anchor.diff:  import '../base/common.dart';
   import '../base/file_system.dart';
   import '../base/logger.dart';
  +import '../base/platform.dart';
   import '../base/process.dart';
  +import '../base/utils.dart';
   import '../cache.dart';
   import '../globals.dart';
   import 'sdk.dart';
  
positive.code:     final int code = await runCommandAndStreamOutput(args,
        workingDirectory: directory,
        mapFunction: _filterOverrideWarnings,
        environment: <String, String>{ 'FLUTTER_ROOT': Cache.flutterRoot }
      );
      status.stop();
      if (code != 0)
  
negative.code: 
  final RegExp _analyzerWarning = new RegExp(r'^! \w+ [^ ]+ from path \.\./\.\./bin/cache/dart-sdk/lib/\w+$');
  
  /// The console environment key used by the pub tool.
  const String _pubEnvironmentKey = 'PUB_ENVIRONMENT';
  
  /// Returns the environment value that should be used when running pub.
  ///
  /// Includes any existing environment variable, if one exists.
  String _getPubEnvironmentValue() {
    final List<String> values = <String>[];
  
    final String existing = platform.environment[_pubEnvironmentKey];
  
    if ((existing != null) && existing.isNotEmpty) {
      values.add(existing);
    }
  
    if (isRunningOnBot) {
      values.add('flutter_bot');
    }
  
    values.add('flutter_cli');
  
    return values.join(':');
  }
  
  String _filterOverrideWarnings(String message) {
    // This function filters out these three messages:
    //   Warning: You are using these overridden dependencies:
  