Replace problematic symbols in idf_component.yml

Fixes #2131

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
   lint:
     name: Lint
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Install
         run: sudo apt-get install -y clang-format

.github/workflows/release.yml

@@ -76,3 +76,20 @@ jobs:
       - name: Publish
         run: bash -eux extras/scripts/publish-particle-library.sh
         timeout-minutes: 5
+
+  platformio:
+    name: PlatformIO
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Python 3.x
+        uses: actions/setup-python@v4
+        with:
+          python-version: "3.x"
+      - name: Install PlatformIO
+        run: pip install platformio
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Publish
+        run: pio pkg publish --no-interactive --no-notify
+        env:
+          PLATFORMIO_AUTH_TOKEN: ${{ secrets.PLATFORMIO_AUTH_TOKEN }}

CHANGELOG.md

@@ -4,7 +4,31 @@ ArduinoJson: change log
 HEAD
 ----
 
+* Improve error messages when using `char` or `char*` (issue #2043)
+* Make string support even more generic (PR #2084 by @d-a-v)
+
+v6.21.5 (2024-01-10)
+-------
+
+* Fix warning `function returns incomplete class type` on IAR (issue #2001)
+* Fix `volatile bool` serialized as `1` or `0` instead of `true` or `false` (issue #2029)
+* Remove unused files in the PlatformIO package
+
+v6.21.4 (2023-12-07)
+-------
+
+* Fix error `'std::string' has not been declared` (issue #1967)
+* Fix error `'std::string_view' has not been declared` (issue #1967)
+* Fix error `no instance of overloaded function...` on recent IAR compilers (issue #2001)
+
+v6.21.3 (2023-07-23)
+-------
+
 * Fix compatibility with the Blynk libary (issue #1914)
+* Fix double lookup in `to<JsonVariant>()`
+* Fix double call to `size()` in `serializeMsgPack()`
+* Include `ARDUINOJSON_SLOT_OFFSET_SIZE` in the namespace name
+* Show a link to the documentation when user passes an unsupported input type
 
 v6.21.2 (2023-04-12)
 -------

CMakeLists.txt

@@ -10,7 +10,7 @@ if(ESP_PLATFORM)
 	return()
 endif()
 
-project(ArduinoJson VERSION 6.21.2)
+project(ArduinoJson VERSION 6.21.5)
 
 if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
 	include(CTest)

README.md

@@ -8,9 +8,9 @@
 [![Continuous Integration](https://ci.appveyor.com/api/projects/status/m7s53wav1l0abssg/branch/6.x?svg=true)](https://ci.appveyor.com/project/bblanchon/arduinojson/branch/6.x)
 [![Fuzzing Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/arduinojson.svg)](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:arduinojson)
 [![Coveralls branch](https://img.shields.io/coveralls/github/bblanchon/ArduinoJson/6.x?logo=coveralls)](https://coveralls.io/github/bblanchon/ArduinoJson?branch=6.x)  
-[![Arduino Library Manager](https://img.shields.io/static/v1?label=Arduino&message=v6.21.2&logo=arduino&logoColor=white&color=blue)](https://www.ardu-badge.com/ArduinoJson/6.21.2)
-[![PlatformIO Registry](https://badges.registry.platformio.org/packages/bblanchon/library/ArduinoJson.svg?version=6.21.2)](https://registry.platformio.org/packages/libraries/bblanchon/ArduinoJson?version=6.21.2) 
-[![ESP IDF](https://img.shields.io/static/v1?label=ESP+IDF&message=v6.21.2&logo=cpu&logoColor=white&color=blue)](https://components.espressif.com/components/bblanchon/arduinojson)  
+[![Arduino Library Manager](https://img.shields.io/static/v1?label=Arduino&message=v6.21.5&logo=arduino&logoColor=white&color=blue)](https://www.ardu-badge.com/ArduinoJson/6.21.5)
+[![PlatformIO Registry](https://badges.registry.platformio.org/packages/bblanchon/library/ArduinoJson.svg?version=6.21.5)](https://registry.platformio.org/packages/libraries/bblanchon/ArduinoJson?version=6.21.5) 
+[![ESP IDF](https://img.shields.io/static/v1?label=ESP+IDF&message=v6.21.5&logo=cpu&logoColor=white&color=blue)](https://components.espressif.com/components/bblanchon/arduinojson)  
 [![GitHub stars](https://img.shields.io/github/stars/bblanchon/ArduinoJson?style=flat&logo=github&color=orange)](https://github.com/bblanchon/ArduinoJson/stargazers)
 [![GitHub Sponsors](https://img.shields.io/github/sponsors/bblanchon?logo=github&color=orange)](https://github.com/sponsors/bblanchon)
 

