Test failures on (mostly) macOS

[pdimov]

https://travis-ci.org/github/boostorg/json/builds/773287795

s390x fails many tests for non-obvious reasons. One thing to note is that it's a big endian platform (the only one such on Travis.)

Xcode 7.3 and 8.3 fail with:

clang-darwin.compile.c++ bin.v2/libs/json/build/clang-darwin-7.3/debug/address-model-32/cxxstd-11-iso/threading-multi/visibility-hidden/src.o
In file included from libs/json/src/src.cpp:10:
In file included from ./boost/json/src.hpp:27:
In file included from ./boost/json.hpp:15:
In file included from ./boost/json/array.hpp:16:
In file included from ./boost/json/storage_ptr.hpp:16:
./boost/json/detail/default_resource.hpp:84:5: error: constexpr constructor never produces a constant expression [-Winvalid-constexpr]
    holder()
    ^
./boost/json/detail/default_resource.hpp:85:11: note: non-literal type 'boost::json::detail::default_resource' cannot be used in a constant expression
        : mr()
          ^
1 error generated.
    "clang++" -x c++ -std=c++11 -fvisibility-inlines-hidden -fPIC -m32 -O0 -fno-inline -Wall -g -fvisibility=hidden -march=i686  -DBOOST_ALL_NO_LIB=1 -DBOOST_CONTAINER_DYN_LINK=1 -DBOOST_JSON_DYN_LINK=1 -DBOOST_JSON_SOURCE -I"."  -c -o "bin.v2/libs/json/build/clang-darwin-7.3/debug/address-model-32/cxxstd-11-iso/threading-multi/visibility-hidden/src.o" "libs/json/src/src.cpp"
...failed clang-darwin.compile.c++ bin.v2/libs/json/build/clang-darwin-7.3/debug/address-model-32/cxxstd-11-iso/threading-multi/visibility-hidden/src.o...

Xcode 9.4 fails with

clang-darwin.link bin.v2/libs/json/test/doc_quick_look.test/clang-darwin-9.1/debug/cxxstd-11-iso/threading-multi/visibility-hidden/doc_quick_look
Undefined symbols for architecture x86_64:
  "std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(char const*)", referenced from:
      boost::json::set3() in doc_quick_look.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
    "clang++"   -o "bin.v2/libs/json/test/doc_quick_look.test/clang-darwin-9.1/debug/cxxstd-11-iso/threading-multi/visibility-hidden/doc_quick_look" "bin.v2/libs/json/test/doc_quick_look.test/clang-darwin-9.1/debug/cxxstd-11-iso/threading-multi/visibility-hidden/doc_quick_look.o" "bin.v2/libs/json/test/doc_quick_look.test/clang-darwin-9.1/debug/cxxstd-11-iso/threading-multi/visibility-hidden/main.o" "bin.v2/libs/json/build/clang-darwin-9.1/debug/cxxstd-11-iso/threading-multi/visibility-hidden/libboost_json.dylib" "bin.v2/libs/container/build/clang-darwin-9.1/debug/cxxstd-11-iso/threading-multi/visibility-hidden/libboost_container.dylib"        -fPIC -m64 -std=c++11 -g -fvisibility=hidden -fvisibility-inlines-hidden
...failed clang-darwin.link bin.v2/libs/json/test/doc_quick_look.test/clang-darwin-9.1/debug/cxxstd-11-iso/threading-multi/visibility-hidden/doc_quick_look...

(interestingly, doc_quick_look is the only thing that fails to link in this manner.)

It also fails one test with

testing.capture-output bin.v2/libs/json/test/value.test/clang-darwin-9.1/release/address-model-32/cxxstd-11-iso/threading-multi/visibility-hidden/value.run
====== BEGIN OUTPUT ======
boost.json.value
#630 value.cpp(1476) failed: static_cast<float>(V) == static_cast<float>(jv.to_number<float>())
#640 value.cpp(1490) failed: static_cast<float>(V) == static_cast<float>(jv.to_number<float>())
6ms, 1 suites, 2 failures, 980 total.
EXIT STATUS: 1
====== END OUTPUT ======

but only in 32 bit mode.

Xcode 10.1 has the same link failure with doc_quick_look. It doesn't support 32 bits so the other failure isn't present. :-)

[grisumbras]

I've been investigating a different thing and built a 32-bit mingw version. That second problem is indeed related to 32 bit address model.

[grisumbras]

I've got these numbers:

2147483647 == V
2147483648 == static_cast<float>(V)

2147483647 == static_cast<std::int64_t>(V)
2147483648 == static_cast<float>(static_cast<std::int64_t>(V))

2147483647 == jv.to_number<float>()
2147483647 == static_cast<float>(jv.to_number<float>())

Somehow to_number is more precise than static_cast.

[grisumbras]

Is there a way I could test a PR on Xcode 7.3 or 8.3?