3c864f993923b3475fc06580e6e1cbc4fd8641cd361679bbe1dd87c9bb42e142bc056d96d59fbc8
   languageName: node
   linkType: hard
 
@@ -2734,7 +2734,7 @@ __metadata:
   resolution: "@hono/zod-openapi@workspace:packages/zod-openapi"
   dependencies:
     "@arethetypeswrong/cli": "npm:^0.17.4"
-    "@asteasolutions/zod-to-openapi": "npm:^7.3.0"
+    "@asteasolutions/zod-to-openapi": "npm:^8.0.0"
     "@hono/zod-validator": "workspace:^"
     hono: "npm:^4.8.4"
     openapi3-ts: "npm:^4.5.0"
@@ -2743,10 +2743,10 @@ __metadata:
     typescript: "npm:^5.8.2"
     vitest: "npm:^3.2.4"
     yaml: "npm:^2.4.3"
-    zod: "npm:^3.22.1"
+    zod: "npm:^4.0.5"
   peerDependencies:
     hono: ">=4.3.6"
-    zod: ">=3.0.0"
+    zod: ^4.0.0
   languageName: unknown
   linkType: soft
 
@@ -16830,7 +16830,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"zod@npm:^3.20.2, zod@npm:^3.22.1, zod@npm:^3.22.3":
+"zod@npm:^3.20.2, zod@npm:^3.22.3":
   version: 3.24.2
   resolution: "zod@npm:3.24.2"
   checksum: 10c0/c638c7220150847f13ad90635b3e7d0321b36cce36f3fc6050ed960689594c949c326dfe2c6fa87c14b126ee5d370ccdebd6efb304f41ef5557a4aaca2824565