Fix a variable-assignment bug (#1372)

Closes #1250

Author: nex3

CHANGELOG.md

@@ -1,3 +1,11 @@
+## 1.35.2
+
+* **Potentially breaking bug fix:** Fixed a bug where certain local variable
+  declarations nested within multiple `@if` statements would incorrectly
+  override a global variable. It's unlikely that any real stylesheets were
+  relying on this bug, but if so they can simply add `!global` to the variable
+  declaration to preserve the old behavior.
+
 ## 1.35.1
 
 * Fix a bug where the quiet dependency flag didn't silence warnings in some

lib/src/async_environment.dart

@@ -740,29 +740,27 @@ class AsyncEnvironment {
   /// executes [callback] and returns its result.
   Future<T> scope<T>(Future<T> callback(),
       {bool semiGlobal = false, bool when = true}) async {
+    // We have to track semi-globalness even if `!when` so that
+    //
+    //     div {
+    //       @if ... {
+    //         $x: y;
+    //       }
+    //     }
+    //
+    // doesn't assign to the global scope.
+    semiGlobal = semiGlobal && _inSemiGlobalScope;
+    var wasInSemiGlobalScope = _inSemiGlobalScope;
+    _inSemiGlobalScope = semiGlobal;
+
     if (!when) {
-      // We still have to track semi-globalness so that
-      //
-      //     div {
-      //       @if ... {
-      //         $x: y;
-      //       }
-      //     }
-      //
-      // doesn't assign to the global scope.
-      var wasInSemiGlobalScope = _inSemiGlobalScope;
-      _inSemiGlobalScope = semiGlobal;
       try {
         return await callback();
       } finally {
         _inSemiGlobalScope = wasInSemiGlobalScope;
       }
     }
 
-    semiGlobal = semiGlobal && _inSemiGlobalScope;
-    var wasInSemiGlobalScope = _inSemiGlobalScope;
-    _inSemiGlobalScope = semiGlobal;
-
     _variables.add({});
     _variableNodes.add({});
     _functions.add({});

lib/src/environment.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_environment.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: d5a12dbc383245a91d1e2fee0e2c4aa38939a3d8
+// Checksum: 6e5ee671e0a6e5b1d6ac87beb6aeee1e4b155d74
 //
 // ignore_for_file: unused_import
 
@@ -746,29 +746,27 @@ class Environment {
   /// If [when] is false, this doesn't create a new scope and instead just
   /// executes [callback] and returns its result.
   T scope<T>(T callback(), {bool semiGlobal = false, bool when = true}) {
+    // We have to track semi-globalness even if `!when` so that
+    //
+    //     div {
+    //       @if ... {
+    //         $x: y;
+    //       }
+    //     }
+    //
+    // doesn't assign to the global scope.
+    semiGlobal = semiGlobal && _inSemiGlobalScope;
+    var wasInSemiGlobalScope = _inSemiGlobalScope;
+    _inSemiGlobalScope = semiGlobal;
+
     if (!when) {
-      // We still have to track semi-globalness so that
-      //
-      //     div {
-      //       @if ... {
-      //         $x: y;
-      //       }
-      //     }
-      //
-      // doesn't assign to the global scope.
-      var wasInSemiGlobalScope = _inSemiGlobalScope;
-      _inSemiGlobalScope = semiGlobal;
       try {
         return callback();
       } finally {
         _inSemiGlobalScope = wasInSemiGlobalScope;
       }
     }
 
-    semiGlobal = semiGlobal && _inSemiGlobalScope;
-    var wasInSemiGlobalScope = _inSemiGlobalScope;
-    _inSemiGlobalScope = semiGlobal;
-
     _variables.add({});
     _variableNodes.add({});
     _functions.add({});

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.35.1
+version: 1.35.2-dev
 description: A Sass implementation in Dart.
 author: Sass Team
 homepage: https://github.com/sass/dart-sass