Fix some Dart analyzer errors, save your work before using this script

apply.dart

import 'dart:io';

import 'package:equatable/equatable.dart';

const kPreferConstConstructors = 'prefer_const_constructors';
const kUnnecessaryConst = 'unnecessary_const';
const kPreferConstDeclarations = 'prefer_const_declarations';

Future<void> main() async {
  final result = await Process.run('dart', ['analyze']);

  final raw = result.stdout as String;

  final supportedFixes = [
    kPreferConstConstructors,
    kUnnecessaryConst,
    kPreferConstDeclarations,
  ];

  final errors = raw
      .split('\n')
      .map((error) => error.trim().replaceAll(r' *', ' ').replaceAll(r'\', '/'))
      .where((error) => error.startsWith('info') || error.startsWith('error'))
      .map((error) {
    final parts = error.split(' - ');

    final type = parts[0],
        location = parts[1].split(':'),
        description = parts[2],
        code = parts[3];

    final path = location[0], line = location[1], column = location[2];

    return StaticError(
      line: int.parse(line),
      column: int.parse(column),
      description: description,
      code: code,
      type: type,
      path: path,
    );
  }).where(
    (error) => error.type == 'info' && supportedFixes.contains(error.code),
  );

  if (errors.isEmpty) return;

  final files = <String, Map<int, StaticError>>{};

  for (final error in errors) {
    files[error.path] ??= {};
    files[error.path]![error.line] = error;
  }

  for (final path in files.keys) {
    final file = File(path);

    final lines = file.readAsLinesSync();

    for (final line in files[path]!.keys) {
      final error = files[path]![line]!;

      final contents = _errorHandler(error, lines);

      file.writeAsStringSync(contents);
    }
  }

  if (errors.isNotEmpty) return main();
}

String _errorHandler(StaticError error, List<String> lines) {
  switch (error.code) {
    case kPreferConstConstructors:
      return _handleConstConstructorsInfo(error, lines);
    case kUnnecessaryConst:
      return _handleUnnecessaryConstInfo(error, lines);
    case kPreferConstDeclarations:
      return _handlePreferConstDeclarationsInfo(error, lines);
  }

  throw UnsupportedError('Got invalid error code: ${error.code}');
}

String _handleConstConstructorsInfo(StaticError error, List<String> lines) {
  final line = error.line;

  final newLine = lines[line - 1]
      .replaceRange(error.column - 1, error.column - 1, 'const ');

  lines[error.line - 1] = newLine;

  final newFile = lines.join('\n');

  return newFile;
}

String _handleUnnecessaryConstInfo(StaticError error, List<String> lines) {
  final line = error.line;

  final newLine = lines[line - 1].replaceFirst('const ', '',
      lines[line - 1].lastIndexOf('const').clamp(0, lines[line - 1].length));

  lines[error.line - 1] = newLine;

  final newFile = lines.join('\n');

  return newFile;
}

String _handlePreferConstDeclarationsInfo(
    StaticError error, List<String> lines) {
  final line = error.line;

  final newLine =
      lines[line - 1].replaceAll('const ', '').replaceAll('final', 'const');

  lines[error.line - 1] = newLine;

  final newFile = lines.join('\n');

  return newFile;
}

class StaticError extends Equatable {
  final int line;
  final int column;
  final String description;
  final String code;
  final String type;
  final String path;

  const StaticError({
    required this.code,
    required this.type,
    required this.line,
    required this.column,
    required this.description,
    required this.path,
  });

  @override
  String toString() => '$type, $path:$line:$column, $description, $code';

  @override
  List<Object> get props => [path, line];
}

Usage: run dart apply.dart in the root project