[gen_l10n] Improvements to `gen_l10n` (#116202)

* init

* fix tests

* fix lint

* extra changes

* oops missed some merge conflicts

* fix lexer add tests

* consistent warnings and errors

* throw error at the end

* improve efficiency, improve code generation

* fix

* nit

* fix test

* remove helper method class

* two d's

* oops

* empty commit as google testing won't pass :(

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

@@ -201,6 +201,10 @@ class GenerateLocalizationsCommand extends FlutterCommand {
             'contained within pairs of single quotes as normal strings and treat all '
             'consecutive pairs of single quotes as a single quote character.',
     );
+    argParser.addFlag(
+      'suppress-warnings',
+      help: 'When specified, all warnings will be suppressed.\n'
+    );
   }
 
   final FileSystem _fileSystem;
@@ -258,6 +262,7 @@ class GenerateLocalizationsCommand extends FlutterCommand {
       final bool areResourceAttributesRequired = boolArgDeprecated('required-resource-attributes');
       final bool usesNullableGetter = boolArgDeprecated('nullable-getter');
       final bool useEscaping = boolArgDeprecated('use-escaping');
+      final bool suppressWarnings = boolArgDeprecated('suppress-warnings');
 
       precacheLanguageAndRegionTags();
 
@@ -281,6 +286,7 @@ class GenerateLocalizationsCommand extends FlutterCommand {
           usesNullableGetter: usesNullableGetter,
           useEscaping: useEscaping,
           logger: _logger,
+          suppressWarnings: suppressWarnings,
         )
           ..loadResources()
           ..writeOutputFiles())

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

@@ -67,6 +67,7 @@ LocalizationsGenerator generateLocalizations({
       usesNullableGetter: options.usesNullableGetter,
       useEscaping: options.useEscaping,
       logger: logger,
+      suppressWarnings: options.suppressWarnings,
     )
       ..loadResources()
       ..writeOutputFiles(isFromYaml: true);
@@ -90,8 +91,6 @@ String _syntheticL10nPackagePath(FileSystem fileSystem) => fileSystem.path.join(
 // For example, if placeholders are used for plurals and no type was specified, then the type will
 // automatically set to 'num'. Similarly, if such placeholders are used for selects, then the type
 // will be set to 'String'. For such placeholders that are used for both, we should throw an error.
-// TODO(thkim1011): Let's store the output of this function in the Message class, so that we don't
-// recompute this. See https://github.com/flutter/flutter/issues/112709
 List<String> generateMethodParameters(Message message) {
   return message.placeholders.values.map((Placeholder placeholder) {
     return '${placeholder.type} ${placeholder.name}';
@@ -456,6 +455,7 @@ class LocalizationsGenerator {
     bool usesNullableGetter = true,
     bool useEscaping = false,
     required Logger logger,
+    bool suppressWarnings = false,
   }) {
     final Directory? projectDirectory = projectDirFromPath(fileSystem, projectPathString);
     final Directory inputDirectory = inputDirectoryFromPath(fileSystem, inputPathString, projectDirectory);
@@ -478,6 +478,7 @@ class LocalizationsGenerator {
       areResourceAttributesRequired: areResourceAttributesRequired,
       useEscaping: useEscaping,
       logger: logger,
+      suppressWarnings: suppressWarnings,
     );
   }
 
@@ -501,10 +502,11 @@ class LocalizationsGenerator {
     this.usesNullableGetter = true,
     required this.logger,
     this.useEscaping = false,
+    this.suppressWarnings = false,
   });
 
   final FileSystem _fs;
-  Iterable<Message> _allMessages = <Message>[];
+  List<Message> _allMessages = <Message>[];
   late final AppResourceBundleCollection _allBundles = AppResourceBundleCollection(inputDirectory);
   late final AppResourceBundle _templateBundle = AppResourceBundle(templateArbFile);
   late final Map<LocaleInfo, String> _inputFileNames = Map<LocaleInfo, String>.fromEntries(
@@ -637,6 +639,9 @@ class LocalizationsGenerator {
   /// Logger to be used during the execution of the script.
   Logger logger;
 
+  /// Whether or not to suppress warnings or not.
+  final bool suppressWarnings;
+
   static bool _isNotReadable(FileStat fileStat) {
     final String rawStatString = fileStat.modeString();
     // Removes potential prepended permission bits, such as '(suid)' and '(guid)'.
@@ -851,9 +856,6 @@ class LocalizationsGenerator {
   // Load _allMessages from templateArbFile and _allBundles from all of the ARB
   // files in inputDirectory. Also initialized: supportedLocales.
   void loadResources() {
-    _allMessages = _templateBundle.resourceIds.map((String id) => Message(
-       _templateBundle, _allBundles, id, areResourceAttributesRequired, useEscaping: useEscaping,
-    ));
     for (final String resourceId in _templateBundle.resourceIds) {
       if (!_isValidGetterAndMethodName(resourceId)) {
         throw L10nException(
@@ -864,7 +866,10 @@ class LocalizationsGenerator {
         );
       }
     }
-
+    // The call to .toList() is absolutely necessary. Otherwise, it is an iterator and will call Message's constructor again.
+    _allMessages = _templateBundle.resourceIds.map((String id) => Message(
+       _templateBundle, _allBundles, id, areResourceAttributesRequired, useEscaping: useEscaping, logger: logger,
+    )).toList();
     if (inputsAndOutputsListFile != null) {
       _inputFileList.addAll(_allBundles.bundles.map((AppResourceBundle bundle) {
         return bundle.file.absolute.path;
@@ -1083,6 +1088,7 @@ class LocalizationsGenerator {
   }
 
   String _generateMethod(Message message, LocaleInfo locale) {
+    try {
     // Determine if we must import intl for date or number formatting.
     if (message.placeholdersRequireFormatting) {
       requiresIntlImport = true;
@@ -1098,74 +1104,37 @@ class LocalizationsGenerator {
         .replaceAll('@(message)', "'${generateString(node.children.map((Node child) => child.value!).join())}'");
     }
 
-    final List<String> helperMethods = <String>[];
-
-    // Get a unique helper method name.
-    int methodNameCount = 0;
-    String getHelperMethodName() {
-      return '_${message.resourceId}${methodNameCount++}';
+    final List<String> tempVariables = <String>[];
+    // Get a unique temporary variable name.
+    int variableCount = 0;
+    String getTempVariableName() {
+      return '_temp${variableCount++}';
     }
 
