Set version to 6.19.4

.github/workflows/ci.yml

@@ -40,6 +40,7 @@ jobs:
           - gcc: "9"
             cxxflags: -fsanitize=address -fno-sanitize-recover=all
           - gcc: "10"
+            cxxflags: -funsigned-char # Issue #1715
           - gcc: "11"
     steps:
       - name: Install
@@ -47,10 +48,10 @@ jobs:
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ trusty main'
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ trusty universe'
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial main'
-          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial universe' 
+          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial universe'
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic main'
-          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic universe' 
-          sudo add-apt-repository -yn 'deb http://mirrors.kernel.org/ubuntu hirsute main universe' 
+          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic universe'
+          sudo add-apt-repository -yn 'deb http://mirrors.kernel.org/ubuntu hirsute main universe'
           sudo apt-get update
           sudo apt-get install -y gcc-${{ matrix.gcc }} g++-${{ matrix.gcc }}
       - name: Checkout
@@ -103,9 +104,9 @@ jobs:
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ trusty main'
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ trusty universe'
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial main'
-          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial universe' 
+          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial universe'
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic main'
-          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic universe' 
+          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic universe'
           sudo apt-get update
           sudo apt-get install -y clang-${{ matrix.clang }}
       - name: Checkout
@@ -131,7 +132,9 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       - name: Install
-        run: sudo apt-get install -y g++-multilib
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y g++-multilib
       - name: Checkout
         uses: actions/checkout@v2
       - name: GCC 32-bit
@@ -424,7 +427,9 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       - name: Install
-        run: sudo apt-get install -y valgrind ninja-build
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y valgrind ninja-build
       - name: Checkout
         uses: actions/checkout@v2
       - name: Configure

CHANGELOG.md

@@ -1,6 +1,27 @@
 ArduinoJson: change log
 =======================
 
+v6.19.4 (2022-04-05)
+-------
+
+* Add `ElementProxy::memoryUsage()`
+* Add `MemberProxy::memoryUsage()` (issue #1730)
+* Add implicit conversion from `JsonDocument` to `JsonVariant`
+* Fix comparisons operators with `const JsonDocument&`
+
+v6.19.3 (2022-03-08)
+-------
+
+* Fix `call of overloaded 'String(const char*, int)' is ambiguous`
+* Fix `JsonString` operator `==` and `!=` for non-zero-terminated string
+* Fix `-Wsign-conversion` on GCC 8 (issue #1715)
+* MessagePack: serialize round floats as integers (issue #1718)
+
+v6.19.2 (2022-02-14)
+-------
+
+* Fix `cannot convert 'pgm_p' to 'const void*'` (issue #1707)
+
 v6.19.1 (2022-01-14)
 -------
 

CMakeLists.txt

@@ -10,7 +10,7 @@ if(ESP_PLATFORM)
    return()
 endif()
 
-project(ArduinoJson VERSION 6.19.1)
+project(ArduinoJson VERSION 6.19.4)
 
 if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
     include(CTest)

README.md

@@ -7,8 +7,8 @@
 [![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)
 [![LGTM Grade](https://img.shields.io/lgtm/grade/cpp/github/bblanchon/ArduinoJson?label=quality&logo=lgtm)](https://lgtm.com/projects/g/bblanchon/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=v6.19.1&logo=arduino&logoColor=white&color=blue)](https://www.ardu-badge.com/ArduinoJson/6.19.1)
-[![PlatformIO Registry](https://badges.registry.platformio.org/packages/bblanchon/library/ArduinoJson.svg?version=6.19.1)](https://registry.platformio.org/packages/libraries/bblanchon/ArduinoJson?version=6.19.1) 
+[![Arduino Library Manager](https://img.shields.io/static/v1?label=Arduino&message=v6.19.4&logo=arduino&logoColor=white&color=blue)](https://www.ardu-badge.com/ArduinoJson/6.19.4)
+[![PlatformIO Registry](https://badges.registry.platformio.org/packages/bblanchon/library/ArduinoJson.svg?version=6.19.4)](https://registry.platformio.org/packages/libraries/bblanchon/ArduinoJson?version=6.19.4) 
 [![GitHub stars](https://img.shields.io/github/stars/bblanchon/ArduinoJson?style=flat&logo=github)](https://github.com/bblanchon/ArduinoJson/stargazers)
 [![GitHub Sponsors](https://img.shields.io/github/sponsors/bblanchon?logo=github)](https://github.com/sponsors/bblanchon)
 

appveyor.yml

@@ -1,4 +1,4 @@
-version: 6.19.1.{build}
+version: 6.19.4.{build}
 environment:
   matrix:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022

extras/CompileOptions.cmake

@@ -18,6 +18,7 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "(GNU|Clang)")
 		-Wparentheses
 		-Wredundant-decls
 		-Wshadow
+		-Wsign-conversion
 		-Wsign-promo
 		-Wstrict-aliasing
 		-Wundef
@@ -92,3 +93,9 @@ if(MSVC)
 		)
 	endif()
 endif()
+
+if(MINGW)
+  # Static link on MinGW to avoid linking with the wrong DLLs when multiple
+	# versions are installed.
+	add_link_options(-static)
+endif()

extras/scripts/publish.sh

@@ -69,7 +69,7 @@ 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-$TAG-wandbox.txt"
+extras/scripts/wandbox/publish.sh "../ArduinoJson-$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"
 
 echo "You can now copy ../ArduinoJson-$TAG.md into arduinojson.org/collections/_versions/$VERSION.md"

extras/scripts/wandbox/publish.sh

@@ -15,13 +15,13 @@ compile() {
   "code":$(read_string "$FILE_PATH"),
   "codes": [{"file":"ArduinoJson.h","code":$(read_string "$ARDUINOJSON_H")}],
   "options": "warning",
-  "compiler": "gcc-4.9.3",
+  "compiler": "gcc-4.9.4",
   "save": true
 }
 END
 	URL=$(curl -sS -H "Content-type: application/json" -d @parameters.json  https://wandbox.org/api/compile.json | jq --raw-output .url)
 	rm parameters.json
-	echo "$1: $URL"
+	[ -n "$URL" ] && echo "$1: $URL"
 }
 
 compile "JsonGeneratorExample"

extras/tests/JsonArray/add.cpp

@@ -40,7 +40,7 @@ TEST_CASE("JsonArray::add()") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("vla") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "world");
 

extras/tests/JsonArray/subscript.cpp

@@ -135,7 +135,7 @@ TEST_CASE("JsonArray::operator[]") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("set(VLA)") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "world");
 
