Set version to 7.2.1

Closes #2135

.devcontainer/clang11/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "Clang 11",
+	"image": "conanio/clang11",
+	"runArgs": [
+		"--name=ArduinoJson-clang11"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang13/Dockerfile

@@ -0,0 +1,5 @@
+FROM ubuntu:22.04
+
+RUN apt-get update
+RUN apt-get install -y cmake git clang-13 libc++-13-dev libc++abi-13-dev
+ENV CC=clang-13 CXX=clang++-13

.devcontainer/clang13/devcontainer.json

@@ -0,0 +1,20 @@
+{
+	"name": "Clang 13",
+	"build": {
+		"dockerfile": "Dockerfile"
+	},
+	"runArgs": [
+		"--name=ArduinoJson-clang13"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang14/Dockerfile

@@ -0,0 +1,5 @@
+FROM ubuntu:22.04
+
+RUN apt-get update
+RUN apt-get install -y cmake git clang-14 libc++-14-dev libc++abi-14-dev
+ENV CC=clang-14 CXX=clang++-14

.devcontainer/clang14/devcontainer.json

@@ -0,0 +1,20 @@
+{
+	"name": "Clang 14",
+	"build": {
+		"dockerfile": "Dockerfile"
+	},
+	"runArgs": [
+		"--name=ArduinoJson-clang14"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang15/Dockerfile

@@ -0,0 +1,5 @@
+FROM ubuntu:22.04
+
+RUN apt-get update
+RUN apt-get install -y cmake git clang-15 libc++-15-dev libc++abi-15-dev
+ENV CC=clang-15 CXX=clang++-15

.devcontainer/clang15/devcontainer.json

@@ -0,0 +1,20 @@
+{
+	"name": "Clang 15",
+	"build": {
+		"dockerfile": "Dockerfile"
+	},
+	"runArgs": [
+		"--name=ArduinoJson-clang15"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang16/Dockerfile

@@ -0,0 +1,5 @@
+FROM ubuntu:22.04
+
+RUN apt-get update
+RUN apt-get install -y cmake git clang-16 libc++-16-dev libc++abi-16-dev
+ENV CC=clang-16 CXX=clang++-16

.devcontainer/clang16/devcontainer.json

@@ -0,0 +1,20 @@
+{
+	"name": "Clang 16",
+	"build": {
+		"dockerfile": "Dockerfile"
+	},
+	"runArgs": [
+		"--name=ArduinoJson-clang16"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang17/Dockerfile

@@ -0,0 +1,5 @@
+FROM ubuntu:24.04
+
+RUN apt-get update
+RUN apt-get install -y cmake git clang-17 libc++-17-dev libc++abi-17-dev
+ENV CC=clang-17 CXX=clang++-17

.devcontainer/clang17/devcontainer.json

@@ -0,0 +1,20 @@
+{
+	"name": "Clang 17",
+	"build": {
+		"dockerfile": "Dockerfile"
+	},
+	"runArgs": [
+		"--name=ArduinoJson-clang17"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.github/workflows/ci.yml

@@ -2,15 +2,19 @@ name: Continuous Integration
 
 on: [push, pull_request]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 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
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Symlinks
         run: find * -type l -printf "::error::%p is a symlink. This is forbidden by the Arduino Library Specification." -exec false {} +
       - name: Clang-format
@@ -47,6 +51,9 @@ jobs:
           - gcc: "11"
           - gcc: "12"
     steps:
+      - name: Workaround for actions/runner-images#9491
+        run: sudo sysctl vm.mmap_rnd_bits=28
+
       - name: Install
         run: |
           sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 40976EAF437D05B5 3B4FE6ACC0B21F32
@@ -55,24 +62,29 @@ jobs:
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ focal main universe'
           sudo apt-get update
           sudo apt-get install -y gcc-${{ matrix.gcc }} g++-${{ matrix.gcc }}
+        timeout-minutes: 5
+
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
+        timeout-minutes: 1
+
       - name: Configure
         run: cmake -DCMAKE_BUILD_TYPE=Debug .
         env:
           CC: gcc-${{ matrix.gcc }}
           CXX: g++-${{ matrix.gcc }}
           CXXFLAGS: ${{ matrix.cxxflags }}
+        timeout-minutes: 1
+
       - name: Build
         run: cmake --build .
+        timeout-minutes: 10
+
       - name: Test
-        run: |
-          echo "## CTest output" >> $GITHUB_STEP_SUMMARY
-          echo '```' >> $GITHUB_STEP_SUMMARY
-          ctest --output-on-failure -C Debug . | tee -a $GITHUB_STEP_SUMMARY
-          echo '```' >> $GITHUB_STEP_SUMMARY
+        run: ctest --output-on-failure -C Debug .
         env:
           UBSAN_OPTIONS: print_stacktrace=1
+        timeout-minutes: 2
 
   clang:
     name: Clang
@@ -132,7 +144,7 @@ jobs:
         if: matrix.clang == 12  # dependency is missing in Ubuntu 22.04
         run: sudo apt-get install -y libunwind-${{ matrix.clang }}-dev
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Configure
         run: cmake -DCMAKE_BUILD_TYPE=Debug .
         env:
@@ -144,11 +156,7 @@ jobs:
       - name: Build
         run: cmake --build .
       - name: Test
-        run: |
-          echo "## CTest output" >> $GITHUB_STEP_SUMMARY
-          echo '```' >> $GITHUB_STEP_SUMMARY
-          ctest --output-on-failure -C Debug . | tee -a $GITHUB_STEP_SUMMARY
-          echo '```' >> $GITHUB_STEP_SUMMARY
+        run: ctest --output-on-failure -C Debug .
         env:
           UBSAN_OPTIONS: print_stacktrace=1
 
