Favicon does not use kit paths

[DblK]

Describe the bug

When setting the following configuration for svelete:

...
kit: {
  ...
  paths: {
    base: '/admin'
  },
}

In the app.html there is the following line <link rel="icon" href="/favicon.png" />.
The %svelte.head% add the path while generating files but favicon is left untouched.

Reproduction

Simply create a new app and change the kit config as previously stated.

Logs

No response

System Info

System:
    OS: macOS 10.15.7
    CPU: (8) x64 Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
    Memory: 18.91 MB / 16.00 GB
    Shell: 5.7.1 - /bin/zsh
  Binaries:
    Node: 14.17.0 - ~/.nvm/versions/node/v14.17.0/bin/node
    npm: 7.24.0 - ~/.nvm/versions/node/v14.17.0/bin/npm
  Browsers:
    Chrome: 96.0.4664.110
    Firefox: 89.0.2
    Safari: 14.0.3
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.9 
    @sveltejs/adapter-static: ^1.0.0-next.24 => 1.0.0-next.24 
    @sveltejs/kit: next => 1.0.0-next.216 
    svelte: ^3.44.0 => 3.44.3

Severity

annoyance

Additional Information

To solve the issue I have to manually change the path for the favicon.
Since I do not know yet where I will serve my app, I will need to change the svelte config BUT also the app.html to avoid 404 error for favicon.

[ghostdevv]

Very interesting to see where this issue will go, as app.html isn't processed and talks of potentially doing that occurred in #3127

I wonder what happens when you import a asset in one of your routes such as <img src="/favicon.png" /> if that image is also broken or if that url is processed

[Conduitry]

I would suggest just putting the <link rel=icon> somewhere else where you do have access to the base information - like __layout.svelte, and then using https://kit.svelte.dev/docs#modules-$app-paths to construct the appropriate URL. I don't think it makes sense to make it any more complicated than that or to process app.html in some way.

I could go either way on whether the create-svelte template apps should be updated like this.

[Rich-Harris]

This will be fixed by #3234 — just add %svelte.assets% to the template (i.e. %svelte.assets%/favicon.png)