🐛 Normalize generated file paths for the l10n generator (flutter#169467)

Multiple places use non-normalized file paths when generating the
localization files.

The PR normalizes file paths when generating the file list JSON file and
the dependency file.

Fixes flutter#163591

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we expect every widget to implement].
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above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
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Fixes] where supported.
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Author: AlexV525

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

@@ -58,6 +58,7 @@ class GenerateLocalizationsTarget extends Target {
     final LocalizationOptions options = parseLocalizationsOptionsFromYAML(
       file: configFile,
       logger: environment.logger,
+      fileSystem: environment.fileSystem,
       defaultArbDir: defaultArbDir,
       defaultSyntheticPackage: !featureFlags.isExplicitPackageDependenciesEnabled,
     );

packages/flutter_tools/lib/src/commands/generate_localizations.dart

@@ -260,6 +260,7 @@ class GenerateLocalizationsCommand extends FlutterCommand {
       options = parseLocalizationsOptionsFromYAML(
         file: _fileSystem.file('l10n.yaml'),
         logger: _logger,
+        fileSystem: _fileSystem,
         defaultArbDir: defaultArbDir,
         defaultSyntheticPackage: !featureFlags.isExplicitPackageDependenciesEnabled,
       );

packages/flutter_tools/lib/src/localizations/gen_l10n.dart

@@ -1000,6 +1000,14 @@ class LocalizationsGenerator {
     return true;
   }
 
+  void _addToFileList(List<String> fileList, String path) {
+    fileList.add(_fs.path.normalize(path));
+  }
+
+  void _addAllToFileList(List<String> fileList, Iterable<String> paths) {
+    fileList.addAll(paths.map(_fs.path.normalize));
+  }
+
   // Load _allMessages from templateArbFile and _allBundles from all of the ARB
   // files in inputDirectory. Also initialized: supportedLocales.
   void loadResources() {
@@ -1030,7 +1038,8 @@ class LocalizationsGenerator {
             .toList();
     hadErrors = _allMessages.any((Message message) => message.hadErrors);
     if (inputsAndOutputsListFile != null) {
-      _inputFileList.addAll(
+      _addAllToFileList(
+        _inputFileList,
         _allBundles.bundles.map((AppResourceBundle bundle) {
           return bundle.file.absolute.path;
         }),
@@ -1492,7 +1501,7 @@ The plural cases must be one of "=0", "=1", "=2", "zero", "one", "two", "few", "
     // Generate the required files for localizations.
     _languageFileMap.forEach((File file, String contents) {
       file.writeAsStringSync(useCRLF ? contents.replaceAll('\n', '\r\n') : contents);
-      _outputFileList.add(file.absolute.path);
+      _addToFileList(_outputFileList, file.absolute.path);
     });
 
     baseOutputFile.writeAsStringSync(
@@ -1527,7 +1536,7 @@ The plural cases must be one of "=0", "=1", "=2", "zero", "one", "two", "few", "
       );
     }
     final File? inputsAndOutputsListFileLocal = inputsAndOutputsListFile;
-    _outputFileList.add(baseOutputFile.absolute.path);
+    _addToFileList(_outputFileList, baseOutputFile.absolute.path);
     if (inputsAndOutputsListFileLocal != null) {
       // Generate a JSON file containing the inputs and outputs of the gen_l10n script.
       if (!inputsAndOutputsListFileLocal.existsSync()) {
@@ -1548,7 +1557,7 @@ The plural cases must be one of "=0", "=1", "=2", "zero", "one", "two", "few", "
   void _generateUntranslatedMessagesFile(Logger logger, File untranslatedMessagesFile) {
     if (_unimplementedMessages.isEmpty) {
       untranslatedMessagesFile.writeAsStringSync('{}');
-      _outputFileList.add(untranslatedMessagesFile.absolute.path);
+      _addToFileList(_outputFileList, untranslatedMessagesFile.absolute.path);
       return;
     }
 
@@ -1576,6 +1585,6 @@ The plural cases must be one of "=0", "=1", "=2", "zero", "one", "two", "few", "
 
     resultingFile += '}\n';
     untranslatedMessagesFile.writeAsStringSync(resultingFile);
-    _outputFileList.add(untranslatedMessagesFile.absolute.path);
+    _addToFileList(_outputFileList, untranslatedMessagesFile.absolute.path);
   }
 }

