From 642dd29666d866284e9c74ce7d57cf2a729e4543 Mon Sep 17 00:00:00 2001
From: Yusuke Wada <yusuke@kamawada.com>
Date: Thu, 11 Jul 2024 18:20:53 +0900
Subject: [PATCH] fix(types): `app.use(path, mw)` return correct schema type
 (#3128)

Co-authored-by: Ame_x <121654029+EdamAme-x@users.noreply.github.com>
---
 src/helper/factory/index.ts |  6 +++++-
 src/types.test.ts           | 15 +++++++++++++++
 src/types.ts                |  2 +-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/helper/factory/index.ts b/src/helper/factory/index.ts
index 42e702f7..041b6e24 100644
--- a/src/helper/factory/index.ts
+++ b/src/helper/factory/index.ts
@@ -241,6 +241,10 @@ export const createFactory = <E extends Env = any, P extends string = any>(init?
   initApp?: InitApp<E>
 }): Factory<E, P> => new Factory<E, P>(init)
 
-export const createMiddleware = <E extends Env = any, P extends string = any, I extends Input = {}>(
+export const createMiddleware = <
+  E extends Env = any,
+  P extends string = string,
+  I extends Input = {}
+>(
   middleware: MiddlewareHandler<E, P, I>
 ): MiddlewareHandler<E, P, I> => createFactory<E, P>().createMiddleware<I>(middleware)
diff --git a/src/types.test.ts b/src/types.test.ts
index eafd2683..c94d1b65 100644
--- a/src/types.test.ts
+++ b/src/types.test.ts
@@ -2225,3 +2225,18 @@ describe('Env types and a path type with `app.use(path, handler...)` - test only
       })
   })
 })
+
+// https://github.com/honojs/hono/issues/3122
+describe('Returning type from `app.use(path, mw)`', () => {
+  const mw = createMiddleware(async (c, next) => {
+    await next()
+  })
+  it('Should not mark `*` as never', () => {
+    const app = new Hono().use('*', mw)
+    type Actual = ExtractSchema<typeof app>
+    type Expected = {
+      '*': {}
+    }
+    type verify = Expect<Equal<Expected, Actual>>
+  })
+})
diff --git a/src/types.ts b/src/types.ts
index e6f3cdeb..d8b7ba4b 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1804,7 +1804,7 @@ export type Schema = {
 }
 
 type ChangePathOfSchema<S extends Schema, Path extends string> = keyof S extends never
-  ? { [K in Path]: never }
+  ? { [K in Path]: {} }
   : { [K in keyof S as Path]: S[K] }
 
 export type Endpoint = {