[pkg-boost-devel] Bug#444359: also breaks other packages

[Jiri Palecek]

On Tuesday 11 December 2007 22:16:12 brian m. carlson wrote:
> On Mon, Dec 10, 2007 at 07:34:27PM -0700, Martin Michlmayr wrote:
> >> In file included from /usr/include/boost/python/class.hpp:29,
> >>                  from /usr/include/boost/python.hpp:18,
> >>                  from src/wrapper/common.hpp:1,
> >>                  from src/wrapper/basics.cpp:11:
> >> /usr/include/boost/python/detail/def_helper.hpp:192: error: declaration
> >> of 'typename
> >> boost::python::detail::keyword_extract<boost::tuples::tuple<const T1&,
> >> const T2&, const T3&, const T4&, boost::python::default_call_policies,
> >> boost::python::detail::keywords<0ul>, const char*, void
> >> (boost::python::detail::not_specified::*)(), boost::tuples::null_type,
> >> boost::tuples::null_type> >::result_type
> >> boost::python::detail::def_helper<T1, T2, T3, T4>::keywords() const'
> >> /usr/include/boost/python/args_fwd.hpp:35: error: changes meaning of
> >> 'keywords' from 'struct boost::python::detail::keywords<0ul>'
>
> Within a scope, each name can have only one meaning.  The latter header
> declares a function named keywords, but before that point the name
> refers to struct boost::python::detail::keywords<0ul>, but after it
> refers to the function.  Hence, before that point, invoking keywords()
> would create a new instance of an object, whereas afterward, it would
> invoke the function.  Changing the meaning of the name like that is not
> allowed.

Yes, but this only applies to classes.

> This looks like a difficult problem, but the general solution is to
> either rename the function or move the declaration of the function to
> someplace where the other name isn't in scope.  The latter doesn't seem
> possible here, so the former looks like the only option.  I'd suggest
> talking to upstream and seeing what they're doing about this.

The problem is not difficult at all. The correct, and minimal fix would be to 
refer to the keywords not-the-member-function as "struct keywords<0>" at the 
beginning of the def_helper class definition.

> >> /usr/include/boost/type_traits/is_convertible.hpp:128: error: static
> >> data member
> >> 'boost::detail::is_convertible_basic_impl<<unnamed>::TagWrap*&,
> >> <unnamed>::TagWrap*>::_m_from' used, but not defined
>
> static data members must be explicitly defined, not just declared.  In
> this case, _m_from is declared, but no explicit initialization has
> occurred.  The solution is to actually define the static data member.

This seems like a bug in the compiler (or something), the static constants 
like this are always initialized (at least should in boost). Check the 
preprocessed source (gcc -E ...) for what's actually in the definition of 
is_convertible_basic_impl.

Regards
    Jiri Palecek