feat(css_formatter): improve formatting for SCSS parenthesized expressions and include arguments by denbezrukov · Pull Request #10269 · biomejs/biome

denbezrukov · 2026-05-05T20:27:00Z

This PR was created with AI assistance (Codex).

Summary

Improves SCSS formatter output for parenthesized expressions, map/list values, and @include keyword arguments to better match Prettier.

Example output:

$map: (
	key: (
		#d82d2d,
		#666,
	),
	other-key: (
		#52bf4a,
		#fff,
	),
);

@include container(
	$foo: (
		$bar + $baz,
		$qux * 2,
	)
);

$map: (
	very-very-very-very-very-very-very-verylong-key:
		very-very-very-very-very-very-very-verylong-value,
	other-key: other-value,
);

Test Plan

cargo test -p biome_css_formatter

…sions and include arguments

changeset-bot · 2026-05-05T20:27:07Z

⚠️ No Changeset found

Latest commit: 1746f6d

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coderabbitai · 2026-05-05T20:36:28Z

Walkthrough

This PR refactors SCSS formatting logic for parenthesised expressions, binary expressions, and list layouts. It introduces new layout helpers to centralise parenthesised-expression and include-keyword-argument formatting decisions, replaces the scss_map_context function with the ScssMapContext::from_node method, and removes the ScssMapOuterParenthesizedValuePayloadKind enum in favour of separate predicate functions. The changes improve indentation, trailing-comma handling, and expansion logic across parenthesised, list, and map contexts whilst maintaining existing formatting behaviour.

Possibly related PRs

biomejs/biome#10217: Modifies SCSS parenthesised-list and map formatting with changes to ScssListLayout::fmt behaviour for outer-parenthesised value lists.
biomejs/biome#10207: Refactors SCSS parenthesised and map formatting with overlapping changes to parenthesised-value detection and layout helpers.
biomejs/biome#10150: Modifies SCSS include-argument formatting and separator/comment handling for parenthesised expressions and lists.

Suggested labels

A-Formatter, L-CSS

Suggested reviewers

dyc3
ematipico

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: improving SCSS parenthesized expression and include argument formatting.
Description check	✅ Passed	The description clearly relates to the changeset, providing concrete examples of improved formatting and 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.

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Commit unit tests in branch db/scss-formatter-17

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coderabbitai

Actionable comments posted: 2

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

crates/biome_css_formatter/src/utils/scss_list_layout.rs (1)
205-240: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Keep keyword-comment expansion scoped to the direct value list.

scss_include_keyword_argument_owner(...) is ancestor-based, so a nested list inside something like $arg: (key: (a, b)) /* end */ can inherit the outer keyword argument’s dangling comment here and get forced into the include-value layout as well. That leaks outer comment ownership into inner lists that should stay inline.
🤖 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_formatter/src/utils/scss_list_layout.rs` around lines 205 -
240, The issue is that scss_include_keyword_argument_owner is being run against
ancestor parenthesized expressions and can surface an outer keyword argument for
nested lists; in is_include_keyword_list_value_expanded_by_comments restrict the
keyword-argument lookup to the immediate parenthesized wrapper only (use
node.syntax().parent().and_then(ScssParenthesizedExpression::cast) instead of
ancestors().skip(1).find_map(...)) and only call
scss_include_keyword_argument_owner on that immediate parenthesized (or directly
on node.syntax() in the no-parenthesized branch) so dangling-comment ownership
is scoped to the direct value list.

🧹 Nitpick comments (1)

crates/biome_css_formatter/src/utils/scss_include_keyword_value.rs (1)

27-36: 💤 Low value

descendants() walk with per-node scss_include_keyword_argument_owner calls is O(n·d) — acceptable for typical SCSS.

No action needed; just flagging it as a future hot-spot if people start writing deeply nested SCSS maps.

🤖 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_formatter/src/utils/scss_include_keyword_value.rs` around
lines 27 - 36, No code change required for correctness, but annotate the
potential O(n·d) hotspot: add a brief comment near the traversal in
scss_include_keyword_value (the block using
value.syntax().descendants().filter_map(ScssParenthesizedExpression::cast).any(...))
noting that repeated calls to scss_include_keyword_argument_owner for each
descendant can become O(n·d) on deeply nested SCSS maps and may need
optimization later (e.g., caching owner lookups or switching to a single
traversal that computes owners and nesting with
is_nested_in_keyword_parentheses).

🤖 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`:
- Around line 19-24: You removed ScssMapOuterParenthesizedValuePayloadKind and
scss_map_context from the pub use list in lib.rs which is semver-breaking for
published crates; either restore those two exports (re-add
ScssMapOuterParenthesizedValuePayloadKind and scss_map_context to the pub use
block that contains ScssMapContext, ScssMapPositionKind, ScssMapRole, etc.) so
existing downstream users keep compatibility, or if the removal is intentional,
update the crate version (major/minor as appropriate) and add a changelog entry
noting the removal before publishing.

