Nuxt Middleware with Firebase and FirebaseUI: Error: Redirected when going from "/anything" to "/login" via a navigation guard - firebase

Question

Nuxt SSR app using FirebaseUI to handle auth flows. Logging in and out works perfectly. When I add Middleware to check auth state and redirect if not logged in I get this error:
Error: Redirected when going from "/list-cheatsheets" to "/login" via a navigation guard.
middleware/auth.js
export default function ({ store, redirect }) {
// If the user is not authenticated
if (!store.state.user) {
return redirect('/login')
}
}
There is absolutely no other redirecting that I can find in the app....
I have been digging and trying things for hours. Others who get this error that I have found aren't using Nuxt and none of those solutions work.

Answer 1

As there is a bounty one cannot mark it duplicate thus following up is a copy of my answer at Redirecting twice in a single Vue navigation
tldr: vm.$router.push(route) is a promise and needs to .catch(e=>gotCaught(e)) errors.
This will be changed in the next major#4
Currently#3 errors are not distinguished whether they are NavigationFailures or regular Errors.
The naive expected route after vm.$router.push(to) should be to. Thus one can expect some failure message once there was a redirect. Before patching router.push to be a promise the error was ignored silently.
The current solution is to antipattern a .catch(...) onto every push, or to anticipate the change in design and wrap it to expose the failure as result.
Future plans have it to put those informations into the result:
let failure = await this.$router.push(to);
if(failure.type == NavigationFailureType[type]){}
else{}
Imo this error is just by design and should be handled:
hook(route, current, (to: any) => { ... abort(createNavigationRedirectedError(current, route)) ...}
So basically if to contains a redirect it is an error, which kinda is equal to using vm.$router.push into a guard.
To ignore the unhandled error behaviour one can pass an empty onComplete (breaks in future releases):
vm.$router.push(Route, ()=>{})
or wrap it in try .. catch
try {
await this.$router.push("/")
} catch {
}
which prevents the promise to throw uncaught.
to support this without redirecting twice means you put the guard to your exit:
let path = "/"
navguard({path}, undefined, (to)=>this.$router.push(to||path))
which will polute every component redirecting to home
btw the router-link component uses an empty onComplete
Assumption that redirecting twice is not allowed is wrong.