Fix a crash when writing @extend without a selector (#2499)

Closes #2497

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 1.83.5-dev
+
+* Fix the error message for `@extend` without a selector and possibly other
+  parsing edge-cases in contexts that allow interpolation..
+
 ## 1.83.4
 
 * No user-visible changes.

lib/src/interpolation_map.dart

@@ -46,6 +46,11 @@ final class InterpolationMap {
     var target = error.span;
     if (target == null) return error;
 
+    if (_interpolation.contents.isEmpty) {
+      return SourceSpanFormatException(
+          error.message, _interpolation.span, error.source);
+    }
+
     var source = mapSpan(target);
     var startIndex = _indexInContents(target.start);
     var endIndex = _indexInContents(target.end);
@@ -83,6 +88,8 @@ final class InterpolationMap {
   /// generated from interpolation, this will return the full [FileSpan] for
   /// that interpolated expression.
   Object /* FileLocation|FileSpan */ _mapLocation(SourceLocation target) {
+    if (_interpolation.contents.isEmpty) return _interpolation.span;
+
     var index = _indexInContents(target);
     if (_interpolation.contents[index] case Expression chunk) {
       return chunk.span;

pkg/sass-parser/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.4.13-dev
+
+* No user-visible changes.
+
 ## 0.4.12
 
 * Fix more bugs in the automated release process.

pkg/sass-parser/package.json

@@ -1,6 +1,6 @@
 {
   "name": "sass-parser",
-  "version": "0.4.12",
+  "version": "0.4.13-dev",
   "description": "A PostCSS-compatible wrapper of the official Sass parser",
   "repository": "sass/sass",
   "author": "Google Inc.",

pkg/sass_api/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 15.0.5-dev
+
+* No user-visible changes.
+
 ## 15.0.4
 
 * No user-visible changes.

pkg/sass_api/pubspec.yaml

@@ -2,15 +2,15 @@ name: sass_api
 # Note: Every time we add a new Sass AST node, we need to bump the *major*
 # version because it's a breaking change for anyone who's implementing the
 # visitor interface(s).
-version: 15.0.4
+version: 15.0.5-dev
 description: Additional APIs for Dart Sass.
 homepage: https://github.com/sass/dart-sass
 
 environment:
   sdk: ">=3.3.0 <4.0.0"
 
 dependencies:
-  sass: 1.83.4
+  sass: 1.83.5
 
 dev_dependencies:
   dartdoc: ^8.0.14

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.83.4
+version: 1.83.5-dev
 description: A Sass implementation in Dart.
 homepage: https://github.com/sass/dart-sass