Svelte 5: CSS Sourcemaps are broken

[rodshtein]

Describe the bug

For now sourcemaps works only with option css === 'injected'
But it's breaks live updates.

sourcecode:

svelte/packages/svelte/src/compiler/phases/3-transform/css/index.js

Line 62 in b665425

if (dev && options.css === 'injected' && css.code) {

Reproduction

package.json

"@sveltejs/adapter-auto": "^3.0.0",
"@sveltejs/kit": "^2.6.1",
"@sveltejs/vite-plugin-svelte": "^4.0.0-next.7",
"svelte": "^5.0.0-next.260",
"vite": "^5.4.8"

svelte.config.js:

kit: {
  adapter: adapter()
},
compilerOptions: {
  dev: true,
  css: 'injected'
}

Logs

No response

System Info

System:
    OS: macOS 14.6.1
    CPU: (8) arm64 Apple M1
    Memory: 91.13 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.15.1 - ~/.nvm/versions/node/v20.15.1/bin/node
    npm: 10.7.0 - ~/.nvm/versions/node/v20.15.1/bin/npm
    pnpm: 8.10.2 - ~/Library/pnpm/pnpm
  Browsers:
    Brave Browser: 129.1.70.119
    Safari: 17.6
  npmPackages:
    svelte: ^5.0.0-next.260 => 5.0.0-next.260

Severity

annoyance