@@ -146,7 +146,7 @@ TEST_CASE("JsonArray::operator[]") {
   }
 
   SECTION("operator=(VLA)") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "world");
 

extras/tests/JsonDeserializer/filter.cpp

@@ -366,7 +366,7 @@ TEST_CASE("Filtering") {
       0
     },
     {
-      // bubble up element error even if array is skipped 
+      // bubble up element error even if array is skipped
       "[1,'2,3]",
       "false",
       10,
@@ -375,7 +375,7 @@ TEST_CASE("Filtering") {
       0
     },
     {
-      // bubble up member error even if object is skipped 
+      // bubble up member error even if object is skipped
       "{'hello':'worl}",
       "false",
       10,
@@ -384,7 +384,7 @@ TEST_CASE("Filtering") {
       0
     },
     {
-      // bubble up colon error even if object is skipped 
+      // bubble up colon error even if object is skipped
       "{'hello','world'}",
       "false",
       10,
@@ -393,7 +393,7 @@ TEST_CASE("Filtering") {
       0
     },
     {
-      // bubble up key error even if object is skipped 
+      // bubble up key error even if object is skipped
       "{'hello:1}",
       "false",
       10,
@@ -404,7 +404,7 @@ TEST_CASE("Filtering") {
     {
       // detect invalid value in skipped object
       "{'hello':!}",
-      "false", 
+      "false",
       10,
       DeserializationError::InvalidInput,
       "null",
@@ -413,235 +413,235 @@ TEST_CASE("Filtering") {
     {
       // ignore invalid value in skipped object
       "{'hello':\\}",
-      "false", 
+      "false",
       10,
       DeserializationError::InvalidInput,
-      "null", 
+      "null",
       0
     },
     {
       // check nesting limit even for ignored objects
       "{}",
-      "false", 
+      "false",
       0,
       DeserializationError::TooDeep,
-      "null", 
+      "null",
       0
     },
     {
       // check nesting limit even for ignored objects
       "{'hello':{}}",
-      "false", 
+      "false",
       1,
       DeserializationError::TooDeep,
-      "null", 
+      "null",
       0
     },
     {
       // check nesting limit even for ignored values in objects
       "{'hello':{}}",
-      "{}", 
+      "{}",
       1,
       DeserializationError::TooDeep,
-      "{}", 
+      "{}",
       JSON_OBJECT_SIZE(0)
     },
     {
       // check nesting limit even for ignored arrays
       "[]",
-      "false", 
+      "false",
       0,
       DeserializationError::TooDeep,
-      "null", 
+      "null",
       0
     },
     {
       // check nesting limit even for ignored arrays
       "[[]]",
-      "false", 
+      "false",
       1,
       DeserializationError::TooDeep,
-      "null", 
+      "null",
       0
     },
     {
       // check nesting limit even for ignored values in arrays
       "[[]]",
-      "[]", 
+      "[]",
       1,
       DeserializationError::TooDeep,
-      "[]", 
+      "[]",
       JSON_ARRAY_SIZE(0)
     },
     {
       // supports back-slash at the end of skipped string
       "\"hell\\",
-      "false", 
+      "false",
       1,
       DeserializationError::IncompleteInput,
-      "null", 
+      "null",
       0
     },
     {
       // invalid comment at after an element in a skipped array
       "[1/]",
-      "false", 
+      "false",
       10,
       DeserializationError::InvalidInput,
-      "null", 
+      "null",
       0
     },
     {
       // incomplete comment at after an element in a skipped array
       "[1/*]",
-      "false", 
+      "false",
       10,
       DeserializationError::IncompleteInput,
-      "null", 
+      "null",
       0
     },
     {
       // missing comma in a skipped array
       "[1 2]",
-      "false", 
+      "false",
       10,
       DeserializationError::InvalidInput,
-      "null", 
+      "null",
       0
     },
     {
       // invalid comment at the beginning of array
       "[/1]",
-      "[false]", 
+      "[false]",
       10,
       DeserializationError::InvalidInput,
-      "[]", 
+      "[]",
       JSON_ARRAY_SIZE(0)
     },
     {
       // incomplete comment at the begining of an array
       "[/*]",
-      "[false]", 
+      "[false]",
       10,
       DeserializationError::IncompleteInput,
-      "[]", 
+      "[]",
       JSON_ARRAY_SIZE(0)
     },
     {
       // invalid comment before key
       "{/1:2}",
-      "{}", 
+      "{}",
       10,
       DeserializationError::InvalidInput,
-      "{}", 
+      "{}",
       JSON_OBJECT_SIZE(0)
     },
     {
       // incomplete comment before key
       "{/*:2}",
-      "{}", 
+      "{}",
       10,
       DeserializationError::IncompleteInput,
-      "{}", 
+      "{}",
       JSON_OBJECT_SIZE(0)
     },
     {
       // invalid comment after key
       "{\"example\"/1:2}",
-      "{}", 
+      "{}",
       10,
       DeserializationError::InvalidInput,
-      "{}", 
+      "{}",
       JSON_OBJECT_SIZE(0)
     },
     {
       // incomplete comment after key
       "{\"example\"/*:2}",
-      "{}", 
+      "{}",
       10,
       DeserializationError::IncompleteInput,
-      "{}", 
+      "{}",
       JSON_OBJECT_SIZE(0)
     },
     {
       // invalid comment after colon
       "{\"example\":/12}",
-      "{}", 
+      "{}",
       10,
       DeserializationError::InvalidInput,
-      "{}", 
+      "{}",
       JSON_OBJECT_SIZE(0)
     },
     {
       // incomplete comment after colon
       "{\"example\":/*2}",
-      "{}", 
+      "{}",
       10,
       DeserializationError::IncompleteInput,
-      "{}", 
+      "{}",
       JSON_OBJECT_SIZE(0)
     },
     {
       // comment next to an integer
       "{\"ignore\":1//,\"example\":2\n}",
-      "{\"example\":true}", 
+      "{\"example\":true}",
       10,
       DeserializationError::Ok,
-      "{}", 
+      "{}",
       JSON_OBJECT_SIZE(0)
     },
     {
       // invalid comment after opening brace of a skipped object
       "{/1:2}",
-      "false", 
+      "false",
       10,
       DeserializationError::InvalidInput,
-      "null", 
+      "null",
       0
     },
     {
       // incomplete after opening brace of a skipped object
       "{/*:2}",
-      "false", 
+      "false",
       10,
       DeserializationError::IncompleteInput,
-      "null", 
+      "null",
       0
     },
     {
       // invalid comment after key of a skipped object
       "{\"example\"/:2}",
-      "false", 
+      "false",
       10,
       DeserializationError::InvalidInput,
-      "null", 
+      "null",
       0
     },
     {
       // incomplete after after key of a skipped object
       "{\"example\"/*:2}",
-      "false", 
+      "false",
       10,
       DeserializationError::IncompleteInput,
-      "null", 
+      "null",
       0
     },
     {
       // invalid comment after value in a skipped object
       "{\"example\":2/}",
-      "false", 
+      "false",
       10,
       DeserializationError::InvalidInput,
-      "null", 
+      "null",
       0
     },
     {
       // incomplete after after value of a skipped object
       "{\"example\":2/*}",
-      "false", 
+      "false",
       10,
       DeserializationError::IncompleteInput,
-      "null", 
+      "null",
       0
     },
   };  // clang-format on
@@ -708,7 +708,7 @@ TEST_CASE("Overloads") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("char[n], Filter") {
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "{}");
     deserializeJson(doc, vla, Filter(filter));
@@ -736,7 +736,7 @@ TEST_CASE("Overloads") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("char[n], Filter, NestingLimit") {
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "{}");
     deserializeJson(doc, vla, Filter(filter), NestingLimit(5));
@@ -764,7 +764,7 @@ TEST_CASE("Overloads") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("char[n], NestingLimit, Filter") {
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "{}");
     deserializeJson(doc, vla, NestingLimit(5), Filter(filter));

