🔴 Hot News: biomejs/biome/pull/

denbezrukov · 2026-10-04T11:00:32Z

This PR was developed with assistance from OpenAI Codex.

Summary

Adds parser and formatter support for dynamic SCSS @supports heads.

$property: display;
$condition: "(display: grid)";

@supports ($property: grid) {
  .by-name {
    display: grid;
  }
}

@supports (#{$condition}) {
  .by-condition {
    display: grid;
  }
}

@supports (#{$condition} and (color: red)) {
  .combined {
    display: grid;
  }
}

Test Plan

cargo test -p biome_css_parser/formatter

agentscanapp · 2026-10-04T11:00:35Z

A maintainer will take a look as soon as they can. In the meantime, please make sure that:

the description follows our PR template
any related issues are linked
existing tests still pass

changeset-bot · 2026-10-04T11:00:38Z

⚠️ No Changeset found

Latest commit: d4a34f6

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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github-actions · 2026-10-04T11:06:53Z

Parser conformance results

scss/sass-spec

Test result	`main` count	This PR count	Difference
Total	11463	11463	0
Passed	11080	11082	✅ ⏫ +2
Failed	383	381	✅ ⏬ -2
Panics	0	0	0
Coverage	96.66%	96.68%	+0.02%

🎉 Fixed (2):

css/supports/syntax/lone_interpolation/parens/alone
css/supports/syntax/lone_interpolation/parens/before_operator

coderabbitai · 2026-10-04T11:09:32Z

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📚 Code guidelines (1)

AGENTS.md — auto-discovered

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository: biomejs/biome/.coderabbit.yaml
Review profile: CHILL
Plan: Advanced
Run ID: 431e40bc-2e5a-4639-993f-73e84bff66e6

📥 Commits

Reviewing files that changed from the base of the PR and between f9977d9 and d4a34f6.

⛔ Files ignored due to path filters (12)

crates/biome_css_factory/src/generated/node_factory.rs is excluded by !**/generated/**, !**/generated/** and included by **
crates/biome_css_factory/src/generated/syntax_factory.rs is excluded by !**/generated/**, !**/generated/** and included by **
crates/biome_css_formatter/tests/specs/scss/at-rule/parity-supports-dynamic-heads.scss.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/error/at_rule/parity-supports-dynamic-heads.css.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/error/scss/at-rule/parity-supports-dynamic-heads.scss.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/error/scss/at-rule/supports-interpolated-property-missing-colon.scss.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/ok/at_rule/parity-supports-dynamic-heads.css.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/ok/scss/at-rule/parity-supports-dynamic-heads.scss.snap is excluded by !**/*.snap and included by **
crates/biome_css_syntax/src/generated/kind.rs is excluded by !**/generated/**, !**/generated/** and included by **
crates/biome_css_syntax/src/generated/macros.rs is excluded by !**/generated/**, !**/generated/** and included by **
crates/biome_css_syntax/src/generated/nodes.rs is excluded by !**/generated/**, !**/generated/** and included by **
crates/biome_css_syntax/src/generated/nodes_mut.rs is excluded by !**/generated/**, !**/generated/** and included by **

📒 Files selected for processing (14)

crates/biome_css_formatter/src/css/any/supports_in_parens.rs
crates/biome_css_formatter/src/generated.rs
crates/biome_css_formatter/src/scss/auxiliary/mod.rs
crates/biome_css_formatter/src/scss/auxiliary/supports_feature_declaration.rs
crates/biome_css_formatter/tests/specs/scss/at-rule/parity-supports-dynamic-heads.scss
crates/biome_css_parser/src/syntax/at_rule/supports/mod.rs
crates/biome_css_parser/tests/css_test_suite/error/at_rule/parity-supports-dynamic-heads.css
crates/biome_css_parser/tests/css_test_suite/error/scss/at-rule/parity-supports-dynamic-heads.scss
crates/biome_css_parser/tests/css_test_suite/error/scss/at-rule/supports-interpolated-property-missing-colon.scss
crates/biome_css_parser/tests/css_test_suite/ok/at_rule/parity-supports-dynamic-heads.css
crates/biome_css_parser/tests/css_test_suite/ok/scss/at-rule/parity-supports-dynamic-heads.scss
crates/biome_grit_patterns/src/grit_target_language/css_target_language/generated_mappings.rs
xtask/codegen/css.ungram
xtask/codegen/src/css_kinds_src.rs

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 9 remain after this review.

