Vite does not generate sourcemaps even with build.sourcemap: true

[Hansenq]

Reproduction

I'm able to reproduce this on the latest create-remix template.

1. Run npx create-remix@latest --template remix-run/remix/templates/vite
2. Edit vite.config.ts to set build.sourcemap to true:

export default defineConfig({
  build: {
    sourcemap: true, // Doesn't work with the "inline" option either
  },
  plugins: [remix(), tsconfigPaths()],
});

3. Run npm run build
4. Look at the files in build/client/assets. None of them end in .js.map, which would be expected if sourcemaps are being generated.

System Info

System:
    OS: macOS 14.3
    CPU: (12) arm64 Apple M2 Pro
    Memory: 119.28 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 21.1.0 - ~/.nvm/versions/node/v21.1.0/bin/node
    npm: 10.2.0 - ~/.nvm/versions/node/v21.1.0/bin/npm
  Browsers:
    Chrome: 122.0.6261.69
    Safari: 17.3
  npmPackages:
    @remix-run/dev: ^2.7.2 => 2.7.2
    @remix-run/node: ^2.7.2 => 2.7.2
    @remix-run/react: ^2.7.2 => 2.7.2
    @remix-run/serve: ^2.7.2 => 2.7.2
    vite: ^5.1.0 => 5.1.4

Used Package Manager

npm

Expected Behavior

When running npm run build with vite's config build.sourcemap set to true, I expect sourcemaps to be in the bundled output. If you look at the bundled output below, none of the files end in .map.js

Actual Behavior

The output is being bundled correctly, but no sourcemaps are being generated.

> build
> remix vite:build

vite v5.1.4 building for production...
✓ 80 modules transformed.
build/client/.vite/manifest.json                0.90 kB │ gzip:  0.26 kB
build/client/assets/_index-D_UUquDl.js          0.76 kB │ gzip:  0.39 kB
build/client/assets/root-B_va2Ysy.js            1.44 kB │ gzip:  0.84 kB
build/client/assets/jsx-runtime-BlSqMCxk.js     8.09 kB │ gzip:  3.04 kB
build/client/assets/entry.client-DxOYqYt_.js   14.18 kB │ gzip:  4.94 kB
build/client/assets/components-Bjtzq-Kj.js    212.63 kB │ gzip: 68.80 kB
✓ built in 447ms
vite v5.1.4 building SSR bundle for production...
✓ 5 modules transformed.
build/server/.vite/manifest.json  0.13 kB
build/server/index.js             6.89 kB
✓ built in 14ms

[markdalgleish]

Fixed by #8965.

[github-actions]

🤖 Hello there,

We just published version 2.8.1-pre.0 which involves this issue. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 2.8.1 which involves this issue. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!