extras/tests/JsonDeserializer/input_types.cpp

@@ -121,7 +121,7 @@ TEST_CASE("deserializeJson(std::istream&)") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
 TEST_CASE("deserializeJson(VLA)") {
-  int i = 9;
+  size_t i = 9;
   char vla[i];
   strcpy(vla, "{\"a\":42}");
 

extras/tests/JsonDocument/CMakeLists.txt

@@ -5,6 +5,7 @@
 add_executable(JsonDocumentTests
 	add.cpp
 	BasicJsonDocument.cpp
+	cast.cpp
 	compare.cpp
 	containsKey.cpp
 	createNested.cpp

extras/tests/JsonDocument/DynamicJsonDocument.cpp

@@ -205,4 +205,26 @@ TEST_CASE("DynamicJsonDocument assignment") {
     REQUIRE_JSON(doc2, "42");
     REQUIRE(doc2.capacity() == 4096);
   }
+
+  SECTION("Assign from MemberProxy") {
+    StaticJsonDocument<200> doc1;
+    doc1["value"] = 42;
+
+    DynamicJsonDocument doc2(4096);
+    doc2 = doc1["value"];
+
+    REQUIRE_JSON(doc2, "42");
+    REQUIRE(doc2.capacity() == 4096);
+  }
+
+  SECTION("Assign from ElementProxy") {
+    StaticJsonDocument<200> doc1;
+    doc1[0] = 42;
+
+    DynamicJsonDocument doc2(4096);
+    doc2 = doc1[0];
+
+    REQUIRE_JSON(doc2, "42");
+    REQUIRE(doc2.capacity() == 4096);
+  }
 }

extras/tests/JsonDocument/ElementProxy.cpp

@@ -10,7 +10,7 @@ using namespace ARDUINOJSON_NAMESPACE;
 TEST_CASE("ElementProxy::add()") {
   DynamicJsonDocument doc(4096);
   doc.addElement();
-  ElementProxy<JsonDocument&> ep = doc[0];
+  ElementProxy<JsonDocument &> ep = doc[0];
 
   SECTION("add(int)") {
     ep.add(42);
@@ -36,7 +36,7 @@ TEST_CASE("ElementProxy::add()") {
 TEST_CASE("ElementProxy::clear()") {
   DynamicJsonDocument doc(4096);
   doc.addElement();
-  ElementProxy<JsonDocument&> ep = doc[0];
+  ElementProxy<JsonDocument &> ep = doc[0];
 
   SECTION("size goes back to zero") {
     ep.add(42);
@@ -96,7 +96,7 @@ TEST_CASE("ElementProxy::operator==()") {
 TEST_CASE("ElementProxy::remove()") {
   DynamicJsonDocument doc(4096);
   doc.addElement();
-  ElementProxy<JsonDocument&> ep = doc[0];
+  ElementProxy<JsonDocument &> ep = doc[0];
 
   SECTION("remove(int)") {
     ep.add(1);
@@ -131,7 +131,7 @@ TEST_CASE("ElementProxy::remove()") {
     ep["a"] = 1;
     ep["b"] = 2;
 
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "b");
     ep.remove(vla);
@@ -143,7 +143,7 @@ TEST_CASE("ElementProxy::remove()") {
 
 TEST_CASE("ElementProxy::set()") {
   DynamicJsonDocument doc(4096);
-  ElementProxy<JsonDocument&> ep = doc[0];
+  ElementProxy<JsonDocument &> ep = doc[0];
 
   SECTION("set(int)") {
     ep.set(42);
@@ -169,7 +169,7 @@ TEST_CASE("ElementProxy::set()") {
 TEST_CASE("ElementProxy::size()") {
   DynamicJsonDocument doc(4096);
   doc.addElement();
-  ElementProxy<JsonDocument&> ep = doc[0];
+  ElementProxy<JsonDocument &> ep = doc[0];
 
   SECTION("returns 0") {
     REQUIRE(ep.size() == 0);
@@ -188,9 +188,24 @@ TEST_CASE("ElementProxy::size()") {
   }
 }
 
+TEST_CASE("ElementProxy::memoryUsage()") {
+  DynamicJsonDocument doc(4096);
+  doc.addElement();
+  ElementProxy<JsonDocument &> ep = doc[0];
+
+  SECTION("returns 0 for null") {
+    REQUIRE(ep.memoryUsage() == 0);
+  }
+
+  SECTION("returns size for string") {
+    ep.set(std::string("hello"));
+    REQUIRE(ep.memoryUsage() == 6);
+  }
+}
+
 TEST_CASE("ElementProxy::operator[]") {
   DynamicJsonDocument doc(4096);
-  ElementProxy<JsonDocument&> ep = doc[1];
+  ElementProxy<JsonDocument &> ep = doc[1];
 
