Program: 61763
Project: 61763
Buggy source:
@Override public GraphTextWriter appendTo(GraphTextWriter writer,LocalData localData) throws InterruptedException {
  if (writer instanceof NulWriter) {
    ((NulWriter)writer).startLoop(loop.id,LoopWithType.LOOP_TYPE_SWITCH);
  }
  if (labelUsed) {
    writer.append("String_Node_Str" + loop.id + "String_Node_Str").newLine();
  }
  writer.append("String_Node_Str");
  switchedObject.toString(writer,localData);
  writer.append("String_Node_Str").startBlock();
  for (int i=0; i < caseCommands.size(); i++) {
    for (int k=0; k < valuesMapping.size(); k++) {
      if (valuesMapping.get(k) == i) {
        writer.append("String_Node_Str");
        caseValues.get(k).toString(writer,localData);
        writer.append("String_Node_Str").newLine();
      }
    }
    writer.indent();
    for (int j=0; j < caseCommands.get(i).size(); j++) {
      if (!caseCommands.get(i).get(j).isEmpty()) {
        caseCommands.get(i).get(j).toStringSemicoloned(writer,localData).newLine();
      }
    }
    writer.unindent();
  }
  if (defaultCommands != null) {
    if (defaultCommands.size() > 0) {
      writer.append("String_Node_Str");
      writer.append("String_Node_Str").newLine();
      writer.indent();
      for (int j=0; j < defaultCommands.size(); j++) {
        if (!defaultCommands.get(j).isEmpty()) {
          defaultCommands.get(j).toStringSemicoloned(writer,localData).newLine();
        }
      }
      writer.unindent();
    }
  }
  writer.endBlock();
  if (writer instanceof NulWriter) {
    LoopWithType loopOjb=((NulWriter)writer).endLoop(loop.id);
    labelUsed=loopOjb.used;
  }
  return writer;
}

Fixed version (ground truth):
@Override public GraphTextWriter appendTo(GraphTextWriter writer,LocalData localData) throws InterruptedException {
  if (writer instanceof NulWriter) {
    ((NulWriter)writer).startLoop(loop.id,LoopWithType.LOOP_TYPE_SWITCH);
  }
  if (labelUsed) {
    writer.append("String_Node_Str" + loop.id + "String_Node_Str").newLine();
  }
  writer.append("String_Node_Str");
  if (writer.getFormatting().spaceBeforeParenthesesSwitchParentheses) {
    writer.append("String_Node_Str");
  }
  writer.append("String_Node_Str");
  switchedObject.toString(writer,localData);
  writer.append("String_Node_Str").startBlock();
  for (int i=0; i < caseCommands.size(); i++) {
    for (int k=0; k < valuesMapping.size(); k++) {
      if (valuesMapping.get(k) == i) {
        writer.append("String_Node_Str");
        caseValues.get(k).toString(writer,localData);
        writer.append("String_Node_Str").newLine();
      }
    }
    writer.indent();
    for (int j=0; j < caseCommands.get(i).size(); j++) {
      if (!caseCommands.get(i).get(j).isEmpty()) {
        caseCommands.get(i).get(j).toStringSemicoloned(writer,localData).newLine();
      }
    }
    writer.unindent();
  }
  if (defaultCommands != null) {
    if (defaultCommands.size() > 0) {
      writer.append("String_Node_Str");
      writer.append("String_Node_Str").newLine();
      writer.indent();
      for (int j=0; j < defaultCommands.size(); j++) {
        if (!defaultCommands.get(j).isEmpty()) {
          defaultCommands.get(j).toStringSemicoloned(writer,localData).newLine();
        }
      }
      writer.unindent();
    }
  }
  writer.endBlock();
  if (writer instanceof NulWriter) {
    LoopWithType loopOjb=((NulWriter)writer).endLoop(loop.id);
    labelUsed=loopOjb.used;
  }
  return writer;
}