@@ -162,7 +170,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y g++-multilib gcc-avr avr-libc
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: AVR
         run: avr-g++ -std=c++11 -Isrc extras/conf_test/avr.cpp
       - name: GCC 32-bit
@@ -180,7 +188,7 @@ jobs:
     needs: [gcc, clang]
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: 32-bit
         run: |
           call "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars32.bat"
@@ -195,17 +203,20 @@ jobs:
   xcode:
     name: XCode
     needs: clang
-    runs-on: macos-11
+    runs-on: macos-13
     strategy:
       fail-fast: false
       matrix:
         include:
-          - xcode: "11.7"
-          - xcode: "12.4"
-          - xcode: "13.2.1"
+          - xcode: "14.1"
+          - xcode: "14.2"
+          - xcode: "14.3.1"
+          - xcode: "15.0.1"
+          - xcode: "15.1"
+          - xcode: "15.2"
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Select XCode version
         run: sudo xcode-select --switch /Applications/Xcode_${{ matrix.xcode }}.app
       - name: Configure
@@ -227,7 +238,7 @@ jobs:
   #   runs-on: ${{ matrix.os }}
   #   steps:
   #     - name: Checkout
-  #       uses: actions/checkout@v3
+  #       uses: actions/checkout@v4
   #     - name: Configure
   #       run: cmake -DCMAKE_BUILD_TYPE=Debug .
   #     - name: Build
@@ -249,7 +260,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install arduino-cli
         run: curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=/usr/local/bin sh
       - name: Install core
@@ -322,14 +333,14 @@ jobs:
             conf_test: esp8266
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Set up cache for pip
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip
       - name: Set up Python 3.x
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: "3.x"
       - name: Install PlatformIO
@@ -341,7 +352,7 @@ jobs:
         if: ${{ matrix.platform == 'nordicnrf52' }}
         run: find examples/ -name '*.ino' -exec sed -i 's/\(#include <ArduinoJson.h>\)/\1\n#include <Adafruit_TinyUSB.h>/' {} +
       - name: Set up cache for platformio
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.platformio
           key: ${{ runner.os }}-platformio-${{ matrix.platform }}
@@ -390,7 +401,7 @@ jobs:
           - board: argon
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install Particle CLI
         run: sudo npm install -g particle-cli
       - name: Login to Particle
@@ -408,7 +419,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y g++-arm-linux-gnueabihf
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Configure
         run: cmake .
         env:
@@ -425,7 +436,7 @@ jobs:
       - name: Install
         run: sudo apt-get install -y lcov ninja-build
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Configure
         run: cmake -G Ninja -DCOVERAGE=true .
       - name: Build
@@ -439,12 +450,12 @@ jobs:
       - name: genhtml
         run: mkdir coverage && genhtml coverage_filtered.info -o coverage -t ArduinoJson
       - name: Upload HTML report
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: Coverage report
           path: coverage
       - name: Upload to Coveralls
-        uses: coverallsapp/github-action@master
+        uses: coverallsapp/github-action@v2
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           path-to-lcov: coverage_filtered.info
@@ -459,7 +470,7 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y valgrind ninja-build
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Configure
         run: cmake -G Ninja -D MEMORYCHECK_COMMAND_OPTIONS="--error-exitcode=1 --leak-check=full"  .
       - name: Build
@@ -468,7 +479,7 @@ jobs:
         run: ctest --output-on-failure -LE WillFail -T memcheck
         id: memcheck
       - name: MemoryChecker.*.log
-        run: cat Testing/Temporary/MemoryChecker.*.log
+        run: cat Testing/Temporary/MemoryChecker.*.log > $GITHUB_STEP_SUMMARY
         if: failure()
 
   clang-tidy:
@@ -479,7 +490,7 @@ jobs:
       - name: Install
         run: sudo apt-get install -y clang-tidy cmake ninja-build
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Configure
         run: cmake -G Ninja -DCMAKE_CXX_CLANG_TIDY="clang-tidy-10;--warnings-as-errors=*" -DCMAKE_BUILD_TYPE=Debug .
         env:
@@ -488,73 +499,51 @@ jobs:
       - name: Check
         run: cmake --build . -- -k 0
 
-  amalgamate-h:
+  amalgamate:
     needs: gcc
     name: Amalgamate ArduinoJson.h
     runs-on: ubuntu-20.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
-      - name: Amalgamate
-        id: amalgamate
+        uses: actions/checkout@v4
+      - name: Setup
         run: |
           if [[ $GITHUB_REF == refs/tags/* ]]; then
             VERSION=${GITHUB_REF#refs/tags/}
           else
             VERSION=${GITHUB_SHA::7}
           fi
-          INPUT=src/ArduinoJson.h
-          OUTPUT=ArduinoJson-$VERSION.h
-          extras/scripts/build-single-header.sh "$INPUT" "$OUTPUT"
-          echo "filename=${OUTPUT}" >> $GITHUB_OUTPUT
-      - name: Smoke test
+          echo "ARDUINOJSON_H=ArduinoJson-$VERSION.h" >> $GITHUB_ENV
+          echo "ARDUINOJSON_HPP=ArduinoJson-$VERSION.hpp" >> $GITHUB_ENV
+      - name: Amalgamate ArduinoJson.h
+        run: extras/scripts/build-single-header.sh "src/ArduinoJson.h" "$ARDUINOJSON_H"
+      - name: Amalgamate ArduinoJson.hpp
+        run: extras/scripts/build-single-header.sh "src/ArduinoJson.hpp" "$ARDUINOJSON_HPP"
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: Single headers
+          path: |
+            ${{ env.ARDUINOJSON_H }}
+            ${{ env.ARDUINOJSON_HPP }}
+      - name: Smoke test ArduinoJson.h
         run: |
           g++ -x c++ - <<END
-          #include "${{ steps.amalgamate.outputs.filename }}"
+          #include "$ARDUINOJSON_H"
           int main() {
             JsonDocument doc;
             deserializeJson(doc, "{}");
           }
           END
-      - name: Upload artifact
-        uses: actions/upload-artifact@v3
-        with:
-          name: Single headers
-          path: ${{ steps.amalgamate.outputs.filename }}
-
-  amalgamate-hpp:
-    needs: gcc
-    name: Amalgamate ArduinoJson.hpp
-    runs-on: ubuntu-20.04
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-      - name: Amalgamate
-        id: amalgamate
-        run: |
-          if [[ $GITHUB_REF == refs/tags/* ]]; then
-            VERSION=${GITHUB_REF#refs/tags/}
-          else
-            VERSION=${GITHUB_SHA::7}
-          fi
-          INPUT=src/ArduinoJson.hpp
-          OUTPUT=ArduinoJson-$VERSION.hpp
-          extras/scripts/build-single-header.sh "$INPUT" "$OUTPUT"
-          echo "filename=${OUTPUT}" >> $GITHUB_OUTPUT
-      - name: Smoke test
+      - name: Smoke test ArduinoJson.hpp
         run: |
           g++ -x c++ - <<END
-          #include "${{ steps.amalgamate.outputs.filename }}"
+          #include "$ARDUINOJSON_HPP"
           int main() {
             ArduinoJson::JsonDocument doc;
             deserializeJson(doc, "{}");
           }
           END
-      - name: Upload artifact
-        uses: actions/upload-artifact@v3
-        with:
-          name: Single headers
-          path: ${{ steps.amalgamate.outputs.filename }}
 
