Merge pull request nlohmann#43 from nlohmann/develop

Sync Fork from Upstream Repo

.github/workflows/ubuntu.yml

@@ -44,7 +44,7 @@ jobs:
     container: nlohmann/json-ci:latest
     strategy:
       matrix:
-        target: [ci_clang_tidy, ci_cppcheck, ci_test_valgrind, ci_test_clang_sanitizer, ci_test_amalgamation, ci_clang_analyze, ci_cpplint, ci_cmake_flags, ci_single_binaries, ci_reproducible_tests, ci_non_git_tests, ci_offline_testdata]
+        target: [ci_clang_tidy, ci_cppcheck, ci_test_valgrind, ci_test_clang_sanitizer, ci_test_amalgamation, ci_clang_analyze, ci_cpplint, ci_cmake_flags, ci_single_binaries, ci_reproducible_tests, ci_non_git_tests, ci_offline_testdata, ci_infer]
     steps:
       - uses: actions/checkout@v2
       - name: cmake
@@ -90,7 +90,7 @@ jobs:
     container: nlohmann/json-ci:latest
     strategy:
       matrix:
-        compiler: [g++-4.8, g++-4.9, g++-5, g++-7, g++-8, g++-9, g++-10, clang++-3.5, clang++-3.6, clang++-3.7, clang++-3.8, clang++-3.9, clang++-4.0, clang++-5.0, clang++-6.0, clang++-7, clang++-8, clang++-9, clang++-10]
+        compiler: [g++-4.8, g++-4.9, g++-5, g++-7, g++-8, g++-9, g++-10, clang++-3.5, clang++-3.6, clang++-3.7, clang++-3.8, clang++-3.9, clang++-4.0, clang++-5.0, clang++-6.0, clang++-7, clang++-8, clang++-9, clang++-10, clang++-11]
     steps:
       - uses: actions/checkout@v2
       - name: cmake

README.md

@@ -1201,8 +1201,8 @@ auto cbor = json::to_msgpack(j); // 0xD5 (fixext2), 0x10, 0xCA, 0xFE
 Though it's 2021 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
 
 - GCC 4.8 - 11.0 (and possibly later)
-- Clang 3.4 - 11.0 (and possibly later)
-- Apple Clang 9.1 - 12.3 (and possibly later)
+- Clang 3.4 - 12.0 (and possibly later)
+- Apple Clang 9.1 - 12.4 (and possibly later)
 - Intel C++ Compiler 17.0.2 (and possibly later)
 - Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
 - Microsoft Visual C++ 2017 / Build Tools 15.5.180.51428 (and possibly later)
@@ -1271,7 +1271,8 @@ The following compilers are currently used in continuous integration at [Travis]
 | Clang 10.0.0 with GNU-like command-line                           | Windows-10.0.17763 | GitHub Actions |
 | Clang 11.0.0 with GNU-like command-line                           | Windows-10.0.17763 | GitHub Actions |
 | Clang 11.0.0 with MSVC-like command-line                          | Windows-10.0.17763 | GitHub Actions |
-| Clang 11.1.0 (11.1.0-++20210204121720+1fdec59bffc1-1~exp1~20210203232336.162 | Ubuntu 20.04.2 LTS | GitHub Actions |
+| Clang 11.0.0 (11.0.0-2~ubuntu20.04.1)                             | Ubuntu 20.04.2 LTS | GitHub Actions |
+| Clang 12.1.0 (12.0.1-++20210423082613+072c90a863aa-1~exp1~20210423063319.76 | Ubuntu 20.04.2 LTS | GitHub Actions |
 | Visual Studio 14 2015 MSVC 19.0.24241.7 (Build Engine version 14.0.25420.1) | Windows-6.3.9600 | AppVeyor |
 | Visual Studio 15 2017 MSVC 19.16.27035.0 (Build Engine version 15.9.21+g9802d43bc3 for .NET Framework) | Windows-10.0.14393 | AppVeyor |
 | Visual Studio 15 2017 MSVC 19.16.27045.0 (Build Engine version 15.9.21+g9802d43bc3 for .NET Framework) | Windows-10.0.14393 | GitHub Actions |

cmake/ci.cmake

@@ -13,12 +13,12 @@ execute_process(COMMAND ${ASTYLE_TOOL} --version OUTPUT_VARIABLE ASTYLE_TOOL_VER
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" ASTYLE_TOOL_VERSION "${ASTYLE_TOOL_VERSION}")
 message(STATUS "🔖 Artistic Style ${ASTYLE_TOOL_VERSION} (${ASTYLE_TOOL})")
 