packages/flutter_tools/lib/src/localizations/localizations_utils.dart

@@ -479,6 +479,7 @@ class LocalizationOptions {
 LocalizationOptions parseLocalizationsOptionsFromYAML({
   required File file,
   required Logger logger,
+  required FileSystem fileSystem,
   required String defaultArbDir,
   required bool defaultSyntheticPackage,
 }) {
@@ -497,14 +498,24 @@ LocalizationOptions parseLocalizationsOptionsFromYAML({
     throw Exception();
   }
   return LocalizationOptions(
-    arbDir: _tryReadUri(yamlNode, 'arb-dir', logger)?.path ?? defaultArbDir,
-    outputDir: _tryReadUri(yamlNode, 'output-dir', logger)?.path,
-    templateArbFile: _tryReadUri(yamlNode, 'template-arb-file', logger)?.path,
-    outputLocalizationFile: _tryReadUri(yamlNode, 'output-localization-file', logger)?.path,
-    untranslatedMessagesFile: _tryReadUri(yamlNode, 'untranslated-messages-file', logger)?.path,
+    arbDir: _tryReadFilePath(yamlNode, 'arb-dir', logger, fileSystem) ?? defaultArbDir,
+    outputDir: _tryReadFilePath(yamlNode, 'output-dir', logger, fileSystem),
+    templateArbFile: _tryReadFilePath(yamlNode, 'template-arb-file', logger, fileSystem),
+    outputLocalizationFile: _tryReadFilePath(
+      yamlNode,
+      'output-localization-file',
+      logger,
+      fileSystem,
+    ),
+    untranslatedMessagesFile: _tryReadFilePath(
+      yamlNode,
+      'untranslated-messages-file',
+      logger,
+      fileSystem,
+    ),
     outputClass: _tryReadString(yamlNode, 'output-class', logger),
     header: _tryReadString(yamlNode, 'header', logger),
-    headerFile: _tryReadUri(yamlNode, 'header-file', logger)?.path,
+    headerFile: _tryReadFilePath(yamlNode, 'header-file', logger, fileSystem),
     useDeferredLoading: _tryReadBool(yamlNode, 'use-deferred-loading', logger),
     preferredSupportedLocales: _tryReadStringList(yamlNode, 'preferred-supported-locales', logger),
     syntheticPackage:
@@ -596,8 +607,8 @@ List<String>? _tryReadStringList(YamlMap yamlMap, String key, Logger logger) {
   throw Exception();
 }
 
-// Try to read a valid `Uri` or null from `yamlMap`, otherwise throw.
-Uri? _tryReadUri(YamlMap yamlMap, String key, Logger logger) {
+// Try to read a valid file `Uri` or null from `yamlMap` to file path, otherwise throw.
+String? _tryReadFilePath(YamlMap yamlMap, String key, Logger logger, FileSystem fileSystem) {
   final String? value = _tryReadString(yamlMap, key, logger);
   if (value == null) {
     return null;
@@ -606,5 +617,5 @@ Uri? _tryReadUri(YamlMap yamlMap, String key, Logger logger) {
   if (uri == null) {
     logger.printError('"$value" must be a relative file URI');
   }
-  return uri;
+  return uri != null ? fileSystem.path.normalize(uri.path) : null;
 }

packages/flutter_tools/test/commands.shard/hermetic/generate_localizations_test.dart

@@ -7,6 +7,7 @@ import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
+import 'package:flutter_tools/src/build_system/depfile.dart' show Depfile;
 import 'package:flutter_tools/src/build_system/targets/localizations.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/generate_localizations.dart';
@@ -516,6 +517,42 @@ format: true
     },
   );
 
+  testUsingContext('generates normalized input & output file paths', () async {
+    final File arbFile = fileSystem.file(fileSystem.path.join('lib', 'l10n', 'app_en.arb'))
+      ..createSync(recursive: true);
+    arbFile.writeAsStringSync('''
+{
+  "helloWorld": "Hello, World!"
+}''');
+    final File configFile = fileSystem.file('l10n.yaml')..createSync();
+    // Writing both forward and backward slashes to test both cases.
+    configFile.writeAsStringSync(r'''
+arb-dir: lib/l10n
+output-dir: lib\l10n
+format: false
+''');
+    final File pubspecFile = fileSystem.file('pubspec.yaml')..createSync();
+    pubspecFile.writeAsStringSync(BasicProjectWithFlutterGen().pubspec);
+
+    processManager.addCommand(const FakeCommand(command: <String>[]));
+    final Environment environment = Environment.test(
+      fileSystem.currentDirectory,
+      artifacts: artifacts,
+      processManager: processManager,
+      fileSystem: fileSystem,
+      logger: BufferLogger.test(),
+    );
+    const Target buildTarget = GenerateLocalizationsTarget();
+    await buildTarget.build(environment);
+
+    final File dependencyFile = environment.buildDir.childFile(buildTarget.depfiles.single);
+    final Depfile depfile = environment.depFileService.parse(dependencyFile);
+
+    final String oppositeSeparator = fileSystem.path.separator == '/' ? r'\' : '/';
+    expect(depfile.inputs, everyElement(isNot(contains(oppositeSeparator))));
+    expect(depfile.outputs, everyElement(isNot(contains(oppositeSeparator))));
+  });
+
   testUsingContext(
     'nullable-getter defaults to true',
     () async {