   esp-idf:
     needs: gcc
@@ -562,14 +551,14 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Setup cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.espressif
           key: ${{ runner.os }}-esp-idf
       - name: Checkout ArduinoJson
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Checkout ESP-IDF
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: espressif/esp-idf
           path: esp-idf
@@ -599,10 +588,10 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v2
+      uses: github/codeql-action/init@v3
       with:
         languages: cpp
 
@@ -612,6 +601,6 @@ jobs:
         cmake --build .
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v2
+      uses: github/codeql-action/analyze@v3
       with:
         category: "/language:cpp"

.github/workflows/lock.yml

@@ -8,7 +8,7 @@ jobs:
   lock:
     runs-on: ubuntu-latest
     steps:
-      - uses: dessant/lock-threads@v4
+      - uses: dessant/lock-threads@v5
         with:
           github-token: ${{ github.token }}
           issue-inactive-days: 30

.github/workflows/release.yml

@@ -16,7 +16,7 @@ jobs:
           echo "tag=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
           echo "version=${GITHUB_REF#refs/tags/v}" >> $GITHUB_OUTPUT
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Write release body
         id: body
         run: |
@@ -48,7 +48,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Upload component to the component registry
         uses: espressif/upload-components-ci-action@v1
         with:
@@ -63,7 +63,7 @@ jobs:
       - name: Install
         run: npm install -g particle-cli
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Login
         run: particle login --token ${{ secrets.PARTICLE_TOKEN }}
       - name: Publish
@@ -74,13 +74,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Set up Python 3.x
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: "3.x"
       - name: Install PlatformIO
         run: pip install platformio
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Publish
         run: pio pkg publish --no-interactive --no-notify
         env:

CHANGELOG.md

@@ -1,6 +1,64 @@
 ArduinoJson: change log
 =======================
 
+v7.2.1 (2024-11-15)
+------
+
+* Forbid `deserializeJson(JsonArray|JsonObject, ...)` (issue #2135)
+* Fix VLA support in `JsonDocument::set()`
+* Fix `operator[](variant)` ignoring NUL characters
+
+v7.2.0 (2024-09-18)
+------
+
+* Store object members with two slots: one for the key and one for the value
+* Store 64-bit numbers (`double` and `long long`) in an additional slot
+* Reduce the slot size (see table below)
+* Improve message when user forgets third arg of `serializeJson()` et al.
+* Set `ARDUINOJSON_USE_DOUBLE` to `0` by default on 8-bit architectures
+* Deprecate `containsKey()` in favor of `doc["key"].is<T>()`
+* Add support for escape sequence `\'` (issue #2124)
+
+| Architecture | before   | after    |
+|--------------|----------|----------|
+| 8-bit        | 8 bytes  | 6 bytes  |
+| 32-bit       | 16 bytes | 8 bytes  |
+| 64-bit       | 24 bytes | 16 bytes |
+
+> ### BREAKING CHANGES
+>
+> After being on the death row for years, the `containsKey()` method has finally been deprecated.
+> You should replace `doc.containsKey("key")` with `doc["key"].is<T>()`, which not only checks that the key exists but also that the value is of the expected type.
+>
+> ```cpp
+> // Before
+> if (doc.containsKey("value")) {
+>   int value = doc["value"];
+>   // ...
+> }
+>
+> // After
+> if (doc["value"].is<int>()) {
+>   int value = doc["value"];
+>   // ...
+> }
+> ```
+
+v7.1.0 (2024-06-27)
+------
+
+* Add `ARDUINOJSON_STRING_LENGTH_SIZE` to the namespace name
+* Add support for MsgPack binary (PR #2078 by @Sanae6)
+* Add support for MsgPack extension
+* Make string support even more generic (PR #2084 by @d-a-v)
+* Optimize `deserializeMsgPack()`
+* Allow using a `JsonVariant` as a key or index (issue #2080)
+  Note: works only for reading, not for writing
+* Support `ElementProxy` and `MemberProxy` in `JsonDocument`'s constructor
+* Don't add partial objects when allocation fails (issue #2081)
+* Read MsgPack's 64-bit integers even if `ARDUINOJSON_USE_LONG_LONG` is `0`
+  (they are set to `null` if they don't fit in a `long`)
+
 v7.0.4 (2024-03-12)
 ------
 

CMakeLists.txt

@@ -10,7 +10,7 @@ if(ESP_PLATFORM)
 	return()
 endif()
 
-project(ArduinoJson VERSION 7.0.4)
+project(ArduinoJson VERSION 7.2.1)
 
 if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
 	include(CTest)

README.md

@@ -148,6 +148,9 @@ ArduinoJson is thankful to its sponsors. Please give them a visit; they deserve
   <a href="https://github.com/1technophile" rel="sponsored">
     <img alt="1technophile" src="https://avatars.githubusercontent.com/u/12672732?s=40&v=4">
   </a>
+  <a href="https://github.com/LArkema" rel="sponsored">
+    <img alt="LArkema" src="https://avatars.githubusercontent.com/u/38381313?s=40&v=4">
+  </a>
 </p>
 
 If you run a commercial project that embeds ArduinoJson, think about [sponsoring the library's development](https://github.com/sponsors/bblanchon): it ensures the code that your products rely on stays actively maintained. It can also give your project some exposure to the makers' community.

appveyor.yml

@@ -1,4 +1,4 @@
-version: 7.0.4.{build}
+version: 7.2.1.{build}
 environment:
   matrix:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022

extras/CompileOptions.cmake

@@ -1,3 +1,7 @@
+if(NOT DEFINED COVERAGE)
+	set(COVERAGE OFF)
+endif()
+
 if(CMAKE_CXX_COMPILER_ID MATCHES "(GNU|Clang)")
 	add_compile_options(
 		-pedantic
@@ -30,7 +34,7 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "(GNU|Clang)")
 endif()
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-	if((CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.8) AND(NOT ${COVERAGE}))
+	if((CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.9) AND(NOT ${COVERAGE}))
 		add_compile_options(-g -Og)
 	else() # GCC 4.8
 		add_compile_options(

extras/conf_test/avr.cpp

@@ -6,12 +6,13 @@ static_assert(ARDUINOJSON_USE_LONG_LONG == 0, "ARDUINOJSON_USE_LONG_LONG");
 
 static_assert(ARDUINOJSON_SLOT_ID_SIZE == 1, "ARDUINOJSON_SLOT_ID_SIZE");
 
+static_assert(ARDUINOJSON_POOL_CAPACITY == 16, "ARDUINOJSON_POOL_CAPACITY");
+
 static_assert(ARDUINOJSON_LITTLE_ENDIAN == 1, "ARDUINOJSON_LITTLE_ENDIAN");
 
-static_assert(ARDUINOJSON_USE_DOUBLE == 1, "ARDUINOJSON_USE_DOUBLE");
+static_assert(ARDUINOJSON_USE_DOUBLE == 0, "ARDUINOJSON_USE_DOUBLE");
 
-static_assert(sizeof(ArduinoJson::detail::VariantSlot) == 8,
-              "sizeof(VariantSlot)");
+static_assert(ArduinoJson::detail::ResourceManager::slotSize == 6, "slot size");
 
 void setup() {}
 void loop() {}

extras/conf_test/esp8266.cpp

@@ -4,12 +4,13 @@ static_assert(ARDUINOJSON_USE_LONG_LONG == 1, "ARDUINOJSON_USE_LONG_LONG");
 
 static_assert(ARDUINOJSON_SLOT_ID_SIZE == 2, "ARDUINOJSON_SLOT_ID_SIZE");
 
+static_assert(ARDUINOJSON_POOL_CAPACITY == 128, "ARDUINOJSON_POOL_CAPACITY");
+
 static_assert(ARDUINOJSON_LITTLE_ENDIAN == 1, "ARDUINOJSON_LITTLE_ENDIAN");
 
 static_assert(ARDUINOJSON_USE_DOUBLE == 1, "ARDUINOJSON_USE_DOUBLE");
 
-static_assert(sizeof(ArduinoJson::detail::VariantSlot) == 16,
-              "sizeof(VariantSlot)");
+static_assert(ArduinoJson::detail::ResourceManager::slotSize == 8, "slot size");
 
 void setup() {}
 void loop() {}

extras/conf_test/x64.cpp

@@ -4,11 +4,13 @@ static_assert(ARDUINOJSON_USE_LONG_LONG == 1, "ARDUINOJSON_USE_LONG_LONG");
 
 static_assert(ARDUINOJSON_SLOT_ID_SIZE == 4, "ARDUINOJSON_SLOT_ID_SIZE");
 
+static_assert(ARDUINOJSON_POOL_CAPACITY == 256, "ARDUINOJSON_POOL_CAPACITY");
+
 static_assert(ARDUINOJSON_LITTLE_ENDIAN == 1, "ARDUINOJSON_LITTLE_ENDIAN");
 
 static_assert(ARDUINOJSON_USE_DOUBLE == 1, "ARDUINOJSON_USE_DOUBLE");
 
-static_assert(sizeof(ArduinoJson::detail::VariantSlot) == 24,
-              "sizeof(VariantSlot)");
+static_assert(ArduinoJson::detail::ResourceManager::slotSize == 16,
+              "slot size");
 
 int main() {}

extras/conf_test/x86.cpp

@@ -4,11 +4,12 @@ static_assert(ARDUINOJSON_USE_LONG_LONG == 1, "ARDUINOJSON_USE_LONG_LONG");
 
 static_assert(ARDUINOJSON_SLOT_ID_SIZE == 2, "ARDUINOJSON_SLOT_ID_SIZE");
 
+static_assert(ARDUINOJSON_POOL_CAPACITY == 128, "ARDUINOJSON_POOL_CAPACITY");
+
 static_assert(ARDUINOJSON_LITTLE_ENDIAN == 1, "ARDUINOJSON_LITTLE_ENDIAN");
 
 static_assert(ARDUINOJSON_USE_DOUBLE == 1, "ARDUINOJSON_USE_DOUBLE");
 
-static_assert(sizeof(ArduinoJson::detail::VariantSlot) == 16,
-              "sizeof(VariantSlot)");
+static_assert(ArduinoJson::detail::ResourceManager::slotSize == 8, "slot size");
 
 int main() {}

extras/fuzzing/CMakeLists.txt

@@ -52,7 +52,16 @@ macro(add_fuzzer name)
 	)
 endmacro()
 