   SECTION("set member") {
     ep["world"] = 42;
@@ -204,3 +219,29 @@ TEST_CASE("ElementProxy::operator[]") {
     REQUIRE(doc.as<std::string>() == "[null,[null,null,42]]");
   }
 }
+
+TEST_CASE("ElementProxy cast to JsonVariantConst") {
+  DynamicJsonDocument doc(4096);
+  doc[0] = "world";
+
+  const ElementProxy<JsonDocument &> ep = doc[0];
+
+  JsonVariantConst var = ep;
+
+  CHECK(var.as<std::string>() == "world");
+}
+
+TEST_CASE("ElementProxy cast to JsonVariant") {
+  DynamicJsonDocument doc(4096);
+  doc[0] = "world";
+
+  ElementProxy<JsonDocument &> ep = doc[0];
+
+  JsonVariant var = ep;
+
+  CHECK(var.as<std::string>() == "world");
+
+  var.set("toto");
+
+  CHECK(doc.as<std::string>() == "[\"toto\"]");
+}

extras/tests/JsonDocument/MemberProxy.cpp

@@ -171,7 +171,7 @@ TEST_CASE("MemberProxy::remove()") {
     mp["a"] = 1;
     mp["b"] = 2;
 
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "b");
     mp.remove(vla);
@@ -229,6 +229,20 @@ TEST_CASE("MemberProxy::size()") {
   }
 }
 
+TEST_CASE("MemberProxy::memoryUsage()") {
+  DynamicJsonDocument doc(4096);
+  MemberProxy<JsonDocument &, const char *> mp = doc["hello"];
+
+  SECTION("returns 0 when null") {
+    REQUIRE(mp.memoryUsage() == 0);
+  }
+
+  SECTION("return the size for a string") {
+    mp.set(std::string("hello"));
+    REQUIRE(mp.memoryUsage() == 6);
+  }
+}
+
 TEST_CASE("MemberProxy::operator[]") {
   DynamicJsonDocument doc(4096);
   MemberProxy<JsonDocument &, const char *> mp = doc["hello"];
@@ -245,3 +259,29 @@ TEST_CASE("MemberProxy::operator[]") {
     REQUIRE(doc.as<std::string>() == "{\"hello\":[null,null,42]}");
   }
 }
+
+TEST_CASE("MemberProxy cast to JsonVariantConst") {
+  DynamicJsonDocument doc(4096);
+  doc["hello"] = "world";
+
+  const MemberProxy<JsonDocument &, const char *> mp = doc["hello"];
+
+  JsonVariantConst var = mp;
+
+  CHECK(var.as<std::string>() == "world");
+}
+
+TEST_CASE("MemberProxy cast to JsonVariant") {
+  DynamicJsonDocument doc(4096);
+  doc["hello"] = "world";
+
+  MemberProxy<JsonDocument &, const char *> mp = doc["hello"];
+
+  JsonVariant var = mp;
+
+  CHECK(var.as<std::string>() == "world");
+
+  var.set("toto");
+
+  CHECK(doc.as<std::string>() == "{\"hello\":\"toto\"}");
+}

extras/tests/JsonDocument/cast.cpp

@@ -0,0 +1,18 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+#include <string>
+
+TEST_CASE("Implicit cast to JsonVariant") {
+  StaticJsonDocument<128> doc;
+
+  doc["hello"] = "world";
+
+  JsonVariant var = doc;
+
+  CHECK(var.as<std::string>() == "{\"hello\":\"world\"}");
+}

extras/tests/JsonDocument/compare.cpp

@@ -75,3 +75,29 @@ TEST_CASE("StaticJsonDocument::operator==(const DynamicJsonDocument&)") {
     REQUIRE(doc1 != doc2);
   }
 }
+
+TEST_CASE("JsonDocument::operator==(const JsonDocument&)") {
+  StaticJsonDocument<256> doc1;
+  StaticJsonDocument<256> doc2;
+  const JsonDocument& ref1 = doc1;
+  const JsonDocument& ref2 = doc2;
+
+  SECTION("Empty") {
+    REQUIRE(ref1 == ref2);
+    REQUIRE_FALSE(ref1 != ref2);
+  }
+
+  SECTION("With same object") {
+    doc1["hello"] = "world";
+    doc2["hello"] = "world";
+    REQUIRE(ref1 == ref2);
+    REQUIRE_FALSE(ref1 != ref2);
+  }
+
+  SECTION("With different object") {
+    doc1["hello"] = "world";
+    doc2["world"] = "hello";
+    REQUIRE_FALSE(ref1 == ref2);
+    REQUIRE(ref1 != ref2);
+  }
+}

extras/tests/JsonDocument/remove.cpp

@@ -41,7 +41,7 @@ TEST_CASE("JsonDocument::remove()") {
     doc["a"] = 1;
     doc["b"] = 2;
 
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "b");
     doc.remove(vla);

extras/tests/JsonObject/containsKey.cpp

@@ -29,7 +29,7 @@ TEST_CASE("JsonObject::containsKey()") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("key is a VLA") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "hello");
 

extras/tests/JsonObject/createNestedArray.cpp

@@ -16,7 +16,7 @@ TEST_CASE("JsonObject::createNestedArray()") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("key is a VLA") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "hello");
 

extras/tests/JsonObject/createNestedObject.cpp

@@ -15,7 +15,7 @@ TEST_CASE("JsonObject::createNestedObject()") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("key is a VLA") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "hello");
 

extras/tests/JsonObject/remove.cpp

@@ -60,7 +60,7 @@ TEST_CASE("JsonObject::remove()") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("key is a vla") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "b");
     obj.remove(vla);

extras/tests/JsonObject/subscript.cpp

@@ -141,13 +141,13 @@ TEST_CASE("JsonObject::operator[]") {
   }
 
   SECTION("should duplicate a non-static JsonString key") {
-    obj[JsonString("hello", false)] = "world";
+    obj[JsonString("hello", JsonString::Copied)] = "world";
     const size_t expectedSize = JSON_OBJECT_SIZE(1) + JSON_STRING_SIZE(5);
     REQUIRE(expectedSize == doc.memoryUsage());
   }
 
