fix(parse/css): handle bogus declarations slightly more gracefully by dyc3 · Pull Request #11321 · biomejs/biome

dyc3 · 2026-08-12T23:10:56Z

Summary

This adds a CssBogusDeclaration node, and makes the parser recovery a little more graceful for declaration lists. This affects top level declaration lists, like in html style attributes.

fixes #11315

Test Plan

snapshots

Docs

changeset-bot · 2026-08-12T23:11:03Z

🦋 Changeset detected

Latest commit: 3bae583

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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github-actions · 2026-08-12T23:11:07Z

✅ Organic activity

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github-actions · 2026-08-12T23:15:45Z

Parser conformance results on

js/262

Test result	`main` count	This PR count	Difference
Total	53598	53598	0
Passed	52315	52315	0
Failed	1241	1241	0
Panics	42	42	0
Coverage	97.61%	97.61%	0.00%

jsx/babel

Test result	`main` count	This PR count	Difference
Total	38	38	0
Passed	37	37	0
Failed	1	1	0
Panics	0	0	0
Coverage	97.37%	97.37%	0.00%

markdown/commonmark

Test result	`main` count	This PR count	Difference
Total	652	652	0
Passed	652	652	0
Failed	0	0	0
Panics	0	0	0
Coverage	100.00%	100.00%	0.00%

symbols/microsoft

Test result	`main` count	This PR count	Difference
Total	5467	5467	0
Passed	1915	1915	0
Failed	3552	3552	0
Panics	0	0	0
Coverage	35.03%	35.03%	0.00%

ts/babel

Test result	`main` count	This PR count	Difference
Total	676	676	0
Passed	592	592	0
Failed	84	84	0
Panics	0	0	0
Coverage	87.57%	87.57%	0.00%

ts/microsoft

Test result	`main` count	This PR count	Difference
Total	18876	18876	0
Passed	13010	13010	0
Failed	5865	5865	0
Panics	1	1	0
Coverage	68.92%	68.92%	0.00%

codspeed-hq · 2026-08-12T23:28:33Z

Merging this PR will not alter performance

✅ 33 untouched benchmarks
⏩ 260 skipped benchmarks¹

_{Comparing dyc3/css-parse-declaration-bogus (3bae583) with main (ff31f40)}

260 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. ↩

coderabbitai · 2026-08-12T23:49:11Z

Walkthrough

The CSS grammar now represents malformed declarations with CssBogusDeclaration. Parser recovery recognises semicolons as declaration boundaries and continues parsing later declarations. The CSS formatter supports the new node. Tests cover malformed @font-face declarations and invalid CSS in HTML style attributes. Changesets document recovery and diagnostic reporting instead of a panic.

Suggested labels: L-HTML, A-Diagnostic

Suggested reviewers: denbezrukov, ematipico

Mergeability Score: 🟡 Moderate · up to 3bae5

This change improves recovery for invalid CSS declarations, but the current implementation can lose the declaration-specific syntax node for some invalid declarations, which may cause incorrect downstream parsing or formatting behavior. Merge should wait until that mapping is added.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the main change: improved CSS parser handling for bogus declarations.
Description check	✅ Passed	The description explains the new CssBogusDeclaration node, parser recovery changes, affected HTML style attributes, and testing.
Linked Issues check	✅ Passed	The parser changes and tests address the issue by representing invalid declarations, producing diagnostics, and avoiding the reported panic.
Out of Scope Changes check	✅ Passed	The changes remain within scope and support CSS recovery, syntax representation, formatting, diagnostics, tests, and release documentation.

✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch dyc3/css-parse-declaration-bogus

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coderabbitai

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/biome_css_syntax/src/lib.rs`:
- Line 110: Update the AnyCssDeclaration mapping in to_bogus to add a
CSS_BOGUS_DECLARATION arm, preserving that declaration-specific bogus node when
converting invalid declarations. Keep the existing CSS_BOGUS handling for other
node kinds and ensure the mapping aligns with the CSS_BOGUS_DECLARATION case
already recognized by is_bogus.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: a1c79adf-12bf-4d05-afce-2469f2bb2edb

📥 Commits

Reviewing files that changed from the base of the PR and between ff31f40 and 3bae583.

