[gen-l10n] Fix untranslated messages (#68553)

dev/tools/localization/bin/gen_l10n.dart

-// Copyright 2014 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import 'dart:io';
-
-/// Runs `flutter generate_localizations with arguments passed in.
-///
-/// This script exists as a legacy entrypoint, since existing users of
-/// gen_l10n tool used to call
-/// `dart ${FLUTTER}/dev/tools/localizations/bin/gen_l10n.dart <options>` to
-/// generate their Flutter project's localizations resources.
-///
-/// Now, the appropriate way to use this tool is to either define an `l10n.yaml`
-/// file in the Flutter project repository, or call
-/// `flutter generate_localizations <options>`, since the code has moved
-/// into `flutter_tools`.
-Future<void> main(List<String> rawArgs) async {
-  final ProcessResult result = await Process.run(
-    'flutter',
-    <String>[
-      'generate_localizations',
-      ...rawArgs,
-    ],
-  );
-
-  stdout.write(result.stdout);
-  stderr.write(result.stderr);
-}

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

@@ -62,13 +62,10 @@ void generateLocalizations({
         useDeferredLoading: options.deferredLoading ?? false,
         useSyntheticPackage: options.useSyntheticPackage ?? true,
         areResourceAttributesRequired: options.areResourceAttributesRequired ?? false,
+        untranslatedMessagesFile: options?.untranslatedMessagesFile?.toFilePath(),
       )
       ..loadResources()
-      ..writeOutputFiles()
-      ..outputUnimplementedMessages(
-        options?.untranslatedMessagesFile?.toFilePath(),
-        logger,
-      );
+      ..writeOutputFiles(logger);
   } on L10nException catch (e) {
     logger.printError(e.message);
     throw Exception();

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

@@ -206,10 +206,10 @@ class GenerateLocalizationsCommand extends FlutterCommand {
           useSyntheticPackage: useSyntheticPackage,
           projectPathString: projectPathString,
           areResourceAttributesRequired: areResourceAttributesRequired,
+          untranslatedMessagesFile: untranslatedMessagesFile,
         )
         ..loadResources()
-        ..writeOutputFiles()
-        ..outputUnimplementedMessages(untranslatedMessagesFile, globals.logger);
+        ..writeOutputFiles(globals.logger);
     } on L10nException catch (e) {
       throwToolExit(e.message);
     }

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

@@ -520,6 +520,10 @@ class LocalizationsGenerator {
   /// classes.
   String _generatedLocalizationsFile;
 
+  /// A generated file that will contain the list of messages for each locale
+  /// that do not have a translation yet.
+  File _untranslatedMessagesFile;
+
   /// The file that contains the list of inputs and outputs for generating
   /// localizations.
   File _inputsAndOutputsListFile;
@@ -554,6 +558,7 @@ class LocalizationsGenerator {
     bool useSyntheticPackage = true,
     String projectPathString,
     bool areResourceAttributesRequired = false,
+    String untranslatedMessagesFile,
   }) {
     _useSyntheticPackage = useSyntheticPackage;
     setProjectDir(projectPathString);
@@ -564,6 +569,7 @@ class LocalizationsGenerator {
     setPreferredSupportedLocales(preferredSupportedLocale);
     _setHeader(headerString, headerFile);
     _setUseDeferredLoading(useDeferredLoading);
+    _setUntranslatedMessagesFile(untranslatedMessagesFile);
     className = classNameString;
     _setInputsAndOutputsListFile(inputsAndOutputsListPath);
     _areResourceAttributesRequired = areResourceAttributesRequired;
@@ -763,6 +769,16 @@ class LocalizationsGenerator {
     _useDeferredLoading = useDeferredLoading;
   }
 
+  void _setUntranslatedMessagesFile(String untranslatedMessagesFileString) {
+    if (untranslatedMessagesFileString == null || untranslatedMessagesFileString.isEmpty) {
+      return;
+    }
+
+    _untranslatedMessagesFile = _fs.file(
+      globals.fs.path.join(untranslatedMessagesFileString),
+    );
+  }
+
   void _setInputsAndOutputsListFile(String inputsAndOutputsListPath) {
     if (inputsAndOutputsListPath == null) {
       return;
@@ -1017,7 +1033,7 @@ class LocalizationsGenerator {
       .replaceAll('@(delegateClass)', delegateClass);
   }
 
