From 9b244076bb345a3aba968dd0628061c63d950ca8 Mon Sep 17 00:00:00 2001
From: Ahmed Gamal <ahmadmoshaa3@gmail.com>
Date: Tue, 13 Oct 2026 20:21:40 +0300
Subject: [PATCH] fix(request): forward duplex to the native request

Since undici 8.11 (Node.js 26.11), Request getters use private-field brand
checks, so reading `duplex` on the lightweight request falls through to the
native getter and throws ERR_INVALID_THIS. This breaks passing the request
as RequestInit, e.g. `new Request(url, c.req.raw)` and `app.mount()`.

Fixes #408
---
 src/request.ts       |  1 +
 test/request.test.ts | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/src/request.ts b/src/request.ts
index a4b0e11..57c6705 100644
--- a/src/request.ts
+++ b/src/request.ts
@@ -660,6 +660,7 @@ Object.defineProperty(requestPrototype, 'signal', {
   'cache',
   'credentials',
   'destination',
+  'duplex',
   'integrity',
   'mode',
   'redirect',
diff --git a/test/request.test.ts b/test/request.test.ts
index a15927c..5ce7e95 100644
--- a/test/request.test.ts
+++ b/test/request.test.ts
@@ -34,6 +34,7 @@ describe('Request', () => {
       expect(req.url).toBe('http://localhost/')
       expect(req.headers.get('host')).toBe('localhost')
       expect(req.keepalive).toBe(false)
+      expect(req.duplex).toBe('half')
     })
 
     it('Should not generate GlobalRequest when accessing method, url or headers', async () => {
@@ -1170,6 +1171,37 @@ describe('Request', () => {
       expect(req2).toBeInstanceOf(GlobalRequest)
       await expect(req2.text()).resolves.toBe('bar')
     })
+
+    it('should be success to create instance with a lightweight GET request as init option', () => {
+      const req = newRequest({
+        method: 'GET',
+        url: '/',
+        headers: {
+          host: 'localhost',
+        },
+        rawHeaders: ['host', 'localhost'],
+      } as IncomingMessage)
+      const req2 = new Request('http://localhost/subapp', req)
+      expect(req2).toBeInstanceOf(GlobalRequest)
+      expect(req2.method).toBe('GET')
+      expect(req2.url).toBe('http://localhost/subapp')
+    })
+
+    it('should be success to create instance with a lightweight POST request as init option', async () => {
+      const req = newRequest({
+        method: 'POST',
+        url: '/',
+        headers: {
+          host: 'localhost',
+        },
+        rawHeaders: ['host', 'localhost'],
+        rawBody: Buffer.from('foo'),
+      } as IncomingMessage & { rawBody: Buffer })
+      const req2 = new Request('http://localhost/subapp', req)
+      expect(req2).toBeInstanceOf(GlobalRequest)
+      expect(req2.method).toBe('POST')
+      await expect(req2.text()).resolves.toBe('foo')
+    })
   })
 })