-    // Do a DFS post order traversal, generating dependent
-    // placeholder, plural, select helper methods, and combine these into
-    // one message. Returns the method/placeholder to use in parent string.
-    HelperMethod generateHelperMethods(Node node, { bool isRoot = false }) {
-      final Set<Placeholder> dependentPlaceholders = <Placeholder>{};
+    // Do a DFS post order traversal through placeholderExpr, pluralExpr, and selectExpr nodes.
+    // When traversing through a placeholderExpr node, return "$placeholderName".
+    // When traversing through a pluralExpr node, return "$tempVarN" and add variable declaration in "tempVariables".
+    // When traversing through a selectExpr node, return "$tempVarN" and add variable declaration in "tempVariables".
+    // When traversing through a message node, return concatenation of all of "generateVariables(child)" for each child.
+    String generateVariables(Node node, { bool isRoot = false }) {
       switch (node.type) {
         case ST.message:
-          final List<HelperMethod> helpers = node.children.map<HelperMethod>((Node node) {
+          final List<String> expressions = node.children.map<String>((Node node) {
             if (node.type == ST.string) {
-              return HelperMethod(<Placeholder>{}, string: node.value);
+              return node.value!;
             }
-            final HelperMethod helper = generateHelperMethods(node);
-            dependentPlaceholders.addAll(helper.dependentPlaceholders);
-            return helper;
+            return generateVariables(node);
           }).toList();
-          final String messageString = generateReturnExpr(helpers);
-
-          // If the message is just a normal string, then only return the string.
-          if (dependentPlaceholders.isEmpty) {
-            return HelperMethod(dependentPlaceholders, string: messageString);
-          }
-
-          // For messages, if we are generating the actual overridden method, then we should also deal with
-          // date and number formatting here.
-          final String helperMethodName = getHelperMethodName();
-          final HelperMethod messageHelper = HelperMethod(dependentPlaceholders, helper: helperMethodName);
-          if (isRoot) {
-            helperMethods.add(methodTemplate
-              .replaceAll('@(name)', message.resourceId)
-              .replaceAll('@(parameters)', generateMethodParameters(message).join(', '))
-              .replaceAll('@(dateFormatting)', generateDateFormattingLogic(message))
-              .replaceAll('@(numberFormatting)', generateNumberFormattingLogic(message))
-              .replaceAll('@(message)', messageString)
-              .replaceAll('@(none)\n', '')
-            );
-          } else {
-            helperMethods.add(messageHelperTemplate
-              .replaceAll('@(name)', helperMethodName)
-              .replaceAll('@(parameters)', messageHelper.methodParameters)
-              .replaceAll('@(message)', messageString)
-            );
-          }
-          return messageHelper;
+          return generateReturnExpr(expressions);
 
         case ST.placeholderExpr:
           assert(node.children[1].type == ST.identifier);
-          final Node identifier = node.children[1];
-          // Check that placeholders exist.
-          final Placeholder? placeholder = message.placeholders[identifier.value];
-          if (placeholder == null) {
-            throw L10nParserException(
-              'Make sure that the specified placeholder is defined in your arb file.',
-              _inputFileNames[locale]!,
-              message.resourceId,
-              translationForMessage,
-              identifier.positionInMessage,
-            );
+          final String identifier = node.children[1].value!;
+          final Placeholder placeholder = message.placeholders[identifier]!;
+          if (placeholder.requiresFormatting) {
+            return '\$${node.children[1].value}String';
           }
-          dependentPlaceholders.add(placeholder);
-          return HelperMethod(dependentPlaceholders, placeholder: placeholder);
+          return '\$${node.children[1].value}';
 
         case ST.pluralExpr:
           requiresIntlImport = true;
@@ -1178,28 +1147,6 @@ class LocalizationsGenerator {
           final Node identifier = node.children[1];
           final Node pluralParts = node.children[5];
 
-          // Check that placeholders exist and is of type int or num.
-          final Placeholder? placeholder = message.placeholders[identifier.value];
-          if (placeholder == null) {
-            throw L10nParserException(
-              'Make sure that the specified placeholder is defined in your arb file.',
-              _inputFileNames[locale]!,
-              message.resourceId,
-              translationForMessage,
-              identifier.positionInMessage,
-            );
-          }
-          if (placeholder.type != 'num' && placeholder.type != 'int') {
-            throw L10nParserException(
-              'The specified placeholder must be of type int or num.',
-              _inputFileNames[locale]!,
-              message.resourceId,
-              translationForMessage,
-              identifier.positionInMessage,
-            );
-          }
-          dependentPlaceholders.add(placeholder);
-
           for (final Node pluralPart in pluralParts.children.reversed) {
             String pluralCase;
             Node pluralMessage;
@@ -1215,26 +1162,22 @@ class LocalizationsGenerator {
               pluralMessage = pluralPart.children[2];
             }
             if (!pluralLogicArgs.containsKey(pluralCases[pluralCase])) {
-              final HelperMethod pluralPartHelper = generateHelperMethods(pluralMessage);
-              pluralLogicArgs[pluralCases[pluralCase]!] = '      ${pluralCases[pluralCase]}: ${pluralPartHelper.helperOrPlaceholder},';
-              dependentPlaceholders.addAll(pluralPartHelper.dependentPlaceholders);
-            } else {
+              final String pluralPartExpression = generateVariables(pluralMessage);
+              pluralLogicArgs[pluralCases[pluralCase]!] = '      ${pluralCases[pluralCase]}: $pluralPartExpression,';
+            } else if (!suppressWarnings) {
               logger.printWarning('''
-The plural part specified below is overrided by a later plural part.
-$translationForMessage
-${Parser.indentForError(pluralPart.positionInMessage)}
-''');
+[${_inputFileNames[locale]}:${message.resourceId}] ICU Syntax Warning: The plural part specified below is overridden by a later plural part.
+    $translationForMessage
+    ${Parser.indentForError(pluralPart.positionInMessage)}''');
             }
           }
-          final String helperMethodName = getHelperMethodName();
-          final HelperMethod pluralHelper = HelperMethod(dependentPlaceholders, helper: helperMethodName);
-          helperMethods.add(pluralHelperTemplate
-            .replaceAll('@(name)', helperMethodName)
-            .replaceAll('@(parameters)', pluralHelper.methodParameters)
+          final String tempVarName = getTempVariableName();
+          tempVariables.add(pluralVariableTemplate
+            .replaceAll('@(varName)', tempVarName)
             .replaceAll('@(count)', identifier.value!)
             .replaceAll('@(pluralLogicArgs)', pluralLogicArgs.values.join('\n'))
           );
-          return pluralHelper;
+          return '\$$tempVarName';
 
         case ST.selectExpr:
           requiresIntlImport = true;
@@ -1244,53 +1187,53 @@ ${Parser.indentForError(pluralPart.positionInMessage)}
           assert(node.children[5].type == ST.selectParts);
 
