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add NLOHMANN_JSON_SERIALIZE_ENUM_STRICT macro that throws on unknown JSON value (Fixes #3992)
Signed-off-by: Ash-Jose <[email protected]>
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‎include/nlohmann/detail/macro_scope.hpp‎

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@@ -224,6 +224,41 @@
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@since version 3.4.0
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*/
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#define NLOHMANN_JSON_SERIALIZE_ENUM(ENUM_TYPE, ...) \
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template<typename BasicJsonType> \
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inline void to_json(BasicJsonType& j, const ENUM_TYPE& e) \
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{ \
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/* NOLINTNEXTLINE(modernize-type-traits) we use C++11 */ \
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static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!"); \
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/* NOLINTNEXTLINE(modernize-avoid-c-arrays) we don't want to depend on <array> */ \
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static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__; \
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auto it = std::find_if(std::begin(m), std::end(m), \
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[e](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
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{ \
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return ej_pair.first == e; \
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}); \
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j = ((it != std::end(m)) ? it : std::begin(m))->second; \
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} \
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template<typename BasicJsonType> \
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inline void from_json(const BasicJsonType& j, ENUM_TYPE& e) \
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{ \
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/* NOLINTNEXTLINE(modernize-type-traits) we use C++11 */ \
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static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!"); \
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/* NOLINTNEXTLINE(modernize-avoid-c-arrays) we don't want to depend on <array> */ \
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static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__; \
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auto it = std::find_if(std::begin(m), std::end(m), \
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[&j](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
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{ \
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return ej_pair.second == j; \
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}); \
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e = ((it != std::end(m)) ? it : std::begin(m))->first; \
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}
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/*!
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@brief macro to briefly define a mapping between an enum and JSON (strict version)
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@def NLOHMANN_JSON_SERIALIZE_ENUM_STRICT
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@since version 3.12.0
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*/
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#define NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(ENUM_TYPE, ...) \
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template<typename BasicJsonType> \
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inline void to_json(BasicJsonType& j, const ENUM_TYPE& e) \
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{ \

‎single_include/nlohmann/json.hpp‎

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@@ -2588,6 +2588,41 @@ JSON_HEDLEY_DIAGNOSTIC_POP
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@since version 3.4.0
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*/
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#define NLOHMANN_JSON_SERIALIZE_ENUM(ENUM_TYPE, ...) \
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template<typename BasicJsonType> \
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inline void to_json(BasicJsonType& j, const ENUM_TYPE& e) \
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{ \
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/* NOLINTNEXTLINE(modernize-type-traits) we use C++11 */ \
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static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!"); \
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/* NOLINTNEXTLINE(modernize-avoid-c-arrays) we don't want to depend on <array> */ \
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static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__; \
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auto it = std::find_if(std::begin(m), std::end(m), \
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[e](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
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{ \
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return ej_pair.first == e; \
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}); \
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j = ((it != std::end(m)) ? it : std::begin(m))->second; \
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} \
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template<typename BasicJsonType> \
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inline void from_json(const BasicJsonType& j, ENUM_TYPE& e) \
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{ \
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/* NOLINTNEXTLINE(modernize-type-traits) we use C++11 */ \
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static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!"); \
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/* NOLINTNEXTLINE(modernize-avoid-c-arrays) we don't want to depend on <array> */ \
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static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__; \
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auto it = std::find_if(std::begin(m), std::end(m), \
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[&j](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
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{ \
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return ej_pair.second == j; \
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}); \
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e = ((it != std::end(m)) ? it : std::begin(m))->first; \
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}
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/*!
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@brief macro to briefly define a mapping between an enum and JSON (strict version)
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@def NLOHMANN_JSON_SERIALIZE_ENUM_STRICT
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@since version 3.12.0
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*/
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#define NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(ENUM_TYPE, ...) \
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template<typename BasicJsonType> \
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inline void to_json(BasicJsonType& j, const ENUM_TYPE& e) \
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{ \

‎tests/src/unit-serialize_enum_strict.cpp‎

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Original file line numberDiff line numberDiff line change
@@ -5,23 +5,23 @@ using json = nlohmann::json;
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namespace ns {
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enum class Color { red, green, blue, unknown };
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NLOHMANN_JSON_SERIALIZE_ENUM(Color, {
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NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(Color, {
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{ Color::unknown, "unknown" },
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{ Color::red, "red" },
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{ Color::green, "green" },
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{ Color::blue, "blue" }
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})
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} // namespace ns
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TEST_CASE("NLOHMANN_JSON_SERIALIZE_ENUM throws on unknown input string")
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TEST_CASE("NLOHMANN_JSON_SERIALIZE_ENUM_STRICT throws on unknown input string")
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{
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json j = "purple"; // not mapped
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ns::Color c;
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CHECK_THROWS_AS((j.get_to(c)), nlohmann::detail::type_error);
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}
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TEST_CASE("NLOHMANN_JSON_SERIALIZE_ENUM still deserializes valid values")
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TEST_CASE("NLOHMANN_JSON_SERIALIZE_ENUM_STRICT still deserializes valid values")
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{
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json j = "green";
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auto c = j.get<ns::Color>();

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