-if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 6)
+# Needs Clang 6+ to compile
+if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 6)
+	if(DEFINED ENV{GITHUB_ACTIONS} AND CMAKE_CXX_COMPILER_VERSION MATCHES "^11\\.")
+		# Clang 11 fails on GitHub Actions with the following error:
+		# > ERROR: UndefinedBehaviorSanitizer failed to allocate 0x0 (0) bytes of SetAlternateSignalStack (error code: 22)
+		# > Sanitizer CHECK failed: /build/llvm-toolchain-11-mnvtwk/llvm-toolchain-11-11.1.0/compiler-rt/lib/sanitizer_common/sanitizer_common.cpp:54 ((0 && "unable to mmap")) != (0) (0, 0)
+		message(WARNING "Fuzzing is disabled on GitHub Actions to workaround a bug in Clang 11")
+		return()
+	endif()
+
 	add_fuzzer(json)
 	add_fuzzer(msgpack)
 endif()

extras/tests/CMakeLists.txt

@@ -5,15 +5,18 @@
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-add_subdirectory(catch)
+link_libraries(ArduinoJson)
 
-link_libraries(ArduinoJson catch)
+# Failing builds should only link with ArduinoJson, not catch
+add_subdirectory(FailingBuilds)
+
+add_subdirectory(catch)
+link_libraries(catch)
 
 include_directories(Helpers)
 add_subdirectory(Cpp17)
 add_subdirectory(Cpp20)
 add_subdirectory(Deprecated)
-add_subdirectory(FailingBuilds)
 add_subdirectory(IntegrationTests)
 add_subdirectory(JsonArray)
 add_subdirectory(JsonArrayConst)

extras/tests/Cpp17/string_view.cpp

@@ -12,6 +12,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 #if !ARDUINOJSON_ENABLE_STRING_VIEW
 #  error ARDUINOJSON_ENABLE_STRING_VIEW must be set to 1
@@ -92,7 +93,7 @@ TEST_CASE("string_view") {
   }
 
   SECTION("String containing NUL") {
-    doc.set(std::string("hello\0world", 11));
+    doc.set("hello\0world"_s);
     REQUIRE(doc.as<std::string_view>().size() == 11);
     REQUIRE(doc.as<std::string_view>() == std::string_view("hello\0world", 11));
   }

extras/tests/Deprecated/CMakeLists.txt

@@ -16,9 +16,10 @@ endif()
 
 add_executable(DeprecatedTests
 	add.cpp
+	BasicJsonDocument.cpp
+	containsKey.cpp
 	createNestedArray.cpp
 	createNestedObject.cpp
-	BasicJsonDocument.cpp
 	DynamicJsonDocument.cpp
 	macros.cpp
 	memoryUsage.cpp

