feat(parser): report spec parse errors via recoverable_errors

crates/oxc_css_parser/src/error.rs

@@ -90,6 +90,19 @@ pub enum ErrorKind {
     UnexpectedLessMixinCall,
     UnexpectedSimpleBlock,
     TopLevelDeclaration,
+
+    // Spec parse errors that CSS Syntax recovers from at EOF / newline. The AST
+    // and recovery stay conformant; these are recorded in `recoverable_errors()`
+    // so downstream consumers can tell recovered-from-broken input apart from
+    // valid CSS. See <https://drafts.csswg.org/css-syntax-3/>.
+    /// A `{}`-block left open at end of file (§5.4.4); `UnterminatedString`
+    /// (already defined) covers the EOF-terminated string (§4.3.5).
+    EofInBlock,
+    /// A string terminated by a newline instead of its quote — a
+    /// `<bad-string-token>` (§4.3.5).
+    BadString,
+    /// A `(`/`[` group left open at end of file.
+    UnclosedParen,
 }
 
 impl Display for ErrorKind {
@@ -203,6 +216,10 @@ impl Display for ErrorKind {
             Self::UnexpectedLessMixinCall => write!(f, "Less mixin call is disallowed"),
             Self::UnexpectedSimpleBlock => write!(f, "simple block is disallowed"),
             Self::TopLevelDeclaration => write!(f, "declaration at top level is disallowed"),
+
+            Self::EofInBlock => write!(f, "unclosed block before end of file"),
+            Self::BadString => write!(f, "unterminated string before line break"),
+            Self::UnclosedParen => write!(f, "unclosed parenthesis before end of file"),
         }
     }
 }

crates/oxc_css_parser/src/parser/stmt.rs

@@ -315,9 +315,14 @@ impl<'a> Parse<'a> for SimpleBlock<'a> {
 
         // CSS Syntax: EOF closes all open constructs (a parse error, but the
         // tree is valid — browsers accept unclosed blocks at EOF). The
-        // dialects' reference compilers reject them.
+        // dialects' reference compilers reject them. Recovery is unchanged; the
+        // parse error is surfaced via `recoverable_errors` so downstream
+        // consumers can tell it apart from a properly closed block.
         if input.syntax == Syntax::Css && matches!(input.cursor.peek()?.token, Token::Eof(..)) {
             let end = input.cursor.peek()?.span.start;
+            input
+                .recoverable_errors
+                .push(Error { kind: ErrorKind::EofInBlock, span: Span { start, end: start + 1 } });
             return Ok(SimpleBlock { statements, span: Span { start, end } });
         }
 
@@ -367,15 +372,49 @@ impl<'a> Parser<'a> {
     ) -> PResult<oxc_allocator::Vec<'a, ComponentValue<'a>>> {
         let mut values = self.vec_with_capacity(3);
         let mut pairs = Vec::with_capacity(1);
+        // Span of the outermost currently-open pair (kept in sync with `pairs`
+        // going empty↔non-empty), so the EOF parse error can point at the
+        // opener like `SimpleBlock` does, not at the end of file.
+        let mut outermost_pair_span: Option<Span> = None;
         loop {
             match &self.cursor.peek()?.token {
-                Token::Dedent(..) | Token::Linebreak(..) | Token::Eof(..) => break,
+                Token::Dedent(..) | Token::Linebreak(..) => break,
+                // CSS Syntax: EOF closes any still-open `(`/`[`/`{` group; recovery
+                // is unchanged, but record the parse error so downstream consumers
+                // can tell it apart from a balanced value. Report the outermost
+                // unclosed opener; a raw-value `{` (e.g. `--x: {` — legal in custom
+                // properties) is a block, not a paren.
+                Token::Eof(..) => {
+                    if let (Some(pair), Some(span)) = (pairs.first(), outermost_pair_span) {
+                        let kind = match pair {
+                            crate::util::PairedToken::Brace => ErrorKind::EofInBlock,
+                            _ => ErrorKind::UnclosedParen,
+                        };
+                        self.recoverable_errors.push(Error { kind, span });
+                    }
+                    break;
+                }
                 Token::Semicolon(..) if pairs.is_empty() => {
                     break;
                 }
                 Token::LBrace(..) if stop_at_top_level_brace && pairs.is_empty() => {
                     break;
                 }
+                // An unterminated string survives as a preserved token (a parse
+                // error kept verbatim; CSS Syntax §4.3.5). The tokenizer emits a
+                // `BadStr` for both recoverable forms; recover the spec's split
+                // from where the string stopped — at EOF it is a `<string-token>`
+                // (canonically closable by appending the quote), at a newline a
+                // `<bad-string-token>`.
+                Token::BadStr(..) => {
+                    let span = self.cursor.peek()?.span.clone();
+                    let kind = if span.end == self.source.len() {
+                        ErrorKind::UnterminatedString
+                    } else {
+                        ErrorKind::BadString
+                    };
+                    self.recoverable_errors.push(Error { kind, span });
+                }
                 // An interpolated string (e.g. `'#{$expr}'` inside
                 // `filter: progid:...`) must be parsed structurally:
                 // the tokenizer needs `scan_string_template` to resume
@@ -386,9 +425,13 @@ impl<'a> Parser<'a> {
                     continue;
                 }
                 token => {
+                    let was_empty = pairs.is_empty();
                     if !crate::util::track_paired_token(token, &mut pairs) {
                         break;
                     }
+                    if was_empty && !pairs.is_empty() {
+                        outermost_pair_span = Some(self.cursor.peek()?.span.clone());
+                    }
                 }
             }
             values.push(ComponentValue::TokenWithSpan(self.cursor.bump()?));

