From: Robert Ramey (ramey_at_[hidden])
Date: 2007-08-15 11:43:27
OK - I see the problem - good example. I don't see an obvious or
easy fix. I'll look into it.
Robert Ramey
Sergey Skorniakov wrote:
> Unfortunately, current tracking implementation can also leads to
> weird version incompatibility. The unlucky combination is
> object_serializable + track_selectivly. Suppose, someone have code
> that serizalizes vector<int> to file (by value). After some time,
> some code that serializes vector<int> as pointer is added to program.
> Its enough to make old files unreadable (or readable with errors).
> Sample code:
>
> void TestTrack2Err(boost::archive::polymorphic_xml_iarchive &ar)
> {
> std::vector<int> *p;
> ar & BOOST_SERIALIZATION_NVP(p);
> // saving of vector<int>* is absent intentionaly to simulate
> different versions of saving and loading code }
> void TestTrack2()
> {
> std::stringstream s;
> std::vector<int> x;
> x.push_back(4);
> {
> boost::archive::polymorphic_text_oarchive ar(s);
> ar & BOOST_SERIALIZATION_NVP(x);
> }
> x.clear();
> {
> boost::archive::polymorphic_text_iarchive ar(s);
> ar & BOOST_SERIALIZATION_NVP(x);
> assert(x.size() == 1); // The vector is empty at this point -
> unless loading of vector<int>* is commented out }
> }
>
> The consequences of error can vary from noting (especially with xml
> archives) to program crashes in some more difficult cases. I have
> recently encountered this error when dealing with a big project (more
> than 500 serialized types) and have no idea how I can get out of a
> difficulty.
>