fix(parser/css): parse conditional block correctly inside embedded snippets

[siketyan]

Summary

Note

AI Assistance Disclosure: I used the Codex agent to investigate the problem, create a regression test, and draft the PR description. All changes and output are reviewed by a human (me).

Fixes #9113

Embedded CSS snippets are parsed as CSS_SNIPPET_ROOT, which allows top-level declarations, but nested conditional blocks like @media { ... } were still using the regular parse_rule_block() path unless the parser was already inside a nesting block. As a result, declarations such as height: 40px; inside @media were misparsed as selectors.

This pull request fixes the parser to treat conditional blocks in embedded snippets the same way as nesting blocks, and parse them with parse_declaration_or_rule_list_block(). This allows declarations inside @media within CSS-in-JS snippets to be parsed correctly.

Test Plan

Added a snapshot test.

Docs

N/A

[changeset-bot]

🦋 Changeset detected

Latest commit: 6fbd0b6

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

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[coderabbitai]

Walkthrough

This pull request addresses issue #9113 by fixing the parsing and formatting of @media and other conditional blocks within embedded CSS snippets. The CSS parser now recognises styled-component embeddings and processes their conditional blocks correctly. A regression test has been added to validate the fix with a TypeScript file containing styled-components template literals with media queries.

Suggested reviewers

• ematipico

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: fixing parser handling of conditional blocks within embedded CSS snippets.
Description check	✅ Passed	The description clearly explains the problem, solution, and includes a test plan; it relates directly to the changeset.
Linked Issues check	✅ Passed	The changes fully address issue #9113 by enabling correct parsing of @media and conditional blocks within embedded CSS snippets.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the conditional block parsing issue in embedded CSS; no unrelated modifications detected.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (1)

crates/biome_css_parser/src/syntax/block/conditional_block.rs (1)

22-24: Keep the rustdoc aligned with the new branch condition.

The docs above still describe only nesting-block state, but Line 23 now also depends on styled embedding context. Worth updating to avoid future head-scratching.

Suggested doc tweak

-/// If the current state of the parser indicates that it's inside a nesting block (e.g., inside a style rule),
-/// this function parses the content as a declaration or rule list block. Otherwise, it parses the content
-/// as a rule block.
+/// If the parser is inside a nesting block (e.g., inside a style rule), or if the source is an embedded
+/// styled snippet, this function parses the content as a declaration-or-rule list block.
+/// Otherwise, it parses the content as a rule block.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/biome_css_parser/src/syntax/block/conditional_block.rs` around lines
22 - 24, Update the rustdoc above the conditional in conditional_block.rs to
reflect that the branch now fires not only when p.state().is_nesting_block is
true but also when the source embedding kind is styled
(p.source_type.as_embedding_kind() matches EmbeddingKind::Styled); edit the doc
text to mention both conditions (nesting-block state and styled embedding
context) and, if present, adjust any examples or notes to show the
styled-embedding case alongside the nesting-block case.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@crates/biome_css_parser/src/syntax/block/conditional_block.rs`:
- Around line 22-24: Update the rustdoc above the conditional in
conditional_block.rs to reflect that the branch now fires not only when
p.state().is_nesting_block is true but also when the source embedding kind is
styled (p.source_type.as_embedding_kind() matches EmbeddingKind::Styled); edit
the doc text to mention both conditions (nesting-block state and styled
embedding context) and, if present, adjust any examples or notes to show the
styled-embedding case alongside the nesting-block case.

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ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 1df7e3a and 6fbd0b6.

📒 Files selected for processing (3)

• .changeset/fast-zebras-move.md
• crates/biome_css_parser/src/syntax/block/conditional_block.rs
• crates/biome_service/src/workspace/server.tests.rs

[codspeed-hq]

Merging this PR will not alter performance

✅ 29 untouched benchmarks
⏩ 227 skipped benchmarks¹

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_{Comparing siketyan:fix/GH-9113 (6fbd0b6) with main (0a60ce0)²}

Footnotes

1. 227 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on main (1df7e3a) during the generation of this report, so 0a60ce0 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