boostorg
Incompability between standalone mode and older boost libraries
I would like to report an edge case that there is some dependency left between standalone Boost::JSON library and older Boost libraries. Below is a minimal example failing to compile with BOOST_STATIC_ASSERT errors inside standard manylinux2014 docker environment, which is based on Centos7 having Boost v1.53 using g++9.3.
#include <iostream>
#include <boost/bimap/bimap.hpp> // From Boost 1.53. (The program compiles when removed.)
#define BOOST_JSON_STANDALONE 1
#include <boost/json.hpp> // From Boost::JSON 1.76.
int main(){
auto ja = boost::json::array({1,2,3});
std::cout << ja << std::endl;
return 0;
}
The compilation produces several error messages such as:
/usr/local/include/boost/json/storage_ptr.hpp:491:39: error: macro "BOOST_STATIC_ASSERT" passed 2 arguments, but takes just 1
491 | memory_resource, T>::value);
| ^
In file included from /usr/include/boost/serialization/tracking.hpp:20,
from /usr/include/boost/serialization/nvp.hpp:32,
from /usr/include/boost/bimap/bimap.hpp:57,
from /workspaces/vevatools/data/bsa_example.cpp:4:
/usr/include/boost/static_assert.hpp:56: note: macro "BOOST_STATIC_ASSERT" defined here
56 | # define BOOST_STATIC_ASSERT( B ) static_assert(B, #B)
You may be surprised to discover that I did not test Boost.JSON with every possible earlier version of Boost :) I'm not sure that this is a supported configuration. @glenfe ?
It defines BOOST_STATIC_ASSERT if it doesn't exist, but it would better if it did not do this: https://github.com/boostorg/json/blob/master/include/boost/json/detail/config.hpp#L93-L95
Instead it could unconditionally use BOOST_JSON_STATIC_ASSERT which in non-standalone mode might make use of BOOST_STATIC_ASSERT.
Ah this is with standalone Boost.JSON, which I suppose in theory should work with any other library. There are a few other boost macros that it defines in standalone.
Same with all the other Boost macros - Boost.JSON shouldn't (re)define them.