   SECTION("should not duplicate a static JsonString key") {
-    obj[JsonString("hello", true)] = "world";
+    obj[JsonString("hello", JsonString::Linked)] = "world";
     const size_t expectedSize = JSON_OBJECT_SIZE(1);
     REQUIRE(expectedSize == doc.memoryUsage());
   }
@@ -172,7 +172,7 @@ TEST_CASE("JsonObject::operator[]") {
 #if defined(HAS_VARIABLE_LENGTH_ARRAY) && \
     !defined(SUBSCRIPT_CONFLICTS_WITH_BUILTIN_OPERATOR)
   SECTION("obj[VLA] = str") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "hello");
 
@@ -182,7 +182,7 @@ TEST_CASE("JsonObject::operator[]") {
   }
 
   SECTION("obj[str] = VLA") {  // issue #416
-    int i = 32;
+    size_t i = 32;
     char vla[i];
     strcpy(vla, "world");
 
@@ -192,7 +192,7 @@ TEST_CASE("JsonObject::operator[]") {
   }
 
   SECTION("obj.set(VLA, str)") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "hello");
 
@@ -202,7 +202,7 @@ TEST_CASE("JsonObject::operator[]") {
   }
 
   SECTION("obj.set(str, VLA)") {
-    int i = 32;
+    size_t i = 32;
     char vla[i];
     strcpy(vla, "world");
 
@@ -212,7 +212,7 @@ TEST_CASE("JsonObject::operator[]") {
   }
 
   SECTION("obj[VLA]") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "hello");
 

extras/tests/JsonVariant/as.cpp

@@ -136,7 +136,7 @@ TEST_CASE("JsonVariant::as()") {
 
     REQUIRE(variant.as<long>() == 42L);
     REQUIRE(variant.as<JsonString>() == "42");
-    REQUIRE(variant.as<JsonString>().isStatic() == true);
+    REQUIRE(variant.as<JsonString>().isLinked() == true);
   }
 
   SECTION("set(\"hello\")") {
@@ -159,7 +159,7 @@ TEST_CASE("JsonVariant::as()") {
     REQUIRE(variant.as<const char*>() == std::string("4.2"));
     REQUIRE(variant.as<std::string>() == std::string("4.2"));
     REQUIRE(variant.as<JsonString>() == "4.2");
-    REQUIRE(variant.as<JsonString>().isStatic() == false);
+    REQUIRE(variant.as<JsonString>().isLinked() == false);
   }
 
   SECTION("set(\"true\")") {

extras/tests/JsonVariant/set.cpp

@@ -71,7 +71,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("VLA") {
-    int n = 16;
+    size_t n = 16;
     char str[n];
 
     strcpy(str, "hello");
@@ -98,7 +98,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
     char str[16];
 
     strcpy(str, "hello");
-    bool result = variant.set(JsonString(str, true));
+    bool result = variant.set(JsonString(str, JsonString::Linked));
     strcpy(str, "world");
 
     REQUIRE(result == true);
@@ -109,7 +109,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
     char str[16];
 
     strcpy(str, "hello");
-    bool result = variant.set(JsonString(str, false));
+    bool result = variant.set(JsonString(str, JsonString::Copied));
     strcpy(str, "world");
 
     REQUIRE(result == true);

extras/tests/JsonVariant/subscript.cpp

@@ -108,7 +108,7 @@ TEST_CASE("JsonVariant::operator[]") {
 #if defined(HAS_VARIABLE_LENGTH_ARRAY) && \
     !defined(SUBSCRIPT_CONFLICTS_WITH_BUILTIN_OPERATOR)
   SECTION("key is a VLA") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "hello");
 
@@ -119,7 +119,7 @@ TEST_CASE("JsonVariant::operator[]") {
   }
 
   SECTION("key is a VLA, const JsonVariant") {
-    int i = 16;
+    size_t i = 16;
     char vla[i];
     strcpy(vla, "hello");
 

extras/tests/Misc/JsonString.cpp

@@ -13,45 +13,54 @@ TEST_CASE("JsonString") {
 
     CHECK(s.isNull() == true);
     CHECK(s.c_str() == 0);
-    CHECK(s.isStatic() == true);
+    CHECK(s.isLinked() == true);
+    CHECK(s == JsonString());
+    CHECK(s != "");
   }
 
-  SECTION("Compare null with boolean") {
+  SECTION("Null converts to false") {
     JsonString s;
 
     CHECK(bool(s) == false);
-    CHECK(false == bool(s));
-    CHECK(bool(s) != true);
-    CHECK(true != bool(s));
   }
 
-  SECTION("Compare non-null with boolean") {
-    JsonString s("hello");
+  SECTION("Empty string converts to true") {
+    JsonString s("");
+
     CHECK(bool(s) == true);
-    CHECK(true == bool(s));
-    CHECK(bool(s) != false);
-    CHECK(false != bool(s));
   }
 
-  SECTION("Compare null with null") {
+  SECTION("Non-empty string converts to true") {
+    JsonString s("");
+
+    CHECK(bool(s) == true);
+  }
+
+  SECTION("Null strings equals each others") {
     JsonString a, b;
 
     CHECK(a == b);
     CHECK_FALSE(a != b);
   }
 
-  SECTION("Compare null with non-null") {
-    JsonString a(0), b("hello");
+  SECTION("Null and empty strings differ") {
+    JsonString a, b("");
 
     CHECK_FALSE(a == b);
     CHECK(a != b);
+
+    CHECK_FALSE(b == a);
+    CHECK(b != a);
   }
 
-  SECTION("Compare non-null with null") {
-    JsonString a("hello"), b(0);
+  SECTION("Null and non-empty strings differ") {
+    JsonString a, b("hello");
 
     CHECK_FALSE(a == b);
     CHECK(a != b);
+
+    CHECK_FALSE(b == a);
+    CHECK(b != a);
   }
 
