page.url does not update when pushState is called

[ottomated]

Describe the bug

When calling pushState from $app/navigation, I expect page imported from $app/state to update its url. However, neither this url nor the one from $app/stores updates correctly.

Reproduction

https://stackblitz.com/edit/page-state-url-bug?file=src%2Froutes%2F%2Bpage.svelte

Logs

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (8) 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: ^4.0.0 => 4.0.0 
    @sveltejs/kit: ^2.16.0 => 2.19.0 
    @sveltejs/vite-plugin-svelte: ^5.0.0 => 5.0.3 
    svelte: ^5.0.0 => 5.22.6 
    vite: ^6.0.0 => 6.2.1

Severity

serious, but I can work around it

Additional Information

No response

[stefanVaporTrade]

I believe my issue is likely related to this. When I store any state using pushState or replaceState, and the user later navigates back to that page using history.back, the page store no longer has that state — it’s empty.

[hmnd]

Apparently this is intentional, but it doesn't feel right... I think it's logical to expect page.url to always reflect the current url, whereas page.route et al make sense to keep as is, since we're likely shallow routing.

[hmnd]

@Rich-Harris sorry for the ping, but given you were the original one to respond on this, I figured you could help. I think your decision may be worth reconsidering. Not updating page.url leads to more inconsistencies and unexpected behavior than doing so, in my experience (see also #10661).

In one case, for instance, I have a modal containing tabs. I want to store the state of these tabs in the url, so I have a ?mode={tab} searchparam. I would have expected the modal to be able to pickup the set searchparam using page.url, so that I can trigger different tabs to show on modal load, just by doing pushState. Instead I don't get anything and have to duplicate the effort by injecting the searchparam value from my modal's load function or similar.