           final Node identifier = node.children[1];
-          // Check that placeholders exist.
-          final Placeholder? placeholder = message.placeholders[identifier.value];
-          if (placeholder == null) {
-            throw L10nParserException(
-              'Make sure that the specified placeholder is defined in your arb file.',
-              _inputFileNames[locale]!,
-              message.resourceId,
-              translationForMessage,
-              identifier.positionInMessage,
-            );
-          }
-          dependentPlaceholders.add(placeholder);
           final List<String> selectLogicArgs = <String>[];
           final Node selectParts = node.children[5];
-
           for (final Node selectPart in selectParts.children) {
             assert(selectPart.children[0].type == ST.identifier || selectPart.children[0].type == ST.other);
             assert(selectPart.children[2].type == ST.message);
             final String selectCase = selectPart.children[0].value!;
             final Node selectMessage = selectPart.children[2];
-            final HelperMethod selectPartHelper = generateHelperMethods(selectMessage);
-            selectLogicArgs.add("        '$selectCase': ${selectPartHelper.helperOrPlaceholder},");
-            dependentPlaceholders.addAll(selectPartHelper.dependentPlaceholders);
+            final String selectPartExpression = generateVariables(selectMessage);
+            selectLogicArgs.add("        '$selectCase': $selectPartExpression,");
           }
-          final String helperMethodName = getHelperMethodName();
-          final HelperMethod selectHelper = HelperMethod(dependentPlaceholders, helper: helperMethodName);
-
-          helperMethods.add(selectHelperTemplate
-            .replaceAll('@(name)', helperMethodName)
-            .replaceAll('@(parameters)', selectHelper.methodParameters)
+          final String tempVarName = getTempVariableName();
+          tempVariables.add(selectVariableTemplate
+            .replaceAll('@(varName)', tempVarName)
             .replaceAll('@(choice)', identifier.value!)
             .replaceAll('@(selectCases)', selectLogicArgs.join('\n'))
           );
-          return HelperMethod(dependentPlaceholders, helper: helperMethodName);
+          return '\$$tempVarName';
         // ignore: no_default_cases
         default:
           throw Exception('Cannot call "generateHelperMethod" on node type ${node.type}');
       }
     }
-    generateHelperMethods(node, isRoot: true);
-    return helperMethods.last.replaceAll('@(helperMethods)', helperMethods.sublist(0, helperMethods.length - 1).join('\n\n'));
+    final String messageString = generateVariables(node, isRoot: true);
+    final String tempVarLines = tempVariables.isEmpty ? '' : '${tempVariables.join('\n')}\n';
+    return methodTemplate
+              .replaceAll('@(name)', message.resourceId)
+              .replaceAll('@(parameters)', generateMethodParameters(message).join(', '))
+              .replaceAll('@(dateFormatting)', generateDateFormattingLogic(message))
+              .replaceAll('@(numberFormatting)', generateNumberFormattingLogic(message))
+              .replaceAll('@(tempVars)', tempVarLines)
+              .replaceAll('@(message)', messageString)
+              .replaceAll('@(none)\n', '');
+    } on L10nParserException catch (error) {
+      logger.printError(error.toString());
+      return '';
+    }
   }
 
   List<String> writeOutputFiles({ bool isFromYaml = false }) {
     // First, generate the string contents of all necessary files.
     final String generatedLocalizationsFile = _generateCode();
 
+    // If there were any syntax errors, don't write to files.
+    if (logger.hadErrorOutput) {
+      throw L10nException('Found syntax errors.');
+    }
+
     // A pubspec.yaml file is required when using a synthetic package. If it does not
     // exist, create a blank one.
     if (useSyntheticPackage) {

packages/flutter_tools/lib/src/localizations/gen_l10n_templates.dart

@@ -139,33 +139,23 @@ const String methodTemplate = '''
   String @(name)(@(parameters)) {
 @(dateFormatting)
 @(numberFormatting)
-@(helperMethods)
-    return @(message);
+@(tempVars)    return @(message);
   }''';
 
-const String messageHelperTemplate = '''
-    String @(name)(@(parameters)) {
-      return @(message);
-    }''';
-
-const String pluralHelperTemplate = '''
-    String @(name)(@(parameters)) {
-      return intl.Intl.pluralLogic(
-        @(count),
-        locale: localeName,
+const String pluralVariableTemplate = '''
+    String @(varName) = intl.Intl.pluralLogic(
+      @(count),
+      locale: localeName,
 @(pluralLogicArgs)
-      );
-    }''';
-
-const String selectHelperTemplate = '''
-    String @(name)(@(parameters)) {
-      return intl.Intl.selectLogic(
-        @(choice),
-        {
+    );''';
+
+const String selectVariableTemplate = '''
+    String @(varName) = intl.Intl.selectLogic(
+      @(choice),
+      {
 @(selectCases)
-        },
-      );
-    }''';
+      },
+    );''';
 
 const String classFileTemplate = '''
 @(header)@(requiresIntlImport)import '@(fileName)';

packages/flutter_tools/lib/src/localizations/gen_l10n_types.dart

@@ -5,6 +5,7 @@
 import 'package:intl/locale.dart';
 
 import '../base/file_system.dart';
+import '../base/logger.dart';
 import '../convert.dart';
 import 'localizations_utils.dart';
 import 'message_parser.dart';
@@ -138,17 +139,31 @@ class L10nParserException extends L10nException {
     this.messageString,
     this.charNumber
   ): super('''
-$error
-[$fileName:$messageId] $messageString
-${List<String>.filled(4 + fileName.length + messageId.length + charNumber, ' ').join()}^''');
+[$fileName:$messageId] $error
+    $messageString
+    ${List<String>.filled(charNumber, ' ').join()}^''');
 
   final String error;
   final String fileName;
   final String messageId;
   final String messageString;
+  // Position of character within the "messageString" where the error is.
   final int charNumber;
 }
 
+class L10nMissingPlaceholderException extends L10nParserException {
+  L10nMissingPlaceholderException(
+    super.error,
+    super.fileName,
+    super.messageId,
+    super.messageString,
+    super.charNumber,
+    this.placeholderName,
+  );
+
+  final String placeholderName;
+}
+
 // One optional named parameter to be used by a NumberFormat.
 //
 // Some of the NumberFormat factory constructors have optional named parameters.
@@ -319,7 +334,10 @@ class Message {
     AppResourceBundleCollection allBundles,
     this.resourceId,
     bool isResourceAttributeRequired,
-    { this.useEscaping = false }
+    {
+      this.useEscaping = false,
+      this.logger,
+    }
   ) : assert(templateBundle != null),
       assert(allBundles != null),
       assert(resourceId != null && resourceId.isNotEmpty),
@@ -335,64 +353,16 @@ class Message {
       filenames[bundle.locale] = bundle.file.basename;
       final String? translation = bundle.translationFor(resourceId);
       messages[bundle.locale] = translation;
-      parsedMessages[bundle.locale] = translation == null ? null : Parser(resourceId, bundle.file.basename, translation, useEscaping: useEscaping).parse();
-    }
-    // Using parsed translations, attempt to infer types of placeholders used by plurals and selects.
-    for (final LocaleInfo locale in parsedMessages.keys) {
-      if (parsedMessages[locale] == null) {
-        continue;
-      }
-      final List<Node> traversalStack = <Node>[parsedMessages[locale]!];
-      while (traversalStack.isNotEmpty) {
-        final Node node = traversalStack.removeLast();
-        if (node.type == ST.pluralExpr) {
-          final Placeholder? placeholder = placeholders[node.children[1].value!];
-          if (placeholder == null) {
-            throw L10nParserException(
-              'Make sure that the specified plural placeholder is defined in your arb file.',
-              filenames[locale]!,
-              resourceId,
-              messages[locale]!,
-              node.children[1].positionInMessage
-            );
-          }
-          placeholders[node.children[1].value!]!.isPlural = true;
-        }
-        if (node.type == ST.selectExpr) {
-          final Placeholder? placeholder = placeholders[node.children[1].value!];
-          if (placeholder == null) {
-            throw L10nParserException(
-              'Make sure that the specified select placeholder is defined in your arb file.',
-              filenames[locale]!,
-              resourceId,
-              messages[locale]!,
-              node.children[1].positionInMessage
-            );
-          }
-          placeholders[node.children[1].value!]!.isSelect = true;
-        }
-        traversalStack.addAll(node.children);
-      }
-    }
-    for (final Placeholder placeholder in placeholders.values) {
-      if (placeholder.isPlural && placeholder.isSelect) {
-        throw L10nException('Placeholder is used as both a plural and select in certain languages.');
-      } else if (placeholder.isPlural) {
-        if (placeholder.type == null) {
-          placeholder.type = 'num';
-        }
-        else if (!<String>['num', 'int'].contains(placeholder.type)) {
-          throw L10nException("Placeholders used in plurals must be of type 'num' or 'int'");
-        }
-      } else if (placeholder.isSelect) {
-        if (placeholder.type == null) {
-          placeholder.type = 'String';
-        } else if (placeholder.type != 'String') {
-          throw L10nException("Placeholders used in selects must be of type 'String'");
-        }
-      }
-      placeholder.type ??= 'Object';
+      parsedMessages[bundle.locale] = translation == null ? null : Parser(
+        resourceId,
+        bundle.file.basename,
+        translation,
+        useEscaping: useEscaping,
+        logger: logger
+      ).parse();
     }
+    // Infer the placeholders
+    _inferPlaceholders(filenames);
   }
 
