Rollback stateCount accounting thrown-off when exception out of rollbackState

But, there is truly a bug here,

  @Override
  protected void rollback(final TEnvironment env)
      throws IOException, InterruptedException {
    if (isEofState()) stateCount--;
    try {
      updateTimestamp();
      rollbackState(env, getCurrentState());
      stateCount--;
    } finally {
      updateTimestamp();
    }
  }
We need to decrease the stateCount when rolling back, so we can rollback for the previous state correctly. But. since a exception is thrown, the decrease for stateCount never happen. So ProcedureExecutor will continue to rollback for only one state(the one throw a exception) until the end of the execution stack.