Program: 33479
Project: 33479
Buggy source:
@Override public List<Row> process(RowScanner rowScanner,CustomColumnFactory customColumnFactory,ColumnFamilyStore table,RowIndex currentIndex) throws Exception {
  Options options=rowScanner.getOptions();
  Group group=new Group(options,aggregates,groupBy,groupByExpressions);
  if (aggregates.length == 1 && !aggregates[0].distinct && groupBy == null) {
    Count count=new Count(aggregates[0],null,false);
    count.count=rowScanner.getCollector().docs().size();
    group.groups.put(new Tuple(Collections.EMPTY_MAP,Collections.EMPTY_MAP,simpleExpressions),count);
    Row row=customColumnFactory.getRowWithMetaColumn(table,currentIndex,group.toByteBuffer());
    return Collections.singletonList(row);
  }
  Tuple tuple=new Tuple(positions,allValidators,simpleExpressions);
  if (rowScanner.getCollector().canByPassRowFetch()) {
    Iterator<IndexEntryCollector.IndexEntry> indexIterator=rowScanner.getCollector().docs().iterator();
    while (indexIterator.hasNext()) {
      IndexEntryCollector.IndexEntry indexEntry=indexIterator.next();
      tuple.load(indexEntry);
      group.addTuple(tuple);
    }
  }
 else {
    if (chunkSize == 1) {
      while (rowScanner.hasNext()) {
        Row row=rowScanner.next();
        tuple.load(row,table);
        group.addTuple(tuple);
      }
    }
 else {
      List<Row> rows;
      while (rowScanner.hasNext()) {
        rows=new ArrayList<>(chunkSize);
        for (int i=0; i < chunkSize; i++) {
          if (!rowScanner.hasNext())           break;
          rows.add(rowScanner.next());
        }
        for (        Row row : rows) {
          tuple.load(row,table);
          group.addTuple(tuple);
        }
      }
    }
  }
  Utils.SimpleTimer timer3=Utils.getStartedTimer(SearchSupport.logger);
  ByteBuffer groupBuffer=group.toByteBuffer();
  timer3.endLogTime("String_Node_Str" + group.groups.size() + "String_Node_Str");
  Row row=customColumnFactory.getRowWithMetaColumn(table,currentIndex,groupBuffer);
  return Collections.singletonList(row);
}

Fixed version (ground truth):
@Override public List<Row> process(RowScanner rowScanner,CustomColumnFactory customColumnFactory,ColumnFamilyStore table,RowIndex currentIndex) throws Exception {
  Options options=rowScanner.getOptions();
  Group group=new Group(options,aggregates,groupBy,groupByExpressions);
  if (aggregates.length == 1 && !aggregates[0].distinct && "String_Node_Str".equalsIgnoreCase(aggregates[0].getType()) && groupBy == null) {
    Count count=new Count(aggregates[0],null,false);
    count.count=rowScanner.getCollector().docs().size();
    group.groups.put(new Tuple(Collections.EMPTY_MAP,Collections.EMPTY_MAP,simpleExpressions),count);
    Row row=customColumnFactory.getRowWithMetaColumn(table,currentIndex,group.toByteBuffer());
    return Collections.singletonList(row);
  }
  Tuple tuple=new Tuple(positions,allValidators,simpleExpressions);
  if (rowScanner.getCollector().canByPassRowFetch()) {
    Iterator<IndexEntryCollector.IndexEntry> indexIterator=rowScanner.getCollector().docs().iterator();
    while (indexIterator.hasNext()) {
      IndexEntryCollector.IndexEntry indexEntry=indexIterator.next();
      tuple.load(indexEntry);
      group.addTuple(tuple);
    }
  }
 else {
    if (chunkSize == 1) {
      while (rowScanner.hasNext()) {
        Row row=rowScanner.next();
        tuple.load(row,table);
        group.addTuple(tuple);
      }
    }
 else {
      List<Row> rows;
      while (rowScanner.hasNext()) {
        rows=new ArrayList<>(chunkSize);
        for (int i=0; i < chunkSize; i++) {
          if (!rowScanner.hasNext())           break;
          rows.add(rowScanner.next());
        }
        for (        Row row : rows) {
          tuple.load(row,table);
          group.addTuple(tuple);
        }
      }
    }
  }
  Utils.SimpleTimer timer3=Utils.getStartedTimer(SearchSupport.logger);
  ByteBuffer groupBuffer=group.toByteBuffer();
  timer3.endLogTime("String_Node_Str" + group.groups.size() + "String_Node_Str");
  Row row=customColumnFactory.getRowWithMetaColumn(table,currentIndex,groupBuffer);
  return Collections.singletonList(row);
}