appveyor.yml

@@ -1,4 +1,4 @@
-version: 6.21.2.{build}
+version: 6.21.5.{build}
 environment:
   matrix:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022

extras/scripts/get-release-page.sh

@@ -4,14 +4,14 @@ set -eu
 
 VERSION="$1"
 CHANGELOG="$2"
-FRONTMATTER="$3"
+ARDUINOJSON_H="$3"
 
 cat << END
 ---
 branch: v6
 version: $VERSION
 date: '$(date +'%Y-%m-%d')'
-$(cat "$FRONTMATTER")
+$(extras/scripts/wandbox/publish.sh "$ARDUINOJSON_H")
 ---
 
 $(awk '/\* /{ FOUND=1; print; next } { if (FOUND) exit}' "$CHANGELOG")

extras/scripts/publish.sh

@@ -73,7 +73,6 @@ push
 extras/scripts/build-arduino-package.sh . "../ArduinoJson-$TAG.zip"
 extras/scripts/build-single-header.sh "src/ArduinoJson.h" "../ArduinoJson-$TAG.h"
 extras/scripts/build-single-header.sh "src/ArduinoJson.hpp" "../ArduinoJson-$TAG.hpp"
-extras/scripts/wandbox/publish.sh "../ArduinoJson-$TAG.h" > "../ArduinoJson-$TAG-wandbox.txt" || echo "Wandbox failed!"
-extras/scripts/get-release-page.sh "$VERSION" "CHANGELOG.md" "../ArduinoJson-$TAG-wandbox.txt" > "../ArduinoJson-$TAG.md"
+extras/scripts/get-release-page.sh "$VERSION" "CHANGELOG.md" "../ArduinoJson-$TAG.h" > "../ArduinoJson-$TAG.md"
 
 echo "You can now copy ../ArduinoJson-$TAG.md into arduinojson.org/collections/_versions/$VERSION.md"

extras/scripts/wandbox/JsonGeneratorExample.cpp

@@ -20,11 +20,6 @@ int main() {
   //
   // DynamicJsonDocument  doc(200);
 
-  // StaticJsonObject allocates memory on the stack, it can be
-  // replaced by DynamicJsonDocument which allocates in the heap.
-  //
-  // DynamicJsonDocument  doc(200);
-
   // Add values in the document
   //
   doc["sensor"] = "gps";

extras/tests/Cpp17/string_view.cpp

@@ -1,8 +1,16 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2023, Benoit BLANCHON
+// MIT License
+
+// we expect ArduinoJson.h to include <string_view>
+// but we don't want it to included accidentally
+#undef ARDUINO
+#define ARDUINOJSON_ENABLE_STD_STREAM 0
+#define ARDUINOJSON_ENABLE_STD_STRING 0
+
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-#include <string_view>
-
 #if !ARDUINOJSON_ENABLE_STRING_VIEW
 #  error ARDUINOJSON_ENABLE_STRING_VIEW must be set to 1
 #endif
@@ -19,7 +27,7 @@ TEST_CASE("string_view") {
 
   SECTION("JsonDocument::set()") {
     doc.set(std::string_view("123", 2));
-    REQUIRE(doc.as<std::string>() == "12");
+    REQUIRE(doc.as<std::string_view>() == "12");
   }
 
