issue building on ubuntu 20.04 with -Wsign-compare

[cenit]

If I try to build v0.162.0 tests, it fails with this error:

[3/106] /usr/bin/c++  -I/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/include -I/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/tests -I/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/third_party -I/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/third_party/catch -fPIC -g -Werror -Wall -Wextra -Wcast-align -Wcast-qual -Wimplicit-fallthrough -pedantic -MD -MT tests/CMakeFiles/unit_tests.dir/bson/src/bson_cursor_tests.cpp.o -MF tests/CMakeFiles/unit_tests.dir/bson/src/bson_cursor_tests.cpp.o.d -o tests/CMakeFiles/unit_tests.dir/bson/src/bson_cursor_tests.cpp.o -c /mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/tests/bson/src/bson_cursor_tests.cpp
FAILED: tests/CMakeFiles/unit_tests.dir/bson/src/bson_cursor_tests.cpp.o 
/usr/bin/c++  -I/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/include -I/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/tests -I/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/third_party -I/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/third_party/catch -fPIC -g -Werror -Wall -Wextra -Wcast-align -Wcast-qual -Wimplicit-fallthrough -pedantic -MD -MT tests/CMakeFiles/unit_tests.dir/bson/src/bson_cursor_tests.cpp.o -MF tests/CMakeFiles/unit_tests.dir/bson/src/bson_cursor_tests.cpp.o.d -o tests/CMakeFiles/unit_tests.dir/bson/src/bson_cursor_tests.cpp.o -c /mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/tests/bson/src/bson_cursor_tests.cpp
In file included from /mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/include/jsoncons_ext/bson/bson.hpp:17,
                 from /mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/tests/bson/src/bson_cursor_tests.cpp:10:
/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/include/jsoncons_ext/bson/bson_encoder.hpp: In instantiation of ‘bool jsoncons::bson::basic_bson_encoder<Sink, Allocator>::visit_uint64(uint64_t, jsoncons::semantic_tag, const jsoncons::ser_context&, std::error_code&) [with Sink = jsoncons::bytes_sink<std::vector<unsigned char> >; Allocator = std::allocator<char>; uint64_t = long unsigned int]’:
/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/include/jsoncons_ext/bson/bson_encoder.hpp:396:10:   required from here
/mnt/vcpkg/buildtrees/jsoncons/src/a2ab3dead7-a018935420.clean/include/jsoncons_ext/bson/bson_encoder.hpp:434:25: error: comparison of integer expressions of different signedness: ‘uint64_t’ {aka ‘long unsigned int’} and ‘int’ [-Werror=sign-compare]
  434 |                 if (val <= (std::numeric_limits<int32_t>::max)())
      |                     ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors

gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[danielaparker]

It's a warning when building with -Wsign-compare. Fixed in 0.162.1. -Wsign-compare enabled for gcc test builds.

[geiseri]

I also see this in a few other places on 20.04:

FAILED: tests/CMakeFiles/unit_tests.dir/fuzz_regression/src/fuzz_regression_tests.cpp.o 
/usr/bin/c++  -I/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include -I/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/tests -I/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/third_party -I/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/third_party/catch -fPIC -g -Werror -Wall -Wextra -Wcast-align -Wcast-qual -Wimplicit-fallthrough -Wsign-compare -pedantic -MD -MT tests/CMakeFiles/unit_tests.dir/fuzz_regression/src/fuzz_regression_tests.cpp.o -MF tests/CMakeFiles/unit_tests.dir/fuzz_regression/src/fuzz_regression_tests.cpp.o.d -o tests/CMakeFiles/unit_tests.dir/fuzz_regression/src/fuzz_regression_tests.cpp.o -c /sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/tests/fuzz_regression/src/fuzz_regression_tests.cpp
In file included from /sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/ubjson/ubjson.hpp:17,
                 from /sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/tests/fuzz_regression/src/fuzz_regression_tests.cpp:6:
/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/ubjson/ubjson_encoder.hpp: In instantiation of ‘bool jsoncons::ubjson::basic_ubjson_encoder<Sink, Allocator>::visit_uint64(uint64_t, jsoncons::semantic_tag, const jsoncons::ser_context&, std::error_code&) [with Sink = jsoncons::bytes_sink<std::vector<unsigned char> >; Allocator = std::allocator<char>; uint64_t = long unsigned int]’:
/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/ubjson/ubjson_encoder.hpp:426:10:   required from here
/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/ubjson/ubjson_encoder.hpp:436:22: error: comparison of integer expressions of different signedness: ‘uint64_t’ {aka ‘long unsigned int’} and ‘short int’ [-Werror=sign-compare]
  436 |         else if (val <= (std::numeric_limits<int16_t>::max)())
      |                  ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/ubjson/ubjson_encoder.hpp:441:22: error: comparison of integer expressions of different signedness: ‘uint64_t’ {aka ‘long unsigned int’} and ‘int’ [-Werror=sign-compare]
  441 |         else if (val <= (std::numeric_limits<int32_t>::max)())
      |                  ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/msgpack/msgpack.hpp:17,
                 from /sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/tests/fuzz_regression/src/fuzz_regression_tests.cpp:7:
/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/msgpack/msgpack_encoder.hpp: In instantiation of ‘bool jsoncons::msgpack::basic_msgpack_encoder<Sink, Allocator>::visit_uint64(uint64_t, jsoncons::semantic_tag, const jsoncons::ser_context&, std::error_code&) [with Sink = jsoncons::bytes_sink<std::vector<unsigned char> >; Allocator = std::allocator<char>; uint64_t = long unsigned int]’:
/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/msgpack/msgpack_encoder.hpp:620:14:   required from here
/sources/vcpkg/buildtrees/jsoncons/src/375ece763c-c0d03ac258.clean/include/jsoncons_ext/msgpack/msgpack_encoder.hpp:670:29: error: comparison of integer expressions of different signedness: ‘uint64_t’ {aka ‘long unsigned int’} and ‘signed char’ [-Werror=sign-compare]
  670 |                     if (val <= (std::numeric_limits<int8_t>::max)())
      |                         ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors