Fix CI on develop after #5600, #5607, and #5755

.github/external_ci/appveyor.yml

@@ -16,6 +16,9 @@ only_commits:
 
 environment:
   matrix:
+    # The Visual Studio 2017 jobs compile everything with /std:c++17, so they
+    # only build the C++17 variant of each test, split into two jobs each to
+    # stay below AppVeyor's 60-minute limit per job.
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       configuration: Debug
       platform: x86
@@ -34,7 +37,13 @@ environment:
       configuration: Release
       platform: x86
       CXX_FLAGS: "/permissive- /std:c++17 /utf-8 /W4 /WX"
-      CMAKE_OPTIONS: ""
+      CMAKE_OPTIONS: "-DJSON_TestStandards=17 -DJSON_TestShard=0/2"
+      GENERATOR: Visual Studio 15 2017
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      configuration: Release
+      platform: x86
+      CXX_FLAGS: "/permissive- /std:c++17 /utf-8 /W4 /WX"
+      CMAKE_OPTIONS: "-DJSON_TestStandards=17 -DJSON_TestShard=1/2"
       GENERATOR: Visual Studio 15 2017
 
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
@@ -55,7 +64,13 @@ environment:
       configuration: Release
       platform: x64
       CXX_FLAGS: "/permissive- /std:c++17 /Zc:__cplusplus /utf-8 /W4 /WX"
-      CMAKE_OPTIONS: ""
+      CMAKE_OPTIONS: "-DJSON_TestStandards=17 -DJSON_TestShard=0/2"
+      GENERATOR: Visual Studio 15 2017
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      configuration: Release
+      platform: x64
+      CXX_FLAGS: "/permissive- /std:c++17 /Zc:__cplusplus /utf-8 /W4 /WX"
+      CMAKE_OPTIONS: "-DJSON_TestStandards=17 -DJSON_TestShard=1/2"
       GENERATOR: Visual Studio 15 2017
 
 init:
@@ -66,7 +81,7 @@ install:
   - if "%platform%"=="x86"    set GENERATOR_PLATFORM=Win32
 
 before_build:
-  - cmake . -G "%GENERATOR%" -A "%GENERATOR_PLATFORM%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin" -DJSON_BuildTests=On "%CMAKE_OPTIONS%"
+  - cmake . -G "%GENERATOR%" -A "%GENERATOR_PLATFORM%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin" -DJSON_BuildTests=On %CMAKE_OPTIONS%
 
 build_script:
   - cmake --build . --config "%configuration%" --parallel 2

cmake/ci.cmake

@@ -376,7 +376,7 @@ 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 -fno-sanitize=unsigned-integer-overflow -fno-sanitize=unsigned-shift-base")
+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 -fsanitize-ignorelist=${PROJECT_SOURCE_DIR}/cmake/clang_sanitizer_ignorelist.txt")
 
 add_custom_target(ci_test_clang_sanitizer
     COMMAND CXX=${CLANG_TOOL} CXXFLAGS=${CLANG_CXX_FLAGS_SANITIZER} ${CMAKE_COMMAND}

cmake/clang_sanitizer_ignorelist.txt

@@ -0,0 +1,8 @@
+# Sanitizer ignore list for ci_test_clang_sanitizer (-fsanitize-ignorelist).
+#
+# libstdc++ 14's <format> declares `_Scanner(basic_string_view<_CharT>, size_t __nargs = -1)`, so every std::format
+# call converts -1 to size_t, which -fsanitize=integer reports as implicit-integer-sign-change. This is
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119429, not a bug in this library. Only that check and only <format> are
+# excluded, so implicit sign changes in the library and the tests are still reported.
+[implicit-integer-sign-change]
+src:*/include/c++/*/format

docs/docset/docSet.sql

@@ -250,6 +250,7 @@ INSERT INTO searchIndex(name, type, path) VALUES ('JSON_TRY_USER', 'Macro', 'api
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_GLOBAL_UDLS', 'Macro', 'api/macros/json_use_global_udls/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_IMPLICIT_CONVERSIONS', 'Macro', 'api/macros/json_use_implicit_conversions/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON', 'Macro', 'api/macros/json_use_legacy_discarded_value_comparison/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS', 'Macro', 'api/macros/json_use_objects_for_enum_keyed_maps/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_USE_SIMDUTF', 'Macro', 'api/macros/json_use_simdutf/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('Macros', 'Macro', 'api/macros/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE', 'Macro', 'api/macros/nlohmann_define_derived_type/index.html');

docs/mkdocs/docs/api/macros/json_use_objects_for_enum_keyed_maps.md

@@ -69,7 +69,7 @@ The default value is `0` (disabled — existing behavior is preserved).
 