   SECTION("JsonDocument::operator[]() const") {

extras/tests/JsonVariant/converters.cpp

@@ -154,10 +154,18 @@ TEST_CASE("ConverterNeedsWriteableRef") {
 }
 
 namespace ArduinoJson {
-void convertToJson(char c, JsonVariant var) {
-  char buf[] = {c, 0};
-  var.set(buf);
-}
+template <>
+struct Converter<char> {
+  static void toJson(char c, JsonVariant var) {
+    char buf[] = {c, 0};
+    var.set(buf);
+  }
+
+  static char fromJson(JsonVariantConst src) {
+    auto p = src.as<const char*>();
+    return p ? p[0] : 0;
+  }
+};
 }  // namespace ArduinoJson
 
 TEST_CASE("Convert char to string") {  // issue #1922
@@ -165,3 +173,9 @@ TEST_CASE("Convert char to string") {  // issue #1922
   doc.set('a');
   REQUIRE(doc.as<std::string>() == "a");
 }
+
+TEST_CASE("Convert string to char") {  // issue #1963
+  StaticJsonDocument<64> doc;
+  doc.set("a");
+  REQUIRE(doc.as<char>() == 'a');
+}

extras/tests/JsonVariant/types.cpp

@@ -140,6 +140,13 @@ TEST_CASE("volatile") {
   DynamicJsonDocument doc(4096);
   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);

extras/tests/Misc/CMakeLists.txt

@@ -6,6 +6,7 @@ add_executable(MiscTests
 	arithmeticCompare.cpp
 	conflicts.cpp
 	FloatParts.cpp
+	issue1967.cpp
 	JsonString.cpp
 	NoArduinoHeader.cpp
 	printable.cpp

extras/tests/Misc/issue1967.cpp

@@ -0,0 +1,13 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2023, Benoit BLANCHON
+// MIT License
+
+// we expect ArduinoJson.h to include <string>
+#define ARDUINOJSON_ENABLE_STD_STRING 1
+
+// but we don't want it to included accidentally
+#undef ARDUINO
+#define ARDUINOJSON_ENABLE_STD_STREAM 0
+#define ARDUINOJSON_ENABLE_STRING_VIEW 0
+
+#include <ArduinoJson.h>

extras/tests/MsgPackDeserializer/doubleToFloat.cpp

@@ -13,7 +13,7 @@ static void check(const char* input, T expected) {
   uint8_t* f = reinterpret_cast<uint8_t*>(&actual);
   const uint8_t* d = reinterpret_cast<const uint8_t*>(input);
   doubleToFloat(d, f);
-  fixEndianess(actual);
+  fixEndianness(actual);
   CHECK(actual == expected);
 }
 

idf_component.yml

@@ -1,8 +1,8 @@
-version: "6.21.2"
+version: "6.21.5"
 description: >-
   A simple and efficient JSON library for embedded C++.
   ArduinoJson supports ✔ serialization, ✔ deserialization, ✔ MessagePack, ✔ fixed allocation, ✔ zero-copy, ✔ streams, ✔ filtering, and more.
-  It is the most popular Arduino library on GitHub ❤❤❤❤❤.
+  It is the most popular Arduino library on GitHub ♥.
   Check out arduinojson.org for a comprehensive documentation.
 url: https://arduinojson.org/
 files:

library.json

@@ -7,16 +7,14 @@
     "type": "git",
     "url": "https://github.com/bblanchon/ArduinoJson.git"
   },
-  "version": "6.21.2",
+  "version": "6.21.5",
   "authors": {
     "name": "Benoit Blanchon",
     "url": "https://blog.benoitblanchon.fr"
   },
-  "exclude": [
-    ".devcontainer",
-    ".github",
-    "extras"
-  ],
+  "export": {
+    "include": ["src", "examples", "LICENSE.txt", "ArduinoJson.h"]
+  },
   "frameworks": "*",
   "platforms": "*",
   "build": {

library.properties

@@ -1,5 +1,5 @@
 name=ArduinoJson
-version=6.21.2
+version=6.21.5
 author=Benoit Blanchon <blog.benoitblanchon.fr>
 maintainer=Benoit Blanchon <blog.benoitblanchon.fr>
 sentence=A simple and efficient JSON library for embedded C++.