   final String resourceId;
@@ -402,6 +372,7 @@ class Message {
   final Map<LocaleInfo, Node?> parsedMessages;
   final Map<String, Placeholder> placeholders;
   final bool useEscaping;
+  final Logger? logger;
 
   bool get placeholdersRequireFormatting => placeholders.values.any((Placeholder p) => p.requiresFormatting);
 
@@ -496,6 +467,63 @@ class Message {
       }),
     );
   }
+
+  // Using parsed translations, attempt to infer types of placeholders used by plurals and selects.
+  // For undeclared placeholders, create a new placeholder.
+  void _inferPlaceholders(Map<LocaleInfo, String> filenames) {
+    // We keep the undeclared placeholders separate so that we can sort them alphabetically afterwards.
+    final Map<String, Placeholder> undeclaredPlaceholders = <String, Placeholder>{};
+    // Helper for getting placeholder by name.
+    Placeholder? getPlaceholder(String name) => placeholders[name] ?? undeclaredPlaceholders[name];
+    for (final LocaleInfo locale in parsedMessages.keys) {
+      if (parsedMessages[locale] == null) {
+        continue;
+      }
+      final List<Node> traversalStack = <Node>[parsedMessages[locale]!];
+      while (traversalStack.isNotEmpty) {
+        final Node node = traversalStack.removeLast();
+        if (<ST>[ST.placeholderExpr, ST.pluralExpr, ST.selectExpr].contains(node.type)) {
+          final String identifier = node.children[1].value!;
+          Placeholder? placeholder = getPlaceholder(identifier);
+          if (placeholder == null) {
+            placeholder = Placeholder(resourceId, identifier, <String, Object?>{});
+            undeclaredPlaceholders[identifier] = placeholder;
+          }
+          if (node.type == ST.pluralExpr) {
+            placeholder.isPlural = true;
+          } else if (node.type == ST.selectExpr) {
+            placeholder.isSelect = true;
+          }
+        }
+        traversalStack.addAll(node.children);
+      }
+    }
+    placeholders.addEntries(
+      undeclaredPlaceholders.entries
+        .toList()
+        ..sort((MapEntry<String, Placeholder> p1, MapEntry<String, Placeholder> p2) => p1.key.compareTo(p2.key))
+    );
+
+    for (final Placeholder placeholder in placeholders.values) {
+      if (placeholder.isPlural && placeholder.isSelect) {
+        throw L10nException('Placeholder is used as both a plural and select in certain languages.');
+      } else if (placeholder.isPlural) {
+        if (placeholder.type == null) {
+          placeholder.type = 'num';
+        }
+        else if (!<String>['num', 'int'].contains(placeholder.type)) {
+          throw L10nException("Placeholders used in plurals must be of type 'num' or 'int'");
+        }
+      } else if (placeholder.isSelect) {
+        if (placeholder.type == null) {
+          placeholder.type = 'String';
+        } else if (placeholder.type != 'String') {
+          throw L10nException("Placeholders used in selects must be of type 'String'");
+        }
+      }
+      placeholder.type ??= 'Object';
+    }
+  }
 }
 
 // Represents the contents of one ARB file.
@@ -834,50 +862,3 @@ final Set<String> _iso639Languages = <String>{
   'zh',
   'zu',
 };
-
-// Used in LocalizationsGenerator._generateMethod.generateHelperMethod.
-class HelperMethod {
-  HelperMethod(this.dependentPlaceholders, {this.helper, this.placeholder, this.string }):
-    assert((() {
-      // At least one of helper, placeholder, string must be nonnull.
-      final bool a = helper == null;
-      final bool b = placeholder == null;
-      final bool c = string == null;
-      return (!a && b && c) || (a && !b && c) || (a && b && !c);
-    })());
-
-  Set<Placeholder> dependentPlaceholders;
-  String? helper;
-  Placeholder? placeholder;
-  String? string;
-
-  String get helperOrPlaceholder {
-    if (helper != null) {
-      return '$helper($methodArguments)';
-    } else if (string != null) {
-      return '$string';
-    } else {
-      if (placeholder!.requiresFormatting) {
-        return '${placeholder!.name}String';
-      } else {
-        return placeholder!.name;
-      }
-    }
-  }
-
-  String get methodParameters {
-    assert(helper != null);
-    return dependentPlaceholders.map((Placeholder placeholder) =>
-      (placeholder.requiresFormatting)
-        ? 'String ${placeholder.name}String'
-        : '${placeholder.type} ${placeholder.name}').join(', ');
-  }
-
-  String get methodArguments {
-    assert(helper != null);
-    return dependentPlaceholders.map((Placeholder placeholder) =>
-      (placeholder.requiresFormatting)
-        ? '${placeholder.name}String'
-        : placeholder.name).join(', ');
-  }
-}

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

@@ -297,25 +297,23 @@ String generateString(String value) {
 
 /// Given a list of strings, placeholders, or helper function calls, concatenate
 /// them into one expression to be returned.
-String generateReturnExpr(List<HelperMethod> helpers) {
-  if (helpers.isEmpty) {
+/// If isSingleStringVar is passed, then we want to convert "'$expr'" to simply "expr".
+String generateReturnExpr(List<String> expressions, { bool isSingleStringVar = false }) {
+  if (expressions.isEmpty) {
     return "''";
-  } else if (
-    helpers.length == 1
-      && helpers[0].string == null
-      && (helpers[0].placeholder?.type == 'String' || helpers[0].helper != null)
-  ) {
-    return helpers[0].helperOrPlaceholder;
+  } else if (isSingleStringVar) {
+    // If our expression is "$varName" where varName is a String, this is equivalent to just varName.
+    return expressions[0].substring(1);
   } else {
-    final String string = helpers.reversed.fold<String>('', (String string, HelperMethod helper) {
-      if (helper.string != null) {
-        return generateString(helper.string!) + string;
+    final String string = expressions.reversed.fold<String>('', (String string, String expression) {
+      if (expression[0] != r'$') {
+        return generateString(expression) + string;
       }
       final RegExp alphanumeric = RegExp(r'^([0-9a-zA-Z]|_)+$');
-      if (alphanumeric.hasMatch(helper.helperOrPlaceholder) && !(string.isNotEmpty && alphanumeric.hasMatch(string[0]))) {
-        return '\$${helper.helperOrPlaceholder}$string';
+      if (alphanumeric.hasMatch(expression.substring(1)) && !(string.isNotEmpty && alphanumeric.hasMatch(string[0]))) {
+        return '$expression$string';
       } else {
-        return '\${${helper.helperOrPlaceholder}}$string';
+        return '\${${expression.substring(1)}}$string';
       }
     });
     return "'$string'";
@@ -340,6 +338,7 @@ class LocalizationOptions {
     this.usesNullableGetter = true,
     this.format = false,
     this.useEscaping = false,
+    this.suppressWarnings = false,
   }) : assert(useSyntheticPackage != null);
 
