Avoid always downcasing file paths on Windows (#1172)

Closes #1169

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 1.30.1
+
+* Properly load files in case-sensitive Windows directories with upper-case
+  names.
+
 ## 1.30.0
 
 * Fix a bug where `@at-root (without: all)` wouldn't properly remove a

lib/src/async_compile.dart

@@ -44,7 +44,7 @@ Future<CompileResult> compileAsync(String path,
       (syntax == null || syntax == Syntax.forPath(path))) {
     importCache ??= AsyncImportCache.none(logger: logger);
     stylesheet = await importCache.importCanonical(
-        FilesystemImporter('.'), p.toUri(p.canonicalize(path)), p.toUri(path));
+        FilesystemImporter('.'), p.toUri(canonicalize(path)), p.toUri(path));
   } else {
     stylesheet = Stylesheet.parse(
         readFile(path), syntax ?? Syntax.forPath(path),

lib/src/compile.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_compile.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: bca3a79dd4a5c3905b07003b123172f3c876d2de
+// Checksum: b2cd6037efa37e300daa45ebed20cb4b61526161
 //
 // ignore_for_file: unused_import
 
@@ -54,7 +54,7 @@ CompileResult compile(String path,
       (syntax == null || syntax == Syntax.forPath(path))) {
     importCache ??= ImportCache.none(logger: logger);
     stylesheet = importCache.importCanonical(
-        FilesystemImporter('.'), p.toUri(p.canonicalize(path)), p.toUri(path));
+        FilesystemImporter('.'), p.toUri(canonicalize(path)), p.toUri(path));
   } else {
     stylesheet = Stylesheet.parse(
         readFile(path), syntax ?? Syntax.forPath(path),

lib/src/executable/watch.dart

@@ -41,8 +41,8 @@ Future<void> watch(ExecutableOptions options, StylesheetGraph graph) async {
   var watcher = _Watcher(options, graph);
   for (var source in options.sourcesToDestinations.keys) {
     var destination = options.sourcesToDestinations[source];
-    graph.addCanonical(FilesystemImporter('.'), p.toUri(p.canonicalize(source)),
-        p.toUri(source),
+    graph.addCanonical(
+        FilesystemImporter('.'), p.toUri(canonicalize(source)), p.toUri(source),
         recanonicalize: false);
     var success = await watcher.compile(source, destination, ifModified: true);
     if (!success && options.stopOnError) {
@@ -188,7 +188,7 @@ class _Watcher {
   }
 
   /// Returns the canonical URL for the stylesheet path [path].
-  Uri _canonicalize(String path) => p.toUri(p.canonicalize(path));
+  Uri _canonicalize(String path) => p.toUri(canonicalize(path));
 
   /// Combine [WatchEvent]s that happen in quick succession.
   ///

lib/src/importer/filesystem.dart

@@ -23,18 +23,13 @@ class FilesystemImporter extends Importer {
   Uri canonicalize(Uri url) {
     if (url.scheme != 'file' && url.scheme != '') return null;
     var resolved = resolveImportPath(p.join(_loadPath, p.fromUri(url)));
-    return resolved == null ? null : p.toUri(p.canonicalize(resolved));
+    return resolved == null ? null : p.toUri(io.canonicalize(resolved));
   }
 
   ImporterResult load(Uri url) {
     var path = p.fromUri(url);
     return ImporterResult(io.readFile(path),
-        sourceMapUrl:
-            // [io.realCasePath] will short-circuit on case-sensitive
-            // filesystems anyway, but we still avoid calling it here so we
-            // don't have to re-parse the URL.
-            io.couldBeCaseInsensitive ? p.toUri(io.realCasePath(path)) : url,
-        syntax: Syntax.forPath(path));
+        sourceMapUrl: url, syntax: Syntax.forPath(path));
   }
 
   DateTime modificationTime(Uri url) => io.modificationTime(p.fromUri(url));

lib/src/io.dart

@@ -17,26 +17,36 @@ export 'io/interface.dart'
 ///
 /// We can't know for sure because different Mac OS systems are configured
 /// differently.
-bool get couldBeCaseInsensitive => isWindows || isMacOS;
+bool get _couldBeCaseInsensitive => isWindows || isMacOS;
+
+/// Returns the canonical form of `path` on disk.
+String canonicalize(String path) => _couldBeCaseInsensitive
+    ? _realCasePath(p.absolute(p.normalize(path)))
+    : p.canonicalize(path);
 
 /// Returns `path` with the case updated to match the path's case on disk.
 ///
 /// This only updates `path`'s basename. It always returns `path` as-is on
-/// operating systems other than Windows or Mac OS, since they almost never uses
+/// operating systems other than Windows or Mac OS, since they almost never use
 /// case-insensitive filesystems.
-String realCasePath(String path) {
+String _realCasePath(String path) {
   // TODO(nweiz): Use an SDK function for this when dart-lang/sdk#35370 and/or
-  // nodejs/node#24942 are fixed.
+  // nodejs/node#24942 are fixed, or at least use FFI functions.
 
-  if (!couldBeCaseInsensitive) return path;
+  if (!_couldBeCaseInsensitive) return path;
 
-  var basename = p.basename(path);
-  var matches = listDir(p.dirname(path))
-      .where((realPath) => equalsIgnoreCase(p.basename(realPath), basename))
+  var realCasePath = p.rootPrefix(path);
+  for (var component in p.split(path.substring(realCasePath.length))) {
+    var matches = listDir(realCasePath)
+        .where((realPath) => equalsIgnoreCase(p.basename(realPath), component))
         .toList();
 
-  // If the file doesn't exist, or if there are multiple options (meaning the
-  // filesystem isn't actually case-insensitive), return `path` as-is.
-  if (matches.length != 1) return path;
-  return matches.first;
+    realCasePath = matches.length != 1
+        // If the file doesn't exist, or if there are multiple options (meaning
+        // the filesystem isn't actually case-insensitive), use `component` as-is.
+        ? p.join(realCasePath, component)
+        : matches[0];
+  }
+
+  return realCasePath;
 }

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.30.0
+version: 1.30.1-dev
 description: A Sass implementation in Dart.
 author: Sass Team
 homepage: https://github.com/sass/dart-sass

test/cli/shared/source_maps.dart

@@ -73,8 +73,8 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
       expect(
           _readJson("out.css.map"),
           containsPair("sources", [
-            p.toUri(p.canonicalize(d.path("dir/other.scss"))).toString(),
-            p.toUri(p.canonicalize(d.path("test.scss"))).toString()
+            p.toUri(canonicalize(d.path("dir/other.scss"))).toString(),
+            p.toUri(canonicalize(d.path("test.scss"))).toString()
           ]));
     });