⛔ Files ignored due to path filters (10)

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/prettier/scss/math/3945.scss.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/error/at_rule/at_rule_keyframes/at_rule_keyframes.css.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/error/at_rule/at_rule_keyframes/at_rule_keyframes_1.css.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/error/declaration/bogus_declaration_recovery.css.snap is excluded by !**/*.snap and included by **
crates/biome_css_parser/tests/css_test_suite/error/tailwind/when-enabled/plugin-with-invalid-options-2.css.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 **

📒 Files selected for processing (12)

.changeset/bright-animals-sniff.md
.changeset/quick-books-join.md
crates/biome_css_formatter/src/css/any/declaration.rs
crates/biome_css_formatter/src/css/bogus/bogus_declaration.rs
crates/biome_css_formatter/src/css/bogus/mod.rs
crates/biome_css_formatter/src/generated.rs
crates/biome_css_parser/src/syntax/declaration.rs
crates/biome_css_parser/tests/css_test_suite/error/declaration/bogus_declaration_recovery.css
crates/biome_css_syntax/src/lib.rs
crates/biome_service/src/file_handlers/html/parse_embedded_nodes.tests.rs
xtask/codegen/css.ungram
xtask/codegen/src/css_kinds_src.rs

coderabbitai · 2026-08-12T23:49:14Z

        matches!(
            self,
            CSS_BOGUS
+                | CSS_BOGUS_DECLARATION


🗄️ Data Integrity & Integration | 🟠 Major | ⚡ Quick win

Add the declaration mapping to to_bogus.

is_bogus now recognises CSS_BOGUS_DECLARATION, but to_bogus has no AnyCssDeclaration arm. When an invalid declaration uses this conversion path, the match falls through to CSS_BOGUS. The grammar does not include CSS_BOGUS in AnyCssDeclaration, so the declaration-specific node cannot be preserved.

Proposed mapping

match self { + kind if AnyCssDeclaration::can_cast(*kind) => CSS_BOGUS_DECLARATION, kind if AnyCssSubSelector::can_cast(*kind) => CSS_BOGUS_SUB_SELECTOR,

Based on learnings, invalid parser syntax uses or_invalid_to_bogus() and must preserve the matching bogus node kind.

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change

| CSS_BOGUS_DECLARATION

match self {

kind if AnyCssDeclaration::can_cast(*kind) => CSS_BOGUS_DECLARATION,

kind if AnyCssSubSelector::can_cast(*kind) => CSS_BOGUS_SUB_SELECTOR,

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@crates/biome_css_syntax/src/lib.rs` at line 110, Update the AnyCssDeclaration mapping in to_bogus to add a CSS_BOGUS_DECLARATION arm, preserving that declaration-specific bogus node when converting invalid declarations. Keep the existing CSS_BOGUS handling for other node kinds and ensure the mapping aligns with the CSS_BOGUS_DECLARATION case already recognized by is_bogus.

Source: Learnings

github-actions Bot added A-Project Area: project A-Parser Area: parser A-Formatter Area: formatter A-Tooling Area: internal tools L-CSS Language: CSS and super languages labels Aug 12, 2026

fix(parse/css): handle bogus declarations slightly more gracefully

3bae583

dyc3 force-pushed the dyc3/css-parse-declaration-bogus branch from 57f110a to 3bae583 Compare August 12, 2026 23:32

dyc3 marked this pull request as ready for review August 12, 2026 23:42

coderabbitai Bot reviewed Aug 12, 2026

View reviewed changes

ematipico approved these changes Aug 13, 2026

View reviewed changes

dyc3 merged commit 41386f3 into main Aug 13, 2026
34 checks passed

dyc3 deleted the dyc3/css-parse-declaration-bogus branch August 13, 2026 10:05

github-actions Bot mentioned this pull request Aug 13, 2026

ci: release #11309

Merged

This was referenced Aug 19, 2026

🐛 Biome crashes when parsing {let} or {const} in Svelte files #11416

Closed

fix(parse/js): handle incomplete declarations more gracefully #11422

Merged

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fix(parse/css): handle bogus declarations slightly more gracefully - #11321

fix(parse/css): handle bogus declarations slightly more gracefully#11321
dyc3 merged 1 commit into
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-                | CSS_BOGUS_DECLARATION
+        match self {
+            kind if AnyCssDeclaration::can_cast(*kind) => CSS_BOGUS_DECLARATION,
+            kind if AnyCssSubSelector::can_cast(*kind) => CSS_BOGUS_SUB_SELECTOR,

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dyc3 commented Aug 12, 2026

Summary

Test Plan

Docs

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github-actions Bot commented Aug 12, 2026

✅ Organic activity

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github-actions Bot commented Aug 12, 2026

Parser conformance results on

js/262

jsx/babel

markdown/commonmark

symbols/microsoft

ts/babel

ts/microsoft

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Merging this PR will not alter performance

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coderabbitai Bot commented Aug 12, 2026

Walkthrough

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