anchor.diff:      final File syntheticPubspec = generatedDirectory.childFile('pubspec.yaml');
   
       // Check if contents of builders changed. If so, invalidate build script
  -    // and regnerate.
  +    // and regenerate.
       final YamlMap builders = flutterProject.builders;
       final List<int> appliedBuilderDigest = _produceScriptId(builders);
       if (scriptIdFile.existsSync() && buildSnapshot.existsSync()) {
  
positive.code: import 'build_script_generator.dart';
  
  /// The minimum version of build_runner we can support in the flutter tool.
  const String kMinimumBuildRunnerVersion = '1.2.8';
  
  /// A wrapper for a build_runner process which delegates to a generated
  /// build script.
  
negative.code:         }
        }
        stringBuffer.writeln('  build_runner: ^$kMinimumBuildRunnerVersion');
        stringBuffer.writeln('  build_daemon: $kSupportedBuildDaemonVersion');
        await syntheticPubspec.writeAsString(stringBuffer.toString());
  
        await pubGet(
  