extras/tests/Deprecated/containsKey.cpp

@@ -0,0 +1,246 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2024, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+#include "Literals.hpp"
+
+TEST_CASE("JsonDocument::containsKey()") {
+  JsonDocument doc;
+
+  SECTION("returns true on object") {
+    doc["hello"] = "world";
+
+    REQUIRE(doc.containsKey("hello") == true);
+  }
+
+  SECTION("returns true when value is null") {
+    doc["hello"] = static_cast<const char*>(0);
+
+    REQUIRE(doc.containsKey("hello") == true);
+  }
+
+  SECTION("returns true when key is a std::string") {
+    doc["hello"] = "world";
+
+    REQUIRE(doc.containsKey("hello"_s) == true);
+  }
+
+  SECTION("returns false  on object") {
+    doc["world"] = "hello";
+
+    REQUIRE(doc.containsKey("hello") == false);
+  }
+
+  SECTION("returns false on array") {
+    doc.add("hello");
+
+    REQUIRE(doc.containsKey("hello") == false);
+  }
+
+  SECTION("returns false on null") {
+    REQUIRE(doc.containsKey("hello") == false);
+  }
+
+  SECTION("supports JsonVariant") {
+    doc["hello"] = "world";
+    doc["key"] = "hello";
+
+    REQUIRE(doc.containsKey(doc["key"]) == true);
+    REQUIRE(doc.containsKey(doc["foo"]) == false);
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("supports VLAs") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "hello");
+
+    doc["hello"] = "world";
+
+    REQUIRE(doc.containsKey(vla) == true);
+  }
+#endif
+}
+
+TEST_CASE("MemberProxy::containsKey()") {
+  JsonDocument doc;
+  auto mp = doc["hello"];
+
+  SECTION("containsKey(const char*)") {
+    mp["key"] = "value";
+
+    REQUIRE(mp.containsKey("key") == true);
+    REQUIRE(mp.containsKey("key") == true);
+  }
+
+  SECTION("containsKey(std::string)") {
+    mp["key"] = "value";
+
+    REQUIRE(mp.containsKey("key"_s) == true);
+    REQUIRE(mp.containsKey("key"_s) == true);
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("supports VLAs") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "hello");
+
+    mp["hello"] = "world";
+
+    REQUIRE(mp.containsKey(vla) == true);
+  }
+#endif
+}
+
+TEST_CASE("JsonObject::containsKey()") {
+  JsonDocument doc;
+  JsonObject obj = doc.to<JsonObject>();
+  obj["hello"] = 42;
+
+  SECTION("returns true only if key is present") {
+    REQUIRE(false == obj.containsKey("world"));
+    REQUIRE(true == obj.containsKey("hello"));
+  }
+
+  SECTION("returns false after remove()") {
+    obj.remove("hello");
+
+    REQUIRE(false == obj.containsKey("hello"));
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("key is a VLA") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "hello");
+
+    REQUIRE(true == obj.containsKey(vla));
+  }
+#endif
+
+  SECTION("key is a JsonVariant") {
+    doc["key"] = "hello";
+    REQUIRE(true == obj.containsKey(obj["key"]));
+    REQUIRE(false == obj.containsKey(obj["hello"]));
+  }
+
+  SECTION("std::string") {
+    REQUIRE(true == obj.containsKey("hello"_s));
+  }
+
+  SECTION("unsigned char[]") {
+    unsigned char key[] = "hello";
+    REQUIRE(true == obj.containsKey(key));
+  }
+}
+
+TEST_CASE("JsonObjectConst::containsKey()") {
+  JsonDocument doc;
+  doc["hello"] = 42;
+  auto obj = doc.as<JsonObjectConst>();
+
+  SECTION("supports const char*") {
+    REQUIRE(false == obj.containsKey("world"));
+    REQUIRE(true == obj.containsKey("hello"));
+  }
+
+  SECTION("supports std::string") {
+    REQUIRE(false == obj.containsKey("world"_s));
+    REQUIRE(true == obj.containsKey("hello"_s));
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("supports VLA") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "hello");
+
+    REQUIRE(true == obj.containsKey(vla));
+  }
+#endif
+
+  SECTION("supports JsonVariant") {
+    doc["key"] = "hello";
+    REQUIRE(true == obj.containsKey(obj["key"]));
+    REQUIRE(false == obj.containsKey(obj["hello"]));
+  }
+}
+
+TEST_CASE("JsonVariant::containsKey()") {
+  JsonDocument doc;
+  JsonVariant var = doc.to<JsonVariant>();
+
+  SECTION("returns false is unbound") {
+    CHECK_FALSE(JsonVariant().containsKey("hello"));
+  }
+
+  SECTION("containsKey(const char*)") {
+    var["hello"] = "world";
+
+    REQUIRE(var.containsKey("hello") == true);
+    REQUIRE(var.containsKey("world") == false);
+  }
+
+  SECTION("containsKey(std::string)") {
+    var["hello"] = "world";
+
+    REQUIRE(var.containsKey("hello"_s) == true);
+    REQUIRE(var.containsKey("world"_s) == false);
+  }
+
+  SECTION("containsKey(JsonVariant)") {
+    var["hello"] = "world";
+    var["key"] = "hello";
+
+    REQUIRE(var.containsKey(doc["key"]) == true);
+    REQUIRE(var.containsKey(doc["foo"]) == false);
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("supports VLAs") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "hello");
+
+    var["hello"] = "world";
+
+    REQUIRE(var.containsKey(vla) == true);
+  }
+#endif
+}
+
+TEST_CASE("JsonVariantConst::containsKey()") {
+  JsonDocument doc;
+  doc["hello"] = "world";
+  JsonVariantConst var = doc.as<JsonVariant>();
+
+  SECTION("support const char*") {
+    REQUIRE(var.containsKey("hello") == true);
+    REQUIRE(var.containsKey("world") == false);
+  }
+
+  SECTION("support std::string") {
+    REQUIRE(var.containsKey("hello"_s) == true);
+    REQUIRE(var.containsKey("world"_s) == false);
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("supports VLA") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "hello");
+
+    REQUIRE(true == var.containsKey(vla));
+  }
+#endif
+
+  SECTION("support JsonVariant") {
+    doc["key"] = "hello";
+    REQUIRE(var.containsKey(var["key"]) == true);
+    REQUIRE(var.containsKey(var["foo"]) == false);
+  }
+}

extras/tests/Deprecated/createNestedArray.cpp

@@ -7,6 +7,8 @@
 
 #include <string>
 
+#include "Literals.hpp"
+
 TEST_CASE("JsonDocument::createNestedArray()") {
   JsonDocument doc;
 
@@ -23,7 +25,7 @@ TEST_CASE("JsonDocument::createNestedArray()") {
   }
 
   SECTION("createNestedArray(std::string)") {
-    JsonArray array = doc.createNestedArray(std::string("key"));
+    JsonArray array = doc.createNestedArray("key"_s);
     array.add(42);
     REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
   }
@@ -59,7 +61,7 @@ TEST_CASE("JsonObject::createNestedArray()") {
   }
 
   SECTION("createNestedArray(std::string)") {
-    JsonArray array = object.createNestedArray(std::string("key"));
+    JsonArray array = object.createNestedArray("key"_s);
     array.add(42);
     REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
   }
@@ -93,7 +95,7 @@ TEST_CASE("JsonVariant::createNestedArray()") {
   }
 
   SECTION("createNestedArray(std::string)") {
-    JsonArray array = variant.createNestedArray(std::string("key"));
+    JsonArray array = variant.createNestedArray("key"_s);
     array.add(42);
     REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
   }

extras/tests/Deprecated/createNestedObject.cpp

@@ -7,6 +7,8 @@
 
 #include <string>
 
+#include "Literals.hpp"
+
 TEST_CASE("JsonDocument::createNestedObject()") {
   JsonDocument doc;
 
@@ -23,7 +25,7 @@ TEST_CASE("JsonDocument::createNestedObject()") {
   }
 
   SECTION("createNestedObject(std::string)") {
-    JsonObject object = doc.createNestedObject(std::string("key"));
+    JsonObject object = doc.createNestedObject("key"_s);
     object["hello"] = "world";
     REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
   }
@@ -59,7 +61,7 @@ TEST_CASE("JsonObject::createNestedObject()") {
   }
 
   SECTION("createNestedObject(std::string)") {
-    JsonObject nestedObject = object.createNestedObject(std::string("key"));
+    JsonObject nestedObject = object.createNestedObject("key"_s);
     nestedObject["hello"] = "world";
     REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
   }
@@ -93,7 +95,7 @@ TEST_CASE("JsonVariant::createNestedObject()") {
   }
 
