mirror of
https://github.com/nlohmann/json.git
synced 2026-09-09 17:58:00 +00:00
Broaden JSON_HEDLEY_WARN_UNUSED_RESULT coverage to pure query functions (#5477)
* 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>
This commit is contained in:
Niels Lohmann
@@ -22890,6 +22890,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief serialization
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/dump/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
string_t dump(const int indent = -1,
|
||||
const char indent_char = ' ',
|
||||
const bool ensure_ascii = false,
|
||||
@@ -22912,6 +22913,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return the type of the JSON value (explicit)
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/type/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr value_t type() const noexcept
|
||||
{
|
||||
return m_data.m_type;
|
||||
@@ -22919,6 +22921,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether type is primitive
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_primitive/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_primitive() const noexcept
|
||||
{
|
||||
return is_null() || is_string() || is_boolean() || is_number() || is_binary();
|
||||
@@ -22926,6 +22929,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether type is structured
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_structured/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_structured() const noexcept
|
||||
{
|
||||
return is_array() || is_object();
|
||||
@@ -22933,6 +22937,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is null
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_null/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_null() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::null;
|
||||
@@ -22940,6 +22945,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is a boolean
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_boolean/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_boolean() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::boolean;
|
||||
@@ -22947,6 +22953,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is a number
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_number/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_number() const noexcept
|
||||
{
|
||||
return is_number_integer() || is_number_float();
|
||||
@@ -22954,6 +22961,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is an integer number
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_number_integer/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_number_integer() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::number_integer || m_data.m_type == value_t::number_unsigned;
|
||||
@@ -22961,6 +22969,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is an unsigned integer number
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_number_unsigned/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_number_unsigned() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::number_unsigned;
|
||||
@@ -22968,6 +22977,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is a floating-point number
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_number_float/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_number_float() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::number_float;
|
||||
@@ -22975,6 +22985,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is an object
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_object/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_object() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::object;
|
||||
@@ -22982,6 +22993,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is an array
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_array/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_array() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::array;
|
||||
@@ -22989,6 +23001,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is a string
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_string/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_string() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::string;
|
||||
@@ -22996,6 +23009,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is a binary array
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_binary/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_binary() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::binary;
|
||||
@@ -23003,6 +23017,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return whether value is discarded
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/is_discarded/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
constexpr bool is_discarded() const noexcept
|
||||
{
|
||||
return m_data.m_type == value_t::discarded;
|
||||
@@ -24334,6 +24349,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief returns the number of occurrences of a key in a JSON object
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/count/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
size_type count(const typename object_t::key_type& key) const
|
||||
{
|
||||
// return 0 for all nonobject types
|
||||
@@ -24344,6 +24360,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/count/
|
||||
template<class KeyType, detail::enable_if_t<
|
||||
detail::is_usable_as_basic_json_key_type<basic_json_t, KeyType>::value, int> = 0>
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
size_type count(KeyType && key) const
|
||||
{
|
||||
// return 0 for all nonobject types
|
||||
@@ -24352,6 +24369,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief check the existence of an element in a JSON object
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/contains/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
bool contains(const typename object_t::key_type& key) const
|
||||
{
|
||||
return is_object() && m_data.m_value.object->find(key) != m_data.m_value.object->end();
|
||||
@@ -24361,6 +24379,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/contains/
|
||||
template<class KeyType, detail::enable_if_t<
|
||||
detail::is_usable_as_basic_json_key_type<basic_json_t, KeyType>::value, int> = 0>
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
bool contains(KeyType && key) const
|
||||
{
|
||||
return is_object() && m_data.m_value.object->find(std::forward<KeyType>(key)) != m_data.m_value.object->end();
|
||||
@@ -24368,12 +24387,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief check the existence of an element in a JSON object given a JSON pointer
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/contains/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
bool contains(const json_pointer& ptr) const
|
||||
{
|
||||
return ptr.contains(this);
|
||||
}
|
||||
|
||||
template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
|
||||
bool contains(const typename ::nlohmann::json_pointer<BasicJsonType>& ptr) const
|
||||
{
|
||||
@@ -24529,6 +24550,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief checks whether the container is empty.
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/empty/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
bool empty() const noexcept
|
||||
{
|
||||
switch (m_data.m_type)
|
||||
@@ -24568,6 +24590,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief returns the number of elements
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/size/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
size_type size() const noexcept
|
||||
{
|
||||
switch (m_data.m_type)
|
||||
@@ -24607,6 +24630,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief returns the maximum possible number of elements
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/max_size/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
size_type max_size() const noexcept
|
||||
{
|
||||
switch (m_data.m_type)
|
||||
@@ -25796,6 +25820,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
/// @brief return the type as string
|
||||
/// @sa https://json.nlohmann.me/api/basic_json/type_name/
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
JSON_HEDLEY_RETURNS_NON_NULL
|
||||
const char* type_name() const noexcept
|
||||
{
|
||||
|
||||
Reference in New Issue
Block a user