fix(middleware): use includes() for NextAuth pages (#5104)

* fix(middleware): use `includes()` for NextAuth pages

Some users could be setting their `signIn` and `error` pages option to
`/` to disable the automatically generated pages, as suggested in [1].

This commit reverts the behaviour for matching `signIn` and `error`
pages in `handleMiddleware` to pre-v4.10.3.

```
const signInPage = "/"
const errorPage = "/"
const publicPaths = [signInPage, errorPage, "/_next", "/favicon.ico"]

// pathname = "/" will return true
publicPaths.some((p) => pathname.startsWith(p))
```

Fixes: aedabc8 ("fix: avoid redirect on always public paths")
Reference [1]: #2330 (reply in thread)
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

* test(middleware): add tests for public paths

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
Co-authored-by: Thang Vu <thvu@hey.com>

Author: Juneezee

packages/next-auth/src/next/middleware.ts

@@ -106,12 +106,13 @@ async function handleMiddleware(
   const signInPage = options?.pages?.signIn ?? "/api/auth/signin"
   const errorPage = options?.pages?.error ?? "/api/auth/error"
   const basePath = parseUrl(process.env.NEXTAUTH_URL).path
-  const publicPaths = [signInPage, errorPage, "/_next", "/favicon.ico"]
+  const publicPaths = ["/_next", "/favicon.ico"]
 
   // Avoid infinite redirects/invalid response
   // on paths that never require authentication
   if (
     pathname.startsWith(basePath) ||
+    [signInPage, errorPage].includes(pathname) ||
     publicPaths.some((p) => pathname.startsWith(p))
   ) {
     return

packages/next-auth/tests/middleware.test.ts

@@ -0,0 +1,40 @@
+import { NextMiddleware } from "next/server"
+import { NextAuthMiddlewareOptions, withAuth } from "../next/middleware"
+
+it("should not match pages as public paths", async () => {
+  const options: NextAuthMiddlewareOptions = {
+    pages: {
+      signIn: "/",
+      error: "/"
+    },
+    secret: "secret"
+  }
+
+  const nextUrl: any = {
+    pathname: "/protected/pathA",
+    search: "",
+    origin: "http://127.0.0.1"
+  }
+  const req: any = { nextUrl, headers: { authorization: "" } }
+
+  const handleMiddleware = withAuth(options) as NextMiddleware
+  const res = await handleMiddleware(req, null)
+  expect(res).toBeDefined()
+  expect(res.status).toBe(307)
+})
+
+it("should not redirect on public paths", async () => {
+  const options: NextAuthMiddlewareOptions = {
+    secret: "secret"
+  }
+  const nextUrl: any = {
+    pathname: "/_next/foo",
+    search: "",
+    origin: "http://127.0.0.1"
+  }
+  const req: any = { nextUrl, headers: { authorization: "" } }
+
+  const handleMiddleware = withAuth(options) as NextMiddleware
+  const res = await handleMiddleware(req, null)
+  expect(res).toBeUndefined()
+})