diff --git a/include/nlohmann/detail/macro_scope.hpp b/include/nlohmann/detail/macro_scope.hpp index 26db66717b..fdd1aa1244 100644 --- a/include/nlohmann/detail/macro_scope.hpp +++ b/include/nlohmann/detail/macro_scope.hpp @@ -37,6 +37,15 @@ #define JSON_DEPRECATED #endif +// allow for portable nodiscard warnings +#if defined(__has_cpp_attribute) && __has_cpp_attribute(nodiscard) + #define JSON_NODISCARD [[nodiscard]] +#elif defined(__has_cpp_attribute) && __has_cpp_attribute(gnu::warn_unused_result) + #define JSON_NODISCARD [[gnu::warn_unused_result]] +#else + #define JSON_NODISCARD +#endif + // allow to disable exceptions #if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND)) && !defined(JSON_NOEXCEPTION) #define JSON_THROW(exception) throw exception diff --git a/include/nlohmann/detail/macro_unscope.hpp b/include/nlohmann/detail/macro_unscope.hpp index 4c5aa915dd..592debf7ec 100644 --- a/include/nlohmann/detail/macro_unscope.hpp +++ b/include/nlohmann/detail/macro_unscope.hpp @@ -16,6 +16,7 @@ #undef JSON_LIKELY #undef JSON_UNLIKELY #undef JSON_DEPRECATED +#undef JSON_NODISCARD #undef JSON_HAS_CPP_14 #undef JSON_HAS_CPP_17 #undef NLOHMANN_BASIC_JSON_TPL_DECLARATION diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp index 3b3da50fff..d13f8a9e8d 100644 --- a/include/nlohmann/json.hpp +++ b/include/nlohmann/json.hpp @@ -317,6 +317,7 @@ class basic_json @since 2.1.0 */ + JSON_NODISCARD static basic_json meta() { basic_json result; @@ -1489,6 +1490,7 @@ class basic_json @since version 1.0.0 */ + JSON_NODISCARD static basic_json array(initializer_list_t init = {}) { return basic_json(init, false, value_t::array); @@ -1532,6 +1534,7 @@ class basic_json @since version 1.0.0 */ + JSON_NODISCARD static basic_json object(initializer_list_t init = {}) { return basic_json(init, false, value_t::object); @@ -6051,6 +6054,7 @@ class basic_json @since version 2.0.3 (contiguous containers) */ + JSON_NODISCARD static basic_json parse(detail::input_adapter&& i, const parser_callback_t cb = nullptr, const bool allow_exceptions = true) @@ -6826,6 +6830,7 @@ class basic_json @a strict parameter since 3.0.0; added @a allow_exceptions parameter since 3.2.0 */ + JSON_NODISCARD static basic_json from_cbor(detail::input_adapter&& i, const bool strict = true, const bool allow_exceptions = true) @@ -6841,6 +6846,7 @@ class basic_json */ template::value, int> = 0> + JSON_NODISCARD static basic_json from_cbor(A1 && a1, A2 && a2, const bool strict = true, const bool allow_exceptions = true) @@ -6933,6 +6939,7 @@ class basic_json @a strict parameter since 3.0.0; added @a allow_exceptions parameter since 3.2.0 */ + JSON_NODISCARD static basic_json from_msgpack(detail::input_adapter&& i, const bool strict = true, const bool allow_exceptions = true) @@ -6948,6 +6955,7 @@ class basic_json */ template::value, int> = 0> + JSON_NODISCARD static basic_json from_msgpack(A1 && a1, A2 && a2, const bool strict = true, const bool allow_exceptions = true) @@ -7019,6 +7027,7 @@ class basic_json @since version 3.1.0; added @a allow_exceptions parameter since 3.2.0 */ + JSON_NODISCARD static basic_json from_ubjson(detail::input_adapter&& i, const bool strict = true, const bool allow_exceptions = true) @@ -7034,6 +7043,7 @@ class basic_json */ template::value, int> = 0> + JSON_NODISCARD static basic_json from_ubjson(A1 && a1, A2 && a2, const bool strict = true, const bool allow_exceptions = true) @@ -7104,6 +7114,7 @@ class basic_json @sa @ref from_ubjson(detail::input_adapter&&, const bool, const bool) for the related UBJSON format */ + JSON_NODISCARD static basic_json from_bson(detail::input_adapter&& i, const bool strict = true, const bool allow_exceptions = true) @@ -7119,6 +7130,7 @@ class basic_json */ template::value, int> = 0> + JSON_NODISCARD static basic_json from_bson(A1 && a1, A2 && a2, const bool strict = true, const bool allow_exceptions = true) @@ -7710,6 +7722,7 @@ class basic_json @since version 2.0.0 */ + JSON_NODISCARD static basic_json diff(const basic_json& source, const basic_json& target, const std::string& path = "") { diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp index e63c14d5ab..6570f8d10e 100644 --- a/single_include/nlohmann/json.hpp +++ b/single_include/nlohmann/json.hpp @@ -152,6 +152,15 @@ using json = basic_json<>; #define JSON_DEPRECATED #endif +// allow for portable nodiscard warnings +#if defined(__has_cpp_attribute) && __has_cpp_attribute(nodiscard) + #define JSON_NODISCARD [[nodiscard]] +#elif