id summary reporter owner description type status milestone component version severity resolution keywords cc 11342 Vector serialization with non-default-constructible element type fails to compile bugs@… Robert Ramey "The following sample compiles in Boost 1.57.0 but doesn't in Boost 1.58.0: {{{ #include #include #include class Foo{ friend class boost::serialization::access; template void serialize(Archive & ar, const unsigned int) { ar & BOOST_SERIALIZATION_NVP(i); } int i; Foo():i(0){} public: Foo(int k):i(k){} }; int main(int argc, char *argv[]) { std::vector< Foo> f; f.push_back(Foo(12)); std::ofstream os(""path""); boost::archive::xml_oarchive oa(os); oa << boost::serialization::make_nvp(""f"", f); os.close(); std::vector g; std::ifstream is(""path""); boost::archive::xml_iarchive ia(is); ia >> boost::serialization::make_nvp(""f"", g); } }}} The problem is a new piece of code that tries to switch on `is_default_constructible` ***at compile time***. That can't work: (from serialization/vector.hpp in the unoptimized version of load(...)): {{{ if(detail::is_default_constructible()){ t.resize(count); // ... snip ... } else{ t.reserve(count); // ... snip ... } }}} Instead of having the branches in the same flow code, it should be dispatched so that only the applicable branch is instantiated. I tested with this simplistic approach: {{{ namespace sehe_bugfix { template inline void load_elements( Archive & ar, std::vector &t, const unsigned int /* file_version */, collection_size_type count, mpl::true_ ){ const boost::archive::library_version_type library_version( ar.get_library_version() ); item_version_type item_version(0); if(boost::archive::library_version_type(3) < library_version){ ar >> BOOST_SERIALIZATION_NVP(item_version); } t.resize(count); typename std::vector::iterator hint; hint = t.begin(); while(count-- > 0){ ar >> boost::serialization::make_nvp(""item"", *hint++); } } template inline void load_elements( Archive & ar, std::vector &t, const unsigned int /* file_version */, collection_size_type count, mpl::false_ ){ const boost::archive::library_version_type library_version( ar.get_library_version() ); item_version_type item_version(0); if(boost::archive::library_version_type(3) < library_version){ ar >> BOOST_SERIALIZATION_NVP(item_version); } t.reserve(count); while(count-- > 0){ detail::stack_construct u(ar, item_version); ar >> boost::serialization::make_nvp(""item"", u.reference()); t.push_back(u.reference()); ar.reset_object_address(& t.back() , & u.reference()); } } } template inline void load( Archive & ar, std::vector &t, const unsigned int file_version, mpl::false_ ){ const boost::archive::library_version_type library_version( ar.get_library_version() ); // retrieve number of elements item_version_type item_version(0); collection_size_type count; ar >> BOOST_SERIALIZATION_NVP(count); sehe_bugfix::load_elements(ar, t, file_version, count, detail::is_default_constructible()); } }}} " Bugs closed To Be Determined serialization Boost 1.58.0 Regression fixed