fix(redirect): add error code to max redirects error

docs/docs/api/Errors.md

@@ -512,6 +512,19 @@ The maximum number of allowed origins has been reached.
 * `name` {string} Always `'MaxOriginsReachedError'`.
 * `code` {string} Always `'UND_ERR_MAX_ORIGINS_REACHED'`.
 
+## Class: `MaxRedirectsError`
+
+<!-- YAML
+added: v8.12.0
+-->
+
+* Extends: {UndiciError}
+
+The maximum number of redirects has been reached.
+
+* `name` {string} Always `'MaxRedirectsError'`.
+* `code` {string} Always `'UND_ERR_REDIRECT_MAX'`.
+
 ## Class: `Socks5ProxyError`
 
 <!-- YAML

lib/core/errors.js

@@ -422,6 +422,24 @@ class ProxyConnectionError extends UndiciError {
   }
 }
 
+const kMaxRedirectsError = Symbol.for('undici.error.UND_ERR_REDIRECT_MAX')
+class MaxRedirectsError extends UndiciError {
+  constructor (message) {
+    super(message)
+    this.name = 'MaxRedirectsError'
+    this.message = message || 'max redirects'
+    this.code = 'UND_ERR_REDIRECT_MAX'
+  }
+
+  static [Symbol.hasInstance] (instance) {
+    return instance && instance[kMaxRedirectsError] === true
+  }
+
+  get [kMaxRedirectsError] () {
+    return true
+  }
+}
+
 const kMaxOriginsReachedError = Symbol.for('undici.error.UND_ERR_MAX_ORIGINS_REACHED')
 class MaxOriginsReachedError extends UndiciError {
   constructor (message) {
@@ -492,6 +510,7 @@ module.exports = {
   SecureProxyConnectionError,
   ProxyConnectionError,
   MaxOriginsReachedError,
+  MaxRedirectsError,
   Socks5ProxyError,
   MessageSizeExceededError
 }

lib/handler/redirect-handler.js

@@ -2,7 +2,7 @@
 
 const util = require('../core/util')
 const assert = require('node:assert')
-const { InvalidArgumentError } = require('../core/errors')
+const { InvalidArgumentError, MaxRedirectsError } = require('../core/errors')
 const { kRequestOrigin } = require('../core/symbols')
 
 const redirectableStatusCodes = [300, 301, 302, 303, 307, 308]
@@ -96,7 +96,7 @@ class RedirectHandler {
     // 3xx without a Location header, is delivered as usual.
     if (this.location && this.history.length >= this.maxRedirections) {
       if (this.opts.throwOnMaxRedirect) {
-        throw new Error('max redirects')
+        throw new MaxRedirectsError()
       }
       this.location = null
     }

test/interceptors/redirect.js

@@ -467,7 +467,7 @@ for (const factory of [
   })
 
   test('should throw when max redirections is reached and throwOnMaxRedirect is set as interceptor default', async t => {
-    t = tspl(t, { plan: 1 })
+    t = tspl(t, { plan: 2 })
 
     const server = await startRedirectingServer()
 
@@ -481,6 +481,7 @@ for (const factory of [
       t.fail('Did not throw')
     } catch (error) {
       t.strictEqual(error.message, 'max redirects')
+      t.strictEqual(error.code, 'UND_ERR_REDIRECT_MAX')
     }
 
     await t.completed
@@ -521,7 +522,7 @@ for (const factory of [
 
       await t.assert.rejects(
         undici.request(`${origin}/3`, { dispatcher }),
-        { message: 'max redirects' }
+        { message: 'max redirects', code: 'UND_ERR_REDIRECT_MAX' }
       )
     })
   }

test/redirect-request.js

@@ -429,7 +429,7 @@ for (const factory of [
   })
 
   test('should throw when max redirections is reached and throwOnMaxRedirect is enabled', async t => {
-    t = tspl(t, { plan: 1 })
+    t = tspl(t, { plan: 2 })
 
     const server = await startRedirectingServer()
 
@@ -444,6 +444,7 @@ for (const factory of [
       } else {
         t.fail(`Unexpected error: ${error.message}`)
       }
+      t.strictEqual(error.code, 'UND_ERR_REDIRECT_MAX')
     }
 
     await t.completed

test/types/errors.test-d.ts

@@ -120,6 +120,11 @@ expectAssignable<errors.MaxOriginsReachedError>(new errors.MaxOriginsReachedErro
 expectAssignable<'MaxOriginsReachedError'>(new errors.MaxOriginsReachedError().name)
 expectAssignable<'UND_ERR_MAX_ORIGINS_REACHED'>(new errors.MaxOriginsReachedError().code)
 
+expectAssignable<errors.UndiciError>(new errors.MaxRedirectsError())
+expectAssignable<errors.MaxRedirectsError>(new errors.MaxRedirectsError())
+expectAssignable<'MaxRedirectsError'>(new errors.MaxRedirectsError().name)
+expectAssignable<'UND_ERR_REDIRECT_MAX'>(new errors.MaxRedirectsError().code)
+
 {
   // @ts-ignore
   function f (): errors.HeadersTimeoutError | errors.ConnectTimeoutError { }

types/errors.d.ts

@@ -169,6 +169,12 @@ declare namespace Errors {
     code: 'UND_ERR_MAX_ORIGINS_REACHED'
   }
 
+  /** The maximum number of redirects has been reached. */
+  export class MaxRedirectsError extends UndiciError {
+    name: 'MaxRedirectsError'
+    code: 'UND_ERR_REDIRECT_MAX'
+  }
+
   /** SOCKS5 proxy related error. */
   export class Socks5ProxyError extends UndiciError {
     constructor (