Build error on Fedora 24 with gcc 6.1.1

[ragnar-ouchterlony]

Built using "cmake -DRAPIDJSON_HAS_STDSTRING=ON .. && make".

System is Fedora 24

gcc is 6.1.1.

Build ends with:

/extra/ragnar/source/rapidjson-master/test/unittest/namespacetest.cpp:39:19: required from here
/extra/ragnar/source/rapidjson-master/include/rapidjson/document.h:755:66: error: throw will always call terminate() [-Werror=terminate]
RAPIDJSON_ASSERT(this != &rhs);

Full output from cmake and make attached.

cmake.txt
build.txt

[pah]

Do you override RAPIDJSON_ASSERT with some kind of exception throwing mechanism?
The functions where this warnings are generated from are marked as RAPIDJSON_NOEXCEPT, which means that indeed throwing an exception from there will lead to a call to std::terminate.

[ragnar-ouchterlony]

No. I have not done any conscious overriding at least. I can reproduce it by doing the following steps:

git clone https://github.com/miloyip/rapidjson
cd rapidjson
mkdir build
cd build
cmake -DRAPIDJSON_HAS_STDSTRING=ON ..
make

[pah]

I have just added #667 with a proposed fix.

For document.h, I decided to keep the offending code, i.e. suppress the warning locally on GCC 6 and later (Clang might need to be added as well at some point).

For schema.h, the RAPIDJSON_NOEXCEPT annotation has been removed, as the corresponding constructor calls RAPIDJSON_NEW, which might indeed throw.

Some tests exposed -Wdangling-else warnings, which have been addressed, too.

[ragnar-ouchterlony]

Thanks for the fix.

But the change in readertest.cpp exposes another build problem for me.

[ 68%] Building CXX object test/unittest/CMakeFiles/unittest.dir/readertest.cpp.o
/extra/ragnar/source/rapidjson/test/unittest/readertest.cpp:32:1: error: unknown option after ‘#pragma GCC diagnostic’ kind [-Werror=pragmas]
RAPIDJSON_DIAG_OFF(dangling-else)
^~~~~~~~~

And I am a bit confused about that flag, since my gcc (from Fedora 24) does not seem to have any "-Wdangling-else" as seen by "gcc --help=warnings". I can also not find any reference to it in the online gcc documentation: https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/Option-Summary.html

$ gcc --version
gcc (GCC) 6.1.1 20160621 (Red Hat 6.1.1-3)

[pah]

Ok, it seems that the -Wdangling-else warnings showed up on a GCC 7.x development version. For now, it should be safe to drop the corresponding suppression in readertest.cpp.

[ragnar-ouchterlony]

Ah, I suspected as much, but did not find it easily.

[pah]

I've raised the GCC version to suppress the warning in readertest.cpp to 7.x or later, see #669.
See this patch for the addition of the flag in April 2016.

[ragnar-ouchterlony]

Great! Now I was able to build without problems.