[gen_l10n] Absolute project path parameter (#63368)

dev/tools/localization/bin/gen_l10n.dart

@@ -120,6 +120,14 @@ void main(List<String> arguments) {
       '\n\n'
       'When null, the JSON file will not be generated.'
   );
+  parser.addOption(
+    'project-dir',
+    valueHelp: 'absolute/path/to/flutter/project',
+    help: 'When specified, the tool uses the path passed into this option '
+      'as the directory of the root Flutter project.'
+      '\n\n'
+      'When null, the relative path to the present working directory will be used.'
+  );
 
   final argslib.ArgResults results = parser.parse(arguments);
   if (results['help'] == true) {
@@ -140,6 +148,7 @@ void main(List<String> arguments) {
   final String headerFile = results['header-file'] as String;
   final bool useDeferredLoading = results['use-deferred-loading'] as bool;
   final String inputsAndOutputsListPath = results['gen-inputs-and-outputs-list'] as String;
+  final String projectPathString = results['project-dir'] as String;
 
   const local.LocalFileSystem fs = local.LocalFileSystem();
   final LocalizationsGenerator localizationsGenerator = LocalizationsGenerator(fs);
@@ -157,6 +166,7 @@ void main(List<String> arguments) {
         headerFile: headerFile,
         useDeferredLoading: useDeferredLoading,
         inputsAndOutputsListPath: inputsAndOutputsListPath,
+        projectPathString: projectPathString,
       )
       ..loadResources()
       ..writeOutputFiles()

dev/tools/localization/gen_l10n.dart

@@ -403,6 +403,11 @@ class LocalizationsGenerator {
   /// This directory is specified with the [initialize] method.
   Directory inputDirectory;
 
+  /// The Flutter project's root directory.
+  ///
+  /// This directory is specified with the [initialize] method.
+  Directory projectDirectory;
+
   /// The directory to generate the project's localizations files in.
   ///
   /// It is assumed that all output files (e.g. The localizations
@@ -518,7 +523,9 @@ class LocalizationsGenerator {
     String headerFile,
     bool useDeferredLoading = false,
     String inputsAndOutputsListPath,
+    String projectPathString,
   }) {
+    setProjectDir(projectPathString);
     setInputDirectory(inputPathString);
     setOutputDirectory(outputPathString ?? inputPathString);
     setTemplateArbFile(templateArbFileName);
@@ -544,22 +551,44 @@ class LocalizationsGenerator {
     return !(statString[1] == 'w' || statString[4] == 'w' || statString[7] == 'w');
   }
 
+  @visibleForTesting
+  void setProjectDir(String projectPathString) {
+    if (projectPathString == null) {
+      return;
+    }
+
+    final Directory directory = _fs.directory(projectPathString);
+    if (!directory.existsSync()) {
+      throw L10nException(
+        'Directory does not exist: $directory.\n'
+        'Please select a directory that contains the project\'s localizations '
+        'resource files.'
+      );
+    }
+    projectDirectory = directory;
+  }
+
   /// Sets the reference [Directory] for [inputDirectory].
   @visibleForTesting
   void setInputDirectory(String inputPathString) {
     if (inputPathString == null)
       throw L10nException('inputPathString argument cannot be null');
-    inputDirectory = _fs.directory(inputPathString);
+    inputDirectory = _fs.directory(
+      projectDirectory != null
+        ? _getAbsoluteProjectPath(inputPathString)
+        : inputPathString
+    );
+
     if (!inputDirectory.existsSync())
       throw FileSystemException(
-        "The 'input-dir' directory, '$inputDirectory', does not exist.\n"
+        "The 'arb-dir' directory, '$inputDirectory', does not exist.\n"
         'Make sure that the correct path was provided.'
       );
 
     final FileStat fileStat = inputDirectory.statSync();
     if (_isNotReadable(fileStat) || _isNotWritable(fileStat))
       throw FileSystemException(
-        "The 'input-dir' directory, '$inputDirectory', doesn't allow reading and writing.\n"
+        "The 'arb-dir' directory, '$inputDirectory', doesn't allow reading and writing.\n"
         'Please ensure that the user has read and write permissions.'
       );
   }
@@ -569,7 +598,11 @@ class LocalizationsGenerator {
   void setOutputDirectory(String outputPathString) {
     if (outputPathString == null)
       throw L10nException('outputPathString argument cannot be null');
-    outputDirectory = _fs.directory(outputPathString);
+    outputDirectory = _fs.directory(
+      projectDirectory != null
+        ? _getAbsoluteProjectPath(outputPathString)
+        : outputPathString
+    );
   }
 
   /// Sets the reference [File] for [templateArbFile].
@@ -667,6 +700,8 @@ class LocalizationsGenerator {
     }
   }
 
+  String _getAbsoluteProjectPath(String relativePath) => _fs.path.join(projectDirectory.path, relativePath);
+
   void _setUseDeferredLoading(bool useDeferredLoading) {
     if (useDeferredLoading == null) {
       throw L10nException('useDeferredLoading argument cannot be null.');

dev/tools/test/localization/gen_l10n_test.dart

@@ -193,6 +193,95 @@ void main() {
       );
     });
 
