Re: [Boost-users] [serialization] assert loading shared_ptr to abstract base class using boost 1.35.0

From: Robert Ramey (ramey_at_[hidden])
Date: 2008-06-24 00:07:07

I think I fixed this in the trunk.

Robert Ramey

Ult Mundane wrote:
>> Hi there,
>>
>> Using the boost::serialization library, I'm hitting an
>> assert while deserializing. It happens only in a specific
>> set of circumstances requiring a shared_ptr to an abstract
>> base class.
>>
>> Class "Derived" is derived from class "AbstractBase" which
>> is abstract. I'm serializing two objects which are of type
>> shared_ptr<AbstractBase> that point to objects of type
>> Derived. After the two shared_ptr's are serialized to disk,
>> when I read them back in I hit an assert in
>> basic_iarchive.cpp: "Assertion `new_cid == cid' failed".
>> This assert happens on the second object only.
>>
>> As far as I can tell from the serialization documentation, I
>> am using the appropriate BOOST_CLASS_EXPORT() line for the
>> derived class, as well as registering the base-derived
>> relationship with base_object(), and I even threw in a
>> couple of BOOST_SERIALIZATION_SHARED_PTR() calls for good
>> measure although I don't think they do anything in my
>> environment.
>>
>> Two additional pieces of information:
>> - If the base class is not abstract, but I still use
>> BOOST_IS_ABSTRACT(), I get the same assert. This might
>> indicate that some necessary polymorphism code isn't being
>> generated as a result of declaring the class abstract.
>> - If I serialize the pointers directly instead of using
>> shared_ptr, it does not hit the assert.
>>
>> I have a workaround for this problem: it works as expected
>> if I define the load_construct_data() template function for
>> the base class do to nothing (assert), instead of using the
>> BOOST_IS_ABSTRACT() macro.
>>
>> Attached is the minimal code to reproduce the problem. I'm
>> using boost 1.35.0 with gcc 3.3.5 on Linux (RHEL4). Is there
>> something I'm missing to make this work?
>>
>> Thanks in advance,
>>
>> Ult
>>
>>
>
>
>
>> #include <fstream>
>>
>> #include <boost/archive/text_oarchive.hpp>
>> #include <boost/archive/text_iarchive.hpp>
>>
>> #include <boost/serialization/shared_ptr.hpp>
>> #include <boost/serialization/is_abstract.hpp>
>> #include <boost/serialization/export.hpp>
>>
>> class AbstractBase
>> {
>>  public:
>>    AbstractBase() : mInt(-1) { }
>>    virtual ~AbstractBase() { }
>>
>>    virtual void func() const = 0;
>>
>>    template<class Archive> void serialize(Archive & ar, const
>>    unsigned int) {
>>      ar & mInt;
>>    }
>>
>>    int mInt;
>> };
>>
>> BOOST_IS_ABSTRACT(AbstractBase);
>> BOOST_SERIALIZATION_SHARED_PTR(AbstractBase);
>> BOOST_CLASS_IMPLEMENTATION(AbstractBase,
>> boost::serialization::object_serializable);
>>
>> class Derived : public AbstractBase
>> {
>>  public:
>>    Derived() : mInt2(-2) { }
>>
>>    void func() const { }
>>
>>    template<class Archive> void serialize(Archive & ar, const
>>    unsigned int) {
>>      ar & boost::serialization::base_object<AbstractBase>(*this);
>>      ar & mInt2;
>>    }
>>    int mInt2;
>> };
>>
>> BOOST_CLASS_EXPORT(Derived);
>> BOOST_SERIALIZATION_SHARED_PTR(Derived);
>> BOOST_CLASS_IMPLEMENTATION(Derived,
>> boost::serialization::object_serializable);
>>
>> int main(int /* argc */, char * /* argv */[])
>> {
>>  char const * fname = "abstract.out";
>>
>>  boost::shared_ptr<AbstractBase> baseA(new Derived());
>>  boost::shared_ptr<AbstractBase> baseB(new Derived());
>>
>>  {
>>    std::ofstream ofs(fname, std::ios::out | std::ios::binary);
>>    boost::archive::text_oarchive oa(ofs);
>>
>>    oa & baseA;
>>    oa & baseB;
>>  }
>>
>>  {
>>    std::ifstream ifs(fname, std::ios::in | std::ios::binary);
>>    boost::archive::text_iarchive ia(ifs);
>>
>>    ia & baseA;
>>    std::cout << "The following line asserts:" << std::endl;
>>    ia & baseB;     // Assertion `new_cid == cid' failed
>>
>>    // Full text of assert:
>>    //
>>    //
>> /dev/libs/boost_1_35_0/libs/serialization/src/basic_iarchive.cpp:432:
>> const boost::archive::detail::basic_pointer_iserializer*
>> boost::archive::detail::basic_iarchive_impl::load_pointer(boost::archive::detail::basic_iarchive&,
>> void*&, const boost::archive::detail::basic_pointer_iserializer*,
>> const boost::archive::detail::basic_pointer_iserializer*(*)(const
>> boost::serialization::extended_type_info&)): Assertion `new_cid ==
>> cid' failed.
>>
>>  }
>> }
>>
>>
>
>
>
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