提升序列化:向前兼容失败，出现输入流错误

您的类型不是多态的。版本控制可能与事情无关。

• http://www.boost.org/doc/libs/1_60_0/libs/serialization/doc/serialization.html#derivedpointers

  事实证明，序列化的对象类型取决于基类（在本例中为 base）是否为多调类。如果 base 不是多态的，也就是说，如果它没有虚函数，则将序列化 base 类型的对象。任何派生类中的信息都将丢失。如果这是想要的（通常不是），那么不需要其他努力。

您可以轻松验证这一点：向量仅反序列化A s：

住在科里鲁

#include <boost/serialization/serialization.hpp>
#include <boost/serialization/version.hpp>
class A {
  public:
    A(){}
  private:
    friend class boost::serialization::access;
    template <class Archive> void serialize(Archive &ar, const unsigned int version) { ar &mAttributeFromA; }
    std::string mAttributeFromA = "mAttributeFromA";
};
BOOST_CLASS_VERSION(A, 0)
class B : public A {
  public:
    B(){}
  private:
    friend class boost::serialization::access;
    template <class Archive> void serialize(Archive &ar, const unsigned int version) {
        ar &mAttributeFromB;
        if (version == 1)
            ar &mNewAttribute;
    }
    std::string mAttributeFromB = "mAttributeFromB";
    std::string mNewAttribute   = "mNewAttribute";
};
BOOST_CLASS_VERSION(B, 1)
#include <boost/ptr_container/serialize_ptr_vector.hpp>
class Manager {
  public:
    boost::ptr_vector<A> mListOfA; // can store A or B
  private:
    friend class boost::serialization::access;
    template <class Archive> void serialize(Archive &ar, const unsigned int /*version*/) { ar &mListOfA; }
};
BOOST_CLASS_VERSION(Manager, 0)
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <sstream>
int main() {
    using namespace boost;
    std::stringstream ss;
    { 
        archive::text_oarchive oa(ss); 
        Manager mgr;
        mgr.mListOfA.push_back(new A);
        mgr.mListOfA.push_back(new B);
        oa << mgr;
    }
    std::cout << ss.str() << "n";
    { 
        archive::text_iarchive ia(ss); 
        Manager mgr;
        ia >> mgr;
        std::cout << "Deserialized: " << mgr.mListOfA.size() << "n";
    }
}

指纹

22 serialization::archive 13 0 0 0 0 2 2 1 0
0 15 mAttributeFromA 2
1 15 mAttributeFromA
Deserialized: 2

溶液：

1. 使层次结构实际上具有多态性
2. 添加基对象的序列化
3. 注册派生类型
4. ???
5. 利润！

样品 （WIP） https://www.livecoding.tv/sehe/

住在科里鲁

#include <boost/serialization/serialization.hpp>
#include <boost/serialization/base_object.hpp>
#include <boost/serialization/export.hpp>
#include <boost/serialization/version.hpp>
class A {
  public:
    A(){}
    virtual ~A() = default;
  private:
    friend class boost::serialization::access;
    template <class Archive> void serialize(Archive &ar, const unsigned int version) {
        ar &mAttributeFromA; 
    }
    std::string mAttributeFromA = "mAttributeFromA";
};
BOOST_CLASS_VERSION(A, 0)
class B : public A {
  public:
    B(){}
  private:
    friend class boost::serialization::access;
    template <class Archive> void serialize(Archive &ar, const unsigned int version)
    {
        ar &boost::serialization::base_object<A>(*this);
        ar &mAttributeFromB;
        if (version == 1)
            ar &mNewAttribute;
    }
    std::string mAttributeFromB = "mAttributeFromB";
    std::string mNewAttribute   = "mNewAttribute";
};
BOOST_CLASS_VERSION(B, 1)
BOOST_CLASS_EXPORT(A)
BOOST_CLASS_EXPORT(B)
#include <boost/ptr_container/serialize_ptr_vector.hpp>
class Manager {
  public:
    boost::ptr_vector<A> mListOfA; // can store A or B
  private:
    friend class boost::serialization::access;
    template <class Archive> void serialize(Archive &ar, const unsigned int /*version*/) { ar &mListOfA; }
};
BOOST_CLASS_VERSION(Manager, 0)
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <sstream>
int main() {
    using namespace boost;
    std::stringstream ss;
    { 
        archive::text_oarchive oa(ss); 
        Manager mgr;
        mgr.mListOfA.push_back(new A);
        mgr.mListOfA.push_back(new B);
        oa << mgr;
    }
    std::cout << ss.str() << "n";
    { 
        archive::text_iarchive ia(ss); 
        Manager mgr;
        ia >> mgr;
        std::cout << "Deserialized: " << mgr.mListOfA.size() << "n";
    }
}

指纹

22 serialization::archive 13 0 0 0 0 2 2 1 0
0 15 mAttributeFromA 3 1 B 1 1
1
2 15 mAttributeFromA 15 mAttributeFromB 13 mNewAttribute
Deserialized: 2

标准提升存档（包括二进制文件）不支持向前（向上）兼容性。

有一个 xml 存档的补丁（5 年前提出，仍然不包括在内），它允许部分向前兼容 - 跳过未知字段。

有一个实验性的3rdaprty ptree存档，它也支持添加新字段。

启用二进制存档的向前兼容性将需要对其进行重大修改。

Google 协议缓冲区提供开箱即用的向前兼容性。