code: private function uncollapseErrors(&$log)
      {
          $groupStack = array();
          for ($i = 0, $count = \count($log); $i < $count; $i++) {
              $method = $log[$i][0];
              if (\in_array($method, array('group', 'groupCollapsed'))) {
                  $groupStack[] = $i;
              } elseif ($method == 'groupEnd') {
                  \array_pop($groupStack);
              } elseif (\in_array($method, array('error', 'warn'))) {
                  foreach ($groupStack as $i2) {
                      $log[$i2][0] = 'group';
                  }
              }
          }
      }
docs: Uncollapse groups containing errors.
  
  @param array $log log or summary
  
  @return void