   /// The `--arb-dir` argument.
@@ -416,6 +415,11 @@ class LocalizationOptions {
   ///
   /// Whether or not the ICU escaping syntax is used.
   final bool useEscaping;
+
+  /// The `suppress-warnings` argument.
+  ///
+  /// Whether or not to suppress warnings.
+  final bool suppressWarnings;
 }
 
 /// Parse the localizations configuration options from [file].
@@ -450,8 +454,9 @@ LocalizationOptions parseLocalizationsOptions({
     useSyntheticPackage: _tryReadBool(yamlNode, 'synthetic-package', logger) ?? true,
     areResourceAttributesRequired: _tryReadBool(yamlNode, 'required-resource-attributes', logger) ?? false,
     usesNullableGetter: _tryReadBool(yamlNode, 'nullable-getter', logger) ?? true,
-    format: _tryReadBool(yamlNode, 'format', logger) ?? true,
+    format: _tryReadBool(yamlNode, 'format', logger) ?? false,
     useEscaping: _tryReadBool(yamlNode, 'use-escaping', logger) ?? false,
+    suppressWarnings: _tryReadBool(yamlNode, 'suppress-warnings', logger) ?? false,
   );
 }
 

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

@@ -6,6 +6,7 @@
 // See https://flutter.dev/go/icu-message-parser.
 
 // Symbol Types
+import '../base/logger.dart';
 import 'gen_l10n_types.dart';
 
 enum ST {
@@ -181,13 +182,17 @@ class Parser {
     this.messageId,
     this.filename,
     this.messageString,
-    { this.useEscaping = false }
+    {
+      this.useEscaping = false,
+      this.logger
+    }
   );
 
   final String messageId;
   final String messageString;
   final String filename;
   final bool useEscaping;
+  final Logger? logger;
 
   static String indentForError(int position) {
     return '${List<String>.filled(position, ' ').join()}^';
@@ -297,6 +302,11 @@ class Parser {
           // Do not add whitespace as a token.
           startIndex = match.end;
           continue;
+        } else if (<ST>[ST.plural, ST.select].contains(matchedType) && tokens.last.type == ST.openBrace) {
+          // Treat "plural" or "select" as identifier if it comes right after an open brace.
+          tokens.add(Node(ST.identifier, startIndex, value: match.group(0)));
+          startIndex = match.end;
+          continue;
         } else {
           tokens.add(Node(matchedType!, startIndex, value: match.group(0)));
           startIndex = match.end;
@@ -566,8 +576,13 @@ class Parser {
   }
 
   Node parse() {
-    final Node syntaxTree = compress(parseIntoTree());
-    checkExtraRules(syntaxTree);
-    return syntaxTree;
+    try {
+      final Node syntaxTree = compress(parseIntoTree());
+      checkExtraRules(syntaxTree);
+      return syntaxTree;
+    } on L10nParserException catch (error) {
+      logger?.printError(error.toString());
+      return Node(ST.empty, 0, value: '');
+    }
   }
 }

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

@@ -1284,6 +1284,40 @@ class AppLocalizationsEn extends AppLocalizations {
   });
 
   group('writeOutputFiles', () {
+    testWithoutContext('multiple messages with syntax error all log their errors', () {
+      final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
+        ..createSync(recursive: true);
+      l10nDirectory.childFile(defaultTemplateArbFileName)
+        .writeAsStringSync(r'''
+{
+  "msg1": "{",
+  "msg2": "{ {"
+}''');
+      l10nDirectory.childFile(esArbFileName)
+        .writeAsStringSync(singleEsMessageArbFileString);
+      try {
+        LocalizationsGenerator(
+          fileSystem: fs,
+          inputPathString: defaultL10nPathString,
+          outputPathString: defaultL10nPathString,
+          templateArbFileName: defaultTemplateArbFileName,
+          outputFileString: defaultOutputFileString,
+          classNameString: defaultClassNameString,
+          logger: logger,
+        )
+          ..loadResources()
+          ..writeOutputFiles();
+      } on L10nException catch (error) {
+        expect(error.message, equals('Found syntax errors.'));
+        expect(logger.errorText, contains('''
+[app_en.arb:msg1] ICU Syntax Error: Expected "identifier" but found no tokens.
+    {
+      ^
+[app_en.arb:msg2] ICU Syntax Error: Expected "identifier" but found "{".
+    { {
+      ^'''));
+      }
+    });
     testWithoutContext('message without placeholders - should generate code comment with description and template message translation', () {
       _standardFlutterDirectoryL10nSetup(fs);
       LocalizationsGenerator(
@@ -1581,47 +1615,31 @@ import 'output-localization-file_en.dart' deferred as output-localization-file_e
     });
 
     group('placeholder tests', () {
-      testWithoutContext('should throw attempting to generate a select message without placeholders', () {
-        const String selectMessageWithoutPlaceholdersAttribute = '''
+      testWithoutContext('should automatically infer placeholders that are not explicitly defined', () {
+        const String messageWithoutDefinedPlaceholder = '''
 {
-  "helloWorld": "Hello {name}",
-  "@helloWorld": {
-    "description": "Improperly formatted since it has no placeholder attribute.",
-    "placeholders": {
-      "hello": {},
-      "world": {}
-    }
-  }
+  "helloWorld": "Hello {name}"
 }''';
 
         final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
           ..createSync(recursive: true);
         l10nDirectory.childFile(defaultTemplateArbFileName)
-          .writeAsStringSync(selectMessageWithoutPlaceholdersAttribute);
-
-        expect(
-          () {
-            LocalizationsGenerator(
-              fileSystem: fs,
-              inputPathString: defaultL10nPathString,
-              outputPathString: defaultL10nPathString,
-              templateArbFileName: defaultTemplateArbFileName,
-              outputFileString: defaultOutputFileString,
-              classNameString: defaultClassNameString,
-              logger: logger,
-            )
-              ..loadResources()
-              ..writeOutputFiles();
-          },
-          throwsA(isA<L10nException>().having(
-            (L10nException e) => e.message,
-            'message',
-            contains('''
-Make sure that the specified placeholder is defined in your arb file.
-[app_en.arb:helloWorld] Hello {name}
-                               ^'''),
-          )),
-        );
+          .writeAsStringSync(messageWithoutDefinedPlaceholder);
+        LocalizationsGenerator(
+          fileSystem: fs,
+          inputPathString: defaultL10nPathString,
+          outputPathString: defaultL10nPathString,
+          templateArbFileName: defaultTemplateArbFileName,
+          outputFileString: defaultOutputFileString,
+          classNameString: defaultClassNameString,
+          logger: logger,
+        )
+          ..loadResources()
+          ..writeOutputFiles();
+        final String localizationsFile = fs.file(
+          fs.path.join(syntheticL10nPackagePath, 'output-localization-file_en.dart'),
+        ).readAsStringSync();
+        expect(localizationsFile, contains('String helloWorld(Object name) {'));
       });
     });
 
