Test to ensure _kn.arb files are properly escaped (#56091)

* Run encode kn character encoding tool when gen_localizations is run

* Add test that ensures *_kn.arb files are properly encoded/escaped in order to be checked in

* Fix *_no.arb test to not incorrectly pass

dev/tools/localization/bin/encode_kn_arb_files.dart

@@ -2,26 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// This program replaces the material_kn.arb and cupertino_kn.arb
-// files in flutter_localizations/packages/lib/src/l10n with versions
-// where the contents of the localized strings have been replaced by JSON
-// escapes. This is done because some of those strings contain characters
-// that can crash Emacs on Linux. There is more information
+// The utility function `encodeKnArbFiles` replaces the material_kn.arb
+// and cupertino_kn.arb files in flutter_localizations/packages/lib/src/l10n
+// with versions where the contents of the localized strings have been
+// replaced by JSON escapes. This is done because some of those strings
+// contain characters that can crash Emacs on Linux. There is more information
 // here: https://github.com/flutter/flutter/issues/36704 and in the README
 // in flutter_localizations/packages/lib/src/l10n.
 //
-// This app needs to be run by hand when material_kn.arb or cupertino_kn.arb
-// have been updated.
-//
-// ## Usage
-//
-// Run this program from the root of the git repository.
-//
-// ```
-// dart dev/tools/localization/bin/encode_kn_arb_files.dart
-// ```
+// This utility is run by `gen_localizations.dart` if --overwrite is passed
+// in as an option.
 
-import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ -29,13 +20,13 @@ import 'package:path/path.dart' as path;
 
 import '../localizations_utils.dart';
 
-Map<String, dynamic> loadBundle(File file) {
+Map<String, dynamic> _loadBundle(File file) {
   if (!FileSystemEntity.isFileSync(file.path))
     exitWithError('Unable to find input file: ${file.path}');
   return json.decode(file.readAsStringSync()) as Map<String, dynamic>;
 }
 
-void encodeBundleTranslations(Map<String, dynamic> bundle) {
+void _encodeBundleTranslations(Map<String, dynamic> bundle) {
   for (final String key in bundle.keys) {
     // The ARB file resource "attributes" for foo are called @foo. Don't need
     // to encode them.
@@ -51,7 +42,7 @@ void encodeBundleTranslations(Map<String, dynamic> bundle) {
   }
 }
 
-void checkEncodedTranslations(Map<String, dynamic> encodedBundle, Map<String, dynamic> bundle) {
+void _checkEncodedTranslations(Map<String, dynamic> encodedBundle, Map<String, dynamic> bundle) {
   bool errorFound = false;
   const JsonDecoder decoder = JsonDecoder();
   for (final String key in bundle.keys) {
@@ -64,7 +55,7 @@ void checkEncodedTranslations(Map<String, dynamic> encodedBundle, Map<String, dy
     exitWithError('JSON unicode translation encoding failed');
 }
 
-void rewriteBundle(File file, Map<String, dynamic> bundle) {
+void _rewriteBundle(File file, Map<String, dynamic> bundle) {
   final StringBuffer contents = StringBuffer();
   contents.writeln('{');
   for (final String key in bundle.keys) {
@@ -74,22 +65,19 @@ void rewriteBundle(File file, Map<String, dynamic> bundle) {
   file.writeAsStringSync(contents.toString());
 }
 
-Future<void> main(List<String> rawArgs) async {
-  checkCwdIsRepoRoot('encode_kn_arb_files');
-
-  final String l10nPath = path.join('packages', 'flutter_localizations', 'lib', 'src', 'l10n');
-  final File materialArbFile = File(path.join(l10nPath, 'material_kn.arb'));
-  final File cupertinoArbFile = File(path.join(l10nPath, 'cupertino_kn.arb'));
+void encodeKnArbFiles(Directory directory) {
+  final File materialArbFile = File(path.join(directory.path, 'material_kn.arb'));
+  final File cupertinoArbFile = File(path.join(directory.path, 'cupertino_kn.arb'));
 
-  final Map<String, dynamic> materialBundle = loadBundle(materialArbFile);
-  final Map<String, dynamic> cupertinoBundle = loadBundle(cupertinoArbFile);
+  final Map<String, dynamic> materialBundle = _loadBundle(materialArbFile);
+  final Map<String, dynamic> cupertinoBundle = _loadBundle(cupertinoArbFile);
 