-find_program(CLANG_TOOL NAMES clang++-HEAD clang++-11 clang++)
+find_program(CLANG_TOOL NAMES clang++-HEAD clang++-12 clang++-11 clang++)
 execute_process(COMMAND ${CLANG_TOOL} --version OUTPUT_VARIABLE CLANG_TOOL_VERSION ERROR_VARIABLE CLANG_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" CLANG_TOOL_VERSION "${CLANG_TOOL_VERSION}")
 message(STATUS "🔖 Clang ${CLANG_TOOL_VERSION} (${CLANG_TOOL})")
 
-find_program(CLANG_TIDY_TOOL NAMES clang-tidy-11 clang-tidy)
+find_program(CLANG_TIDY_TOOL NAMES clang-tidy-12 clang-tidy-11 clang-tidy)
 execute_process(COMMAND ${CLANG_TIDY_TOOL} --version OUTPUT_VARIABLE CLANG_TIDY_TOOL_VERSION ERROR_VARIABLE CLANG_TIDY_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" CLANG_TIDY_TOOL_VERSION "${CLANG_TIDY_TOOL_VERSION}")
 message(STATUS "🔖 Clang-Tidy ${CLANG_TIDY_TOOL_VERSION} (${CLANG_TIDY_TOOL})")
@@ -486,7 +486,7 @@ add_custom_target(ci_test_coverage
 # Sanitizers.
 ###############################################################################
 
-set(CLANG_CXX_FLAGS_SANITIZER "-g -O1 -fsanitize=address -fsanitize=undefined -fsanitize=integer -fsanitize=nullability -fno-omit-frame-pointer -fno-sanitize-recover=all -fsanitize-recover=unsigned-integer-overflow")
+set(CLANG_CXX_FLAGS_SANITIZER "-g -O1 -fsanitize=address -fsanitize=undefined -fsanitize=integer -fsanitize=nullability -fno-omit-frame-pointer -fno-sanitize-recover=all -fno-sanitize=unsigned-integer-overflow -fno-sanitize=unsigned-shift-base")
 
 add_custom_target(ci_test_clang_sanitizer
     COMMAND CXX=${CLANG_TOOL} CXXFLAGS=${CLANG_CXX_FLAGS_SANITIZER} ${CMAKE_COMMAND}
@@ -637,7 +637,7 @@ add_custom_target(ci_pvs_studio
 add_custom_target(ci_infer
     COMMAND mkdir -p ${PROJECT_BINARY_DIR}/build_infer
     COMMAND cd ${PROJECT_BINARY_DIR}/build_infer && ${INFER_TOOL} compile -- ${CMAKE_COMMAND} -DCMAKE_BUILD_TYPE=Debug ${PROJECT_SOURCE_DIR} -DJSON_BuildTests=ON -DJSON_MultipleHeaders=ON
-    COMMAND cd ${PROJECT_BINARY_DIR}/build_infer && ${INFER_TOOL} run -- make --parallel ${N}
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_infer && ${INFER_TOOL} run -- make
     COMMENT "Check code with Infer"
 )
 

include/nlohmann/adl_serializer.hpp

@@ -1,14 +1,17 @@
 #pragma once
 
+#include <type_traits>
 #include <utility>
 
 #include <nlohmann/detail/conversions/from_json.hpp>
 #include <nlohmann/detail/conversions/to_json.hpp>
+#include <nlohmann/detail/meta/identity_tag.hpp>
+#include <nlohmann/detail/meta/type_traits.hpp>
 
 namespace nlohmann
 {
 
-template<typename, typename>
+template<typename ValueType, typename>
 struct adl_serializer
 {
     /*!
@@ -17,17 +20,39 @@ struct adl_serializer
     This function is usually called by the `get()` function of the
     @ref basic_json class (either explicit or via conversion operators).
 
