Redirect to a custom signIn and signout signOut pages isn't working with domain names

[qstyler]

Environment

  System:
    OS: macOS 15.1.1
    CPU: (10) arm64 Apple M1 Max
    Memory: 891.56 MB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.11.0 - /usr/local/bin/node
    Yarn: 1.22.22 - /opt/homebrew/bin/yarn
    npm: 10.2.5 - /opt/homebrew/bin/npm
    pnpm: 8.15.7 - /opt/homebrew/bin/pnpm
  Browsers:
    Chrome: 131.0.6778.109
    Edge: 131.0.2903.86
    Safari: 18.1.1
  npmPackages:
    @auth/unstorage-adapter: ^2.0.0 => 2.7.4
    next: latest => 15.0.4
    next-auth: beta => 5.0.0-beta.25
    react: ^18.2.0 => 18.3.1

Reproduction URL

https://github.com/qstyler/next-auth-example/blob/main/auth.ts#L61

Describe the issue

When you give your signIn custom page values with the full domain name next-auth will not respect that and will fall into an infinite redirect loop.
I relied on this behaviour in the v4 and I expect it to keep working in v5.

How to reproduce

Add a custom signIn page to next-auth configuration:

  pages: {
    signIn: 'http://localhost:3000/any-page-will-break'
  },

Go to the protected resource (middleware-example in your example)

➜  ~ curl -I http://localhost:3000/middleware-example
HTTP/1.1 307 Temporary Redirect
location: /http://localhost:3000/any-page-will-break?callbackUrl=http%3A%2F%2Flocalhost%3A3000%2Fmiddleware-example

The location header will have a slash at the beginning. You will either get into an infinite loop or get a 404 message depending on your settings.

Expected behavior

Redirect correctly to the provided full URL of the page. Without a slash.

location: http://localhost:3000/any-page-will-break?callbackUrl=http%3A%2F%2Flocalhost%3A3000%2Fmiddleware-example

[nic-vo]

I think you need to use relative paths instead of absolute. If you pass in { pages: { signIn: "/page_name" }} instead, the config should work both in your dev environment and wherever it's deployed.

Servers and browsers generally understand that paths starting with a / are all relative to the domain

[TDanyStark]

I Have the same problem, but my path if it is absolute

export const authConfig = {
pages: {
signIn: '/login',
},

I followed the next.js guide
https://nextjs.org/learn/dashboard-app/adding-authentication

but when I try to access a protected route, for example /dashboard, the middleware redirect to
/login?callbackUrl=http%3A%2F%2Flocalhost%3A3000%2Fdashboard

then when i do login with the email and password, my app redirect to the /dashboard view, BUT you still see in the URL
/login?callbackUrl=http%3A%2F%2Flocalhost%3A3000%2Fdashboard

I fixed it by simply deleting the custom login page., BUT i need my custom page, I've tried everything, Youtube Videos, I read the auth js documentation.