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

@@ -51,6 +51,7 @@ nullable-getter: false
     final LocalizationOptions options = parseLocalizationsOptionsFromYAML(
       file: configFile,
       logger: BufferLogger.test(),
+      fileSystem: fileSystem,
       defaultArbDir: fileSystem.path.join('lib', 'l10n'),
       defaultSyntheticPackage: true,
     );
@@ -90,6 +91,7 @@ nullable-getter: false
     final LocalizationOptions options = parseLocalizationsOptionsFromYAML(
       file: configFile,
       logger: BufferLogger.test(),
+      fileSystem: fileSystem,
       defaultArbDir: fileSystem.path.join('lib', 'l10n'),
       defaultSyntheticPackage: true,
     );
@@ -118,6 +120,7 @@ nullable-getter: false
     final LocalizationOptions options = parseLocalizationsOptionsFromYAML(
       file: configFile,
       logger: BufferLogger.test(),
+      fileSystem: fileSystem,
       defaultArbDir: fileSystem.path.join('lib', 'l10n'),
       defaultSyntheticPackage: false,
     );
@@ -136,6 +139,7 @@ preferred-supported-locales: ['en_US', 'de']
       final LocalizationOptions options = parseLocalizationsOptionsFromYAML(
         file: configFile,
         logger: BufferLogger.test(),
+        fileSystem: fileSystem,
         defaultArbDir: fileSystem.path.join('lib', 'l10n'),
         defaultSyntheticPackage: true,
       );
@@ -156,6 +160,7 @@ use-deferred-loading: string
         () => parseLocalizationsOptionsFromYAML(
           file: configFile,
           logger: BufferLogger.test(),
+          fileSystem: fileSystem,
           defaultArbDir: fileSystem.path.join('lib', 'l10n'),
           defaultSyntheticPackage: true,
         ),
@@ -174,6 +179,7 @@ template-arb-file: {name}_en.arb
       () => parseLocalizationsOptionsFromYAML(
         file: configFile,
         logger: BufferLogger.test(),
+        fileSystem: fileSystem,
         defaultArbDir: fileSystem.path.join('lib', 'l10n'),
         defaultSyntheticPackage: true,
       ),

packages/flutter_tools/test/general.shard/generate_localizations_test.dart

@@ -7,6 +7,7 @@ import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/convert.dart';
+import 'package:flutter_tools/src/globals.dart' as globals show platform;
 import 'package:flutter_tools/src/localizations/gen_l10n.dart';
 import 'package:flutter_tools/src/localizations/gen_l10n_types.dart';
 import 'package:flutter_tools/src/localizations/localizations_utils.dart';
@@ -89,16 +90,18 @@ void main() {
     bool relaxSyntax = false,
     bool useNamedParameters = false,
     void Function(Directory)? setup,
+    FileSystem? fileSystem,
   }) {
-    final Directory l10nDirectory = fs.directory(defaultL10nPath)..createSync(recursive: true);
+    final Directory l10nDirectory = (fileSystem ?? fs).directory(defaultL10nPath)
+      ..createSync(recursive: true);
     for (final String locale in localeToArbFile.keys) {
       l10nDirectory.childFile('app_$locale.arb').writeAsStringSync(localeToArbFile[locale]!);
     }
     if (setup != null) {
       setup(l10nDirectory);
     }
     return LocalizationsGenerator(
-        fileSystem: fs,
+        fileSystem: fileSystem ?? fs,
         inputPathString: l10nDirectory.path,
         outputPathString: outputPathString ?? l10nDirectory.path,
         templateArbFileName: defaultTemplateArbFileName,
@@ -613,6 +616,29 @@ void main() {
     );
   });
 
+  testUsingContext('generates normalized input & output file paths', () {
+    final FileSystem fs = MemoryFileSystem.test(
+      style: globals.platform.isWindows ? FileSystemStyle.windows : FileSystemStyle.posix,
+    );
+    setupLocalizations(
+      <String, String>{'en': singleMessageArbFileString, 'es': singleEsMessageArbFileString},
+      fileSystem: fs,
+      inputsAndOutputsListPath: defaultL10nPath,
+    );
+    final File inputsAndOutputsList = fs.file(
+      fs.path.join(defaultL10nPath, 'gen_l10n_inputs_and_outputs.json'),
+    );
+    expect(inputsAndOutputsList.existsSync(), isTrue);
+
+    final Map<String, dynamic> jsonResult =
+        json.decode(inputsAndOutputsList.readAsStringSync()) as Map<String, dynamic>;
+    final String oppositeSeparator = globals.platform.isWindows ? '/' : r'\';
+    final List<dynamic> inputList = jsonResult['inputs'] as List<dynamic>;
+    expect(inputList, everyElement(isNot(contains(oppositeSeparator))));
+    final List<dynamic> outputList = jsonResult['outputs'] as List<dynamic>;
+    expect(outputList, everyElement(isNot(contains(oppositeSeparator))));
+  });
+
   testWithoutContext('setting both a headerString and a headerFile should fail', () {
     expect(
       () {