Add wxUniChar overload for nlohmann's internal char_traits

common/settings/grid_settings.cpp

@@ -21,23 +21,10 @@
 #include <settings/grid_settings.h>
 #include <nlohmann/json.hpp>
 #include <wx/translation.h>
+#include <core/json_serializers.h>
 
 #include <units_provider.h>
 
-namespace nlohmann
-{
-template <>
-struct adl_serializer<wxString>
-{
-    static void to_json( json& j, const wxString& s ) { j = s.ToUTF8(); }
-
-    static void from_json( const json& j, wxString& s )
-    {
-        s = wxString::FromUTF8( j.get<std::string>().c_str() );
-    }
-};
-} // namespace nlohmann
-
 wxString GRID::MessageText( EDA_IU_SCALE aScale, EDA_UNITS aUnits, bool aDisplayUnits ) const
 {
     EDA_DATA_TYPE type = EDA_DATA_TYPE::DISTANCE;

libs/core/include/core/json_serializers.h

@@ -28,6 +28,26 @@
 #include <wx/string.h>
 #include <optional>
 
+NLOHMANN_JSON_NAMESPACE_BEGIN
+namespace detail
+{
+// silly hack to silence warnings about std::char_traits<wxUniChar> not being supported by the standard
+// nolhmann json internally has its own char_traits templated to support some exotic char traits
+template <>
+struct char_traits<wxUniChar> : std::char_traits<char>
+{
+    using char_type = wxUniChar;
+    using int_type = uint32_t;      // this is wxwidget's internal data type
+
+    // Redefine to_int_type function
+    static int_type to_int_type( char_type c ) noexcept { return static_cast<int_type>( c ); }
+
+    static char_type to_char_type( int_type i ) noexcept { return static_cast<char_type>( i ); }
+
+    static constexpr int_type eof() noexcept { return static_cast<int_type>( EOF ); }
+};
+} // namespace detail
+NLOHMANN_JSON_NAMESPACE_END
 
 namespace nlohmann
 {