Starting with CMake 3.27, deprecation warnings are issued
when asking for policy settings for CMake 3.4 or earlier.
The cmake_minimum_required() command accepts a version
range, which allows NEW policy settings up to the upper end
of that range to be used, but without raising the minimum
CMake version above the bottom of that range. This means
NEW policy settings will be used where available, without
requiring them. This change updates the project's
cmake_minimum_required() calls to use a version range to
extend the upper policy version to 3.14 where it wasn't already
at that version or higher. This prevents the deprecation warning
from CMake 3.27, and gives breathing space before a future
CMake release will start issuing similar deprecation warnings
again.
* Move UDLs into nlohmann::literals::json_literals namespace
* Add 'using namespace' to unit tests
* Add 'using namespace' to examples
* Add 'using namespace' to README
* Move UDL mkdocs pages out of basic_json/
* Update documentation
* Update docset index
* Add JSON_GlobalUDLs CMake option
* Add unit test
* Build examples without global UDLs
* Add CI target
As nlohmann_json is a header-only library, its pkg-config and cmake
config files should be installed to `share/` (GNUInstallDirs' DATADIR),
as `share/` is the canonical directory where architecture-independent
files should be stored, while `lib/` is for architecture-dependent stuff
(see the [FHS][]).
Apart from being technically correct, installing to `share/` can help
with cross-compiling, for example in Debian-based environments. If
you're interested, I'd suggest reading this [thread][].
Related to #1697
[FHS]: https://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.html#usrshareArchitectureindependentData
[thread]: https://github.com/marzer/tomlplusplus/pull/165#issuecomment-1193146210
* Add C++20 3-way comparison operator and fix broken comparisons
Fixes#3207.
Fixes#3409.
* Fix iterators to meet (more) std::ranges requirements
Fixes#3130.
Related discussion: #3408
* Add note about CMake standard version selection to unit tests
Document how CMake chooses which C++ standard version to use when
building tests.
* Update documentation
* CI: add legacy discarded value comparison
* Fix internal linkage errors when building a module
* Refactor unit test creation
Add functions for creating tests and to supply test- and
standard-specific build settings.
Raises minimum CMake version to 3.13 in test directory.
json_test_add_test_for(
<file>
MAIN <main>
[CXX_STANDARDS <version_number>...] [FORCE])
Given a <file> unit-foo.cpp, produces
test-foo_cpp<version_number>
if C++ standard <version_number> is supported by the compiler and
thesource file contains JSON_HAS_CPP_<version_number>. Use FORCE to
create the test regardless of the file containing
JSON_HAS_CPP_<version_number>. Test targets are linked against <main>.
CXX_STANDARDS defaults to "11".
json_test_set_test_options(
all|<tests>
[CXX_STANDARDS all|<args>...]
[COMPILE_DEFINITIONS <args>...]
[COMPILE_FEATURES <args>...]
[COMPILE_OPTIONS <args>...]
[LINK_LIBRARIES <args>...]
[LINK_OPTIONS <args>...])
Supply test- and standard-specific build settings.
Specify multiple tests using a list e.g., "test-foo;test-bar".
Must be called BEFORE the test is created.
* Use CMAKE_MODULE_PATH
* Don't undef some macros if JSON_TEST_KEEP_MACROS is defined
* Use JSON_TEST_KEEP_MACROS
Incidentally enables the regression tests for #2546 and #3070.
A CHECK_THROWS_WITH_AS in #3070 was disabled which is tracked in #3377
and a line in from_json(..., std_fs::path&) was marked with LCOV_EXCL_LINE.
* Add three-way comparison feature test macro
* Disable broken comparison if JSON_HAS_THREE_WAY_COMPARISON
* Fix redefinition of inline constexpr statics
Redelcaration of inline constexpr static data members in namespace scope
was deprecated in C++17. Fixes -Werror=deprecated compilation failures.
* Fix more test build failures due to missing noexcept
* CI: update cmake_flags test to use CMake 3.13 in test directory
Also change default for JSON_BuildTests option to depend on CMake
version.
* CI: turn *_CXXFLAGS into CMake lists
* CI: use JSON_TestStandards to set CXX_STANDARD
* CI: pass extra CXXFLAGS to standards tests
Without SYSTEM static analysis like clang-tidy raise warnings on
json.hpp. This is not desirable for projects embedding nlohmann_json
Tests:
- Validated that without the option OFF the warnings are raised as
before
- Validated that with the option ON the warnings are silenced
When the testsuite is enabled, the "cmake_add_subdirectory" test
adds a second copy of the project into the build configuration, and the
project files are installed twice.
This becomes super problematic when it tries to install a file from
CMAKE_BINARY_DIR which is only available in CMAKE_CURRENT_BINARY_DIR
and bombs out with the following error message:
```
[...]
-- Installing: <DESTDIR>/usr/lib/cmake/nlohmann_json/nlohmann_jsonTargets.cmake
CMake Error at test/cmake_add_subdirectory/nlohmann_json/cmake_install.cmake:73 (file):
file INSTALL cannot find
"......./nlohmann-json/builddir/test/cmake_add_subdirectory/nlohmann_json.pc":
No such file or directory.
Call Stack (most recent call first):
test/cmake_add_subdirectory/cmake_install.cmake:47 (include)
test/cmake_install.cmake:49 (include)
cmake_install.cmake:94 (include)
```
The meson builds install a pkg-config file, but the cmake builds don't.
This adds a pkg-config file to the cmake builds that is functionally
equivalent to the one generated from meson.
Projects that import json via [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html) or `add_subdirectory` pointed at a git submodule may want to set `JSON_BuildTests` to "NO". However, this doesn't work without creating an identical `option()` in the importing project. Enabling CMP0077 in supported versions of CMake changes the behavior of `option()` to allow importing projects to set default values for the variables without touching the cache.
See the documentation for CMP0077 here: https://cmake.org/cmake/help/latest/policy/CMP0077.html