   SECTION("Compare different strings") {
@@ -82,4 +91,13 @@ TEST_CASE("JsonString") {
     ss << JsonString("hello world!");
     CHECK(ss.str() == "hello world!");
   }
+
+  SECTION("Construct with a size") {
+    JsonString s("hello world", 5);
+
+    CHECK(s.size() == 5);
+    CHECK(s.isLinked() == true);
+    CHECK(s == "hello");
+    CHECK(s != "hello world");
+  }
 }

extras/tests/MixedConfiguration/CMakeLists.txt

@@ -16,6 +16,7 @@ add_executable(MixedConfigurationTests
 	enable_progmem_1.cpp
 	enable_string_deduplication_0.cpp
 	enable_string_deduplication_1.cpp
+	issue1707.cpp
 	use_double_0.cpp
 	use_double_1.cpp
 )

extras/tests/MixedConfiguration/issue1707.cpp

@@ -0,0 +1,17 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#define ARDUINO
+#define memcpy_P(dest, src, n) memcpy((dest), (src), (n))
+
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+TEST_CASE("Issue1707") {
+  StaticJsonDocument<128> doc;
+
+  DeserializationError err = deserializeJson(doc, F("{\"hello\":12}"));
+  REQUIRE(err == DeserializationError::Ok);
+}

extras/tests/MsgPackDeserializer/filter.cpp

@@ -1068,7 +1068,7 @@ TEST_CASE("Overloads") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("char[n], Filter") {
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "{}");
     deserializeMsgPack(doc, vla, Filter(filter));
@@ -1096,7 +1096,7 @@ TEST_CASE("Overloads") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("char[n], Filter, NestingLimit") {
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "{}");
     deserializeMsgPack(doc, vla, Filter(filter), NestingLimit(5));
@@ -1124,7 +1124,7 @@ TEST_CASE("Overloads") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
   SECTION("char[n], NestingLimit, Filter") {
-    int i = 4;
+    size_t i = 4;
     char vla[i];
     strcpy(vla, "{}");
     deserializeMsgPack(doc, vla, NestingLimit(5), Filter(filter));

extras/tests/MsgPackDeserializer/input_types.cpp

@@ -72,7 +72,7 @@ TEST_CASE("deserializeMsgPack(std::istream&)") {
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
 TEST_CASE("deserializeMsgPack(VLA)") {
-  int i = 16;
+  size_t i = 16;
   char vla[i];
   memcpy(vla, "\xDE\x00\x01\xA5Hello\xA5world", 15);
 

extras/tests/MsgPackSerializer/serializeVariant.cpp

@@ -144,4 +144,18 @@ TEST_CASE("serialize MsgPack value") {
     checkVariant(serialized("\xDA\xFF\xFF"), "\xDA\xFF\xFF");
     checkVariant(serialized("\xDB\x00\x01\x00\x00", 5), "\xDB\x00\x01\x00\x00");
   }
+
+  SECTION("serialize round double as integer") {  // Issue #1718
+    checkVariant(-32768.0, "\xD1\x80\x00");
+    checkVariant(-129.0, "\xD1\xFF\x7F");
+    checkVariant(-128.0, "\xD0\x80");
+    checkVariant(-33.0, "\xD0\xDF");
+    checkVariant(-32.0, "\xE0");
+    checkVariant(-1.0, "\xFF");
+    checkVariant(0.0, "\x00");
+    checkVariant(127.0, "\x7F");
+    checkVariant(128.0, "\xCC\x80");
+    checkVariant(255.0, "\xCC\xFF");
+    checkVariant(256.0, "\xCD\x01\x00");
+  }
 }

library.json

@@ -7,7 +7,7 @@
     "type": "git",
     "url": "https://github.com/bblanchon/ArduinoJson.git"
   },
-  "version": "6.19.1",
+  "version": "6.19.4",
   "authors": {
     "name": "Benoit Blanchon",
     "url": "https://blog.benoitblanchon.fr"

library.properties

@@ -1,5 +1,5 @@
 name=ArduinoJson
-version=6.19.1
+version=6.19.4
 author=Benoit Blanchon <blog.benoitblanchon.fr>
 maintainer=Benoit Blanchon <blog.benoitblanchon.fr>
 sentence=A simple and efficient JSON library for embedded C++.

src/ArduinoJson/Array/ElementProxy.hpp

@@ -118,6 +118,10 @@ class ElementProxy : public VariantOperators<ElementProxy<TArray> >,
     return getUpstreamElement().size();
   }
 
+  FORCE_INLINE size_t memoryUsage() const {
+    return getUpstreamElement().memoryUsage();
+  }
+
   template <typename TNestedKey>
   VariantRef getMember(TNestedKey* key) const {
     return getUpstreamElement().getMember(key);

src/ArduinoJson/Collection/CollectionImpl.hpp

@@ -64,7 +64,7 @@ inline bool CollectionData::copyFrom(const CollectionData& src,
   for (VariantSlot* s = src._head; s; s = s->next()) {
     VariantData* var;
     if (s->key() != 0) {
-      String key(s->key(), !s->ownsKey());
+      String key(s->key(), s->ownsKey() ? String::Copied : String::Linked);
       var = addMember(adaptString(key), pool, getStringStoragePolicy(key));
     } else {
       var = addElement(pool);

src/ArduinoJson/Document/JsonDocument.hpp

@@ -14,7 +14,8 @@
 
 namespace ARDUINOJSON_NAMESPACE {
 
-class JsonDocument : public Visitable {
+class JsonDocument : public Visitable,
+                     public VariantOperators<const JsonDocument&> {
  public:
   template <typename TVisitor>
   typename TVisitor::result_type accept(TVisitor& visitor) const {
@@ -295,16 +296,12 @@ class JsonDocument : public Visitable {
     _data.remove(adaptString(key));
   }
 
+  FORCE_INLINE operator VariantRef() {
+    return getVariant();
+  }
+
   FORCE_INLINE operator VariantConstRef() const {
-    return VariantConstRef(&_data);
-  }
-
-  bool operator==(VariantConstRef rhs) const {
-    return getVariant() == rhs;
-  }
-
-  bool operator!=(VariantConstRef rhs) const {
-    return getVariant() != rhs;
+    return getVariant();
   }
 
  protected:

src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp

@@ -481,7 +481,7 @@ class MsgPackDeserializer {
     T size;
     if (!readInteger(size))
       return false;
-    return skipBytes(size + 1);
+    return skipBytes(size + 1U);
   }
 
