From 76cfd6b331be205497935a94e922b2eac26b5394 Mon Sep 17 00:00:00 2001
From: Natalie Weizenbaum <nweiz@google.com>
Date: Fri, 18 Oct 2024 23:32:45 +0000
Subject: [PATCH] Fix `@import url("...")` in plain CSS (#2398)

Closes #2397
---
 CHANGELOG.md           |  2 ++
 lib/src/parse/css.dart | 31 +++++++++++++++++++++++++++----
 pubspec.yaml           |  2 +-
 3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3b93fabaa..ab6796d6b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## 1.80.3
 
+* Fix a bug where `@import url("...")` would crash in plain CSS files.
+
 * Improve consistency of how warnings are emitted by different parts of the
   compiler. This should result in minimal user-visible changes, but different
   types of warnings should now respond more reliably to flags like `--quiet`,
diff --git a/lib/src/parse/css.dart b/lib/src/parse/css.dart
index 050d031ba..4fd9ae2df 100644
--- a/lib/src/parse/css.dart
+++ b/lib/src/parse/css.dart
@@ -7,6 +7,7 @@ import 'package:string_scanner/string_scanner.dart';
 
 import '../ast/sass.dart';
 import '../functions.dart';
+import '../interpolation_buffer.dart';
 import 'scss.dart';
 
 /// The set of all function names disallowed in plain CSS.
@@ -86,16 +87,38 @@ class CssParser extends ScssParser {
   ImportRule _cssImportRule(LineScannerState start) {
     var urlStart = scanner.state;
     var url = switch (scanner.peekChar()) {
-      $u || $U => dynamicUrl() as StringExpression,
+      $u || $U => switch (dynamicUrl()) {
+          StringExpression string => string.text,
+          InterpolatedFunctionExpression(
+            :var name,
+            arguments: ArgumentInvocation(
+              positional: [StringExpression string],
+              named: Map(isEmpty: true),
+              rest: null,
+              keywordRest: null,
+            ),
+            :var span
+          ) =>
+            (InterpolationBuffer()
+                  ..addInterpolation(name)
+                  ..writeCharCode($lparen)
+                  ..addInterpolation(string.asInterpolation())
+                  ..writeCharCode($rparen))
+                .interpolation(span),
+          // This shouldn't be reachable.
+          var expression =>
+            error("Unsupported plain CSS import.", expression.span)
+        },
       _ => StringExpression(interpolatedString().asInterpolation(static: true))
+          .text
     };
 
     whitespace();
     var modifiers = tryImportModifiers();
     expectStatementSeparator("@import rule");
-    return ImportRule([
-      StaticImport(url.text, scanner.spanFrom(urlStart), modifiers: modifiers)
-    ], scanner.spanFrom(start));
+    return ImportRule(
+        [StaticImport(url, scanner.spanFrom(urlStart), modifiers: modifiers)],
+        scanner.spanFrom(start));
   }
 
   ParenthesizedExpression parentheses() {
diff --git a/pubspec.yaml b/pubspec.yaml
index e63fe63e1..d3ed7ffac 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: sass
-version: 1.80.3-dev
+version: 1.80.3
 description: A Sass implementation in Dart.
 homepage: https://github.com/sass/dart-sass