+    @note This function is chosen for default-constructible value types.
+
     @param[in] j        JSON value to read from
     @param[in,out] val  value to write to
     */
-    template<typename BasicJsonType, typename ValueType>
-    static auto from_json(BasicJsonType&& j, ValueType& val) noexcept(
+    template<typename BasicJsonType, typename TargetType = ValueType>
+    static auto from_json(BasicJsonType && j, TargetType& val) noexcept(
         noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), val)))
     -> decltype(::nlohmann::from_json(std::forward<BasicJsonType>(j), val), void())
     {
         ::nlohmann::from_json(std::forward<BasicJsonType>(j), val);
     }
 
+    /*!
+    @brief convert a JSON value to any value type
+
+    This function is usually called by the `get()` function of the
+    @ref basic_json class (either explicit or via conversion operators).
+
+    @note This function is chosen for value types which are not default-constructible.
+
+    @param[in] j  JSON value to read from
+
+    @return copy of the JSON value, converted to @a ValueType
+    */
+    template<typename BasicJsonType, typename TargetType = ValueType>
+    static auto from_json(BasicJsonType && j) noexcept(
+    noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), detail::identity_tag<TargetType> {})))
+    -> decltype(::nlohmann::from_json(std::forward<BasicJsonType>(j), detail::identity_tag<TargetType> {}))
+    {
+        return ::nlohmann::from_json(std::forward<BasicJsonType>(j), detail::identity_tag<TargetType> {});
+    }
+
     /*!
     @brief convert any value type to a JSON value
 
@@ -37,13 +62,12 @@ struct adl_serializer
     @param[in,out] j  JSON value to write to
     @param[in] val    value to read from
     */
-    template<typename BasicJsonType, typename ValueType>
-    static auto to_json(BasicJsonType& j, ValueType&& val) noexcept(
-        noexcept(::nlohmann::to_json(j, std::forward<ValueType>(val))))
-    -> decltype(::nlohmann::to_json(j, std::forward<ValueType>(val)), void())
+    template<typename BasicJsonType, typename TargetType = ValueType>
+    static auto to_json(BasicJsonType& j, TargetType && val) noexcept(
+        noexcept(::nlohmann::to_json(j, std::forward<TargetType>(val))))
+    -> decltype(::nlohmann::to_json(j, std::forward<TargetType>(val)), void())
     {
-        ::nlohmann::to_json(j, std::forward<ValueType>(val));
+        ::nlohmann::to_json(j, std::forward<TargetType>(val));
     }
 };
-
 }  // namespace nlohmann

include/nlohmann/detail/conversions/from_json.hpp

@@ -15,6 +15,7 @@
 #include <nlohmann/detail/exceptions.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/cpp_future.hpp>
+#include <nlohmann/detail/meta/identity_tag.hpp>
 #include <nlohmann/detail/meta/type_traits.hpp>
 #include <nlohmann/detail/value_t.hpp>
 
@@ -187,7 +188,10 @@ auto from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr,
     }
 }
 
-template<typename BasicJsonType, typename ConstructibleArrayType>
+template<typename BasicJsonType, typename ConstructibleArrayType,
+         enable_if_t<
+             std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
+             int> = 0>
 auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, priority_tag<1> /*unused*/)
 -> decltype(
     arr.reserve(std::declval<typename ConstructibleArrayType::size_type>()),
@@ -208,7 +212,10 @@ auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, p
     arr = std::move(ret);
 }
 
-template<typename BasicJsonType, typename ConstructibleArrayType>
+template<typename BasicJsonType, typename ConstructibleArrayType,
+         enable_if_t<
+             std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
+             int> = 0>
 void from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr,
                           priority_tag<0> /*unused*/)
 {
@@ -247,6 +254,25 @@ void())
     from_json_array_impl(j, arr, priority_tag<3> {});
 }
 
+template < typename BasicJsonType, typename T, std::size_t... Idx >
+std::array<T, sizeof...(Idx)> from_json_inplace_array_impl(BasicJsonType&& j,
+        identity_tag<std::array<T, sizeof...(Idx)>> /*unused*/, index_sequence<Idx...> /*unused*/)
+{
+    return { { std::forward<BasicJsonType>(j).at(Idx).template get<T>()... } };
+}
+
+template < typename BasicJsonType, typename T, std::size_t N >
+auto from_json(BasicJsonType&& j, identity_tag<std::array<T, N>> tag)
+-> decltype(from_json_inplace_array_impl(std::forward<BasicJsonType>(j), tag, make_index_sequence<N> {}))
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
+    }
+
+    return from_json_inplace_array_impl(std::forward<BasicJsonType>(j), tag, make_index_sequence<N> {});
+}
+
 template<typename BasicJsonType>
 void from_json(const BasicJsonType& j, typename BasicJsonType::binary_t& bin)
 {
@@ -322,22 +348,47 @@ void from_json(const BasicJsonType& j, ArithmeticType& val)
     }
 }
 