   MemoryPool *_pool;

src/ArduinoJson/MsgPack/MsgPackSerializer.hpp

@@ -23,6 +23,11 @@ class MsgPackSerializer : public Visitor<size_t> {
 
   template <typename T>
   typename enable_if<sizeof(T) == 4, size_t>::type visitFloat(T value32) {
+    if (canConvertNumber<Integer>(value32)) {
+      Integer truncatedValue = Integer(value32);
+      if (value32 == T(truncatedValue))
+        return visitSignedInteger(truncatedValue);
+    }
     writeByte(0xCA);
     writeInteger(value32);
     return bytesWritten();
@@ -32,13 +37,10 @@ class MsgPackSerializer : public Visitor<size_t> {
   ARDUINOJSON_NO_SANITIZE("float-cast-overflow")
   typename enable_if<sizeof(T) == 8, size_t>::type visitFloat(T value64) {
     float value32 = float(value64);
-    if (value32 == value64) {
-      writeByte(0xCA);
-      writeInteger(value32);
-    } else {
-      writeByte(0xCB);
-      writeInteger(value64);
-    }
+    if (value32 == value64)
+      return visitFloat(value32);
+    writeByte(0xCB);
+    writeInteger(value64);
     return bytesWritten();
   }
 

src/ArduinoJson/Object/MemberProxy.hpp

@@ -94,6 +94,10 @@ class MemberProxy : public VariantOperators<MemberProxy<TObject, TStringRef> >,
     return getUpstreamMember().size();
   }
 
+  FORCE_INLINE size_t memoryUsage() const {
+    return getUpstreamMember().memoryUsage();
+  }
+
   FORCE_INLINE void remove(size_t index) const {
     getUpstreamMember().remove(index);
   }

src/ArduinoJson/Object/Pair.hpp

@@ -13,7 +13,8 @@ class Pair {
  public:
   Pair(MemoryPool* pool, VariantSlot* slot) {
     if (slot) {
-      _key = String(slot->key(), !slot->ownsKey());
+      _key = String(slot->key(),
+                    slot->ownsKey() ? String::Copied : String::Linked);
       _value = VariantRef(pool, slot->data());
     }
   }
@@ -35,7 +36,8 @@ class PairConst {
  public:
   PairConst(const VariantSlot* slot) {
     if (slot) {
-      _key = String(slot->key(), !slot->ownsKey());
+      _key = String(slot->key(),
+                    slot->ownsKey() ? String::Copied : String::Linked);
       _value = VariantConstRef(slot->data());
     }
   }

src/ArduinoJson/Polyfills/pgmspace.hpp

@@ -99,7 +99,7 @@ inline void* memcpy_P(void* dst, ARDUINOJSON_NAMESPACE::pgm_p src, size_t n) {
 #ifndef pgm_read_dword
 inline uint32_t pgm_read_dword(ARDUINOJSON_NAMESPACE::pgm_p p) {
   uint32_t result;
-  memcpy_P(&result, p, 4);
+  memcpy_P(&result, p.address, 4);
   return result;
 }
 #endif
@@ -107,7 +107,7 @@ inline uint32_t pgm_read_dword(ARDUINOJSON_NAMESPACE::pgm_p p) {
 #ifndef pgm_read_ptr
 inline void* pgm_read_ptr(ARDUINOJSON_NAMESPACE::pgm_p p) {
   void* result;
-  memcpy_P(&result, p, sizeof(result));
+  memcpy_P(&result, p.address, sizeof(result));
   return result;
 }
 #endif

src/ArduinoJson/StringStorage/StringCopier.hpp

@@ -22,7 +22,7 @@ class StringCopier {
   String save() {
     ARDUINOJSON_ASSERT(_ptr);
     ARDUINOJSON_ASSERT(_size < _capacity);  // needs room for the terminator
-    return String(_pool->saveStringFromFreeZone(_size), _size, false);
+    return String(_pool->saveStringFromFreeZone(_size), _size, String::Copied);
   }
 
   void append(const char* s) {
@@ -52,7 +52,7 @@ class StringCopier {
     ARDUINOJSON_ASSERT(_ptr);
     ARDUINOJSON_ASSERT(_size < _capacity);
     _ptr[_size] = 0;
-    return String(_ptr, _size, false);
+    return String(_ptr, _size, String::Copied);
   }
 
  private:

src/ArduinoJson/StringStorage/StringMover.hpp

@@ -33,7 +33,7 @@ class StringMover {
 
   String str() const {
     _writePtr[0] = 0;  // terminator
-    return String(_startPtr, size(), true);
+    return String(_startPtr, size(), String::Linked);
   }
 
   size_t size() const {

src/ArduinoJson/Strings/Adapters/RamString.hpp

@@ -106,13 +106,13 @@ inline SizedRamString adaptString(const char* s, size_t n) {
   return SizedRamString(s, n);
 }
 
-template <int N>
+template <size_t N>
 struct IsString<char[N]> : true_type {};
 
-template <int N>
+template <size_t N>
 struct IsString<const char[N]> : true_type {};
 
-template <int N>
+template <size_t N>
 inline SizedRamString adaptString(char s[N]) {
   return SizedRamString(s, strlen(s));
 }

src/ArduinoJson/Strings/StoragePolicy.hpp

@@ -12,7 +12,7 @@ namespace ARDUINOJSON_NAMESPACE {
 struct LinkStringStoragePolicy {
   template <typename TAdaptedString, typename TCallback>
   bool store(TAdaptedString str, MemoryPool *, TCallback callback) {
-    String storedString(str.data(), str.size(), true);
+    String storedString(str.data(), str.size(), String::Linked);
     callback(storedString);
     return !str.isNull();
   }
@@ -50,7 +50,7 @@ inline LinkStringStoragePolicy getStringStoragePolicy(const char *) {
 }
 
 inline LinkOrCopyStringStoragePolicy getStringStoragePolicy(const String &s) {
-  return LinkOrCopyStringStoragePolicy(s.isStatic());
+  return LinkOrCopyStringStoragePolicy(s.isLinked());
 }
 
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Strings/String.hpp

@@ -14,15 +14,15 @@ namespace ARDUINOJSON_NAMESPACE {
 
 class String : public SafeBoolIdom<String> {
  public:
-  String() : _data(0), _size(0), _isStatic(true) {}
+  enum Ownership { Copied, Linked };
 
-  String(const char* data, bool isStaticData = true)
-      : _data(data),
-        _size(data ? ::strlen(data) : 0),
-        _isStatic(isStaticData) {}
+  String() : _data(0), _size(0), _ownership(Linked) {}
 
