Fix volatile bool serialized as 1 or 0

Ported from 5d1d2721d1

CHANGELOG.md

@@ -6,6 +6,7 @@ HEAD
 
 * Fix "no matching function" with `JsonObjectConst::operator[]` (issue #2019)
 * Remove unused files in the PlatformIO package
+* Fix `volatile bool` serialized as `1` or `0` instead of `true` or `false` (issue #2029)
 
 v7.0.0 (2024-01-03)
 ------

extras/tests/JsonVariant/types.cpp

@@ -140,6 +140,13 @@ TEST_CASE("volatile") {
   JsonDocument doc;
   JsonVariant variant = doc.to<JsonVariant>();
 
+  SECTION("volatile bool") {  // issue #2029
+    volatile bool f = true;
+    variant.set(f);
+    CHECK(variant.is<bool>() == true);
+    CHECK(variant.as<bool>() == true);
+  }
+
   SECTION("volatile int") {
     volatile int f = 42;
     variant.set(f);

src/ArduinoJson/Variant/VariantRefBaseImpl.hpp

@@ -132,7 +132,8 @@ VariantRefBase<TDerived>::operator[](const TString& key) const {
 template <typename TDerived>
 template <typename T>
 inline bool VariantRefBase<TDerived>::set(const T& value) const {
-  Converter<T>::toJson(value, getOrCreateVariant());
+  Converter<typename detail::remove_cv<T>::type>::toJson(value,
+                                                         getOrCreateVariant());
   auto resources = getResourceManager();
   return resources && !resources->overflowed();
 }