   SECTION("createNestedObject(std::string)") {
-    JsonObject object = variant.createNestedObject(std::string("key"));
+    JsonObject object = variant.createNestedObject("key"_s);
     object["hello"] = "world";
     REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
   }

extras/tests/FailingBuilds/CMakeLists.txt

@@ -2,7 +2,11 @@
 # Copyright © 2014-2024, Benoit BLANCHON
 # MIT License
 
-macro(build_should_fail target)
+macro(add_failing_build source_file)
+	get_filename_component(target ${source_file} NAME_WE)
+
+	add_executable(${target} ${source_file})
+
 	set_target_properties(${target}
 		PROPERTIES
 			EXCLUDE_FROM_ALL TRUE
@@ -16,21 +20,13 @@ macro(build_should_fail target)
 	set_tests_properties(${target}
 		PROPERTIES
 			WILL_FAIL TRUE
-			LABELS "WillFail;Catch"
+			LABELS "WillFail"
 	)
 endmacro()
 
-add_executable(Issue978 Issue978.cpp)
-build_should_fail(Issue978)
-
-add_executable(read_long_long read_long_long.cpp)
-build_should_fail(read_long_long)
-
-add_executable(write_long_long write_long_long.cpp)
-build_should_fail(write_long_long)
-
-add_executable(variant_as_char variant_as_char.cpp)
-build_should_fail(variant_as_char)
-
-add_executable(assign_char assign_char.cpp)
-build_should_fail(assign_char)
+add_failing_build(Issue978.cpp)
+add_failing_build(read_long_long.cpp)
+add_failing_build(write_long_long.cpp)
+add_failing_build(variant_as_char.cpp)
+add_failing_build(assign_char.cpp)
+add_failing_build(deserialize_object.cpp)

extras/tests/FailingBuilds/deserialize_object.cpp

@@ -0,0 +1,12 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2024, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+
+// See issue #2135
+
+int main() {
+  JsonObject obj;
+  deserializeJson(obj, "");
+}

extras/tests/Helpers/Allocators.hpp

@@ -5,11 +5,13 @@
 #pragma once
 
 #include <ArduinoJson/Memory/Allocator.hpp>
+#include <ArduinoJson/Memory/MemoryPool.hpp>
 #include <ArduinoJson/Memory/StringBuilder.hpp>
-#include <ArduinoJson/Memory/VariantPool.hpp>
 
 #include <sstream>
 
+namespace {
+
 struct FailingAllocator : ArduinoJson::Allocator {
   static FailingAllocator* instance() {
     static FailingAllocator allocator;
@@ -54,31 +56,31 @@ class AllocatorLogEntry {
 
 inline AllocatorLogEntry Allocate(size_t s) {
   char buffer[32];
-  sprintf(buffer, "allocate(%zu)", s);
+  snprintf(buffer, sizeof(buffer), "allocate(%zu)", s);
   return AllocatorLogEntry(buffer);
 }
 
 inline AllocatorLogEntry AllocateFail(size_t s) {
   char buffer[32];
-  sprintf(buffer, "allocate(%zu) -> nullptr", s);
+  snprintf(buffer, sizeof(buffer), "allocate(%zu) -> nullptr", s);
   return AllocatorLogEntry(buffer);
 }
 
 inline AllocatorLogEntry Reallocate(size_t s1, size_t s2) {
   char buffer[32];
-  sprintf(buffer, "reallocate(%zu, %zu)", s1, s2);
+  snprintf(buffer, sizeof(buffer), "reallocate(%zu, %zu)", s1, s2);
   return AllocatorLogEntry(buffer);
 }
 
 inline AllocatorLogEntry ReallocateFail(size_t s1, size_t s2) {
   char buffer[32];
-  sprintf(buffer, "reallocate(%zu, %zu) -> nullptr", s1, s2);
+  snprintf(buffer, sizeof(buffer), "reallocate(%zu, %zu) -> nullptr", s1, s2);
   return AllocatorLogEntry(buffer);
 }
 
 inline AllocatorLogEntry Deallocate(size_t s) {
   char buffer[32];
-  sprintf(buffer, "deallocate(%zu)", s);
+  snprintf(buffer, sizeof(buffer), "deallocate(%zu)", s);
   return AllocatorLogEntry(buffer);
 }
 
@@ -260,14 +262,17 @@ class TimebombAllocator : public ArduinoJson::Allocator {
   size_t countdown_ = 0;
   Allocator* upstream_;
 };
+}  // namespace
 
 inline size_t sizeofPoolList(size_t n = ARDUINOJSON_INITIAL_POOL_COUNT) {
-  return sizeof(ArduinoJson::detail::VariantPool) * n;
+  using namespace ArduinoJson::detail;
+  return sizeof(MemoryPool<VariantData>) * n;
 }
 
 inline size_t sizeofPool(
     ArduinoJson::detail::SlotCount n = ARDUINOJSON_POOL_CAPACITY) {
-  return ArduinoJson::detail::VariantPool::slotsToBytes(n);
+  using namespace ArduinoJson::detail;
+  return MemoryPool<VariantData>::slotsToBytes(n);
 }
 
 inline size_t sizeofStringBuffer(size_t iteration = 1) {

extras/tests/Helpers/Literals.hpp

@@ -0,0 +1,12 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2024, Benoit BLANCHON
+// MIT License
+
+#pragma once
+
+#include <string>
+
+// the space before _s is required by GCC 4.8
+inline std::string operator"" _s(const char* str, size_t len) {
+  return std::string(str, len);
+}

extras/tests/JsonArray/add.cpp

@@ -6,6 +6,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofArray;
 
@@ -51,7 +52,7 @@ TEST_CASE("JsonArray::add(T)") {
 
     array.add(vla);
 
-    REQUIRE(std::string("world") == array[0]);
+    REQUIRE("world"_s == array[0]);
   }
 #endif
 
@@ -115,7 +116,7 @@ TEST_CASE("JsonArray::add(T)") {
   }
 
   SECTION("should duplicate std::string") {
-    array.add(std::string("world"));
+    array.add("world"_s);
     REQUIRE(spy.log() == AllocatorLog{
                              Allocate(sizeofPool()),
                              Allocate(sizeofString("world")),
@@ -139,7 +140,7 @@ TEST_CASE("JsonArray::add(T)") {
   }
 
