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fix(parse/css): fix parsing --*: initial; with tailwindDirectives enabled #7852

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Oct 25, 2025
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fix(parse/css): fix parsing --*: initial; with tailwindDirectives enabled #7852

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5 changes: 5 additions & 0 deletions .changeset/itchy-aliens-ask.md
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@@ -0,0 +1,5 @@
---
"@biomejs/biome": patch
---

Fixed #7843: The CSS parser, when `tailwindDirectives` is enabled, correctly parses `--*: initial;`.
37 changes: 27 additions & 10 deletions crates/biome_css_factory/src/generated/node_factory.rs
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7 changes: 7 additions & 0 deletions crates/biome_css_parser/src/lexer/mod.rs
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Expand Up @@ -1011,6 +1011,12 @@ impl<'src> CssLexer<'src> {
&& current == b'-'
&& self.peek_byte() == Some(b'*')
{
// HACK: handle `--*`
if self.prev_byte() == Some(b'-') {
self.advance(1);
return Some(current as char);
}
// otherwise, handle cases like `--color-*`
return None;
Comment on lines +1014 to 1020
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@coderabbitai coderabbitai bot Oct 25, 2025

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⚠️ Potential issue | 🔴 Critical

Don’t swallow the * in --* during ident lexing.

This advances past *, removing it from the token stream. The parser then can’t see *, breaking the new lookaheads (--*: / --color-*:) and the Tailwind-exclusive wrapper that expects *. Let the ident consume -- and stop before * so * remains a separate token.

Fix: remove this special-case entirely and rely on the existing logic (plus the MUL start tweak).

Apply this diff:

-        if self.options.is_tailwind_directives_enabled()
-            && current == b'-'
-            && self.peek_byte() == Some(b'*')
-        {
-            // HACK: handle `--*`
-            if self.prev_byte() == Some(b'-') {
-                self.advance(1);
-                return Some(current as char);
-            }
-            // otherwise, handle cases like `--color-*`
-            return None;
-        }

Committable suggestion skipped: line range outside the PR's diff.

🤖 Prompt for AI Agents 
In crates/biome_css_parser/src/lexer/mod.rs around lines 1014 to 1020, the ident
lexing special-case that checks for prev_byte() == Some(b'-') and calls
advance(1) is swallowing a '*' in sequences like `--*` and `--color-*`; remove
this special-case entirely so the ident consumes `--` but stops before `*`,
allowing the `*` to remain as its own token and preserving downstream lookaheads
(`--*:` / `--color-*:`) and Tailwind wrapper handling; rely on the existing
ident logic (and the existing MUL start tweak) instead of advancing past `*`.

}

Expand Down Expand Up @@ -1305,6 +1311,7 @@ impl<'src> CssLexer<'src> {
// or the third and fourth code points are a valid escape
// return true.
BSL => self.is_valid_escape_at(3),
MUL => true,
_ => false,
}
}
Expand Down
39 changes: 27 additions & 12 deletions crates/biome_css_parser/src/syntax/property/mod.rs
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Expand Up @@ -6,19 +6,21 @@ use crate::parser::CssParser;
use crate::syntax::css_modules::{
composes_not_allowed, expected_classes_list, expected_composes_import_source,
};
use crate::syntax::parse_error::{expected_component_value, expected_identifier};
use crate::syntax::parse_error::{
expected_component_value, expected_identifier, tailwind_disabled,
};
use crate::syntax::{
is_at_any_value, is_at_dashed_identifier, is_at_identifier, is_at_string, parse_any_value,
parse_custom_identifier_with_keywords, parse_dashed_identifier, parse_regular_identifier,
parse_string,
CssSyntaxFeatures, is_at_any_value, is_at_dashed_identifier, is_at_identifier, is_at_string,
parse_any_value, parse_custom_identifier_with_keywords, parse_dashed_identifier,
parse_regular_identifier, parse_string,
};
use biome_css_syntax::CssSyntaxKind::*;
use biome_css_syntax::{CssSyntaxKind, T};
use biome_parser::parse_lists::ParseNodeList;
use biome_parser::parse_recovery::{ParseRecovery, ParseRecoveryTokenSet, RecoveryResult};
use biome_parser::prelude::ParsedSyntax;
use biome_parser::prelude::ParsedSyntax::{Absent, Present};
use biome_parser::{Parser, TokenSet, token_set};
use biome_parser::{Parser, SyntaxFeature, TokenSet, token_set};

