When using hash history, a slash is added to the href when changing window.location.hash and search params before the hash get added to href

[JamesHyot]

Which project does this relate to?

Router

Describe the bug

PR #3644 for issue #3595 introduced two breaking changes in v1.112.8 :

• an additional slash is added in some cases
• search params are mixed between "server search params" and "hash search params"

I have to agree with the opinion of Tanner in #1449, maybe this breaking change should not have been introduced.
I think the additional slash can be safely removed, and maybe the new search behaviour can be an option ?

I'll try and create a PR for this if that's OK

Your Example Website or App

https://stackblitz.com/edit/github-ujeikeh5?file=src%2Froutes%2Findex.tsx

Steps to Reproduce the Bug or Issue

1. Go to About
2. Navigate to Other using the yellow or orange links
3. See that the href displayed is //other instead of /other (also the header link is not "active")
4. If you add a search param in the preview url (for instance https://wmaibpqbzggithub-fcsj--3000--495c5120.local-corp.webcontainer.io/**?toto=tutu**#/about), navigating using window.location.hash or tags results in an href value of //other?toto=tutu

Expected behavior

The previous behaviour was that when using window.location.hash = '#/about' or a regular , the href would have only one /.

Also the search params sent to the server (before the # character) are now received by the router and are not separate from the "search params" that come after the # character. I do have a use case in my application where I use regular search params so that the server can dynamically change the source of my SPA script, and "hash search params" so that my @tanstack/react-router routes can use them for navigation. I do agree it is a pretty uncommon use case

Screenshots or Videos

No response

Platform

• OS: [Windows]
• Browser: [Edge, Firefox]
• Version: [Edge 134.0.3124.51, Firefox 136.0]

I don't think the issue is platform specific

Additional context

No response

[schiller-manuel]

if its feasible to make this opt in, then we can add an option. otherwise we will just revert that PR