From 1de0ac6ba691cf8b6b9390e815c4bf4bb2733d84 Mon Sep 17 00:00:00 2001
From: Matteo Collina <hello@matteocollina.com>
Date: Mon, 14 Sep 2026 07:02:55 +0000
Subject: [PATCH] fix(redirect): ignore informational responses in history

Signed-off-by: Matteo Collina <hello@matteocollina.com>
---
 lib/handler/redirect-handler.js |  5 +++++
 test/interceptors/redirect.js   | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/lib/handler/redirect-handler.js b/lib/handler/redirect-handler.js
index a5d92508631..7b0a0cf927d 100644
--- a/lib/handler/redirect-handler.js
+++ b/lib/handler/redirect-handler.js
@@ -57,6 +57,11 @@ class RedirectHandler {
   }
 
   onResponseStart (controller, statusCode, headers, statusMessage) {
+    if (statusCode < 200) {
+      this.handler.onResponseStart?.(controller, statusCode, headers, statusMessage)
+      return
+    }
+
     if (this.opts.throwOnMaxRedirect && this.history.length >= this.maxRedirections) {
       throw new Error('max redirects')
     }
diff --git a/test/interceptors/redirect.js b/test/interceptors/redirect.js
index cf0f0a815a9..69c2c5c2087 100644
--- a/test/interceptors/redirect.js
+++ b/test/interceptors/redirect.js
@@ -812,6 +812,38 @@ test('should redirect to relative URL according to RFC 7231', async t => {
   t.strictEqual(finalPath, '/absolute/b')
 })
 
+test('informational responses are not added to redirect history', async t => {
+  t = tspl(t, { plan: 4 })
+
+  const server = createServer((_req, res) => {
+    for (let i = 0; i < 20; i++) {
+      res.writeProcessing()
+    }
+    res.end('hello world!')
+  }).listen(0)
+
+  after(() => server.close())
+  await once(server, 'listening')
+
+  const dispatcher = new undici.Client(`http://localhost:${server.address().port}`)
+    .compose(redirect({ maxRedirections: 1, throwOnMaxRedirect: true }))
+  after(() => dispatcher.close())
+
+  const infos = []
+  const response = await dispatcher.request({
+    method: 'GET',
+    path: '/',
+    onInfo: info => infos.push(info)
+  })
+
+  t.strictEqual(response.statusCode, 200)
+  t.strictEqual(await response.body.text(), 'hello world!')
+  t.strictEqual(infos.length, 20)
+  t.deepStrictEqual(response.context.history, [
+    new URL(`http://localhost:${server.address().port}/`)
+  ])
+})
+
 test('same-origin redirect preserves plain object headers with polluted Object.prototype[Symbol.iterator]', async (t) => {
   const { strictEqual } = tspl(t, { plan: 2 })