Revert "Use platform appropriate filepaths" (#47395)

packages/flutter_tools/lib/src/build_system/targets/assets.dart

@@ -34,7 +34,7 @@ Future<Depfile> copyAssets(Environment environment, Directory outputDirectory) a
     assetBundle.entries.entries.map<Future<void>>((MapEntry<String, DevFSContent> entry) async {
       final PoolResource resource = await pool.request();
       try {
-        final File file = fs.file(outputDirectory.uri.resolve(entry.key));
+        final File file = fs.file(fs.path.join(outputDirectory.path, entry.key));
         outputs.add(file);
         file.parent.createSync(recursive: true);
         final DevFSContent content = entry.value;

packages/flutter_tools/lib/src/bundle.dart

@@ -195,7 +195,7 @@ Future<void> writeBundle(
     assetEntries.entries.map<Future<void>>((MapEntry<String, DevFSContent> entry) async {
       final PoolResource resource = await pool.request();
       try {
-        final File file = fs.file(bundleDir.uri.resolve(entry.key));
+        final File file = fs.file(fs.path.join(bundleDir.path, entry.key));
         file.parent.createSync(recursive: true);
         await file.writeAsBytes(await entry.value.contentsAsBytes());
       } finally {

packages/flutter_tools/test/general.shard/build_system/targets/assets_test.dart

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:io';
+
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/build_system/targets/assets.dart';
@@ -25,6 +27,8 @@ void main() {
         ..createSync(recursive: true);
       fs.file(fs.path.join('assets', 'foo', 'bar.png'))
         ..createSync(recursive: true);
+      fs.file(fs.path.join('assets', 'wildcard', '#bar.png'))
+        ..createSync(recursive: true);
       fs.file('.packages')
         ..createSync();
       fs.file('pubspec.yaml')
@@ -35,6 +39,7 @@ name: example
 flutter:
   assets:
     - assets/foo/bar.png
+    - assets/wildcard/
 ''');
     });
   });
@@ -45,14 +50,16 @@ flutter:
     expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'AssetManifest.json')).existsSync(), true);
     expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'FontManifest.json')).existsSync(), true);
     expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'LICENSE')).existsSync(), true);
-    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets', 'foo', 'bar.png')).existsSync(), true);
+    // See https://github.com/flutter/flutter/issues/35293
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), true);
+    // See https://github.com/flutter/flutter/issues/46163
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/wildcard/%23bar.png')).existsSync(), true);
   }));
 
   test('Does not leave stale files in build directory', () => testbed.run(() async {
     await buildSystem.build(const CopyAssets(), environment);
-    final File assetFile = fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets', 'foo', 'bar.png'));
 
-    expect(assetFile.existsSync(), true);
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), true);
     // Modify manifest to remove asset.
     fs.file('pubspec.yaml')
       ..createSync()
@@ -63,8 +70,9 @@ flutter:
 ''');
     await buildSystem.build(const CopyAssets(), environment);
 
-    expect(assetFile.existsSync(), false);
-  }));
+    // See https://github.com/flutter/flutter/issues/35293
+    expect(fs.file(fs.path.join(environment.buildDir.path, 'flutter_assets', 'assets/foo/bar.png')).existsSync(), false);
+  }), skip: Platform.isWindows); // See https://github.com/google/file.dart/issues/131
 
   test('FlutterPlugins updates required files as needed', () => testbed.run(() async {
     fs.file('pubspec.yaml')