@@ -1909,119 +1927,64 @@ Make sure that the specified placeholder is defined in your arb file.
     });
 
     group('plural messages', () {
-      testWithoutContext('should throw attempting to generate a plural message without placeholders', () {
-        const String pluralMessageWithoutPlaceholdersAttribute = '''
+      testWithoutContext('warnings are generated when plural parts are repeated', () {
+        const String pluralMessageWithOverriddenParts = '''
 {
-  "helloWorlds": "{count,plural, =0{Hello}=1{Hello World}=2{Hello two worlds}few{Hello {count} worlds}many{Hello all {count} worlds}other{Hello other {count} worlds}}",
+  "helloWorlds": "{count,plural, =0{Hello}zero{hello} other{hi}}",
   "@helloWorlds": {
-    "description": "Improperly formatted since it has no placeholder attribute."
+    "description": "Properly formatted but has redundant zero cases."
   }
 }''';
-
         final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
           ..createSync(recursive: true);
         l10nDirectory.childFile(defaultTemplateArbFileName)
-          .writeAsStringSync(pluralMessageWithoutPlaceholdersAttribute);
-
-        expect(
-          () {
-            LocalizationsGenerator(
-              fileSystem: fs,
-              inputPathString: defaultL10nPathString,
-              outputPathString: defaultL10nPathString,
-              templateArbFileName: defaultTemplateArbFileName,
-              outputFileString: defaultOutputFileString,
-              classNameString: defaultClassNameString,
-              logger: logger,
-            )
-              ..loadResources()
-              ..writeOutputFiles();
-          },
-          throwsA(isA<L10nException>().having(
-            (L10nException e) => e.message,
-            'message',
-            contains('''
-Make sure that the specified plural placeholder is defined in your arb file.
-[app_en.arb:helloWorlds] {count,plural, =0{Hello}=1{Hello World}=2{Hello two worlds}few{Hello {count} worlds}many{Hello all {count} worlds}other{Hello other {count} worlds}}
-                          ^'''),
-          )),
-        );
+          .writeAsStringSync(pluralMessageWithOverriddenParts);
+        LocalizationsGenerator(
+          fileSystem: fs,
+          inputPathString: defaultL10nPathString,
+          outputPathString: defaultL10nPathString,
+          templateArbFileName: defaultTemplateArbFileName,
+          outputFileString: defaultOutputFileString,
+          classNameString: defaultClassNameString,
+          logger: logger,
+        )
+          ..loadResources()
+          ..writeOutputFiles();
+        expect(logger.hadWarningOutput, isTrue);
+        expect(logger.warningText, contains('''
+[app_en.arb:helloWorlds] ICU Syntax Warning: The plural part specified below is overridden by a later plural part.
+    {count,plural, =0{Hello}zero{hello} other{hi}}
+                   ^'''));
       });
 
-      testWithoutContext('should throw attempting to generate a plural message with an empty placeholders map', () {
-        const String pluralMessageWithEmptyPlaceholdersMap = '''
+      testWithoutContext('should automatically infer plural placeholders that are not explicitly defined', () {
+        const String pluralMessageWithoutPlaceholdersAttribute = '''
 {
   "helloWorlds": "{count,plural, =0{Hello}=1{Hello World}=2{Hello two worlds}few{Hello {count} worlds}many{Hello all {count} worlds}other{Hello other {count} worlds}}",
   "@helloWorlds": {
-    "description": "Improperly formatted since it has no placeholder attribute.",
-    "placeholders": {}
+    "description": "Improperly formatted since it has no placeholder attribute."
   }
 }''';
 
         final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
           ..createSync(recursive: true);
         l10nDirectory.childFile(defaultTemplateArbFileName)
-          .writeAsStringSync(pluralMessageWithEmptyPlaceholdersMap);
-
-        expect(
-          () {
-            LocalizationsGenerator(
-              fileSystem: fs,
-              inputPathString: defaultL10nPathString,
-              outputPathString: defaultL10nPathString,
-              templateArbFileName: defaultTemplateArbFileName,
-              outputFileString: defaultOutputFileString,
-              classNameString: defaultClassNameString,
-              logger: logger,
-            )
-              ..loadResources()
-              ..writeOutputFiles();
-          },
-          throwsA(isA<L10nException>().having(
-            (L10nException e) => e.message,
-            'message',
-            contains('''
-Make sure that the specified plural placeholder is defined in your arb file.
-[app_en.arb:helloWorlds] {count,plural, =0{Hello}=1{Hello World}=2{Hello two worlds}few{Hello {count} worlds}many{Hello all {count} worlds}other{Hello other {count} worlds}}
-                          ^'''),
-          )),
-        );
-      });
-
-      testWithoutContext('should throw attempting to generate a plural message with no resource attributes', () {
-        const String pluralMessageWithoutResourceAttributes = '''
-{
-  "helloWorlds": "{count,plural, =0{Hello}=1{Hello World}=2{Hello two worlds}few{Hello {count} worlds}many{Hello all {count} worlds}other{Hello other {count} worlds}}"
-}''';
-
-        final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
-          ..createSync(recursive: true);
-        l10nDirectory.childFile(defaultTemplateArbFileName)
-          .writeAsStringSync(pluralMessageWithoutResourceAttributes);
-
-        expect(
-          () {
-            LocalizationsGenerator(
-              fileSystem: fs,
-              inputPathString: defaultL10nPathString,
-              outputPathString: defaultL10nPathString,
-              templateArbFileName: defaultTemplateArbFileName,
-              outputFileString: defaultOutputFileString,
-              classNameString: defaultClassNameString,
-              logger: logger,
-            )
-              ..loadResources()
-              ..writeOutputFiles();
-          },
-          throwsA(isA<L10nException>().having(
-            (L10nException e) => e.message,
-            'message',
-            contains('''
-Make sure that the specified plural placeholder is defined in your arb file.
-[app_en.arb:helloWorlds] {count,plural, =0{Hello}=1{Hello World}=2{Hello two worlds}few{Hello {count} worlds}many{Hello all {count} worlds}other{Hello other {count} worlds}}
-                          ^'''),
-          )),
-        );
+          .writeAsStringSync(pluralMessageWithoutPlaceholdersAttribute);
+        LocalizationsGenerator(
+          fileSystem: fs,
+          inputPathString: defaultL10nPathString,
+          outputPathString: defaultL10nPathString,
+          templateArbFileName: defaultTemplateArbFileName,
+          outputFileString: defaultOutputFileString,
+          classNameString: defaultClassNameString,
+          logger: logger,
+        )
+          ..loadResources()
+          ..writeOutputFiles();
+        final String localizationsFile = fs.file(
+          fs.path.join(syntheticL10nPackagePath, 'output-localization-file_en.dart'),
+        ).readAsStringSync();
+        expect(localizationsFile, contains('String helloWorlds(num count) {'));
       });
 
