anchor.diff:  String builderBase;
   int buildNumber;
   String token;
  -List<String> configurations;
  -Map<String, List<Map<String, dynamic>>> failures = {};
   http.Client client;
   
   String get buildTable => builder.endsWith('-try') ? 'try_builds' : 'builds';
  
positive.code:   return 'missing hash for commit $index';
  }
  
  Future<void> printActiveFailures() async {
    for (final configuration in configurations) {
      final response =
          await runFirestoreQuery(unapprovedFailuresQuery(configuration));
  
negative.code:         ', expected ',
          failure['expected'],
          ') at ',
          failure['start_commit'].substring(0, 6),
          if (failure['end_commit'] != failure['start_commit']) ...[
            '..',
            failure['end_commit'].substring(0, 6)
          ]
        ].join(''));
      }
  