+template<typename BasicJsonType, typename... Args, std::size_t... Idx>
+std::tuple<Args...> from_json_tuple_impl_base(BasicJsonType&& j, index_sequence<Idx...> /*unused*/)
+{
+    return std::make_tuple(std::forward<BasicJsonType>(j).at(Idx).template get<Args>()...);
+}
+
+template < typename BasicJsonType, class A1, class A2 >
+std::pair<A1, A2> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::pair<A1, A2>> /*unused*/, priority_tag<0> /*unused*/)
+{
+    return {std::forward<BasicJsonType>(j).at(0).template get<A1>(),
+            std::forward<BasicJsonType>(j).at(1).template get<A2>()};
+}
+
 template<typename BasicJsonType, typename A1, typename A2>
-void from_json(const BasicJsonType& j, std::pair<A1, A2>& p)
+void from_json_tuple_impl(BasicJsonType&& j, std::pair<A1, A2>& p, priority_tag<1> /*unused*/)
 {
-    p = {j.at(0).template get<A1>(), j.at(1).template get<A2>()};
+    p = from_json_tuple_impl(std::forward<BasicJsonType>(j), identity_tag<std::pair<A1, A2>> {}, priority_tag<0> {});
 }
 
-template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
-void from_json_tuple_impl(const BasicJsonType& j, Tuple& t, index_sequence<Idx...> /*unused*/)
+template<typename BasicJsonType, typename... Args>
+std::tuple<Args...> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::tuple<Args...>> /*unused*/, priority_tag<2> /*unused*/)
 {
-    t = std::make_tuple(j.at(Idx).template get<typename std::tuple_element<Idx, Tuple>::type>()...);
+    return from_json_tuple_impl_base<BasicJsonType, Args...>(std::forward<BasicJsonType>(j), index_sequence_for<Args...> {});
 }
 
 template<typename BasicJsonType, typename... Args>
-void from_json(const BasicJsonType& j, std::tuple<Args...>& t)
+void from_json_tuple_impl(BasicJsonType&& j, std::tuple<Args...>& t, priority_tag<3> /*unused*/)
 {
-    from_json_tuple_impl(j, t, index_sequence_for<Args...> {});
+    t = from_json_tuple_impl_base<BasicJsonType, Args...>(std::forward<BasicJsonType>(j), index_sequence_for<Args...> {});
+}
+
+template<typename BasicJsonType, typename TupleRelated>
+auto from_json(BasicJsonType&& j, TupleRelated&& t)
+-> decltype(from_json_tuple_impl(std::forward<BasicJsonType>(j), std::forward<TupleRelated>(t), priority_tag<3> {}))
+{
+    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    {
+        JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name()), j));
+    }
+
+    return from_json_tuple_impl(std::forward<BasicJsonType>(j), std::forward<TupleRelated>(t), priority_tag<3> {});
 }
 
 template < typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
@@ -383,11 +434,11 @@ void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyE
 struct from_json_fn
 {
     template<typename BasicJsonType, typename T>
-    auto operator()(const BasicJsonType& j, T& val) const
-    noexcept(noexcept(from_json(j, val)))
-    -> decltype(from_json(j, val), void())
+    auto operator()(const BasicJsonType& j, T&& val) const
+    noexcept(noexcept(from_json(j, std::forward<T>(val))))
+    -> decltype(from_json(j, std::forward<T>(val)))
     {
-        return from_json(j, val);
+        return from_json(j, std::forward<T>(val));
     }
 };
 }  // namespace detail

include/nlohmann/detail/meta/identity_tag.hpp

@@ -0,0 +1,10 @@
+#pragma once
+
+namespace nlohmann
+{
+namespace detail
+{
+// dispatching helper struct
+template <class T> struct identity_tag {};
+}  // namespace detail
+}  // namespace nlohmann