       testWithoutContext('should throw attempting to generate a plural message with incorrect format for placeholders', () {
@@ -2065,7 +2028,7 @@ Make sure that the specified plural placeholder is defined in your arb file.
     });
 
     group('select messages', () {
-      testWithoutContext('should throw attempting to generate a select message without placeholders', () {
+      testWithoutContext('should auotmatically infer select placeholders that are not explicitly defined', () {
         const String selectMessageWithoutPlaceholdersAttribute = '''
 {
   "genderSelect": "{gender, select, female {She} male {He} other {they} }",
@@ -2078,106 +2041,21 @@ Make sure that the specified plural placeholder is defined in your arb file.
           ..createSync(recursive: true);
         l10nDirectory.childFile(defaultTemplateArbFileName)
           .writeAsStringSync(selectMessageWithoutPlaceholdersAttribute);
-
-        expect(
-          () {
-            LocalizationsGenerator(
-              fileSystem: fs,
-              inputPathString: defaultL10nPathString,
-              outputPathString: defaultL10nPathString,
-              templateArbFileName: defaultTemplateArbFileName,
-              outputFileString: defaultOutputFileString,
-              classNameString: defaultClassNameString,
-              logger: logger,
-            )
-              ..loadResources()
-              ..writeOutputFiles();
-          },
-          throwsA(isA<L10nException>().having(
-            (L10nException e) => e.message,
-            'message',
-            contains('''
-Make sure that the specified select placeholder is defined in your arb file.
-[app_en.arb:genderSelect] {gender, select, female {She} male {He} other {they} }
-                           ^'''),
-          )),
-        );
-      });
-
-      testWithoutContext('should throw attempting to generate a select message with an empty placeholders map', () {
-        const String selectMessageWithEmptyPlaceholdersMap = '''
-{
-  "genderSelect": "{gender, select, female {She} male {He} other {they} }",
-  "@genderSelect": {
-    "description": "Improperly formatted since it has no placeholder attribute.",
-    "placeholders": {}
-  }
-}''';
-
-        final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
-          ..createSync(recursive: true);
-        l10nDirectory.childFile(defaultTemplateArbFileName)
-            .writeAsStringSync(selectMessageWithEmptyPlaceholdersMap);
-
-        expect(
-          () {
-            LocalizationsGenerator(
-              fileSystem: fs,
-              inputPathString: defaultL10nPathString,
-              outputPathString: defaultL10nPathString,
-              templateArbFileName: defaultTemplateArbFileName,
-              outputFileString: defaultOutputFileString,
-              classNameString: defaultClassNameString,
-              logger: logger,
-            )
-              ..loadResources()
-              ..writeOutputFiles();
-          },
-          throwsA(isA<L10nException>().having(
-            (L10nException e) => e.message,
-            'message',
-            contains('''
-Make sure that the specified select placeholder is defined in your arb file.
-[app_en.arb:genderSelect] {gender, select, female {She} male {He} other {they} }
-                           ^'''),
-          )),
-        );
-      });
-
-      testWithoutContext('should throw attempting to generate a select message with no resource attributes', () {
-        const String selectMessageWithoutResourceAttributes = '''
-{
-  "genderSelect": "{gender, select, female {She} male {He} other {they} }"
-}''';
-
-        final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
-          ..createSync(recursive: true);
-        l10nDirectory.childFile(defaultTemplateArbFileName)
-            .writeAsStringSync(selectMessageWithoutResourceAttributes);
-
-        expect(
-          () {
-            LocalizationsGenerator(
-              fileSystem: fs,
-              inputPathString: defaultL10nPathString,
-              outputPathString: defaultL10nPathString,
-              templateArbFileName: defaultTemplateArbFileName,
-              outputFileString: defaultOutputFileString,
-              classNameString: defaultClassNameString,
-              logger: logger,
-            )
-              ..loadResources()
-              ..writeOutputFiles();
-          },
-          throwsA(isA<L10nException>().having(
-            (L10nException e) => e.message,
-            'message',
-            contains('''
-Make sure that the specified select placeholder is defined in your arb file.
-[app_en.arb:genderSelect] {gender, select, female {She} male {He} other {they} }
-                           ^'''),
-          )),
-        );
+        LocalizationsGenerator(
+          fileSystem: fs,
+          inputPathString: defaultL10nPathString,
+          outputPathString: defaultL10nPathString,
+          templateArbFileName: defaultTemplateArbFileName,
+          outputFileString: defaultOutputFileString,
+          classNameString: defaultClassNameString,
+          logger: logger,
+        )
+          ..loadResources()
+          ..writeOutputFiles();
+        final String localizationsFile = fs.file(
+          fs.path.join(syntheticL10nPackagePath, 'output-localization-file_en.dart'),
+        ).readAsStringSync();
+        expect(localizationsFile, contains('String genderSelect(String gender) {'));
       });
 
       testWithoutContext('should throw attempting to generate a select message with incorrect format for placeholders', () {
@@ -2234,30 +2112,25 @@ Make sure that the specified select placeholder is defined in your arb file.
           ..createSync(recursive: true);
         l10nDirectory.childFile(defaultTemplateArbFileName)
           .writeAsStringSync(selectMessageWithoutPlaceholdersAttribute);
-
-        expect(
-          () {
-            LocalizationsGenerator(
-              fileSystem: fs,
-              inputPathString: defaultL10nPathString,
-              outputPathString: defaultL10nPathString,
-              templateArbFileName: defaultTemplateArbFileName,
-              outputFileString: defaultOutputFileString,
-              classNameString: defaultClassNameString,
-              logger: logger,
-            )
-              ..loadResources()
-              ..writeOutputFiles();
-          },
-          throwsA(isA<L10nException>().having(
-            (L10nException e) => e.message,
-            'message',
-            contains('''
-Select expressions must have an "other" case.
-[app_en.arb:genderSelect] {gender, select,}
-                                          ^'''),
-          )),
-        );
+        try {
+          LocalizationsGenerator(
+            fileSystem: fs,
+            inputPathString: defaultL10nPathString,
+            outputPathString: defaultL10nPathString,
+            templateArbFileName: defaultTemplateArbFileName,
+            outputFileString: defaultOutputFileString,
+            classNameString: defaultClassNameString,
+            logger: logger,
+          )
+            ..loadResources()
+            ..writeOutputFiles();
+        } on L10nException {
+          expect(logger.errorText, contains('''
+[app_en.arb:genderSelect] ICU Syntax Error: Select expressions must have an "other" case.
+    {gender, select,}
+                    ^''')
+          );
+        }
       });
     });
 
@@ -2984,37 +2857,66 @@ AppLocalizations lookupAppLocalizations(Locale locale) {
 '''));
   });
 