#[inline]
pub(crate) fn is_at_any_property(p: &mut CssParser) -> bool {
Expand Down Expand Up @@ -160,7 +162,11 @@ const END_OF_COMPOSES_CLASS_TOKEN_SET: TokenSet<CssSyntaxKind> =
#[inline]
fn is_at_generic_property(p: &mut CssParser) -> bool {
is_at_identifier(p)
&& (p.nth_at(1, T![:]) || (p.nth_at(1, T![-]) && p.nth_at(2, T![*]) && p.nth_at(3, T![:])))
&& (p.nth_at(1, T![:])
// handle --*:
|| (p.nth_at(1, T![*]) && p.nth_at(2, T![:]))
// handle --color-*:
|| (p.nth_at(1, T![-]) && p.nth_at(2, T![*]) && p.nth_at(3, T![:])))
}

#[inline]
Expand All @@ -174,13 +180,22 @@ fn parse_generic_property(p: &mut CssParser) -> ParsedSyntax {
if is_at_dashed_identifier(p) {
let ident = parse_dashed_identifier(p).ok();
if let Some(ident) = ident
&& p.options().is_tailwind_directives_enabled()
&& p.at(T![-])
&& p.at_ts(token_set![T![-], T![*]])
{
let m = ident.precede(p);
p.expect(T![-]);
p.expect(T![*]);
m.complete(p, TW_VALUE_THEME_REFERENCE);
CssSyntaxFeatures::Tailwind
.parse_exclusive_syntax(
p,
|p| {
let m = ident.precede(p);
if p.at(T![-]) {
p.expect(T![-]);
}
p.expect(T![*]);
Present(m.complete(p, TW_VALUE_THEME_REFERENCE))
},
|p, m| tailwind_disabled(p, m.range(p)),
)
.ok();
}
} else {
parse_regular_identifier(p).ok();
Expand Down
5 changes: 5 additions & 0 deletions crates/biome_css_parser/tests/css_test_suite/error/tailwind/when-disabled/custom-theme.css
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/* Negative test for crates/biome_css_parser/tests/css_test_suite/ok/tailwind/theme/custom-theme.css */

.reset {
--*: initial;
}
126 changes: 126 additions & 0 deletions .../biome_css_parser/tests/css_test_suite/error/tailwind/when-disabled/custom-theme.css.snap
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---
source: crates/biome_css_parser/tests/spec_test.rs
expression: snapshot
---
## Input

```css
/* Negative test for crates/biome_css_parser/tests/css_test_suite/ok/tailwind/theme/custom-theme.css */

.reset {
--*: initial;
}

```


## AST

```
CssRoot {
bom_token: missing (optional),
rules: CssRuleList [
CssQualifiedRule {
prelude: CssSelectorList [
CssCompoundSelector {
nesting_selectors: CssNestedSelectorList [],
simple_selector: missing (optional),
sub_selectors: CssSubSelectorList [
CssClassSelector {
dot_token: [email protected] "." [Comments("/* Negative test for ..."), Newline("\n"), Newline("\n")] [],
name: CssCustomIdentifier {
value_token: [email protected] "reset" [] [Whitespace(" ")],
},
},
],
},
],
block: CssDeclarationOrRuleBlock {
l_curly_token: [email protected] "{" [] [],
items: CssDeclarationOrRuleList [
CssDeclarationWithSemicolon {
declaration: CssDeclaration {
property: CssBogusProperty {
items: [
CssBogusSupportsCondition {
items: [
CssDashedIdentifier {
value_token: [email protected] "--" [Newline("\n"), Whitespace("\t")] [],
},
[email protected] "*" [] [],
],
},
[email protected] ":" [] [Whitespace(" ")],
CssGenericComponentValueList [
CssIdentifier {
value_token: [email protected] "initial" [] [],
},
],
],
},
important: missing (optional),
},
semicolon_token: [email protected] ";" [] [],
},
],
r_curly_token: [email protected] "}" [Newline("\n")] [],
},
},
],
eof_token: [email protected] "" [Newline("\n")] [],
}
```

