About a new Boost.Assert flag "BOOST_ASSERT_HANDLER_IS_NORETURN" (available from Boost 1.88)

assertion_failed.cc

#include <stdexcept>

namespace boost
{
    void assertion_failed(char const * expr, char const * function, char const * file, long line){
        (void)function;
        (void)file;
        (void)line;
        throw std::runtime_error(expr);
    }
    void assertion_failed_msg(char const * expr, char const * msg, char const * function, char const * file, long line){
        (void)msg;
        (void)function;
        (void)file;
        (void)line;
        throw std::runtime_error(expr);
    }
}

prog.cc

#define BOOST_ENABLE_ASSERT_HANDLER
//#define BOOST_ASSERT_HANDLER_IS_NORETURN

#include <boost/config.hpp> // BOOST_NORETURN
namespace boost
{
#if defined(BOOST_ASSERT_HANDLER_IS_NORETURN)
    BOOST_NORETURN
#endif
    void assertion_failed(char const * expr, char const * function, char const * file, long line); // user-defined
#if defined(BOOST_ASSERT_HANDLER_IS_NORETURN)
    BOOST_NORETURN
#endif
    void assertion_failed_msg(char const * expr, char const * msg, char const * function, char const * file, long line); // user-defined
}

#include <boost/array.hpp>
#include <cstdio>

int main(int argc, char **argv){
    (void)argv;
    boost::array<int, 3> a;
    if(argc==1)printf("%d\n", a[3]);
}

With -Wall, this program¹ raises Warray-bounds because:

1. BOOST_ENABLE_ASSERT_HANDLER is defined
2. assertion_failed is defined in different .cc and the compiler cannot notice this function throws
3. array.hpp impl is return BOOST_ASSERT_MSG( i < N, "out of range" ), elems[i];
4. assertion_failed declaration is not BOOST_NORETURN and short-circuit does not work

This can be a problem when -Werror is set.

Hence I introduced a new flag BOOST_ASSERT_HANDLER_IS_NORETURN ( https://github.com/boostorg/assert/pull/40 ) to make sure the short-circuit work.

You can confirm https://wandbox.org/permlink/iOhTvSL4wutMEROa does not raise Warray-bounds any longer.

1. I understand this is extreme example, but can be reproduced by boost::heap::fibonacci_heap<int> hp; hp.push(1); hp.pop(); as well, which is normal example. https://wandbox.org/permlink/1UtnWOMXIVSL3I62 ↩