-  void writeOutputFiles() {
+  void writeOutputFiles(Logger logger) {
     // First, generate the string contents of all necessary files.
     _generateCode();
 
@@ -1054,6 +1070,20 @@ class LocalizationsGenerator {
     });
 
     baseOutputFile.writeAsStringSync(_generatedLocalizationsFile);
+
+    if (_untranslatedMessagesFile != null) {
+      _generateUntranslatedMessagesFile(logger);
+    } else if (_unimplementedMessages.isNotEmpty) {
+      _unimplementedMessages.forEach((LocaleInfo locale, List<String> messages) {
+        logger.printStatus('"$locale": ${messages.length} untranslated message(s).');
+      });
+      logger.printStatus(
+        'To see a detailed report, use the --untranslated-messages-file \n'
+        'option in the tool to generate a JSON format file containing \n'
+        'all messages that need to be translated.'
+      );
+    }
+
     if (_inputsAndOutputsListFile != null) {
       _outputFileList.add(baseOutputFile.absolute.path);
 
@@ -1071,34 +1101,21 @@ class LocalizationsGenerator {
     }
   }
 
-  void outputUnimplementedMessages(String untranslatedMessagesFile, Logger logger) {
+  void _generateUntranslatedMessagesFile(Logger logger) {
     if (logger == null) {
       throw L10nException(
         'Logger must be defined when generating untranslated messages file.'
       );
     }
 
-    if (untranslatedMessagesFile == null || untranslatedMessagesFile == '') {
-      _unimplementedMessages.forEach((LocaleInfo locale, List<String> messages) {
-        logger.printStatus('"$locale": ${messages.length} untranslated message(s).');
-      });
-      logger.printStatus(
-        'To see a detailed report, use the --untranslated-messages-file \n'
-        'option in the tool to generate a JSON format file containing \n'
-        'all messages that need to be translated.'
-      );
-    } else {
-      _writeUnimplementedMessagesFile(untranslatedMessagesFile);
-    }
-  }
-
-  void _writeUnimplementedMessagesFile(String untranslatedMessagesFile) {
     if (_unimplementedMessages.isEmpty) {
+      _untranslatedMessagesFile.writeAsStringSync('{}');
+      if (_inputsAndOutputsListFile != null) {
+        _outputFileList.add(_untranslatedMessagesFile.absolute.path);
+      }
       return;
     }
 
-    final File unimplementedMessageTranslationsFile = _fs.file(untranslatedMessagesFile);
-
     String resultingFile = '{\n';
     int count = 0;
     final int numberOfLocales = _unimplementedMessages.length;
@@ -1122,6 +1139,9 @@ class LocalizationsGenerator {
     });
 
     resultingFile += '}\n';
-    unimplementedMessageTranslationsFile.writeAsStringSync(resultingFile);
+    _untranslatedMessagesFile.writeAsStringSync(resultingFile);
+    if (_inputsAndOutputsListFile != null) {
+      _outputFileList.add(_untranslatedMessagesFile.absolute.path);
+    }
   }
 }

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

@@ -66,11 +66,11 @@ void main() {
         useSyntheticPackage: false,
         projectPathString: '/',
         areResourceAttributesRequired: true,
+        untranslatedMessagesFile: 'untranslated',
       ),
     ).called(1);
     verify(mockLocalizationsGenerator.loadResources()).called(1);
-    verify(mockLocalizationsGenerator.writeOutputFiles()).called(1);
-    verify(mockLocalizationsGenerator.outputUnimplementedMessages('untranslated', logger)).called(1);
+    verify(mockLocalizationsGenerator.writeOutputFiles(logger)).called(1);
   });
 
   testUsingContext('generateLocalizations throws exception on missing flutter: generate: true flag', () async {

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

@@ -1444,7 +1444,7 @@ void main() {
     await residentRunner.runSourceGenerators();
 
     expect(testLogger.errorText, isEmpty);
-    expect(testLogger.statusText, contains('use the --untranslated-messages-file'));
+    expect(testLogger.statusText, isEmpty);
   }));
 
   testUsingContext('ResidentRunner can run source generation - generation fails', () => testbed.run(() async {