[Boost-users] boost 1.40 beta, serialization via base pointer crashes

18 Aug 2009

      The following example works on Linux/gcc but crashes on latest AIX v10.1
compiler

#include <fstream>
#include <assert.h>
#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/serialization/base_object.hpp>
#include <boost/serialization/string.hpp>         // no need to include
<string>
#include <boost/serialization/export.hpp>    // explicit code for exports
(place last)

class RepeatBase {
public:
    RepeatBase() {}
    virtual ~RepeatBase() {}
    virtual const std::string& name() const = 0;
private:
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & ar, const unsigned int version) {}
};

class RepeatDerived : public RepeatBase {
public:
    RepeatDerived( const std::string& name) : name_(name) {}
    RepeatDerived()  {}
    virtual const std::string& name() const { return name_;}
private:
    std::string  name_;
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & ar, const unsigned int version) {
        // save/load base class information
          ar & boost::serialization::base_object<RepeatBase>(*this);
         ar & name_;
    }
};

class Defs {
public:
    Defs(const std::string& f) : fileName_(f), repeat_(new RepeatDerived(f))
{}
    Defs() : repeat_(NULL) {}
    ~Defs() { delete repeat_;}
       bool operator==(const Defs& rhs) const { return fileName_ ==
rhs.fileName_;}

    const std::string& fileName() const { return fileName_;}

private:
    std::string fileName_;
    RepeatBase* repeat_;

    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & ar, const unsigned int /*version*/)  {
        ar & fileName_;
        ar & repeat_;
    }
};

BOOST_CLASS_EXPORT(RepeatBase);
BOOST_CLASS_EXPORT(RepeatDerived);
BOOST_SERIALIZATION_ASSUME_ABSTRACT(RepeatBase)

int main()
{
    // With this explicit cast we get a bit further, but still crashes on
AIX
    // i.e crash on ar.save_pointer(vp, bpos);
        //
    // boost::serialization::void_cast_register<RepeatDerived,
RepeatBase>(0,0);

    const Defs saveDefs("saveFile.txt");
    {
        // Save the defs file
        std::ofstream ofs( saveDefs.fileName().c_str() );
        boost::archive::text_oarchive oa( ofs );
        oa << saveDefs;
    }
    {
        // Restore the defs file
        Defs loadDefs;
        std::ifstream ifs(saveDefs.fileName().c_str());
        boost::archive::text_iarchive ia(ifs);
        ia >> loadDefs;

        assert( saveDefs == loadDefs );
     }
    return 0;
}
//=========================================================================================

   This bug was present in boost 1.39 and is still broken in boost 1.40.
   The code above shows that base/derived relationship work on one compiler
   but is _competely_ broken another. Explicitly registering the
base/derived
   relationship just moves the crash to a later point.

     template<class T>
     struct polymorphic
     {
         static void save(
             Archive &ar,
             T & t
         ){
              ......

             // convert pointer to more derived type. if this is thrown
             // it means that the base/derived relationship hasn't be
registered
             vp = serialization::void_downcast(
                 *true_type,
                 *this_type,
                 static_cast<const void *>(&t)
             );
             if(NULL == vp){
                 boost::serialization::throw_exception(

archive_exception(archive_exception::unregistered_cast)  //< crash1 here
                 );
             }

            .....
        ar.save_pointer(vp, bpos);  //< crashe2 here after explicit
base/derived registration

   I thought this bug had been fixed, so I am not sure if this is a
regression ?
   Is there any way I can help, as this is show stopper bug for us.

  Best regards,
Ta,
   Avi

[Boost-users] boost 1.40 beta, serialization via base pointer crashes

Avi Bahra