-  String(const char* data, size_t sz, bool isStaticData = true)
-      : _data(data), _size(sz), _isStatic(isStaticData) {}
+  String(const char* data, Ownership ownership = Linked)
+      : _data(data), _size(data ? ::strlen(data) : 0), _ownership(ownership) {}
+
+  String(const char* data, size_t sz, Ownership ownership = Linked)
+      : _data(data), _size(sz), _ownership(ownership) {}
 
   const char* c_str() const {
     return _data;
@@ -32,8 +32,8 @@ class String : public SafeBoolIdom<String> {
     return !_data;
   }
 
-  bool isStatic() const {
-    return _isStatic;
+  bool isLinked() const {
+    return _ownership == Linked;
   }
 
   size_t size() const {
@@ -46,23 +46,19 @@ class String : public SafeBoolIdom<String> {
   }
 
   friend bool operator==(String lhs, String rhs) {
+    if (lhs._size != rhs._size)
+      return false;
     if (lhs._data == rhs._data)
       return true;
     if (!lhs._data)
       return false;
     if (!rhs._data)
       return false;
-    return strcmp(lhs._data, rhs._data) == 0;
+    return memcmp(lhs._data, rhs._data, lhs._size) == 0;
   }
 
   friend bool operator!=(String lhs, String rhs) {
-    if (lhs._data == rhs._data)
-      return false;
-    if (!lhs._data)
-      return true;
-    if (!rhs._data)
-      return true;
-    return strcmp(lhs._data, rhs._data) != 0;
+    return !(lhs == rhs);
   }
 
 #if ARDUINOJSON_ENABLE_STD_STREAM
@@ -75,7 +71,7 @@ class String : public SafeBoolIdom<String> {
  private:
   const char* _data;
   size_t _size;
-  bool _isStatic;
+  Ownership _ownership;
 };
 
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Variant/ConverterImpl.hpp

@@ -208,7 +208,7 @@ class MemoryPoolPrint : public Print {
 
   String str() {
     ARDUINOJSON_ASSERT(_size < _capacity);
-    return String(_pool->saveStringFromFreeZone(_size), _size, false);
+    return String(_pool->saveStringFromFreeZone(_size), _size, String::Copied);
   }
 
   size_t write(uint8_t c) {

src/ArduinoJson/Variant/VariantCompare.hpp

@@ -131,9 +131,9 @@ struct RawComparer : ComparerBase {
 template <typename T>
 struct Comparer<T, typename enable_if<IsVisitable<T>::value>::type>
     : ComparerBase {
-  T rhs;
+  const T *rhs;  // TODO: should be a VariantConstRef
 
-  explicit Comparer(T value) : rhs(value) {}
+  explicit Comparer(const T &value) : rhs(&value) {}
 
   CompareResult visitArray(const CollectionData &lhs) {
     ArrayComparer comparer(lhs);
@@ -183,7 +183,7 @@ struct Comparer<T, typename enable_if<IsVisitable<T>::value>::type>
  private:
   template <typename TComparer>
   CompareResult accept(TComparer &comparer) {
-    CompareResult reversedResult = rhs.accept(comparer);
+    CompareResult reversedResult = rhs->accept(comparer);
     switch (reversedResult) {
       case COMPARE_RESULT_GREATER:
         return COMPARE_RESULT_LESS;

src/ArduinoJson/Variant/VariantData.hpp

@@ -210,7 +210,7 @@ class VariantData {
 
   void setString(String s) {
     ARDUINOJSON_ASSERT(s);
-    if (s.isStatic())
+    if (s.isLinked())
       setType(VALUE_IS_LINKED_STRING);
     else
       setType(VALUE_IS_OWNED_STRING);

src/ArduinoJson/Variant/VariantImpl.hpp

@@ -73,9 +73,11 @@ inline T VariantData::asFloat() const {
 inline String VariantData::asString() const {
   switch (type()) {
     case VALUE_IS_LINKED_STRING:
-      return String(_content.asString.data, _content.asString.size, true);
+      return String(_content.asString.data, _content.asString.size,
+                    String::Linked);
     case VALUE_IS_OWNED_STRING:
-      return String(_content.asString.data, _content.asString.size, false);
+      return String(_content.asString.data, _content.asString.size,
+                    String::Copied);
     default:
       return String();
   }
@@ -166,7 +168,7 @@ inline VariantConstRef operator|(VariantConstRef preferedValue,
 
 // Out of class definition to avoid #1560
 inline bool VariantRef::set(char value) const {
-  return set<signed char>(value);
+  return set(static_cast<signed char>(value));
 }
 
 // TODO: move somewhere else
@@ -174,7 +176,7 @@ template <typename TAdaptedString, typename TCallback>
 bool CopyStringStoragePolicy::store(TAdaptedString str, MemoryPool *pool,
                                     TCallback callback) {
   const char *copy = pool->saveString(str);
-  String storedString(copy, str.size(), false);
+  String storedString(copy, str.size(), String::Copied);
   callback(storedString);
   return copy != 0;
 }

src/ArduinoJson/Variant/VariantRef.hpp

@@ -119,7 +119,7 @@ class VariantRef : public VariantRefBase<VariantData>,
   ARDUINOJSON_DEPRECATED(
       "Support for char is deprecated, use int8_t or uint8_t instead")
       as() const {
-    return as<signed char>();
+    return static_cast<char>(as<signed char>());
   }
 
   template <typename T>
@@ -265,7 +265,7 @@ class VariantConstRef : public VariantRefBase<const VariantData>,
   ARDUINOJSON_DEPRECATED(
       "Support for char is deprecated, use int8_t or uint8_t instead")
       as() const {
-    return as<signed char>();
+    return static_cast<char>(as<signed char>());
   }
 
   template <typename T>

src/ArduinoJson/Variant/VariantSlot.hpp

@@ -78,7 +78,7 @@ class VariantSlot {
 
   void setKey(String k) {
     ARDUINOJSON_ASSERT(k);
-    if (k.isStatic())
+    if (k.isLinked())
       _flags &= VALUE_MASK;
     else
       _flags |= OWNED_KEY_BIT;

src/ArduinoJson/version.hpp

@@ -4,7 +4,7 @@
 
 #pragma once
 
-#define ARDUINOJSON_VERSION "6.19.1"
+#define ARDUINOJSON_VERSION "6.19.4"
 #define ARDUINOJSON_VERSION_MAJOR 6
 #define ARDUINOJSON_VERSION_MINOR 19
-#define ARDUINOJSON_VERSION_REVISION 1
+#define ARDUINOJSON_VERSION_REVISION 4