+    test('sets absolute path of the target Flutter project', () {
+      // Set up project directory.
+      final Directory l10nDirectory = fs.currentDirectory
+        .childDirectory('absolute')
+        .childDirectory('path')
+        .childDirectory('to')
+        .childDirectory('flutter_project')
+        .childDirectory('lib')
+        .childDirectory('l10n')
+        ..createSync(recursive: true);
+      l10nDirectory.childFile(defaultTemplateArbFileName)
+        .writeAsStringSync(singleMessageArbFileString);
+      l10nDirectory.childFile(esArbFileName)
+        .writeAsStringSync(singleEsMessageArbFileString);
+
+      // Run localizations generator in specified absolute path.
+      final LocalizationsGenerator generator = LocalizationsGenerator(fs);
+      final String flutterProjectPath = path.join('absolute', 'path', 'to', 'flutter_project');
+      try {
+        generator.initialize(
+          projectPathString: flutterProjectPath,
+          inputPathString: defaultL10nPathString,
+          outputPathString: defaultL10nPathString,
+          templateArbFileName: defaultTemplateArbFileName,
+          outputFileString: defaultOutputFileString,
+          classNameString: defaultClassNameString,
+        );
+        generator.loadResources();
+        generator.writeOutputFiles();
+      } on L10nException catch (e) {
+        throw TestFailure('Unexpected failure during test setup: ${e.message}');
+      } on Exception catch (e) {
+        throw TestFailure('Unexpected failure during test setup: $e');
+      }
+
+      // Output files should be generated in the provided absolute path.
+      expect(
+        fs.isFileSync(path.join(
+          flutterProjectPath,
+          'lib',
+          'l10n',
+          'output-localization-file_en.dart',
+        )),
+        true,
+      );
+      expect(
+        fs.isFileSync(path.join(
+          flutterProjectPath,
+          'lib',
+          'l10n',
+          'output-localization-file_es.dart',
+        )),
+        true,
+      );
+    });
+
+    test('throws error when directory at absolute path does not exist', () {
+      // Set up project directory.
+      final Directory l10nDirectory = fs.currentDirectory
+        .childDirectory('lib')
+        .childDirectory('l10n')
+        ..createSync(recursive: true);
+      l10nDirectory.childFile(defaultTemplateArbFileName)
+        .writeAsStringSync(singleMessageArbFileString);
+      l10nDirectory.childFile(esArbFileName)
+        .writeAsStringSync(singleEsMessageArbFileString);
+
+      // Project path should be intentionally a directory that does not exist.
+      final LocalizationsGenerator generator = LocalizationsGenerator(fs);
+      try {
+        generator.initialize(
+          projectPathString: 'absolute/path/to/flutter_project',
+          inputPathString: defaultL10nPathString,
+          outputPathString: defaultL10nPathString,
+          templateArbFileName: defaultTemplateArbFileName,
+          outputFileString: defaultOutputFileString,
+          classNameString: defaultClassNameString,
+        );
+      } on L10nException catch (e) {
+        expect(e.message, contains('Directory does not exist'));
+        return;
+      }
+
+      fail(
+        'An exception should be thrown when the directory '
+        'specified in projectPathString does not exist.'
+      );
+    });
+
     group('className should only take valid Dart class names', () {
       LocalizationsGenerator generator;
       setUp(() {

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

@@ -36,11 +36,13 @@ Future<void> generateLocalizations({
     'bin',
     'gen_l10n.dart',
   );
+
   final ProcessResult result = await processManager.run(<String>[
     dartBinaryPath,
     '--disable-dart-dev',
     genL10nPath,
     '--gen-inputs-and-outputs-list=${dependenciesDir.path}',
+    '--project-dir=${projectDir.path}',
     if (options.arbDirectory != null)
       '--arb-dir=${options.arbDirectory.toFilePath()}',
     if (options.templateArbFile != null)

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

@@ -17,13 +17,15 @@ void main() {
   testWithoutContext('generateLocalizations forwards arguments correctly', () async {
     final FileSystem fileSystem = MemoryFileSystem.test();
     final Logger logger = BufferLogger.test();
+    final String projectDir = fileSystem.path.join('path', 'to', 'flutter_project');
     final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
-      const FakeCommand(
+      FakeCommand(
         command: <String>[
           'dart',
           '--disable-dart-dev',
           'dev/tools/localization/bin/gen_l10n.dart',
           '--gen-inputs-and-outputs-list=/',
+          '--project-dir=$projectDir',
           '--arb-dir=arb',
           '--template-arb-file=example.arb',
           '--output-localization-file=bar',
@@ -36,7 +38,11 @@ void main() {
         ],
       ),
     ]);
-    final Directory arbDirectory = fileSystem.directory('arb')
+    final Directory flutterProjectDirectory = fileSystem
+      .directory(fileSystem.path.join('path', 'to', 'flutter_project'))
+      ..createSync(recursive: true);
+    final Directory arbDirectory = flutterProjectDirectory
+      .childDirectory('arb')
       ..createSync();
     arbDirectory.childFile('foo.arb').createSync();
     arbDirectory.childFile('bar.arb').createSync();
@@ -57,7 +63,7 @@ void main() {
       logger: logger,
       fileSystem: fileSystem,
       processManager: processManager,
-      projectDir: fileSystem.currentDirectory,
+      projectDir: flutterProjectDirectory,
       dartBinaryPath: 'dart',
       flutterRoot: '',
       dependenciesDir: fileSystem.currentDirectory,

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

@@ -1189,6 +1189,7 @@ void main() {
         '--disable-dart-dev',
         globals.fs.path.join(Cache.flutterRoot, 'dev', 'tools', 'localization', 'bin', 'gen_l10n.dart'),
         '--gen-inputs-and-outputs-list=${dependencies.absolute.path}',
+        '--project-dir=${globals.fs.currentDirectory.path}',
       ],
       onRun: () {
         dependencies
@@ -1218,6 +1219,7 @@ void main() {
         '--disable-dart-dev',
         globals.fs.path.join(Cache.flutterRoot, 'dev', 'tools', 'localization', 'bin', 'gen_l10n.dart'),
         '--gen-inputs-and-outputs-list=${dependencies.absolute.path}',
+        '--project-dir=${globals.fs.currentDirectory.path}',
       ],
       exitCode: 1,
       stderr: 'stderr'