Hydration error from regression when updating Svelte from 5.6.1 to 5.6.2

[samal-rasmussen]

Describe the bug

After I update Svelte from 5.6.1 to 5.6.2 I get this hydration error:
HierarchyRequestError: Failed to execute 'appendChild' on 'Node': This node type does not support this method.

So I'm not 100% if this is considered a Svelte or SvelteKit bug.

Reproduction

This can be reproduced with the code snipped below:

<script>
  import { browser } from "$app/environment";
</script>

{#if !browser}
  <slot />
{/if}

<div>
  <slot />
</div>

I am conditionally rendering something differently on mobile and desktop, but I can't check media queries on the backend, so the condition is short circuiting on a check on browser, so I end up getting different results on the server and client. I stripped out all the media query stuff because it had no bearing on the bug.

I've put it in a stackblitz:
https://stackblitz.com/edit/svelte-kit-rvd1ht?file=src%2Froutes%2F%2Bpage.svelte

Logs

No response

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (3) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 18.20.3 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.2.3 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    @sveltejs/adapter-auto: 3.3.1 => 3.3.1 
    @sveltejs/kit: 2.9.0 => 2.9.0 
    @sveltejs/vite-plugin-svelte: 5.0.1 => 5.0.1 
    svelte: 5.6.2 => 5.6.2 
    vite: 6.0.3 => 6.0.3

Severity

blocking an upgrade

Additional Information

@trueadm I see the only thing in Svelte 5.6.2 was the addition of tree shaking on if statements that you made.

[Wizzel1]

I am still getting this error with svelte: 5.12.0

Edit: Nevermind, I was able to solve it with a dependency update