CSS import regression in Vite 2.8

[Artur-]

Describe the bug

When you import CSS using the inline flag, like

import prismCss from 'prismjs/themes/prism-okaidia.css?inline';

the value is available in development mode but becomes an empty string in the built version

Reproduction

https://github.com/Artur-/vite-vaadin-problem6

System Info

System:
    OS: macOS 12.2
    CPU: (10) arm64 Apple M1 Max
    Memory: 1.75 GB / 64.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 17.3.0 - ~/.nvm/versions/node/v17.3.0/bin/node
    npm: 8.3.0 - ~/.nvm/versions/node/v17.3.0/bin/npm
  Browsers:
    Chrome: 97.0.4692.99
    Firefox: 95.0.2
    Safari: 15.3
  npmPackages:
    vite: ^2.8.0-beta.6 => 2.8.0-beta.6

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[Artur-]

With VIte 2.7.13, the value is available in both development mode and when built for production
Starting from 2.8.0-beta.0 it is only available in development mode

[Artur-]

Bisect says this was introduced by #6233 / 000ba2e

[patak-dev]

I'll send a PR to revert #6233 soon. @egoist we can add better test cases before adding that fix back, we would like to get 2.8 out of the door this week.

Thanks for digging into this issue @Artur-

[bluwy]

To be fair, css?inline isn't documented and I'm not sure if it's public API. Does it work like ?raw? There was a similar question over at sveltejs/vite-plugin-svelte#232 before

[Artur-]

Interestingly enough this fails only when importing from node_module, if you import from a file in the project it works as expected also in 2.8. That is why this test still passes:

vite/packages/playground/css/main.js

Lines 69 to 70 in 651e0ba

	import inlined from './inlined.css?inline'
	text('.inlined-code', inlined)

[patak-dev]

@bluwy looks like it was never added to the documentation, but ?inline was added here #2148 (comment) to be able to do Web Components IIRC