Fix clang -Wdeprecated-copy warning when using -std=gnu++2b in boost/archive/detail/helper_collection.hpp

[Romain-Geissler-1A]

In file included from magadm/CmdGetInfoHTHSession.cpp:24:
In file included from /remote/users/mlamesch/CloneFromPlatinum/SI_Pack23-2/common/include/si/common/HTHSegmentationCacheInfoSerialization.h:19:
In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/archive/text_iarchive.hpp:24:
In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/archive/basic_text_iarchive.hpp:30:
In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/archive/detail/common_iarchive.hpp:21:
In file included from /data/mwrep/res/osp/Boost/23-0-0-0/include/boost/archive/detail/basic_iarchive.hpp:28:
/data/mwrep/res/osp/Boost/23-0-0-0/include/boost/archive/detail/helper_collection.hpp:58:44: error: definition of implicit copy constructor for 'predicate' is deprecated because it has a user-declared copy assignment operator [-Werror,-Wdeprecated-copy]
        BOOST_DELETED_FUNCTION(predicate & operator=(const predicate & rhs))
                                           ^
/opt/1A/toolchain/x86_64-v23.0.2/lib64/gcc/x86_64-1a-linux-gnu/13.0.0/../../../../include/c++/13.0.0/bits/predefined_ops.h:325:37: note: in implicit copy constructor for 'boost::archive::detail::helper_collection::predicate' first required here
    { return _Iter_pred<_Predicate>(_GLIBCXX_MOVE(__pred)); }
                                    ^
/opt/1A/toolchain/x86_64-v23.0.2/lib64/gcc/x86_64-1a-linux-gnu/13.0.0/../../../../include/c++/13.0.0/bits/move.h:167:30: note: expanded from macro '_GLIBCXX_MOVE'
                             ^
/opt/1A/toolchain/x86_64-v23.0.2/lib64/gcc/x86_64-1a-linux-gnu/13.0.0/../../../../include/c++/13.0.0/bits/stl_algo.h:3923:26: note: in instantiation of function template specialization '__gnu_cxx::__ops::__pred_iter<boost::archive::detail::helper_collection::predicate>' requested here
                            __gnu_cxx::__ops::__pred_iter(__pred));
                                              ^
/data/mwrep/res/osp/Boost/23-0-0-0/include/boost/archive/detail/helper_collection.hpp:75:18: note: in instantiation of function template specialization 'std::find_if<__gnu_cxx::__normal_iterator<std::pair<const void *, boost::shared_ptr<void>> *, std::vector<std::pair<const void *, boost::shared_ptr<void>>>>, boost::archive::detail::helper_collection::predicate>' requested here
            std::find_if(
                 ^

[robertramey]

Did you actually test this? When merge this change I get compile error:

`class helper_collection { helper_collection(const helper_collection&); // non-copyable helper_collection& operator = (const helper_collection&); // non-copyable

// note: we dont' actually "share" the function object pointer
// we only use shared_ptr to make sure that it get's deleted

typedef std::pair<
    const void *,
    boost::shared_ptr<void>
> helper_value_type;
template<class T>
boost::shared_ptr<void> make_helper_ptr(){
    // use boost::shared_ptr rather than std::shared_ptr to maintain
    // c++03 compatibility
    return boost::make_shared<T>();
}

typedef std::vector<helper_value_type> collection;
collection m_collection;

struct predicate {
    BOOST_DEFAULTED_FUNCTION(predicate(const predicate& rhs), { m_ti = rhs.m_ti; }) // Cannot assign to non-static data member 'm_ti' with const-qualified type 'const void *const'
    BOOST_DELETED_FUNCTION(predicate & operator=(const predicate & rhs))
public:
    const void * const m_ti;  // Non-static data member 'm_ti' declared const here
    bool operator()(helper_value_type const &rhs) const {
        return m_ti == rhs.first;
    }
    predicate(const void * ti) :
        m_ti(ti)
    {}
};

protected: helper_collection(){} ~helper_collection(){} public: template Helper& find_helper(void * const id = 0) { collection::const_iterator it = std::find_if( m_collection.begin(), m_collection.end(), predicate(id) );

    void * rval = 0;
    if(it == m_collection.end()){
        m_collection.push_back(
            std::make_pair(id, make_helper_ptr<Helper>())
        );
        rval = m_collection.back().second.get();
    }
    else{
        rval = it->second.get();
    }
    return *static_cast<Helper *>(rval);
}

}; `

[Romain-Geissler-1A]

I am not at work right now, so I cannot check, but all patches we submit we usually apply it in our own code base. However it’s been a long time we don’t use C++03 anymore, so in our case what we test is the explicitly defaulted copy constructor. I actually expect the CI to detect these kind of things to prevent from merging too soon.

i guess here the fix is to initialize the member outside the body, but I don’t know if this is allowed by this boost macro. I can have a look on Friday when I am back to work.