src/ArduinoJson/Deserialization/Reader.hpp

@@ -18,7 +18,9 @@ struct Reader {
   Reader(TSource& source) : source_(&source) {}
 
   int read() {
-    return source_->read();  // Error here? You passed an unsupported input type
+    // clang-format off
+    return source_->read();  // Error here? See https://arduinojson.org/v6/invalid-input/
+    // clang-format on
   }
 
   size_t readBytes(char* buffer, size_t length) {

src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp

@@ -6,7 +6,7 @@
 
 #include <ArduinoJson/Deserialization/deserialize.hpp>
 #include <ArduinoJson/Memory/MemoryPool.hpp>
-#include <ArduinoJson/MsgPack/endianess.hpp>
+#include <ArduinoJson/MsgPack/endianness.hpp>
 #include <ArduinoJson/MsgPack/ieee754.hpp>
 #include <ArduinoJson/Polyfills/type_traits.hpp>
 #include <ArduinoJson/Variant/VariantData.hpp>
@@ -258,7 +258,7 @@ class MsgPackDeserializer {
     if (err)
       return err;
 
-    fixEndianess(value);
+    fixEndianness(value);
 
     return DeserializationError::Ok;
   }
@@ -287,7 +287,7 @@ class MsgPackDeserializer {
     if (err)
       return err;
 
-    fixEndianess(value);
+    fixEndianness(value);
     variant->setFloat(value);
 
     return DeserializationError::Ok;
@@ -303,7 +303,7 @@ class MsgPackDeserializer {
     if (err)
       return err;
 
-    fixEndianess(value);
+    fixEndianness(value);
     variant->setFloat(value);
 
     return DeserializationError::Ok;
@@ -322,7 +322,7 @@ class MsgPackDeserializer {
       return err;
 
     doubleToFloat(i, o);
-    fixEndianess(value);
+    fixEndianness(value);
     variant->setFloat(value);
 
     return DeserializationError::Ok;

src/ArduinoJson/MsgPack/MsgPackSerializer.hpp

@@ -4,7 +4,7 @@
 
 #pragma once
 
-#include <ArduinoJson/MsgPack/endianess.hpp>
+#include <ArduinoJson/MsgPack/endianness.hpp>
 #include <ArduinoJson/Polyfills/assert.hpp>
 #include <ArduinoJson/Polyfills/type_traits.hpp>
 #include <ArduinoJson/Serialization/CountingDecorator.hpp>
@@ -47,7 +47,7 @@ class MsgPackSerializer : public Visitor<size_t> {
   size_t visitArray(const CollectionData& array) {
     size_t n = array.size();
     if (n < 0x10) {
-      writeByte(uint8_t(0x90 + array.size()));
+      writeByte(uint8_t(0x90 + n));
     } else if (n < 0x10000) {
       writeByte(0xDC);
       writeInteger(uint16_t(n));
@@ -190,7 +190,7 @@ class MsgPackSerializer : public Visitor<size_t> {
 
   template <typename T>
   void writeInteger(T value) {
-    fixEndianess(value);
+    fixEndianness(value);
     writeBytes(reinterpret_cast<uint8_t*>(&value), sizeof(value));
   }
 

src/ArduinoJson/MsgPack/endianness.hpp

@@ -15,32 +15,32 @@ inline void swapBytes(uint8_t& a, uint8_t& b) {
   b = t;
 }
 
-inline void fixEndianess(uint8_t* p, integral_constant<size_t, 8>) {
+inline void fixEndianness(uint8_t* p, integral_constant<size_t, 8>) {
   swapBytes(p[0], p[7]);
   swapBytes(p[1], p[6]);
   swapBytes(p[2], p[5]);
   swapBytes(p[3], p[4]);
 }
 
-inline void fixEndianess(uint8_t* p, integral_constant<size_t, 4>) {
+inline void fixEndianness(uint8_t* p, integral_constant<size_t, 4>) {
   swapBytes(p[0], p[3]);
   swapBytes(p[1], p[2]);
 }
 