crates/oxc_css_parser/tests/recoverable/eof/bad-string-newline.css.error.snap

@@ -0,0 +1,8 @@
+---
+source: crates/oxc_css_parser/tests/recoverable.rs
+---
+error: unterminated string before line break
+  ┌─ bad-string-newline.css:2:12
+  │
+2 │   content: "
+  │            ^

crates/oxc_css_parser/tests/recoverable/eof/unclosed-at-rule-block.css.error.snap

@@ -0,0 +1,8 @@
+---
+source: crates/oxc_css_parser/tests/recoverable.rs
+---
+error: unclosed block before end of file
+  ┌─ unclosed-at-rule-block.css:1:27
+  │
+1 │ @media (min-width: 500px) {
+  │                           ^

crates/oxc_css_parser/tests/recoverable/eof/unclosed-block.css.error.snap

@@ -0,0 +1,8 @@
+---
+source: crates/oxc_css_parser/tests/recoverable.rs
+---
+error: unclosed block before end of file
+  ┌─ unclosed-block.css:1:5
+  │
+1 │ div {
+  │     ^

crates/oxc_css_parser/tests/recoverable/eof/unclosed-brace-custom-property.css

@@ -0,0 +1,2 @@
+a {
+  --x: ({

crates/oxc_css_parser/tests/recoverable/eof/unclosed-brace-custom-property.css.error.snap

@@ -0,0 +1,14 @@
+---
+source: crates/oxc_css_parser/tests/recoverable.rs
+---
+error: unclosed parenthesis before end of file
+  ┌─ unclosed-brace-custom-property.css:2:8
+  │
+2 │   --x: ({
+  │        ^
+
+error: unclosed block before end of file
+  ┌─ unclosed-brace-custom-property.css:1:3
+  │
+1 │ a {
+  │   ^

crates/oxc_css_parser/tests/recoverable/eof/unclosed-brace-in-value.css

@@ -0,0 +1,2 @@
+a {
+  --x: {

crates/oxc_css_parser/tests/recoverable/eof/unclosed-brace-in-value.css.error.snap

@@ -0,0 +1,14 @@
+---
+source: crates/oxc_css_parser/tests/recoverable.rs
+---
+error: unclosed block before end of file
+  ┌─ unclosed-brace-in-value.css:2:8
+  │
+2 │   --x: {
+  │        ^
+
+error: unclosed block before end of file
+  ┌─ unclosed-brace-in-value.css:1:3
+  │
+1 │ a {
+  │   ^

crates/oxc_css_parser/tests/recoverable/eof/unclosed-paren.css

@@ -0,0 +1,2 @@
+a {
+  width: calc(100% - 10px

crates/oxc_css_parser/tests/recoverable/eof/unclosed-paren.css.error.snap

@@ -0,0 +1,14 @@
+---
+source: crates/oxc_css_parser/tests/recoverable.rs
+---
+error: unclosed parenthesis before end of file
+  ┌─ unclosed-paren.css:2:14
+  │
+2 │   width: calc(100% - 10px
+  │              ^
+
+error: unclosed block before end of file
+  ┌─ unclosed-paren.css:1:3
+  │
+1 │ a {
+  │   ^

crates/oxc_css_parser/tests/recoverable/eof/unterminated-string-eof.css

@@ -0,0 +1,2 @@
+a {
+  content: "abc

crates/oxc_css_parser/tests/recoverable/eof/unterminated-string-eof.css.error.snap