-  encodeBundleTranslations(materialBundle);
-  encodeBundleTranslations(cupertinoBundle);
+  _encodeBundleTranslations(materialBundle);
+  _encodeBundleTranslations(cupertinoBundle);
 
-  checkEncodedTranslations(materialBundle, loadBundle(materialArbFile));
-  checkEncodedTranslations(cupertinoBundle, loadBundle(cupertinoArbFile));
+  _checkEncodedTranslations(materialBundle, _loadBundle(materialArbFile));
+  _checkEncodedTranslations(cupertinoBundle, _loadBundle(cupertinoArbFile));
 
-  rewriteBundle(materialArbFile, materialBundle);
-  rewriteBundle(cupertinoArbFile, cupertinoBundle);
+  _rewriteBundle(materialArbFile, materialBundle);
+  _rewriteBundle(cupertinoArbFile, cupertinoBundle);
 }

dev/tools/localization/bin/gen_localizations.dart

@@ -50,6 +50,8 @@ import '../gen_material_localizations.dart';
 import '../localizations_utils.dart';
 import '../localizations_validator.dart';
 
+import 'encode_kn_arb_files.dart';
+
 /// This is the core of this script; it generates the code used for translations.
 String generateArbBasedLocalizationSubclasses({
   @required Map<LocaleInfo, Map<String, String>> localeToResources,
@@ -526,6 +528,16 @@ void main(List<String> rawArgs) {
     exitWithError('$exception');
   }
 
+  // Only rewrite material_kn.arb and cupertino_en.arb if overwriting the
+  // Material and Cupertino localizations files.
+  if (options.writeToFile) {
+    // Encodes the material_kn.arb file and the cupertino_en.arb files before
+    // generating localizations. This prevents a subset of Emacs users from
+    // crashing when opening up the Flutter source code.
+    // See https://github.com/flutter/flutter/issues/36704 for more context.
+    encodeKnArbFiles(directory);
+  }
+
   precacheLanguageAndRegionTags();
 
   // Maps of locales to resource key/value pairs for Material ARBs.

packages/flutter_localizations/test/cupertino/translations_test.dart

@@ -2,12 +2,19 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:convert';
 import 'dart:io';
 
+import 'package:path/path.dart' as path;
+
 import 'package:flutter/cupertino.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../test_utils.dart';
+
+final String rootDirectoryPath = Directory.current.parent.path;
+
 void main() {
   for (final String language in kCupertinoSupportedLanguages) {
     testWidgets('translations exist for $language', (WidgetTester tester) async {
@@ -129,8 +136,13 @@ void main() {
 
   // Regression test for https://github.com/flutter/flutter/issues/53036.
   testWidgets('`nb` uses `no` as its synonym when `nb` arb file is not present', (WidgetTester tester) async {
-    final File nbCupertinoArbFile = File('lib/src/l10n/cupertino_nb.arb');
-    final File noCupertinoArbFile = File('lib/src/l10n/cupertino_no.arb');
+    final File nbCupertinoArbFile = File(
+      path.join(rootDirectoryPath, 'lib', 'src', 'l10n', 'cupertino_nb.arb'),
+    );
+    final File noCupertinoArbFile = File(
+      path.join(rootDirectoryPath, 'lib', 'src', 'l10n', 'cupertino_no.arb'),
+    );
+
 
     if (noCupertinoArbFile.existsSync() && !nbCupertinoArbFile.existsSync()) {
       Locale locale = const Locale.fromSubtags(languageCode: 'no', scriptCode: null, countryCode: null);
@@ -151,4 +163,31 @@ void main() {
       expect(localizations.cutButtonLabel, cutButtonLabelNo);
     }
   });
+
+  // Regression test for https://github.com/flutter/flutter/issues/36704.
+  testWidgets('kn arb file should be properly Unicode escaped', (WidgetTester tester) async {
+    final File file = File(
+      path.join(rootDirectoryPath, 'lib', 'src', 'l10n', 'cupertino_kn.arb'),
+    );
+
+    final Map<String, dynamic> bundle = json.decode(file.readAsStringSync()) as Map<String, dynamic>;
+
+    // Encodes the arb resource values if they have not already been
+    // encoded.
+    encodeBundleTranslations(bundle);
+
+    // Generates the encoded arb output file in as a string.
+    final String encodedArbFile = generateArbString(bundle);
+
+    // After encoding the bundles, the generated string should match
+    // the existing material_kn.arb.
+    if (Platform.isWindows) {
+      // On Windows, the character '\n' can output the two-character sequence
+      // '\r\n' (and when reading the file back, '\r\n' is translated back
+      // into a single '\n' character).
+      expect(file.readAsStringSync().replaceAll('\r\n', '\n'), encodedArbFile);
+    } else {
+      expect(file.readAsStringSync(), encodedArbFile);
+    }
+  });
 }