-inline void fixEndianess(uint8_t* p, integral_constant<size_t, 2>) {
+inline void fixEndianness(uint8_t* p, integral_constant<size_t, 2>) {
   swapBytes(p[0], p[1]);
 }
 
-inline void fixEndianess(uint8_t*, integral_constant<size_t, 1>) {}
+inline void fixEndianness(uint8_t*, integral_constant<size_t, 1>) {}
 
 template <typename T>
-inline void fixEndianess(T& value) {
-  fixEndianess(reinterpret_cast<uint8_t*>(&value),
-               integral_constant<size_t, sizeof(T)>());
+inline void fixEndianness(T& value) {
+  fixEndianness(reinterpret_cast<uint8_t*>(&value),
+                integral_constant<size_t, sizeof(T)>());
 }
 #else
 template <typename T>
-inline void fixEndianess(T&) {}
+inline void fixEndianness(T&) {}
 #endif
 
 ARDUINOJSON_END_PRIVATE_NAMESPACE

src/ArduinoJson/Namespace.hpp

@@ -11,14 +11,15 @@
 #ifndef ARDUINOJSON_VERSION_NAMESPACE
 
 #  define ARDUINOJSON_VERSION_NAMESPACE                                       \
-    ARDUINOJSON_CONCAT3(                                                      \
+    ARDUINOJSON_CONCAT4(                                                      \
         ARDUINOJSON_VERSION_MACRO,                                            \
         ARDUINOJSON_BIN2ALPHA(                                                \
             ARDUINOJSON_ENABLE_PROGMEM, ARDUINOJSON_USE_LONG_LONG,            \
             ARDUINOJSON_USE_DOUBLE, ARDUINOJSON_ENABLE_STRING_DEDUPLICATION), \
         ARDUINOJSON_BIN2ALPHA(                                                \
             ARDUINOJSON_ENABLE_NAN, ARDUINOJSON_ENABLE_INFINITY,              \
-            ARDUINOJSON_ENABLE_COMMENTS, ARDUINOJSON_DECODE_UNICODE))
+            ARDUINOJSON_ENABLE_COMMENTS, ARDUINOJSON_DECODE_UNICODE),         \
+        ARDUINOJSON_SLOT_OFFSET_SIZE)
 
 #endif
 

src/ArduinoJson/Polyfills/preprocessor.hpp

@@ -6,8 +6,8 @@
 
 #define ARDUINOJSON_CONCAT_(A, B) A##B
 #define ARDUINOJSON_CONCAT2(A, B) ARDUINOJSON_CONCAT_(A, B)
-#define ARDUINOJSON_CONCAT3(A, B, C) \
-  ARDUINOJSON_CONCAT2(ARDUINOJSON_CONCAT2(A, B), C)
+#define ARDUINOJSON_CONCAT4(A, B, C, D) \
+  ARDUINOJSON_CONCAT2(ARDUINOJSON_CONCAT2(A, B), ARDUINOJSON_CONCAT2(C, D))
 
 #define ARDUINOJSON_BIN2ALPHA_0000() A
 #define ARDUINOJSON_BIN2ALPHA_0001() B
@@ -15,7 +15,7 @@
 #define ARDUINOJSON_BIN2ALPHA_0011() D
 #define ARDUINOJSON_BIN2ALPHA_0100() E
 #define ARDUINOJSON_BIN2ALPHA_0101() F
-#define ARDUINOJSON_BIN2ALPHA_0110() F
+#define ARDUINOJSON_BIN2ALPHA_0110() G
 #define ARDUINOJSON_BIN2ALPHA_0111() H
 #define ARDUINOJSON_BIN2ALPHA_1000() I
 #define ARDUINOJSON_BIN2ALPHA_1001() J

src/ArduinoJson/Strings/Adapters/RamString.hpp

@@ -8,6 +8,7 @@
 #include <string.h>  // strcmp
 
 #include <ArduinoJson/Polyfills/assert.hpp>
+#include <ArduinoJson/Polyfills/attributes.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
 #include <ArduinoJson/Strings/StringAdapter.hpp>
 