## CST

```
0: [email protected]
0: (empty)
1: [email protected]
0: [email protected]
0: [email protected]
0: [email protected]
0: [email protected]
1: (empty)
2: [email protected]
0: [email protected]
0: [email protected] "." [Comments("/* Negative test for ..."), Newline("\n"), Newline("\n")] []
1: [email protected]
0: [email protected] "reset" [] [Whitespace(" ")]
1: [email protected]
0: [email protected] "{" [] []
1: [email protected]
0: [email protected]
0: [email protected]
0: [email protected]
0: [email protected]
0: [email protected]
0: [email protected] "--" [Newline("\n"), Whitespace("\t")] []
1: [email protected] "*" [] []
1: [email protected] ":" [] [Whitespace(" ")]
2: [email protected]
0: [email protected]
0: [email protected] "initial" [] []
1: (empty)
1: [email protected] ";" [] []
2: [email protected] "}" [Newline("\n")] []
2: [email protected] "" [Newline("\n")] []

```

## Diagnostics

```
custom-theme.css:4:2 parse ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

× Tailwind-specific syntax is disabled.

3 │ .reset {
> 4 │ --*: initial;
│ ^^^
5 │ }
6 │

i Enable `tailwindDirectives` in the css parser options, or remove this if you are not using Tailwind CSS.

```
5 changes: 5 additions & 0 deletions crates/biome_css_parser/tests/css_test_suite/ok/tailwind/theme/custom-theme.css
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/* From tailwind docs: https://tailwindcss.com/docs/theme#using-a-custom-theme */

@theme {
--*: initial;
}
93 changes: 93 additions & 0 deletions crates/biome_css_parser/tests/css_test_suite/ok/tailwind/theme/custom-theme.css.snap
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---
source: crates/biome_css_parser/tests/spec_test.rs
expression: snapshot
---
## Input

```css
/* From tailwind docs: https://tailwindcss.com/docs/theme#using-a-custom-theme */

@theme {
--*: initial;
}

```


## AST

```
CssRoot {
bom_token: missing (optional),
rules: CssRuleList [
CssAtRule {
at_token: [email protected] "@" [Comments("/* From tailwind docs ..."), Newline("\n"), Newline("\n")] [],
rule: TwThemeAtRule {
theme_token: [email protected] "theme" [] [Whitespace(" ")],
name: missing (optional),
block: CssDeclarationOrRuleBlock {
l_curly_token: [email protected] "{" [] [],
items: CssDeclarationOrRuleList [
CssDeclarationWithSemicolon {
declaration: CssDeclaration {
property: CssGenericProperty {
name: TwValueThemeReference {
reference: CssDashedIdentifier {
value_token: [email protected] "--" [Newline("\n"), Whitespace("\t")] [],
},
minus_token: missing (optional),
star_token: [email protected] "*" [] [],
},
colon_token: [email protected] ":" [] [Whitespace(" ")],
value: CssGenericComponentValueList [
CssIdentifier {
value_token: [email protected] "initial" [] [],
},
],
},
important: missing (optional),
},
semicolon_token: [email protected] ";" [] [],
},
],
r_curly_token: [email protected] "}" [Newline("\n")] [],
},
},
},
],
eof_token: [email protected] "" [Newline("\n")] [],
}
```

## CST

```
0: [email protected]
0: (empty)
1: [email protected]
0: [email protected]
0: [email protected] "@" [Comments("/* From tailwind docs ..."), Newline("\n"), Newline("\n")] []
1: [email protected]
0: [email protected] "theme" [] [Whitespace(" ")]
1: (empty)
2: [email protected]
0: [email protected] "{" [] []
1: [email protected]
0: [email protected]
0: [email protected]
0: [email protected]
0: [email protected]
0: [email protected]
0: [email protected] "--" [Newline("\n"), Whitespace("\t")] []
1: (empty)
2: [email protected] "*" [] []
1: [email protected] ":" [] [Whitespace(" ")]
2: [email protected]
0: [email protected]
0: [email protected] "initial" [] []
1: (empty)
1: [email protected] ";" [] []
2: [email protected] "}" [Newline("\n")] []
2: [email protected] "" [Newline("\n")] []

```
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