@@ -0,0 +1,14 @@
+---
+source: crates/oxc_css_parser/tests/recoverable.rs
+---
+error: unterminated string
+  ┌─ unterminated-string-eof.css:2:12
+  │
+2 │   content: "abc
+  │            ^^^^
+
+error: unclosed block before end of file
+  ┌─ unterminated-string-eof.css:1:3
+  │
+1 │ a {
+  │   ^

tasks/conformance/snapshots/less.js.snap

@@ -1,7 +1,7 @@
 suite: less.js
 sha: 8ae2cc3bfa79f0718ad6fe5f263a1d6819fe9d5c
-files: 459   success: 427   failed: 8   expected: 24
-clean: 427  recovered: 0  hard_error: 8  panic: 0
+files: 459   success: 426   failed: 9   expected: 24
+clean: 426  recovered: 1  hard_error: 8  panic: 0
 
 failures:
 ERROR    packages/test-data/tests-config/debug/all/linenumbers-all.css    expect token `:`, but found `{`
@@ -12,6 +12,7 @@ ERROR    packages/test-data/tests-unit/import/import/invalid-css.less    expect
 ERROR    packages/test-data/tests-unit/property-name-interp/property-name-interp.css    CSS rule is expected
 ERROR    packages/test-data/tests-unit/property-name-interp/property-name-interp.less    expect token `(`, but found `{`
 ERROR    packages/test-data/tests-unit/strings/strings.less    expect token `;`, but found `{`
+RECOVER  packages/test-data/tests-unit/urls/actual.css    unterminated string
 
 expected failures (error tests, correct behavior):
 ERROR    packages/test-data/tests-error/eval/multiple-guards-on-css-selectors.less    expect token `;`, but found `<ident>`

tasks/conformance/snapshots/sass-spec.snap

@@ -1,10 +1,19 @@
 suite: sass-spec
 sha: a2ead9225786d49e91f5cc36755b7713596a2338
-files: 26787   success: 26493   failed: 2   expected: 292
-clean: 26493  recovered: 0  hard_error: 2  panic: 0
+files: 26787   success: 26484   failed: 11   expected: 292
+clean: 26484  recovered: 9  hard_error: 2  panic: 0
 
 failures:
+RECOVER  spec/core_functions/string/unquote.hrx::meaningful_css_characters/output.css    unclosed block before end of file
 ERROR    spec/non_conformant/extend-tests/selector_list.hrx::input.scss    expect token `;`, but found `#{`
+RECOVER  spec/non_conformant/parser/interpolate/27_escaped_double_quotes/01_inline.hrx::output.css    unterminated string before line break
+RECOVER  spec/non_conformant/parser/interpolate/27_escaped_double_quotes/02_variable.hrx::output.css    unterminated string before line break
+RECOVER  spec/non_conformant/parser/interpolate/27_escaped_double_quotes/03_inline_double.hrx::output.css    unterminated string before line break
+RECOVER  spec/non_conformant/parser/interpolate/27_escaped_double_quotes/04_variable_double.hrx::output.css    unterminated string before line break
+RECOVER  spec/non_conformant/parser/interpolate/28_escaped_single_quotes/01_inline.hrx::output.css    unterminated string before line break
+RECOVER  spec/non_conformant/parser/interpolate/28_escaped_single_quotes/02_variable.hrx::output.css    unterminated string before line break
+RECOVER  spec/non_conformant/parser/interpolate/28_escaped_single_quotes/03_inline_double.hrx::output.css    unterminated string before line break
+RECOVER  spec/non_conformant/parser/interpolate/28_escaped_single_quotes/04_variable_double.hrx::output.css    unterminated string before line break
 ERROR    spec/non_conformant/sass/pseudo.hrx::input.sass    CSS rule is expected
 
 expected failures (error tests, correct behavior):

tasks/conformance/snapshots/summary.snap

@@ -7,14 +7,14 @@ css-parsing-tests           0        0       0         0       0      0        0
 wpt                         7        5       0         2       5      0        0      0
 webref                      0        0       0         0       0      0        0      0
 postcss-parser-tests       30       28       2         0      28      1        1      0
-sass-spec               26787    26493       2       292   26493      0        2      0
-less.js                   459      427       8        24     427      0        8      0
+sass-spec               26787    26484      11       292   26484      9        2      0
+less.js                   459      426       9        24     426      1        8      0
 ------------------------------------------------------------------------
-total                   27283    26953      12       318   26953      1       11      0
+total                   27283    26943      22       318   26943     11       11      0
 
 # by syntax
 syntax                  files  success  failed  expected   clean  recov  harderr  panic
-css                     11788    11757       7        24   11757      1        6      0
+css                     11788    11747      17        24   11747     11        6      0
 scss                    14750    14519       1       230   14519      0        1      0
 sass                      439      398       1        40     398      0        1      0
 less                      306      279       3        24     279      0        3      0