Walkthrough

The parser now handles SCSS variables and interpolated heads in @supports conditions. The change adds a syntax node for variable-based supports declarations and formatter support for that node. New parser and formatter fixtures cover valid forms and error cases.

Suggested reviewers: ematipico

Priority: ⬇️ Low

Change: Feature

Merge Risk: ⚪ Minimal · up to d4a34

The investigated parser and formatter cases preserve the expected behavior. No identified issue prevents merging after normal checks.

Security Architecture Review

Security architecture risk: ⚪ Minimal · up to d4a34

The examined changes add parsing and formatting support for dynamic SCSS conditions while preserving language-mode checks. No material security risk introduced or worsened by this change was identified.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

inferred — The reviewed reachability expansion is source text reaching additional syntax nodes and their formatting consumers. The inspected branches and adapters do not introduce interpolation execution, external operations, or additional privileges. Exposure through unexamined hosting environments is not established by this evidence.

Trust Boundaries and Controls

inferred — The relevant control is a language-mode and syntax-classification boundary, not an authentication boundary. Attacker-supplied interpolation remains parsed syntax in the examined paths, and formatter access is through typed nodes and the existing formatting context.

Resilience and Maintainability Implications

observed — The direct supports interpolation parser owns its opening delimiter, reports an absent head, and expects a closing delimiter on its completion paths. Condition continuation retains existing chain recovery, while the variable-declaration branch explicitly expects its colon and closing parenthesis. Inspection found no new progress or parser-state ownership defect in these paths; runtime behavior was not tested.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarises the main change: support for dynamic SCSS `@supports` heads.
Description check	✅ Passed	The description explains the parser and formatter support and gives relevant SCSS examples and a test plan.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

Commit to this branch
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codspeed · 2026-10-04T11:26:45Z

Merging this PR will not alter performance

⚠️

3 benchmarks measured no execution time

Nothing ran under measurement, usually because the compiler removed the code under test. These results are not comparable, so they count as unchanged.

Preventing compiler optimizations

✅ 114 untouched benchmarks
⏩ 299 skipped benchmarks¹

Performance Changes

	Benchmark	`BASE`	`HEAD`	Efficiency
⚠️	`grit_query_anchor_kinds[code_snippet]`	< 1 ns	< 1 ns	N/A
⚠️	`grit_query_anchor_kinds[metavariable]`	< 1 ns	< 1 ns	N/A
⚠️	`grit_query_anchor_kinds[or_pattern]`	< 1 ns	< 1 ns	N/A

_{Comparing dbezrukov/scss-supports-dynamic-heads (d4a34f6) with main (f9977d9)²}

299 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. ↩
No successful run was found on main (a1463aa) during the generation of this report, so f9977d9 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

denbezrukov added 3 commits October 3, 2026 20:39

feat(css): support dynamic supports heads

d78caa2

test(css_parser): cover dynamic supports boundaries

03930b3

test(css_formatter): cover dynamic supports heads

d4a34f6

github-actions Bot added A-Parser Area: parser A-Formatter Area: formatter A-Tooling Area: internal tools L-CSS Language: CSS and super languages L-Grit Language: GritQL labels Oct 4, 2026

ematipico approved these changes Oct 4, 2026

View reviewed changes

denbezrukov merged commit 74af6b1 into main Oct 4, 2026
36 checks passed

denbezrukov deleted the dbezrukov/scss-supports-dynamic-heads branch October 4, 2026 14:05

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feat(css): support dynamic supports heads - #12127

feat(css): support dynamic supports heads#12127
denbezrukov merged 3 commits into
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denbezrukov commented Oct 4, 2026

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Parser conformance results

scss/sass-spec

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Merging this PR will not alter performance

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