pkg/analyzer/tool/messages/generate.dart

// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// This file contains code to generate scanner and parser message
/// based on the information in pkg/front_end/messages.yaml.
///
/// For each message in messages.yaml that contains an 'index:' field,
/// this tool generates an error with the name specified by the 'analyzerCode:'
/// field and an entry in the fastaAnalyzerErrorList for that generated error.
/// The text in the 'analyzerCode:' field must contain the name of the class
/// containing the error and the name of the error separated by a `.`
/// (e.g. ParserErrorCode.EQUALITY_CANNOT_BE_EQUALITY_OPERAND).
///
/// It is expected that 'pkg/front_end/tool/fasta generate-messages'
/// has already been successfully run.
import 'dart:io';

import 'package:_fe_analyzer_shared/src/scanner/scanner.dart';
import 'package:analyzer/error/error.dart';
import 'package:analyzer/src/dart/error/syntactic_errors.dart';
import 'package:analyzer_utilities/package_root.dart' as pkg_root;
import 'package:analyzer_utilities/tools.dart';
import 'package:path/path.dart';
import 'package:yaml/yaml.dart' show loadYaml;

import 'error_code_info.dart';

main() async {
  await GeneratedContent.generateAll(analyzerPkgPath, allTargets);

  _SyntacticErrorGenerator()
    ..generateFormatCode()
    ..checkForManualChanges()
    ..printSummary();
}

/// A list of all targets generated by this code generator.
final List<GeneratedContent> allTargets = <GeneratedContent>[
  GeneratedFile('lib/src/dart/error/syntactic_errors.g.dart',
      (String pkgPath) async {
    final codeGenerator = _SyntacticErrorGenerator();

    codeGenerator.generateFormatCode();
    return codeGenerator.out.toString();
  }),
];

/// The path to the `analyzer` package.
final String analyzerPkgPath =
    normalize(join(pkg_root.packageRoot, 'analyzer'));

class _SyntacticErrorGenerator {
  final Map<String, ErrorCodeInfo> messages;
  final CfeToAnalyzerErrorCodeTables tables;
  final String errorConverterSource;
  final String syntacticErrorsSource;
  final String parserSource;
  final out = StringBuffer('''
//
// THIS FILE IS GENERATED. DO NOT EDIT.
//
// Instead modify 'pkg/front_end/messages.yaml' and run
// 'dart pkg/analyzer/tool/messages/generate.dart' to update.

part of 'syntactic_errors.dart';

''');

  factory _SyntacticErrorGenerator() {
    String frontEndPkgPath = normalize(join(pkg_root.packageRoot, 'front_end'));
    String frontEndSharedPkgPath =
        normalize(join(pkg_root.packageRoot, '_fe_analyzer_shared'));

    Map<dynamic, dynamic> messagesYaml = loadYaml(
        File(join(frontEndPkgPath, 'messages.yaml')).readAsStringSync());
    String errorConverterSource = File(join(analyzerPkgPath,
            joinAll(posix.split('lib/src/fasta/error_converter.dart'))))
        .readAsStringSync();
    String syntacticErrorsSource = File(join(analyzerPkgPath,
            joinAll(posix.split('lib/src/dart/error/syntactic_errors.dart'))))
        .readAsStringSync();
    String parserSource = File(join(frontEndSharedPkgPath,
            joinAll(posix.split('lib/src/parser/parser.dart'))))
        .readAsStringSync();

    return _SyntacticErrorGenerator._(decodeCfeMessagesYaml(messagesYaml),
        errorConverterSource, syntacticErrorsSource, parserSource);
  }

  _SyntacticErrorGenerator._(this.messages, this.errorConverterSource,
      this.syntacticErrorsSource, this.parserSource)
      : tables = CfeToAnalyzerErrorCodeTables(messages);

  void checkForManualChanges() {
    // Check for ParserErrorCodes that could be removed from
    // error_converter.dart now that those ParserErrorCodes are auto generated.
    int converterCount = 0;
    for (var errorCode in tables.infoToAnalyzerCode.values) {
      if (errorConverterSource.contains('"$errorCode"')) {
        if (converterCount == 0) {
          print('');
          print('The following ParserErrorCodes could be removed'
              ' from error_converter.dart:');
        }
        print('  $errorCode');
        ++converterCount;
      }
    }
    if (converterCount > 3) {
      print('  $converterCount total');
    }

    // Check that the public ParserErrorCodes have been updated
    // to reference the generated codes.
    int publicCount = 0;
    for (var errorCode in tables.infoToAnalyzerCode.values) {
      if (!syntacticErrorsSource.contains(' _$errorCode')) {
        if (publicCount == 0) {
          print('');
          print('The following ParserErrorCodes should be updated'
              ' in syntactic_errors.dart');
          print('to reference the associated generated error code:');
        }
        print('  static const ParserErrorCode $errorCode = _$errorCode;');
        ++publicCount;
      }
    }