In `@crates/biome_css_syntax/src/scss_ext/map.rs`:
- Around line 54-85: Add runnable doctest examples to the doc comments for the
map-shape classifier functions (e.g., is_scss_map_outer_parenthesized_value_map
and is_scss_map_outer_parenthesized_value_list and the similar functions around
the other map helpers) by replacing or augmenting the prose examples with Rust
doc code blocks (/// ```rust ... ``` ) that construct minimal Scss AST nodes (or
call existing test helpers) and assert the expected boolean result; ensure the
examples compile by importing or referencing any helper constructors in the
doctest prelude (or use fully-qualified paths) and keep the examples focused
(one assertion per example) so they run as doctests during cargo test.

---

Outside diff comments:
In `@crates/biome_css_formatter/src/utils/scss_list_layout.rs`:
- Around line 205-240: The issue is that scss_include_keyword_argument_owner is
being run against ancestor parenthesized expressions and can surface an outer
keyword argument for nested lists; in
is_include_keyword_list_value_expanded_by_comments restrict the keyword-argument
lookup to the immediate parenthesized wrapper only (use
node.syntax().parent().and_then(ScssParenthesizedExpression::cast) instead of
ancestors().skip(1).find_map(...)) and only call
scss_include_keyword_argument_owner on that immediate parenthesized (or directly
on node.syntax() in the no-parenthesized branch) so dangling-comment ownership
is scoped to the direct value list.

---

Nitpick comments:
In `@crates/biome_css_formatter/src/utils/scss_include_keyword_value.rs`:
- Around line 27-36: No code change required for correctness, but annotate the
potential O(n·d) hotspot: add a brief comment near the traversal in
scss_include_keyword_value (the block using
value.syntax().descendants().filter_map(ScssParenthesizedExpression::cast).any(...))
noting that repeated calls to scss_include_keyword_argument_owner for each
descendant can become O(n·d) on deeply nested SCSS maps and may need
optimization later (e.g., caching owner lookups or switching to a single
traversal that computes owners and nesting with
is_nested_in_keyword_parentheses).

🪄 Autofix (Beta)

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

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Review profile: CHILL

Plan: Pro

Run ID: a5f921f4-3c01-4f75-8710-2919e750b88e

📥 Commits

Reviewing files that changed from the base of the PR and between 3bd2b6a and 1746f6d.

⛔ Files ignored due to path filters (2)

crates/biome_css_formatter/tests/specs/prettier/scss/math/7419.scss.snap is excluded by !**/*.snap and included by **
crates/biome_css_formatter/tests/specs/scss/at-rule/include-arguments.scss.snap is excluded by !**/*.snap and included by **

📒 Files selected for processing (12)

crates/biome_css_formatter/src/scss/auxiliary/binary_expression.rs
crates/biome_css_formatter/src/scss/auxiliary/parenthesized_expression.rs
crates/biome_css_formatter/src/utils/mod.rs
crates/biome_css_formatter/src/utils/scss_control_condition.rs
crates/biome_css_formatter/src/utils/scss_include_keyword_value.rs
crates/biome_css_formatter/src/utils/scss_keyword_argument_layout.rs
crates/biome_css_formatter/src/utils/scss_list_layout.rs
crates/biome_css_formatter/src/utils/scss_separator_comments.rs
crates/biome_css_formatter/tests/specs/scss/at-rule/include-arguments.scss
crates/biome_css_syntax/src/lib.rs
crates/biome_css_syntax/src/scss_ext/map.rs
crates/biome_css_syntax/src/scss_ext/mod.rs

codspeed · 2026-05-05T20:37:43Z

Merging this PR will not alter performance

✅ 29 untouched benchmarks
⏩ 227 skipped benchmarks¹

_{Comparing db/scss-formatter-17 (1746f6d) with main (c5d7d89)}

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. ↩

feat(css_formatter): improve formatting for SCSS parenthesized expres…

1746f6d

…sions and include arguments

github-actions Bot added A-Parser Area: parser A-Formatter Area: formatter L-CSS Language: CSS and super languages labels May 5, 2026

coderabbitai Bot reviewed May 5, 2026

View reviewed changes

Comment thread crates/biome_css_syntax/src/lib.rs

Comment thread crates/biome_css_syntax/src/scss_ext/map.rs

denbezrukov merged commit ab4fa00 into main May 6, 2026
27 of 28 checks passed

denbezrukov deleted the db/scss-formatter-17 branch May 6, 2026 06:53

coderabbitai Bot mentioned this pull request May 10, 2026

feat(css_parser): support for SCSS @include ... using clauses #10327

Merged

coderabbitai Bot mentioned this pull request May 18, 2026

feat(css_formatter): preserve source-tight scss binary edges #10413

Merged

This was referenced Jun 2, 2026

fix(css_formatter): add spacing SCSS binary expressions #10537

Merged

feat(css_formatter): keep SCSS scalar parentheses inline #10599

Merged

coderabbitai Bot mentioned this pull request Jul 23, 2026

fix(css_formatter): indent commented SCSS function arguments #11043

Merged

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feat(css_formatter): improve formatting for SCSS parenthesized expressions and include arguments - #10269

feat(css_formatter): improve formatting for SCSS parenthesized expressions and include arguments#10269
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denbezrukov commented May 5, 2026

Summary

Test Plan

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changeset-bot Bot commented May 5, 2026

⚠️ No Changeset found

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coderabbitai Bot commented May 5, 2026

Walkthrough

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codspeed Bot commented May 5, 2026

Merging this PR will not alter performance

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