Routing endpoints missing searchParams

[timwis]

Describe the bug

The new routing endpoints are great, but I think I've come across a bug. If you use goto to set a querystring/searchParam, the routing endpoint can't read the searchParam when using client-side routing. But it can if you refresh the page (server-side routing).

Reproduction

Use this basic reproduction on stackblitz.

1. Click Open in a New Window at the top-right of stackblitz, since the built-in browser doesn't update the URL visibly
2. Enter a value in the text box and submit the form (client-side routing)
3. You'll see the querystring printed is blank, but the browser's URL contains a query string
4. Refresh the page (server-side routing) and you'll see the querystring comes through
5. Press back, then forwards (client-side routing), and you'll see it's blank again

I've left a couple lines commented out to illustrate the conditions under which it works as expected:

• If you use a load function instead of a routing endpoint (uncomment the load function)
• Or if you use a standard <form> submission, instead of goto (uncomment the <form> tag and comment out the one beneath)

Logs

No response

System Info

System: (note: reproduced the issue on stackblitz)
    OS: macOS 12.1
    CPU: (10) arm64 Apple M1 Pro
    Memory: 90.80 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 17.3.1 - /opt/homebrew/bin/node
    npm: 8.3.0 - /opt/homebrew/bin/npm
  Browsers:
    Chrome: 98.0.4758.80
    Firefox: 96.0.1
    Safari: 15.2
  npmPackages:
    @sveltejs/adapter-auto: ^1.0.0-next.17 => 1.0.0-next.17 
    @sveltejs/kit: ^1.0.0-next.260 => 1.0.0-next.260 
    svelte: ^3.44.0 => 3.46.3

Severity

serious, but I can work around it

Additional Information

My guess, not being familiar with sveltekit's codebase, is that the issue could be with how goto sets HTML5 history - perhaps it's not including the query/searchParams there. But that's a rather wild guess.

[CaptainCodeman]

See #3777