ordered_json::reset() compile error with nvcc

[lashgar]

Compiling this code:

#include <nlohmann/json.hpp>
int main()
{
  nlohmann::ordered_json metadata;
  metadata.erase("key"); 
  return 0;
}

with following command:
/usr/local/cuda-11.4/bin/nvcc -I/path/to/nlohmann-json/include/ -c file.cu -o a.out
fails with:

(const BasicJsonType &) [with BasicJsonType=nlohmann::json]"
          detected during instantiation of "std::size_t nlohmann::detail::hash(const BasicJsonType &) [with BasicJsonType=nlohmann::json]" 
/path/to/nlohmann-json/include/nlohmann/json.hpp(8709): here

/path/to/nlohmann-json/include/nlohmann/ordered_map.hpp: In instantiation of ‘typename std::vector<std::pair<const _Key, _Tp>, Allocator>::size_type nlohmann::ordered_map<Key, T, IgnoredLess, Allocator>::erase(const Key&) [with Key = std::__cxx11::basic_string<char>; T = nlohmann::basic_json<nlohmann::ordered_map>; IgnoredLess = std::less<>; Allocator = std::allocator<std::pair<const std::__cxx11::basic_string<char>, nlohmann::basic_json<nlohmann::ordered_map> > >; typename std::vector<std::pair<const _Key, _Tp>, Allocator>::size_type = long unsigned int]’:
/path/to/nlohmann-json/include/nlohmann/json.hpp:4241:37:   required from ‘nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::size_type nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::erase(const typename ObjectType<StringType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>, std::less<void>, AllocatorType<std::pair<const StringType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType> > > >::key_type&) [with ObjectType = nlohmann::ordered_map; ArrayType = std::vector; StringType = std::__cxx11::basic_string<char>; BooleanType = bool; NumberIntegerType = long int; NumberUnsignedType = long unsigned int; NumberFloatType = double; AllocatorType = std::allocator; JSONSerializer = nlohmann::adl_serializer; BinaryType = std::vector<unsigned char>; nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::size_type = long unsigned int; typename ObjectType<StringType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>, std::less<void>, AllocatorType<std::pair<const StringType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType> > > >::key_type = std::__cxx11::basic_string<char>]’
file.cu:7:21:   required from here
/path/to/nlohmann-json/include/nlohmann/ordered_map.hpp:92:6: error: object type ‘std::pair<const std::__cxx11::basic_string<char>, nlohmann::basic_json<nlohmann::ordered_map> >’ does not match destructor name ~‘value_type’
   92 |                     it->~value_type(); // Destroy but keep allocation
      |      ^         
make: *** [Makefile:13: toy] Error 1

nlohmann json version: 3.9.1
gcc version: 9.3

Tested with nvcc version 11.0, 11.1, 11.2, 11.3, and 11.4 with same error. This code compiles fine with gcc. Possibly an nvcc/C++ bug, but there might be a solution in nlohmann/json side?

[nlohmann]

Thanks for reporting. We really need an NVCC running in our CI - see also #2676. We have nvcc 10.1.243 in our Docker image (https://github.com/nlohmann/json-ci), but so far failed to properly build the library with it. Is there a way to build the test suite with it?

[nlohmann]

We now added NVCC to the CI. I added your code example to check if I can reproduce the issue.

[nlohmann]

I can reproduce your findings:

FAILED: CMakeFiles/json_cuda.dir/json_cuda.cu.o 
/usr/local/cuda/bin/nvcc -forward-unknown-to-host-compiler -ccbin=g++-8  -I/__w/json/json/test/cuda_example/../../include -g --generate-code=arch=compute_52,code=[compute_52,sm_52] -MD -MT CMakeFiles/json_cuda.dir/json_cuda.cu.o -MF CMakeFiles/json_cuda.dir/json_cuda.cu.o.d -x cu -c /__w/json/json/test/cuda_example/json_cuda.cu -o CMakeFiles/json_cuda.dir/json_cuda.cu.o
/__w/json/json/test/cuda_example/../../include/nlohmann/ordered_map.hpp: In instantiation of 'typename std::vector<std::pair<const _Key, _Tp>, Allocator>::size_type nlohmann::ordered_map<Key, T, IgnoredLess, Allocator>::erase(const Key&) [with Key = std::__cxx11::basic_string<char>; T = nlohmann::basic_json<nlohmann::ordered_map>; IgnoredLess = std::less<>; Allocator = std::allocator<std::pair<const std::__cxx11::basic_string<char>, nlohmann::basic_json<nlohmann::ordered_map> > >; typename std::vector<std::pair<const _Key, _Tp>, Allocator>::size_type = long unsigned int]':
make[3]: *** [CMakeFiles/ci_cuda_example.dir/build.make:71: CMakeFiles/ci_cuda_example] Error 1
/__w/json/json/test/cuda_example/../../include/nlohmann/json.hpp:2399:39:   required from 'nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::size_type nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::erase(const typename ObjectType<StringType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>, std::less<void>, AllocatorType<std::pair<const StringType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType> > > >::key_type&) [with ObjectType = nlohmann::ordered_map; ArrayType = std::vector; StringType = std::__cxx11::basic_string<char>; BooleanType = bool; NumberIntegerType = long int; NumberUnsignedType = long unsigned int; NumberFloatType = double; AllocatorType = std::allocator; JSONSerializer = nlohmann::adl_serializer; BinaryType = std::vector<unsigned char>; nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::size_type = long unsigned int; typename ObjectType<StringType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>, std::less<void>, AllocatorType<std::pair<const StringType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType> > > >::key_type = std::__cxx11::basic_string<char>]'
/__w/json/json/test/cuda_example/json_cuda.cu:10:21:   required from here
/__w/json/json/test/cuda_example/../../include/nlohmann/ordered_map.hpp:98:7: error: object type 'std::pair<const std::__cxx11::basic_string<char>, nlohmann::basic_json<nlohmann::ordered_map> >' does not match destructor name ~'value_type'
                     it->~value_type(); // Destroy but keep allocation
       ^     

I am, however, not sure if this is actually an error, because value_type is an alias for std::pair<const Key, T>. Any ideas?

[lashgar]

I suggest using NVCC 11.0 or later in the CI. Older versions have a very poor support of C++ and parser fails in reading template notations. CUDA officially supports C++-17 starting version 11.0.

[nlohmann]

We use 11.0.221 in the CI.

[nlohmann]

@lashgar I could fix the issue in our CI. Can you please check whether #3234 works for you?

[lashgar]

@nlohmann , yes, #3234 fixes the issue. I tested with nvcc 11.5. Thank you.

Happy new year! 🎉