 ## Examples
 
-??? example "Default behavior (macro not defined)"
+??? example "Example: default behavior (macro not defined)"
 
     Without the macro, a map with enum keys is stored as an array of pairs:
 
@@ -96,7 +96,7 @@ The default value is `0` (disabled — existing behavior is preserved).
     }
     ```
 
-??? example "Objects for enum-keyed maps (macro defined to 1)"
+??? example "Example: objects for enum-keyed maps (macro defined to 1)"
 
     With the macro, the same map is stored as an object:
 

include/nlohmann/detail/conversions/from_json.hpp

@@ -172,7 +172,7 @@ inline void from_json(const BasicJsonType& j, EnumType& e)
           typename BasicJsonType::number_unsigned_t, underlying_type>::type;
     value_type val;
     get_arithmetic_value(j, val);
-    e = static_cast<EnumType>(static_cast<underlying_type>(val));
+    e = static_cast<EnumType>(bool_aware_static_cast<underlying_type>(val));
 }
 #endif  // JSON_DISABLE_ENUM_SERIALIZATION
 

include/nlohmann/detail/conversions/to_json.hpp

@@ -287,9 +287,20 @@ struct external_constructor<value_t::object>
 /////////////
 
 #ifdef JSON_HAS_CPP_17
+// whether storing the value of a std::optional<T> cannot throw; MSVC 2017
+// evaluates std::is_nothrow_assignable as true even if T's to_json throws, so
+// the exception would call std::terminate (#5642)
+#if defined(_MSC_VER) && !defined(__clang__) && _MSC_VER < 1920
+    template<typename BasicJsonType, typename T>
+    using is_nothrow_optional_to_json = std::false_type;
+#else
+    template<typename BasicJsonType, typename T>
+    using is_nothrow_optional_to_json = std::is_nothrow_assignable<BasicJsonType&, const T&>;
+#endif
+
 template<typename BasicJsonType, typename T,
          enable_if_t<std::is_constructible<BasicJsonType, T>::value, int> = 0>
-void to_json(BasicJsonType& j, const std::optional<T>& opt) noexcept(std::is_nothrow_assignable<BasicJsonType&, const T&>::value)
+void to_json(BasicJsonType& j, const std::optional<T>& opt) noexcept(is_nothrow_optional_to_json<BasicJsonType, T>::value)
 {
     if (opt.has_value())
     {
@@ -365,7 +376,7 @@ inline void to_json(BasicJsonType& j, EnumType e) noexcept
 {
     using underlying_type = typename std::underlying_type<EnumType>::type;
     static constexpr value_t integral_value_t = std::is_unsigned<underlying_type>::value ? value_t::number_unsigned : value_t::number_integer;
-    external_constructor<integral_value_t>::construct(j, static_cast<underlying_type>(e));
+    external_constructor<integral_value_t>::construct(j, bool_aware_static_cast<underlying_type>(e));
 }
 #endif  // JSON_DISABLE_ENUM_SERIALIZATION
 

include/nlohmann/detail/input/binary_reader.hpp

@@ -662,10 +662,11 @@ class binary_reader
         }
 
         // the value is -1 - number, which fits into number_integer_t
-        // whenever number does
+        // whenever number does; the outer cast undoes the integral promotion
+        // for number_integer_t types narrower than int
         if (JSON_HEDLEY_LIKELY(value_in_range_of<number_integer_t>(number)))
         {
-            return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
+            return sax->number_integer(conditional_static_cast<number_integer_t>(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number)));
         }
 
         // like the lexer does for JSON text, store a value too small for
@@ -4003,7 +4004,8 @@ class binary_reader
         {
             return sax->number_unsigned(static_cast<number_unsigned_t>(number));
         }
-        return emit_float(number);
+        // std::isfinite has no integer overloads in MSVC's <cmath>
+        return emit_float(static_cast<long double>(number));
     }
 
     /*!
@@ -4026,7 +4028,8 @@ class binary_reader
         {
             return sax->number_unsigned(static_cast<number_unsigned_t>(number));
         }
-        return emit_float(number);
+        // std::isfinite has no integer overloads in MSVC's <cmath>
+        return emit_float(static_cast<long double>(number));
     }
 
     /*!
@@ -4037,7 +4040,8 @@ class binary_reader
     and NaN in the input are passed on unchanged. Integers only overflow if
     number_float_t cannot represent 2^64, e.g., a half-precision type.
 
-    @tparam NumberType a floating-point or integer type
+    @tparam NumberType a floating-point type (emit_signed and emit_unsigned
+                       convert integers to long double first)
     @param[in] number  the number
     @return whether the SAX parser accepted the value
 

include/nlohmann/detail/meta/type_traits.hpp

@@ -906,6 +906,21 @@ T conditional_static_cast(U value)
     return value;
 }
 
+// like conditional_static_cast, but converts to bool by comparing with zero,
+// because MSVC 2015 warns about any conversion to bool (C4800), even with an
+// explicit cast; used for enums whose underlying type is bool
+template < typename T, typename U, enable_if_t < !std::is_same<T, bool>::value, int > = 0 >
+T bool_aware_static_cast(U value)
+{
+    return conditional_static_cast<T>(value);
+}
+
+template<typename T, typename U, enable_if_t<std::is_same<T, bool>::value, int> = 0>
+bool bool_aware_static_cast(U value)
+{
+    return value != U();
+}
+
 template<typename... Types>
 using all_integral = conjunction<std::is_integral<Types>...>;