defined(__has_cpp_attribute) && __has_cpp_attribute(gnu::warn_unused_result) + #define JSON_NODISCARD [[gnu::warn_unused_result]] +#else + #define JSON_NODISCARD +#endif + // allow to disable exceptions #if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND)) && !defined(JSON_NOEXCEPTION) #define JSON_THROW(exception) throw exception @@ -12793,6 +12802,7 @@ class basic_json @since 2.1.0 */ + JSON_NODISCARD static basic_json meta() { basic_json result; @@ -13965,6 +13975,7 @@ class basic_json @since version 1.0.0 */ + JSON_NODISCARD static basic_json array(initializer_list_t init = {}) { return basic_json(init, false, value_t::array); @@ -14008,6 +14019,7 @@ class basic_json @since version 1.0.0 */ + JSON_NODISCARD static basic_json object(initializer_list_t init = {}) { return basic_json(init, false, value_t::object); @@ -18527,6 +18539,7 @@ class basic_json @since version 2.0.3 (contiguous containers) */ + JSON_NODISCARD static basic_json parse(detail::input_adapter&& i, const parser_callback_t cb = nullptr, const bool allow_exceptions = true) @@ -19302,6 +19315,7 @@ class basic_json @a strict parameter since 3.0.0; added @a allow_exceptions parameter since 3.2.0 */ + JSON_NODISCARD static basic_json from_cbor(detail::input_adapter&& i, const bool strict = true, const bool allow_exceptions = true) @@ -19317,6 +19331,7 @@ class basic_json */ template::value, int> = 0> + JSON_NODISCARD static basic_json from_cbor(A1 && a1, A2 && a2, const bool strict = true, const bool allow_exceptions = true) @@ -19409,6 +19424,7 @@ class basic_json @a strict parameter since 3.0.0; added @a allow_exceptions parameter since 3.2.0 */ + JSON_NODISCARD static basic_json from_msgpack(detail::input_adapter&& i, const bool strict = true, const bool allow_exceptions = true) @@ -19424,6 +19440,7 @@ class basic_json */ template::value, int> = 0> + JSON_NODISCARD static basic_json from_msgpack(A1 && a1, A2 && a2, const bool strict = true, const bool allow_exceptions = true) @@ -19495,6 +19512,7 @@ class basic_json @since version 3.1.0; added @a allow_exceptions parameter since 3.2.0 */ + JSON_NODISCARD static basic_json from_ubjson(detail::input_adapter&& i, const bool strict = true, const bool allow_exceptions = true) @@ -19510,6 +19528,7 @@ class basic_json */ template::value, int> = 0> + JSON_NODISCARD static basic_json from_ubjson(A1 && a1, A2 && a2, const bool strict = true, const bool allow_exceptions = true) @@ -19580,6 +19599,7 @@ class basic_json @sa @ref from_ubjson(detail::input_adapter&&, const bool, const bool) for the related UBJSON format */ + JSON_NODISCARD static basic_json from_bson(detail::input_adapter&& i, const bool strict = true, const bool allow_exceptions = true) @@ -19595,6 +19615,7 @@ class basic_json */ template::value, int> = 0> + JSON_NODISCARD static basic_json from_bson(A1 && a1, A2 && a2, const bool strict = true, const bool allow_exceptions = true) @@ -20186,6 +20207,7 @@ class basic_json @since version 2.0.0 */ + JSON_NODISCARD static basic_json diff(const basic_json& source, const basic_json& target, const std::string& path = "") { @@ -20505,6 +20527,7 @@ inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std #undef JSON_LIKELY #undef JSON_UNLIKELY #undef JSON_DEPRECATED +#undef JSON_NODISCARD #undef JSON_HAS_CPP_14 #undef JSON_HAS_CPP_17 #undef NLOHMANN_BASIC_JSON_TPL_DECLARATION diff --git a/test/src/unit-cbor.cpp b/test/src/unit-cbor.cpp index e96f4cd070..c74da4f420 100644 --- a/test/src/unit-cbor.cpp +++ b/test/src/unit-cbor.cpp @@ -1962,7 +1962,7 @@ TEST_CASE("all CBOR first bytes", "[!throws]") try { - json::from_cbor(std::vector(1, byte)); + auto res = json::from_cbor(std::vector(1, byte)); } catch (const json::parse_error& e) { diff --git a/test/src/unit-readme.cpp b/test/src/unit-readme.cpp index 280a834e5c..34cb7d1599 100644 --- a/test/src/unit-readme.cpp +++ b/test/src/unit-readme.cpp @@ -305,7 +305,7 @@ TEST_CASE("README", "[hide]") // } // calculate a JSON patch from two JSON values - json::diff(j_result, j_original); + auto res = json::diff(j_result, j_original); // [ // { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] }, // { "op":"remove","path":"/hello" }, diff --git a/test/src/unit-ubjson.cpp b/test/src/unit-ubjson.cpp index 6279a5d3ea..d6e04c3d24 100644 --- a/test/src/unit-ubjson.cpp +++ b/test/src/unit-ubjson.cpp @@ -2128,7 +2128,7 @@ TEST_CASE("all UBJSON first bytes", "[!throws]") try { - json::from_ubjson(std::vector(1, byte)); + auto res = json::from_ubjson(std::vector(1, byte)); } catch (const json::parse_error& e) {