feat: Add a lint for unsupported CSS Module selector (parcel-bundler#784)

Author: kdy1

selectors/parser.rs

@@ -198,6 +198,7 @@ pub enum SelectorParseErrorKind<'i> {
   UnexpectedTokenInAttributeSelector(Token<'i>),
   PseudoElementExpectedIdent(Token<'i>),
   UnsupportedPseudoClassOrElement(CowRcStr<'i>),
+  AmbiguousCssModuleClass(CowRcStr<'i>),
   UnexpectedIdent(CowRcStr<'i>),
   ExpectedNamespace(CowRcStr<'i>),
   ExpectedBarInAttr(Token<'i>),

src/error.rs

@@ -232,6 +232,9 @@ pub enum SelectorError<'i> {
   ),
   /// An unsupported pseudo class or pseudo element was encountered.
   UnsupportedPseudoClassOrElement(CowArcStr<'i>),
+
+  /// Ambiguous CSS module class.
+  AmbiguousCssModuleClass(CowArcStr<'i>),
 }
 
 impl<'i> fmt::Display for SelectorError<'i> {
@@ -257,6 +260,7 @@ impl<'i> fmt::Display for SelectorError<'i> {
       UnexpectedIdent(name) => write!(f, "Unexpected identifier: {}", name),
       UnexpectedTokenInAttributeSelector(token) => write!(f, "Unexpected token in attribute selector: {:?}", token),
       UnsupportedPseudoClassOrElement(name) => write!(f, "Unsupported pseudo class or element: {}", name),
+      AmbiguousCssModuleClass(_) => write!(f, "Ambiguous CSS module class not supported"),
     }
   }
 }
@@ -297,6 +301,7 @@ impl<'i> From<SelectorParseErrorKind<'i>> for SelectorError<'i> {
         SelectorError::ExplicitNamespaceUnexpectedToken(t.into())
       }
       SelectorParseErrorKind::ClassNeedsIdent(t) => SelectorError::ClassNeedsIdent(t.into()),
+      SelectorParseErrorKind::AmbiguousCssModuleClass(name) => SelectorError::AmbiguousCssModuleClass(name.into()),
     }
   }
 }

src/selector.rs

@@ -190,6 +190,10 @@ impl<'a, 'o, 'i> parcel_selectors::parser::Parser<'i> for SelectorParser<'a, 'o,
       "corner-present" => WebKitScrollbar(WebKitScrollbarPseudoClass::CornerPresent),
       "window-inactive" => WebKitScrollbar(WebKitScrollbarPseudoClass::WindowInactive),
 
+      "local" | "global" if self.options.css_modules.is_some() => {
+        return Err(loc.new_custom_error(SelectorParseErrorKind::AmbiguousCssModuleClass(name.clone())))
+      },
+
       _ => {
         if !name.starts_with('-') {
           self.options.warn(loc.new_custom_error(SelectorParseErrorKind::UnsupportedPseudoClassOrElement(name.clone())));

tests/cli_integration_tests.rs

@@ -389,6 +389,37 @@ fn css_modules_pattern() -> Result<(), Box<dyn std::error::Error>> {
   Ok(())
 }
 
+#[test]
+fn css_modules_next_64299() -> Result<(), Box<dyn std::error::Error>> {
+  let file = assert_fs::NamedTempFile::new("test.css")?;
+  file.write_str(
+    "
+  .blue {
+    background: blue;
+
+    :global {
+      .red {
+        background: red;
+      }
+    }
+
+    &:global {
+      &.green {
+        background: green;
+      }
+    }
+  }
+  ",
+  )?;
+
+  let mut cmd = Command::cargo_bin("lightningcss")?;
+  cmd.arg(file.path());
+  cmd.arg("--css-modules");
+  cmd.assert().failure();
+
+  Ok(())
+}
+
 #[test]
 fn sourcemap() -> Result<(), Box<dyn std::error::Error>> {
   let (input, _, _) = css_module_test_vals();