* Broaden JSON_HEDLEY_WARN_UNUSED_RESULT coverage to pure query functions
Add JSON_HEDLEY_WARN_UNUSED_RESULT to the unambiguous, const,
side-effect-free observer functions whose return value is the entire
purpose of the call:
- dump()
- type(), type_name()
- all is_* predicates (is_primitive, is_structured, is_null,
is_boolean, is_number, is_number_integer, is_number_unsigned,
is_number_float, is_object, is_array, is_string, is_binary,
is_discarded)
- empty(), size(), max_size()
- count(...) (both overloads) and contains(...) (all overloads,
including the deprecated json_pointer<BasicJsonType> overload)
This mirrors the direction the standard library has taken with
[[nodiscard]] on the analogous std::vector/std::map members, and
catches real bugs such as `j.empty();` (meant `j.clear();`) or
`j.contains(k);` with the result thrown away.
Deliberately out of scope (left for a separate, later policy
decision, per the issue): at(), value(), get*(), flatten(),
unflatten(), patch(), merge_patch(), begin()/end(), comparison
operators, erase(), and emplace().
Compiling the full test suite (tests/src/unit-*.cpp) with
-Wunused-result -Werror uncovered one real hit: a regression test in
unit-regression2.cpp called dump() purely to check it does not throw,
discarding the result. Fixed by explicitly casting to void, since the
call is intentionally result-less there.
Fixes#5410
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix discarded nodiscard results across the test suite for GCC's warn_unused_result
A plain (void) cast on a call expression suppresses the C++17 [[nodiscard]]
warning but not GCC's warning for functions annotated via the GNU
__attribute__((warn_unused_result)) form -- which is what
JSON_HEDLEY_WARN_UNUSED_RESULT expands to on GCC. Several existing tests
that call a newly-annotated function (dump(), empty()) purely to check
that it throws/does not throw, discarding the result via (void), newly
warned (and failed -Werror builds) once the annotation was broadened.
Route those discards through a small ignore_return_value() helper
instead, which actually consumes the value and suppresses the warning
on both attribute forms.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Use utils::ignore_return_value() for the issue #1445 dump() discard too
Addresses review feedback from @gregmarr on PR #5477: this call site was
still using the older "capture in a variable, then (void) it" pattern
from before this PR introduced utils::ignore_return_value(), instead of
the helper now used at every other discarded-nodiscard-result call site
this PR touches.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix for printing long doubles bug in dump_float
When you use long double as a floating point type with the current version of this file and try to dump json it prints trash instead of actual number. This if-else fixes the problem. On using long double you just need to add an 'L' modifier before 'g' in format string.
Signed-off-by: Kirill Lokotkov <klokotkov@ya.ru>
* C++11 compatibility
Signed-off-by: Kirill Lokotkov <klokotkov@ya.ru>
* Shorter solution
Signed-off-by: Kirill Lokotkov <klokotkov@ya.ru>
* Applied amalgamate
Signed-off-by: rusloker <klokotkov@ya.ru>
* Add unit tests for `dump()` with `long double` in custom `basic_json`
Signed-off-by: rusloker <klokotkov@ya.ru>
* Fix UB in `snprintf_float` by using `%.*Lg` for `long double`
Signed-off-by: rusloker <klokotkov@ya.ru>
* Use `std::array` for `values` in serialization unit tests to improve type safety
Signed-off-by: rusloker <klokotkov@ya.ru>
* Fix brace initialization for `std::array` in serialization unit tests
Signed-off-by: rusloker <klokotkov@ya.ru>
* Remove comments in `snprintf_float` regarding `%Lg` usage
Signed-off-by: rusloker <klokotkov@ya.ru>
* Skip `long double` infinity dump assertions under Valgrind
Signed-off-by: rusloker <klokotkov@ya.ru>
* Clarify Valgrind bug-tracker reference in `long double` test
Signed-off-by: rusloker <klokotkov@ya.ru>
* Satisfy clang-tidy in `long double` infinity probe
Signed-off-by: rusloker <klokotkov@ya.ru>
---------
Signed-off-by: Kirill Lokotkov <klokotkov@ya.ru>
Signed-off-by: rusloker <klokotkov@ya.ru>
Niels Lohmann
Kirill Lokotkov
