feat(css_parser): add vueScopedCss option for Vue SFC scoped CSS selectors

[kiroushi]

AI disclosure: This PR was developed with AI assistance (Claude Code). All changes were reviewed manually.

Summary

Fixes #7923.

Adds a new css.parser.vueScopedCss configuration option that enables parsing of Vue SFC scoped CSS selectors (:deep(), :slotted()). This follows the same pattern as the existing css.parser.cssModules option for :local()/:global().

When disabled (the default), the parser emits a helpful diagnostic with a hint to enable the option:

`:deep` and `:slotted` are Vue SFC scoped CSS selectors, not standard CSS features.
  You can enable Vue SFC scoped CSS parsing by setting the `css.parser.vueScopedCss`
  option to `true` in your configuration file.

Usage in biome.json:

{
  "css": {
    "parser": {
      "vueScopedCss": true
    }
  }
}

Note: :global() is already handled by the cssModules option and is not part of this change.

Test Plan

• OK test: :deep(.b) and :slotted(.b) parse successfully with vueScopedCss: true.
• Error/disabled test: Without the option, both selectors produce a diagnostic with the hint.
• Error/enabled test: Malformed syntax (missing selector, empty parens, missing closing paren, etc.) produces proper error recovery, mirroring the existing CSS Modules error tests.
• All 203 CSS parser tests pass.

Docs

A documentation PR will be submitted to the next branch of the website to document the new css.parser.vueScopedCss option alongside the existing cssModules and tailwindDirectives options.

[changeset-bot]

🦋 Changeset detected

Latest commit: 8ad946a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@biomejs/biome	Patch
@biomejs/cli-win32-x64	Patch
@biomejs/cli-win32-arm64	Patch
@biomejs/cli-darwin-x64	Patch
@biomejs/cli-darwin-arm64	Patch
@biomejs/cli-linux-x64	Patch
@biomejs/cli-linux-arm64	Patch
@biomejs/cli-linux-x64-musl	Patch
@biomejs/cli-linux-arm64-musl	Patch
@biomejs/wasm-web	Patch
@biomejs/wasm-bundler	Patch
@biomejs/wasm-nodejs	Patch
@biomejs/backend-jsonrpc	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[coderabbitai]

Walkthrough

This PR adds support for parsing Vue SFC scoped CSS selectors (:deep() and :slotted()). It introduces a new configuration option css.parser.vueScopedCss that can be enabled via --css-parse-vue-scoped-css CLI flag. The implementation adds lexer tokens for the new keywords, updates pseudo-class function selector parsing to recognise these Vue-specific selectors alongside CSS Modules syntax, and propagates the setting through the configuration and service layers. Error handling is included to report when Vue scoped CSS is encountered with the feature disabled.

Possibly related PRs

• feat(cli): add parsing arguments #7723 — Exposes CSS parser configuration options and CLI flags similar to the --css-parse-vue-scoped-css flag added here.
• feat(html): support CSS modules syntax and vue css syntax #8399 — Makes overlapping changes to CSS parser for Vue scoped CSS support, including lexer tokens and pseudo-class function selector parsing.

Suggested labels

A-Parser, L-CSS, A-Tooling

Suggested reviewers

• dyc3
• ematipico
• arendjr

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: adding a new vueScopedCss configuration option for parsing Vue SFC scoped CSS selectors, which is the primary objective of this PR.
Description check	✅ Passed	The description is well-detailed and directly related to the changeset. It explains the feature, configuration usage, test coverage, and references the linked issue #7923.
Linked Issues check	✅ Passed	All code changes successfully implement the requirements from #7923: the PR adds support for parsing Vue SFC scoped CSS selectors (:deep() and :slotted()) with proper configuration options, error handling, and test coverage.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to implementing Vue SFC scoped CSS selector support. No unrelated modifications detected; all alterations serve the stated objective.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

No actionable comments were generated in the recent review. 🎉

Tip

Issue Planner is now in beta. Read the docs and try it out! Share your feedback on Discord.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[dyc3]

This has already been implemented on next and will be available in 2.4