tests/src/unit-no-macro-leak.cpp previously hardcoded a static list of
~151 #ifdef/#error checks, one per JSON_HEDLEY_* macro name known at the
time it was written. That list would silently go stale the next time
`make update_hedley` pulls in a vendor update that adds, removes, or
renames a macro, since nothing would force it to be regenerated.
Add cmake/scripts/gen_hedley_undef_check.cmake, which derives the full
list of JSON_HEDLEY_* macro names directly from
include/nlohmann/thirdparty/hedley/hedley.hpp:
- tests/CMakeLists.txt uses it (MODE=checks) to (re)generate
hedley_undef_checks.inc at configure and build time, and wires the
generating custom target as a dependency of the test-no-macro-leak_cpp*
targets so it can never build against a stale copy. unit-no-macro-leak.cpp
now just #include-s the generated file inside its TEST_CASE instead of
carrying the checks itself.
- The Makefile's `update_hedley` target now delegates hedley_undef.hpp
generation to the same script (MODE=undef, new `update_hedley_undef`
target), so the vendored header, the generated #undef list, and the
generated test checks are all derived from the same extraction logic and
cannot drift apart.
This mirrors the approach taken independently in #5415 for the same
issue (#5408), credited there to a self-regenerating mechanism that
"can never drift again" -- ported into this branch instead of the
static list originally proposed here.
Verified with a local CMake configure + build + ctest, both against
include/ (JSON_MultipleHeaders=ON) and against the amalgamated
single_include/nlohmann/json.hpp (JSON_MultipleHeaders=OFF), and by
temporarily deleting a #undef line from hedley_undef.hpp to confirm the
generated test actually fails on a real leak.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
include/nlohmann/detail/macro_unscope.hpp includes hedley_undef.hpp to
#undef every JSON_HEDLEY_* macro so none of them leak into the including
translation unit. Four macros were missing from that list and therefore
stayed defined after #include <nlohmann/json.hpp>:
- JSON_HEDLEY_PRAGMA
- JSON_HEDLEY_PREDICT_TRUE
- JSON_HEDLEY_PREDICT_FALSE
- JSON_HEDLEY_CLANG_HAS_DECLSPEC_ATTRIBUTE
hedley_undef.hpp is generated (via `make update_hedley`) by grepping
hedley.hpp for its own internal `#undef JSON_HEDLEY_X` redefinition
guards. JSON_HEDLEY_PRAGMA/PREDICT_TRUE/PREDICT_FALSE have no such guard
in upstream Hedley, so they were never picked up. The guard for
JSON_HEDLEY_CLANG_HAS_DECLSPEC_ATTRIBUTE also has an upstream typo
(`JSON_HEDLEY_CLANG_HAS_DECLSPEC_DECLSPEC_ATTRIBUTE`), so hedley_undef.hpp
was undefining the wrong (never-defined) name.
Fixes:
- include/nlohmann/thirdparty/hedley/hedley_undef.hpp: corrected the
DECLSPEC_ATTRIBUTE typo and added the three missing #undef lines,
keeping the file's alphabetical ordering.
- Makefile (update_hedley target): changed hedley_undef.hpp generation to
extract macro names directly from every `#define JSON_HEDLEY_...` in
hedley.hpp instead of from existing `#undef` guards, so a future
`make update_hedley` run undefines every macro Hedley actually defines,
even ones without a pre-existing redefinition guard. This was not run
in this PR (it would also pull in an unrelated upstream Hedley sync);
hedley_undef.hpp was hand-patched instead and single_include was
regenerated with `make amalgamate`.
- tests/src/unit-no-macro-leak.cpp: new regression test (picked up
automatically by tests/CMakeLists.txt's existing unit-*.cpp glob) that
includes json.hpp and then #ifdef/#error-checks every JSON_HEDLEY_*
macro name, so any future leak of any of the 151 vendored macros fails
the build, not just the four fixed here.
Fixes#5408.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Add versioned inline namespace
Add a versioned inline namespace to prevent ABI issues when linking code
using multiple library versions.
* Add namespace macros
* Encode ABI information in inline namespace
Add _diag suffix to inline namespace if JSON_DIAGNOSTICS is enabled, and
_ldvcmp suffix if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON is enabled.
* Move ABI-affecting macros into abi_macros.hpp
* Move std_fs namespace definition into std_fs.hpp
* Remove std_fs namespace from unit test
* Format more files in tests directory
* Add unit tests
* Update documentation
* Fix GDB pretty printer
* fixup! Add namespace macros
* Derive ABI prefix from NLOHMANN_JSON_VERSION_*
We need to have a proper sed, even on MacOSX. So let's use the variable
introduced in 191aa0fd (🔧 overworked maintaner targets,
2019-03-28) in more places.
This serves as a minimal release-only way to embed json into a project.
Add meson support to this directly, to make it usable standalone as a
meson subproject.
Implements #1672
Niels Lohmann
ss
Florian Albrechtskirchinger
Vertexwahn
Niels Lohmann
Thomas Braun
Eli Schwartz