@@ -27,7 +28,7 @@ class ZeroTerminatedRamString {
     return !str_;
   }
 
-  size_t size() const {
+  FORCE_INLINE size_t size() const {
     return str_ ? ::strlen(str_) : 0;
   }
 

src/ArduinoJson/Strings/StringTraits.hpp

@@ -38,16 +38,15 @@ struct has_data<T,
                                            const char*>::value>::type>
     : true_type {};
 
-// size_t length() const
+// unsigned int length() const
 // - String
 
 template <class T, class = void>
 struct has_length : false_type {};
 
 template <class T>
-struct has_length<
-    T, typename enable_if<
-           is_same<decltype(declval<const T>().length()), size_t>::value>::type>
+struct has_length<T, typename enable_if<is_unsigned<
+                         decltype(declval<const T>().length())>::value>::type>
     : true_type {};
 
 // size_t size() const

src/ArduinoJson/Variant/ConverterImpl.hpp

@@ -8,10 +8,22 @@
 #include <ArduinoJson/Variant/JsonVariantConst.hpp>
 #include <ArduinoJson/Variant/VariantFunctions.hpp>
 
+#if ARDUINOJSON_ENABLE_STD_STRING
+#  include <string>
+#endif
+
+#if ARDUINOJSON_ENABLE_STRING_VIEW
+#  include <string_view>
+#endif
+
 ARDUINOJSON_BEGIN_PUBLIC_NAMESPACE
 
 template <typename T, typename Enable>
 struct Converter {
+  static_assert(!detail::is_same<T, char>::value,
+                "type 'char' is not supported, use 'signed char', 'unsigned "
+                "char' or another integer type instead");
+
   static void toJson(const T& src, JsonVariant dst) {
     // clang-format off
     convertToJson(src, dst); // Error here? See https://arduinojson.org/v6/unsupported-set/
@@ -19,6 +31,9 @@ struct Converter {
   }
 
   static T fromJson(JsonVariantConst src) {
+    static_assert(!detail::is_same<T, char*>::value,
+                  "type 'char*' is not supported, use 'const char*' instead");
+
     // clang-format off
     T result; // Error here? See https://arduinojson.org/v6/non-default-constructible/
     convertFromJson(src, result);  // Error here? See https://arduinojson.org/v6/unsupported-as/
@@ -27,6 +42,9 @@ struct Converter {
   }
 
   static bool checkJson(JsonVariantConst src) {
+    static_assert(!detail::is_same<T, char*>::value,
+                  "type 'char*' is not supported, use 'const char*' instead");
+
     T dummy = T();
     // clang-format off
     return canConvertFromJson(src, dummy);  // Error here? See https://arduinojson.org/v6/unsupported-is/

src/ArduinoJson/Variant/VariantImpl.hpp

@@ -110,6 +110,13 @@ inline JsonVariant VariantRefBase<TDerived>::add() const {
                      variantAddElement(getOrCreateData(), getPool()));
 }
 
+template <typename TDerived>
+template <typename T>
+inline typename enable_if<ConverterNeedsWriteableRef<T>::value, T>::type
+VariantRefBase<TDerived>::as() const {
+  return Converter<T>::fromJson(getVariant());
+}
+
 template <typename TDerived>
 inline JsonVariant VariantRefBase<TDerived>::getVariant() const {
   return JsonVariant(getPool(), getData());
@@ -120,6 +127,30 @@ inline JsonVariant VariantRefBase<TDerived>::getOrCreateVariant() const {
   return JsonVariant(getPool(), getOrCreateData());
 }
 
