Improve Client-Side Routing on Page Not Found

[Manas1820]

Describe your changes.

The issue is well described in #3720 and also fixes it.

In the useClientSideRouting function, the routeNotFound state was incorrectly set to false even when the current route was actually not found. To address this, I added a hard check to verify the pathname after attempting a redirection. If the pathname remains /404 after the redirection attempt, the routeNotFound state is correctly set to true. This ensures that the correct 404 page is displayed when the route is genuinely not found.

Example is mentioned in the same issue's thread

Type of change

• Bug fix (non-breaking change which fixes an issue)

New Feature Submission:

• Does your submission pass the tests?
• Have you linted your code locally prior to submission?

Changes To Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you successfully ran tests with your changes locally?

[masenf]

Thanks for your contribution. Seems to resolve the issue on my end.

Is there a reason why we check the router.pathname inside a chained function instead of before we even attempt the router.replace?

[Manas1820]

@masenf Just did it to be completely sure, thought that when router.replace is called, it might initiate a client-side navigation that potentially changes the current route. By checking router.pathname after router.replace completes, we can be completely positive that we have reached the final state.