packages/flutter_localizations/test/material/translations_test.dart

@@ -2,12 +2,19 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:convert';
 import 'dart:io';
 
+import 'package:path/path.dart' as path;
+
 import 'package:flutter/material.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../test_utils.dart';
+
+final String rootDirectoryPath = Directory.current.parent.path;
+
 void main() {
   for (final String language in kMaterialSupportedLanguages) {
     testWidgets('translations exist for $language', (WidgetTester tester) async {
@@ -467,8 +474,12 @@ void main() {
 
   // Regression test for https://github.com/flutter/flutter/issues/53036.
   testWidgets('`nb` uses `no` as its synonym when `nb` arb file is not present', (WidgetTester tester) async {
-    final File nbMaterialArbFile = File('lib/src/l10n/material_nb.arb');
-    final File noMaterialArbFile = File('lib/src/l10n/material_no.arb');
+    final File nbMaterialArbFile = File(
+      path.join(rootDirectoryPath, 'lib', 'src', 'l10n', 'material_nb.arb'),
+    );
+    final File noMaterialArbFile = File(
+      path.join(rootDirectoryPath, 'lib', 'src', 'l10n', 'material_no.arb'),
+    );
 
     // No need to run test if `nb` arb file exists or if `no` arb file does not exist.
     if (noMaterialArbFile.existsSync() && !nbMaterialArbFile.existsSync()) {
@@ -492,4 +503,33 @@ void main() {
       expect(localizations.okButtonLabel, okButtonLabelNo);
     }
   });
+
+  // Regression test for https://github.com/flutter/flutter/issues/36704.
+  testWidgets('kn arb file should be properly Unicode escaped', (WidgetTester tester) async {
+    final File file = File(
+      path.join(rootDirectoryPath, 'lib', 'src', 'l10n', 'material_kn.arb'),
+    );
+
+    final Map<String, dynamic> bundle = json.decode(
+      file.readAsStringSync(),
+    ) as Map<String, dynamic>;
+
+    // Encodes the arb resource values if they have not already been
+    // encoded.
+    encodeBundleTranslations(bundle);
+
+    // Generates the encoded arb output file in as a string.
+    final String encodedArbFile = generateArbString(bundle);
+
+    // After encoding the bundles, the generated string should match
+    // the existing material_kn.arb.
+    if (Platform.isWindows) {
+      // On Windows, the character '\n' can output the two-character sequence
+      // '\r\n' (and when reading the file back, '\r\n' is translated back
+      // into a single '\n' character).
+      expect(file.readAsStringSync().replaceAll('\r\n', '\n'), encodedArbFile);
+    } else {
+      expect(file.readAsStringSync(), encodedArbFile);
+    }
+  });
 }

packages/flutter_localizations/test/test_utils.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.
+
+// Encodes ARB file resource values with Unicode escapes.
+void encodeBundleTranslations(Map<String, dynamic> bundle) {
+  for (final String key in bundle.keys) {
+    // The ARB file resource "attributes" for foo are called @foo. Don't need
+    // to encode them.
+    if (key.startsWith('@'))
+      continue;
+    final String translation = bundle[key] as String;
+    // Rewrite the string as a series of unicode characters in JSON format.
+    // Like "\u0012\u0123\u1234".
+    bundle[key] = translation.runes.map((int code) {
+      final String codeString = '00${code.toRadixString(16)}';
+      return '\\u${codeString.substring(codeString.length - 4)}';
+    }).join();
+  }
+}
+
+String generateArbString(Map<String, dynamic> bundle) {
+  final StringBuffer contents = StringBuffer();
+  contents.writeln('{');
+  for (final String key in bundle.keys) {
+    contents.writeln('  "$key": "${bundle[key]}"${key == bundle.keys.last ? '' : ','}');
+  }
+  contents.writeln('}');
+  return contents.toString();
+}