-  // TODO(thkim1011): Uncomment when implementing escaping.
-  // See https://github.com/flutter/flutter/issues/113455.
-//   testWithoutContext('escaping with single quotes', () {
-//     const String arbFile = '''
-// {
-//   "singleQuote": "Flutter''s amazing!",
-//   "@singleQuote": {
-//     "description": "A message with a single quote."
-//   }
-// }''';
-
-//     final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
-//       ..createSync(recursive: true);
-//     l10nDirectory.childFile(defaultTemplateArbFileName)
-//         .writeAsStringSync(arbFile);
-
-//     LocalizationsGenerator(
-//       fileSystem: fs,
-//       inputPathString: defaultL10nPathString,
-//       outputPathString: defaultL10nPathString,
-//       templateArbFileName: defaultTemplateArbFileName,
-//       outputFileString: defaultOutputFileString,
-//       classNameString: defaultClassNameString,
-//       logger: logger,
-//     )
-//       ..loadResources()
-//       ..writeOutputFiles();
-
-//     final String localizationsFile = fs.file(
-//       fs.path.join(syntheticL10nPackagePath, 'output-localization-file_en.dart'),
-//     ).readAsStringSync();
-//     expect(localizationsFile, contains(r"Flutter\'s amazing"));
-//   });
+  testWithoutContext('escaping with single quotes', () {
+    const String arbFile = '''
+{
+  "singleQuote": "Flutter''s amazing!",
+  "@singleQuote": {
+    "description": "A message with a single quote."
+  }
+}''';
+
+    final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
+      ..createSync(recursive: true);
+    l10nDirectory.childFile(defaultTemplateArbFileName)
+        .writeAsStringSync(arbFile);
+
+    LocalizationsGenerator(
+      fileSystem: fs,
+      inputPathString: defaultL10nPathString,
+      outputPathString: defaultL10nPathString,
+      templateArbFileName: defaultTemplateArbFileName,
+      outputFileString: defaultOutputFileString,
+      classNameString: defaultClassNameString,
+      logger: logger,
+      useEscaping: true,
+    )
+      ..loadResources()
+      ..writeOutputFiles();
+
+    final String localizationsFile = fs.file(
+      fs.path.join(syntheticL10nPackagePath, 'output-localization-file_en.dart'),
+    ).readAsStringSync();
+    expect(localizationsFile, contains(r"Flutter\'s amazing"));
+  });
+
+  testWithoutContext('suppress warnings flag actually suppresses warnings', () {
+    const String pluralMessageWithOverriddenParts = '''
+{
+  "helloWorlds": "{count,plural, =0{Hello}zero{hello} other{hi}}",
+  "@helloWorlds": {
+    "description": "Properly formatted but has redundant zero cases.",
+    "placeholders": {
+      "count": {}
+    }
+  }
+}''';
+    final Directory l10nDirectory = fs.currentDirectory.childDirectory('lib').childDirectory('l10n')
+      ..createSync(recursive: true);
+    l10nDirectory.childFile(defaultTemplateArbFileName)
+      .writeAsStringSync(pluralMessageWithOverriddenParts);
+    LocalizationsGenerator(
+      fileSystem: fs,
+      inputPathString: defaultL10nPathString,
+      outputPathString: defaultL10nPathString,
+      templateArbFileName: defaultTemplateArbFileName,
+      outputFileString: defaultOutputFileString,
+      classNameString: defaultClassNameString,
+      logger: logger,
+      suppressWarnings: true,
+    )
+      ..loadResources()
+      ..writeOutputFiles();
+    expect(logger.hadWarningOutput, isFalse);
+  });
 }

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

@@ -218,6 +218,14 @@ void main() {
     ]));
   });
 
+  testWithoutContext('lexer identifier names can be "select" or "plural"', () {
+    final List<Node> tokens = Parser('keywords', 'app_en.arb', '{ select } { plural, select, singular{test} other{hmm} }').lexIntoTokens();
+    expect(tokens[1].value, equals('select'));
+    expect(tokens[1].type, equals(ST.identifier));
+    expect(tokens[5].value, equals('plural'));
+    expect(tokens[5].type, equals(ST.identifier));
+  });
+
   testWithoutContext('lexer: lexically correct but syntactically incorrect', () {
     final List<Node> tokens = Parser(
       'syntax',
@@ -242,9 +250,9 @@ void main() {
   testWithoutContext('lexer unmatched single quote', () {
     const String message = "here''s an unmatched single quote: '";
     const String expectedError = '''
-ICU Lexing Error: Unmatched single quotes.
-[app_en.arb:escaping] here''s an unmatched single quote: '
-                                                         ^''';
+[app_en.arb:escaping] ICU Lexing Error: Unmatched single quotes.
+    here''s an unmatched single quote: '
+                                       ^''';
     expect(
       () => Parser('escaping', 'app_en.arb', message, useEscaping: true).lexIntoTokens(),
       throwsA(isA<L10nException>().having(
@@ -257,9 +265,9 @@ ICU Lexing Error: Unmatched single quotes.
   testWithoutContext('lexer unexpected character', () {
     const String message = '{ * }';
     const String expectedError = '''
-ICU Lexing Error: Unexpected character.
-[app_en.arb:lex] { * }
-                   ^''';
+[app_en.arb:lex] ICU Lexing Error: Unexpected character.
+    { * }
+      ^''';
     expect(
       () => Parser('lex', 'app_en.arb', message).lexIntoTokens(),
       throwsA(isA<L10nException>().having(
@@ -460,11 +468,11 @@ ICU Lexing Error: Unexpected character.
   testWithoutContext('parser unexpected token', () {
     // unexpected token
     const String expectedError1 = '''
-ICU Syntax Error: Expected "}" but found "=".
-[app_en.arb:unexpectedToken] { placeholder =
-                                           ^''';
+[app_en.arb:unexpectedToken] ICU Syntax Error: Expected "}" but found "=".
+    { placeholder =
+                  ^''';
     expect(
-      () => Parser('unexpectedToken', 'app_en.arb', '{ placeholder =').parse(),
+      () => Parser('unexpectedToken', 'app_en.arb', '{ placeholder =').parseIntoTree(),
       throwsA(isA<L10nException>().having(
         (L10nException e) => e.message,
         'message',
@@ -472,11 +480,11 @@ ICU Syntax Error: Expected "}" but found "=".
     )));
 
     const String expectedError2 = '''
-ICU Syntax Error: Expected "number" but found "}".
-[app_en.arb:unexpectedToken] { count, plural, = }
-                                                ^''';
+[app_en.arb:unexpectedToken] ICU Syntax Error: Expected "number" but found "}".
+    { count, plural, = }
+                       ^''';
     expect(
-      () => Parser('unexpectedToken', 'app_en.arb', '{ count, plural, = }').parse(),
+      () => Parser('unexpectedToken', 'app_en.arb', '{ count, plural, = }').parseIntoTree(),
       throwsA(isA<L10nException>().having(
         (L10nException e) => e.message,
         'message',
@@ -484,11 +492,11 @@ ICU Syntax Error: Expected "number" but found "}".
     )));
 
     const String expectedError3 = '''
-ICU Syntax Error: Expected "identifier" but found ",".
-[app_en.arb:unexpectedToken] { , plural , = }
-                               ^''';
+[app_en.arb:unexpectedToken] ICU Syntax Error: Expected "identifier" but found ",".
+    { , plural , = }
+      ^''';
     expect(
-      () => Parser('unexpectedToken', 'app_en.arb', '{ , plural , = }').parse(),
+      () => Parser('unexpectedToken', 'app_en.arb', '{ , plural , = }').parseIntoTree(),
       throwsA(isA<L10nException>().having(
         (L10nException e) => e.message,
         'message',