Adapter-static not putting CSS referenced assets in the right place

Describe the bug

Resources linked to from CSS (i.e. background-image: url(...)) are not found after building a SvelteKit site with adapter-static. The following works in vite (npm run dev) but not after building the site. One could work around it with absolute URLs, yet it’s pretty annoying with many assets.

Reproduction

Create these files:

• A random image at static/wallpaper.jpg

• A component src/lib/components/something.svelte:

<div class="paper">something</div>

<style lang="postcss">
.paper {
    background-image: url(./wallpaper.jpg)
}
</style>

• Use the component in src/routes/__layout.svelte:

<script>
import Something from "$lib/components/something.svelte"
</script>

<Something />

<slot />

• config (svelte.config.js):

import preprocess from 'svelte-preprocess'
// import adapter from '@sveltejs/adapter-auto'
import adapter from '@sveltejs/adapter-static'
import path from 'path'

/** @type {import('@sveltejs/kit').Config} */
const config = {
	kit: {
		adapter: adapter(),
		prerender: { default: true },
	},

	preprocess: [preprocess({ postcss: true })]
}

export default config

• Build the app with adapter-static (npm build) and run a test HTTP server:

python3 -m http.server 9000 --directory build

• Observe in your browser’s dev tools that the request to wallpaper.jpg is 404ing since it goes to http://localhost/_app/assets/pages/wallpaper.jpg instead of the ‘http://localhost/wallpaper.jpg’

Logs

No response

System Info

System:
    OS: Linux 5.16 Arch Linux
    CPU: (24) x64 AMD Ryzen 9 5900X 12-Core Processor
    Memory: 50.72 GB / 62.78 GB
    Container: Yes
    Shell: 5.8.1 - /usr/bin/zsh
  Binaries:
    Node: 17.7.1 - /usr/bin/node
    npm: 8.5.4 - /usr/bin/npm
  Browsers:
    Brave Browser: 99.1.36.112
    Firefox: 98.0
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.31 
    @sveltejs/adapter-static: ^1.0.0-next.29 => 1.0.0-next.29 
    @sveltejs/kit: next => 1.0.0-next.295 
    svelte: ^3.46.4 => 3.46.4

Severity

serious, but I can work around it

Additional Information

No response

[dominikg]

note that url() values in style blocks of svelte components are not processed by default, see https://kit.svelte.dev/docs/assets#importing

If you want to reference an asset placed in the static directory in css without additional processing, it should be done with an absolute path /image.png.

[Rich-Harris]

I can’t reproduce this, with or without postcss, so I’m going to close this issue. It’s possible that it works now, but without a repro there’s no way of knowing.