Don't trim escaped whitespace (#523)

Related to sass/ruby-sass#96

Author: nex3

CHANGELOG.md

@@ -10,6 +10,8 @@
   command-line interface, Dart API, and JS API. These load paths are checked
   just after the load paths explicitly passed by the user.
 
+* Properly compile selectors that end in escaped whitespace.
+
 [content-args]: https://github.com/sass/language/blob/master/accepted/content-args.md
 [at-rule-interpolation]: https://github.com/sass/language/blob/master/accepted/at-rule-interpolation.md
 

lib/src/utils.dart

@@ -48,11 +48,15 @@ int countOccurrences(String string, int codeUnit) {
 }
 
 /// Like [String.trim], but only trims ASCII whitespace.
-String trimAscii(String string) {
+///
+/// If [excludeEscape] is `true`, this doesn't trim whitespace included in a CSS
+/// escape.
+String trimAscii(String string, {bool excludeEscape: false}) {
   var start = _firstNonWhitespace(string);
   return start == null
       ? ""
-      : string.substring(start, _lastNonWhitespace(string) + 1);
+      : string.substring(
+          start, _lastNonWhitespace(string, excludeEscape: excludeEscape) + 1);
 }
 
 /// Like [String.trimLeft], but only trims ASCII whitespace.
@@ -62,13 +66,16 @@ String trimAsciiLeft(String string) {
 }
 
 /// Like [String.trimRight], but only trims ASCII whitespace.
-String trimAsciiRight(String string) {
-  var end = _lastNonWhitespace(string);
+///
+/// If [excludeEscape] is `true`, this doesn't trim whitespace included in a CSS
+/// escape.
+String trimAsciiRight(String string, {bool excludeEscape: false}) {
+  var end = _lastNonWhitespace(string, excludeEscape: excludeEscape);
   return end == null ? "" : string.substring(0, end + 1);
 }
 
 /// Returns the index of the first character in [string] that's not ASCII
-/// whitepsace, or [null] if [string] is entirely spaces.
+/// whitespace, or [null] if [string] is entirely spaces.
 int _firstNonWhitespace(String string) {
   for (var i = 0; i < string.length; i++) {
     if (!isWhitespace(string.codeUnitAt(i))) return i;
@@ -78,9 +85,22 @@ int _firstNonWhitespace(String string) {
 
 /// Returns the index of the last character in [string] that's not ASCII
 /// whitespace, or [null] if [string] is entirely spaces.
-int _lastNonWhitespace(String string) {
+///
+/// If [excludeEscape] is `true`, this doesn't move past whitespace that's
+/// included in a CSS escape.
+int _lastNonWhitespace(String string, {bool excludeEscape: false}) {
   for (var i = string.length - 1; i >= 0; i--) {
-    if (!isWhitespace(string.codeUnitAt(i))) return i;
+    var codeUnit = string.codeUnitAt(i);
+    if (!isWhitespace(codeUnit)) {
+      if (excludeEscape &&
+          i != 0 &&
+          i != string.length &&
+          codeUnit == $backslash) {
+        return i + 1;
+      } else {
+        return i;
+      }
+    }
   }
   return null;
 }

lib/src/visitor/async_evaluate.dart

@@ -584,8 +584,10 @@ class _EvaluateVisitor
 
     var list = _adjustParseError(
         targetText.span,
-        () => new SelectorList.parse(targetText.value.trim(),
-            logger: _logger, allowParent: false));
+        () => new SelectorList.parse(
+            trimAscii(targetText.value, excludeEscape: true),
+            logger: _logger,
+            allowParent: false));
 
     for (var complex in list.components) {
       if (complex.components.length != 1 ||
@@ -1687,7 +1689,8 @@ class _EvaluateVisitor
       {bool trim: false, bool warnForColor: false}) async {
     var result =
         await _performInterpolation(interpolation, warnForColor: warnForColor);
-    return new CssValue(trim ? result.trim() : result, interpolation.span);
+    return new CssValue(trim ? trimAscii(result, excludeEscape: true) : result,
+        interpolation.span);
   }
 
   /// Evaluates [interpolation].

lib/src/visitor/evaluate.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_evaluate.dart.
 // See tool/synchronize.dart for details.
 //
-// Checksum: 0dc10210feef4db5d092a631d32ee93dd5a12907
+// Checksum: abeba8d186777d0dc1eedf9f9d29e4514bcd7619
 
 import 'async_evaluate.dart' show EvaluateResult;
 export 'async_evaluate.dart' show EvaluateResult;
@@ -585,8 +585,10 @@ class _EvaluateVisitor
 
     var list = _adjustParseError(
         targetText.span,
-        () => new SelectorList.parse(targetText.value.trim(),
-            logger: _logger, allowParent: false));
+        () => new SelectorList.parse(
+            trimAscii(targetText.value, excludeEscape: true),
+            logger: _logger,
+            allowParent: false));
 
     for (var complex in list.components) {
       if (complex.components.length != 1 ||
@@ -1664,7 +1666,8 @@ class _EvaluateVisitor
       {bool trim: false, bool warnForColor: false}) {
     var result =
         _performInterpolation(interpolation, warnForColor: warnForColor);
-    return new CssValue(trim ? result.trim() : result, interpolation.span);
+    return new CssValue(trim ? trimAscii(result, excludeEscape: true) : result,
+        interpolation.span);
   }
 
   /// Evaluates [interpolation].

lib/src/visitor/serialize.dart

@@ -15,6 +15,7 @@ import '../ast/node.dart';
 import '../ast/selector.dart';
 import '../color_names.dart';
 import '../exception.dart';
+import '../utils.dart';
 import '../util/character.dart';
 import '../util/no_source_map_buffer.dart';
 import '../util/number.dart';
@@ -396,7 +397,7 @@ class _SerializeVisitor implements CssVisitor, ValueVisitor, SelectorVisitor {
       _buffer.write(value);
       return;
     } else if (minimumIndentation == -1) {
-      _buffer.write(value.trimRight());
+      _buffer.write(trimAsciiRight(value, excludeEscape: true));
       _buffer.writeCharCode($space);
       return;
     }