    // Fail if there are manual changes to be made, but do so
    // in a fire and forget manner so that the files are still generated.
    if (converterCount > 0 || publicCount > 0) {
      print('');
      throw 'Error: missing manual code changes';
    }
  }

  void generateErrorCodes() {
    final entryMap = tables.analyzerCodeToInfo;
    for (var errorCode in entryMap.keys.toList()..sort()) {
      final entry = entryMap[errorCode]!;
      final className = 'ParserErrorCode';
      out.writeln();
      out.writeln('const $className _$errorCode =');
      out.writeln(entry.toAnalyzerCode(className, errorCode));
    }
  }

  void generateFastaAnalyzerErrorCodeList() {
    out.writeln('final fastaAnalyzerErrorCodes = <ErrorCode?>[');
    for (var entry in tables.indexToInfo) {
      var name = tables.infoToAnalyzerCode[entry];
      out.writeln('${name == null ? 'null' : '_$name'},');
    }
    out.writeln('];');
  }

  void generateFormatCode() {
    generateFastaAnalyzerErrorCodeList();
    generateErrorCodes();
  }

  void printSummary() {
    // Build a map of error message to ParserErrorCode
    final messageToName = <String, String>{};
    for (ErrorCode errorCode in errorCodeValues) {
      if (errorCode is ParserErrorCode) {
        String message = errorCode.message.replaceAll(RegExp(r'\{\d+\}'), '');
        messageToName[message] = errorCode.name;
      }
    }

    String messageFromEntryTemplate(ErrorCodeInfo entry) {
      String template = entry.template!;
      String message = template.replaceAll(RegExp(r'#\w+'), '');
      return message;
    }

    // Remove entries that have already been translated
    for (ErrorCodeInfo entry in tables.infoToAnalyzerCode.keys) {
      messageToName.remove(messageFromEntryTemplate(entry));
    }

    // Print the # of autogenerated ParserErrorCodes.
    print('${tables.infoToAnalyzerCode.length} of '
        '${messageToName.length} ParserErrorCodes generated.');

    // List the ParserErrorCodes that could easily be auto generated
    // but have not been already.
    final analyzerToFasta = <String, List<String>>{};
    messages.forEach((fastaName, entry) {
      final analyzerName = messageToName[messageFromEntryTemplate(entry)];
      if (analyzerName != null) {
        analyzerToFasta
            .putIfAbsent(analyzerName, () => <String>[])
            .add(fastaName);
      }
    });
    if (analyzerToFasta.isNotEmpty) {
      print('');
      print('The following ParserErrorCodes could be auto generated:');
      for (String analyzerName in analyzerToFasta.keys.toList()..sort()) {
        List<String> fastaNames = analyzerToFasta[analyzerName]!;
        if (fastaNames.length == 1) {
          print('  $analyzerName = ${fastaNames.first}');
        } else {
          print('  $analyzerName = $fastaNames');
        }
      }
      if (analyzerToFasta.length > 3) {
        print('  ${analyzerToFasta.length} total');
      }
    }

    // List error codes in the parser that have not been translated.
    final untranslatedFastaErrorCodes = <String>{};
    Token token = scanString(parserSource).tokens;
    while (!token.isEof) {
      if (token.isIdentifier) {
        String? fastaErrorCode;
        String lexeme = token.lexeme;
        if (lexeme.length > 7) {
          if (lexeme.startsWith('message')) {
            fastaErrorCode = lexeme.substring(7);
          } else if (lexeme.length > 8) {
            if (lexeme.startsWith('template')) {
              fastaErrorCode = lexeme.substring(8);
            }
          }
        }
        if (fastaErrorCode != null &&
            tables.frontEndCodeToInfo[fastaErrorCode] == null) {
          untranslatedFastaErrorCodes.add(fastaErrorCode);
        }
      }
      token = token.next!;
    }
    if (untranslatedFastaErrorCodes.isNotEmpty) {
      print('');
      print('The following error codes in the parser are not auto generated:');
      final sorted = untranslatedFastaErrorCodes.toList()..sort();
      for (String fastaErrorCode in sorted) {
        String analyzerCode = '';
        String template = '';
        var entry = messages[fastaErrorCode];
        if (entry != null) {
          // TODO(paulberry): handle multiple analyzer codes
          if (entry.index == null && entry.analyzerCode.length == 1) {
            analyzerCode = entry.analyzerCode.single;
            template = entry.template!;
          }
        }
        print('  ${fastaErrorCode.padRight(30)} --> $analyzerCode'
            '\n      $template');
      }
    }
  }
}