Ticket #10740: bug.2.cpp

#include <iostream>
#include <vector>
#include <fstream>
#include <cassert>

#include <boost/serialization/vector.hpp>
#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/xml_iarchive.hpp>

struct dummy {
    template<class Archive>
    void serialize(Archive& ar, unsigned int version) {}
};

int main() {
    // One-level container 
    // For comparison only. This shows the expected behaviour. 
    {
        // Create a dummy object in a vector
        std::vector<dummy> l(1);

        // Let pd point to that dummy object
        dummy* pd = &l.back();

        // Serialize and deserialize the vector and the pointer
        // Here, the order is important: We have to (de)serialize the vector first,
        // otherwise we run into an issue similar to what is described at 
        // http://www.boost.org/doc/libs/1_57_0/libs/serialization/doc/exceptions.html#pointer_conflict
        {
            std::ofstream ofs("one_level.xml");
            boost::archive::xml_oarchive oa(ofs);
            oa << BOOST_SERIALIZATION_NVP(l) << BOOST_SERIALIZATION_NVP(pd);
        }
        {
            std::ifstream ifs("one_level.xml");
            boost::archive::xml_iarchive ia(ifs);
            ia >> BOOST_SERIALIZATION_NVP(l) >> BOOST_SERIALIZATION_NVP(pd);
        }

        // Thanks to address tracking, pd still points to the dummy object, 
        // even if the latter is loaded at a different address.
        assert(&l.back() == pd); // Does not fire
    }

    std::cout << std::endl;

    // Two-level container 
    // This is buggy. 
    {
        // Create a dummy object in a *nested* vector
        std::vector<std::vector<dummy>> l(1, std::vector<dummy>(1));

        // Again, let pd point to the dummy object
        dummy* pd = &l.back().back();

        // Same as before...
        {
            std::ofstream ofs("two_level.xml");
            boost::archive::xml_oarchive oa(ofs);
            oa << BOOST_SERIALIZATION_NVP(l) << BOOST_SERIALIZATION_NVP(pd);
        }
        {
            std::ifstream ifs("two_level.xml");
            boost::archive::xml_iarchive ia(ifs);
            ia >> BOOST_SERIALIZATION_NVP(l) >> BOOST_SERIALIZATION_NVP(pd);
        }

        // Again, we would like pd to point to the dummy object, independent
        // of where it is loaded. This is not the case, however. 
        assert(&l.back().back() == pd); // Does fire!!!
    }

    return 0;
}