+template <typename TDerived>
+template <typename T>
+inline typename enable_if<ConverterNeedsWriteableRef<T>::value, bool>::type
+VariantRefBase<TDerived>::is() const {
+  return Converter<T>::checkJson(getVariant());
+}
+
+template <typename TDerived>
+template <typename T>
+inline bool VariantRefBase<TDerived>::set(const T& value) const {
+  Converter<typename detail::remove_cv<T>::type>::toJson(value,
+                                                         getOrCreateVariant());
+  MemoryPool* pool = getPool();
+  return pool && !pool->overflowed();
+}
+
+template <typename TDerived>
+template <typename T>
+inline bool VariantRefBase<TDerived>::set(T* value) const {
+  Converter<T*>::toJson(value, getOrCreateVariant());
+  MemoryPool* pool = getPool();
+  return pool && !pool->overflowed();
+}
+
 template <typename TDerived>
 template <typename T>
 inline typename enable_if<is_same<T, JsonArray>::value, JsonArray>::type
@@ -138,8 +169,9 @@ template <typename TDerived>
 template <typename T>
 typename enable_if<is_same<T, JsonVariant>::value, JsonVariant>::type
 VariantRefBase<TDerived>::to() const {
-  variantSetNull(getOrCreateData());
-  return *this;
+  auto data = getOrCreateData();
+  variantSetNull(data);
+  return JsonVariant(getPool(), data);
 }
 
 template <typename TDerived>

src/ArduinoJson/Variant/VariantRefBase.hpp

@@ -57,11 +57,10 @@ class VariantRefBase : public VariantTag {
   // https://arduinojson.org/v6/api/jsonvariant/as/
   template <typename T>
   FORCE_INLINE typename enable_if<ConverterNeedsWriteableRef<T>::value, T>::type
-  as() const {
-    return Converter<T>::fromJson(getVariant());
-  }
+  as() const;
 
-  template <typename T>
+  template <typename T,
+            typename = typename enable_if<!is_same<T, TDerived>::value>::type>
   FORCE_INLINE operator T() const {
     return as<T>();
   }
@@ -91,18 +90,14 @@ class VariantRefBase : public VariantTag {
   template <typename T>
   FORCE_INLINE
       typename enable_if<ConverterNeedsWriteableRef<T>::value, bool>::type
-      is() const {
-    return Converter<T>::checkJson(getVariant());
-  }
+      is() const;
 
   // Returns true if the value is of the specified type.
   // https://arduinojson.org/v6/api/jsonvariant/is/
   template <typename T>
-  FORCE_INLINE typename enable_if<!ConverterNeedsWriteableRef<T>::value &&
-                                      !is_same<T, char*>::value &&
-                                      !is_same<T, char>::value,
-                                  bool>::type
-  is() const {
+  FORCE_INLINE
+      typename enable_if<!ConverterNeedsWriteableRef<T>::value, bool>::type
+      is() const {
     return Converter<T>::checkJson(getVariantConst());
   }
 
@@ -122,20 +117,12 @@ class VariantRefBase : public VariantTag {
   // Copies the specified value.
   // https://arduinojson.org/v6/api/jsonvariant/set/
   template <typename T>
-  FORCE_INLINE bool set(const T& value) const {
-    Converter<T>::toJson(value, getOrCreateVariant());
-    MemoryPool* pool = getPool();
-    return pool && !pool->overflowed();
-  }
+  FORCE_INLINE bool set(const T& value) const;
 
   // Copies the specified value.
   // https://arduinojson.org/v6/api/jsonvariant/set/
   template <typename T>
-  FORCE_INLINE bool set(T* value) const {
-    Converter<T*>::toJson(value, getOrCreateVariant());
-    MemoryPool* pool = getPool();
-    return pool && !pool->overflowed();
-  }
+  FORCE_INLINE bool set(T* value) const;
 
   // Returns the size of the array or object.
   // https://arduinojson.org/v6/api/jsonvariant/size/

src/ArduinoJson/version.hpp

@@ -4,8 +4,8 @@
 
 #pragma once
 
-#define ARDUINOJSON_VERSION "6.21.2"
+#define ARDUINOJSON_VERSION "6.21.5"
 #define ARDUINOJSON_VERSION_MAJOR 6
 #define ARDUINOJSON_VERSION_MINOR 21
-#define ARDUINOJSON_VERSION_REVISION 2
-#define ARDUINOJSON_VERSION_MACRO V6212
+#define ARDUINOJSON_VERSION_REVISION 5
+#define ARDUINOJSON_VERSION_MACRO V6215