id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
7240	serialization backward compatibility issue with class_id_type attribute	ggagniard@…	Robert Ramey	"There is a backward compatibility issue in current boost::serialization around the class_id_type attribute.

It is actually impossible to read binary archives written with boost 1.39 (format 5) with a boost release > 1.43.

For instance, with boost 1.47.0 :

test_serialization: /home/ggagniard/dev/boost-1.47.0.bug/include/boost/archive/basic_archive.hpp:116: boost::archive::class_id_type::class_id_type(int): Assertion `t_ <= boost::integer_traits<base_type>::const_max' failed.

Please note that the same error still occurs with boost 1.50.0, the current stable release.

After having a look at the class_id_type serialization in binary archives, I think I found the culprit :

In boost/archive/basic_binary_iarchive.hpp :

{{{
    void load_override(class_id_type & t, int version){
        library_version_type lvt = this->get_library_version();
        if(boost::archive::library_version_type(7) < lvt){
            this->detail_common_iarchive::load_override(t, version);
        }
        else
        if(boost::archive::library_version_type(6) < lvt){
            int_least16_t x=0;
            * this->This() >> x;
            t = boost::archive::class_id_type(x);
        }
        else{
            int x=0;
            * this->This() >> x;
            t = boost::archive::class_id_type(x);
        }
    }
}}}

Here, archives whose version <= 6 get their class_id_type read as an int ...

However, in boost 1.43 (format 7) :

{{{
    void load_override(class_id_type & t, int){
        // upto 32K classes
        int_least16_t x=0;
        * this->This() >> x;
        t = class_id_type(x);
    }
}}}

It is clear than any library version <= 7 have their class_id_type serialized as a int_least16_t, so the current load_override method is incorrect for versions <= 6 ..."	Patches	new	To Be Determined	serialization	Boost 1.50.0	Showstopper