   SECTION("should duplicate serialized(std::string)") {
-    array.add(serialized(std::string("{}")));
+    array.add(serialized("{}"_s));
     REQUIRE(spy.log() == AllocatorLog{
                              Allocate(sizeofPool()),
                              Allocate(sizeofString("{}")),
@@ -147,7 +148,7 @@ TEST_CASE("JsonArray::add(T)") {
   }
 
   SECTION("should duplicate serialized(std::string)") {
-    array.add(serialized(std::string("\0XX", 3)));
+    array.add(serialized("\0XX"_s));
     REQUIRE(spy.log() == AllocatorLog{
                              Allocate(sizeofPool()),
                              Allocate(sizeofString(" XX")),
@@ -179,3 +180,52 @@ TEST_CASE("JsonArray::add<T>()") {
     REQUIRE(doc.as<std::string>() == "[42]");
   }
 }
+
+TEST_CASE("JsonObject::add(JsonObject) ") {
+  JsonDocument doc1;
+  doc1["key1"_s] = "value1"_s;
+
+  TimebombAllocator allocator(10);
+  SpyingAllocator spy(&allocator);
+  JsonDocument doc2(&spy);
+  JsonArray array = doc2.to<JsonArray>();
+
+  SECTION("success") {
+    bool result = array.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == true);
+    REQUIRE(doc2.as<std::string>() == "[{\"key1\":\"value1\"}]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             Allocate(sizeofString("key1")),
+                             Allocate(sizeofString("value1")),
+                         });
+  }
+
+  SECTION("partial failure") {  // issue #2081
+    allocator.setCountdown(2);
+
+    bool result = array.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == false);
+    REQUIRE(doc2.as<std::string>() == "[]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             Allocate(sizeofString("key1")),
+                             AllocateFail(sizeofString("value1")),
+                             Deallocate(sizeofString("key1")),
+                         });
+  }
+
+  SECTION("complete failure") {
+    allocator.setCountdown(0);
+
+    bool result = array.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == false);
+    REQUIRE(doc2.as<std::string>() == "[]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             AllocateFail(sizeofPool()),
+                         });
+  }
+}

extras/tests/JsonArray/copyArray.cpp

@@ -6,6 +6,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("copyArray()") {
   SECTION("int[] -> JsonArray") {
@@ -18,7 +19,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(array, json);
-    CHECK(std::string("[1,2,3]") == json);
+    CHECK("[1,2,3]"_s == json);
   }
 
   SECTION("std::string[] -> JsonArray") {
@@ -31,7 +32,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(array, json);
-    CHECK(std::string("[\"a\",\"b\",\"c\"]") == json);
+    CHECK("[\"a\",\"b\",\"c\"]"_s == json);
   }
 
   SECTION("const char*[] -> JsonArray") {
@@ -44,7 +45,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(array, json);
-    CHECK(std::string("[\"a\",\"b\",\"c\"]") == json);
+    CHECK("[\"a\",\"b\",\"c\"]"_s == json);
   }
 
   SECTION("const char[][] -> JsonArray") {
@@ -57,7 +58,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(array, json);
-    CHECK(std::string("[\"a\",\"b\",\"c\"]") == json);
+    CHECK("[\"a\",\"b\",\"c\"]"_s == json);
   }
 
   SECTION("const char[][] -> JsonDocument") {
@@ -69,7 +70,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(doc, json);
-    CHECK(std::string("[\"a\",\"b\",\"c\"]") == json);
+    CHECK("[\"a\",\"b\",\"c\"]"_s == json);
   }
 
   SECTION("const char[][] -> MemberProxy") {
@@ -81,7 +82,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(doc, json);
-    CHECK(std::string("{\"data\":[\"a\",\"b\",\"c\"]}") == json);
+    CHECK("{\"data\":[\"a\",\"b\",\"c\"]}"_s == json);
   }
 
   SECTION("int[] -> JsonDocument") {
@@ -93,7 +94,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(doc, json);
-    CHECK(std::string("[1,2,3]") == json);
+    CHECK("[1,2,3]"_s == json);
   }
 
   SECTION("int[] -> MemberProxy") {
@@ -105,7 +106,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(doc, json);
-    CHECK(std::string("{\"data\":[1,2,3]}") == json);
+    CHECK("{\"data\":[1,2,3]}"_s == json);
   }
 
   SECTION("int[] -> JsonArray, but not enough memory") {
@@ -127,7 +128,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(array, json);
-    CHECK(std::string("[[1,2,3],[4,5,6]]") == json);
+    CHECK("[[1,2,3],[4,5,6]]"_s == json);
   }
 
   SECTION("int[][] -> MemberProxy") {
@@ -139,7 +140,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(doc, json);
-    CHECK(std::string("{\"data\":[[1,2,3],[4,5,6]]}") == json);
+    CHECK("{\"data\":[[1,2,3],[4,5,6]]}"_s == json);
   }
 
   SECTION("int[][] -> JsonDocument") {
@@ -151,7 +152,7 @@ TEST_CASE("copyArray()") {
     CHECK(ok);
 
     serializeJson(doc, json);
-    CHECK(std::string("[[1,2,3],[4,5,6]]") == json);
+    CHECK("[[1,2,3],[4,5,6]]"_s == json);
   }
 
   SECTION("int[][] -> JsonArray, but not enough memory") {
@@ -223,9 +224,9 @@ TEST_CASE("copyArray()") {
     size_t result = copyArray(array, destination);
 
     CHECK(3 == result);
-    CHECK(std::string("a12345") == destination[0]);
-    CHECK(std::string("b123456") == destination[1]);
-    CHECK(std::string("c123456") == destination[2]);  // truncated
+    CHECK("a12345"_s == destination[0]);
+    CHECK("b123456"_s == destination[1]);
+    CHECK("c123456"_s == destination[2]);  // truncated
     CHECK(std::string("") == destination[3]);
   }
 

extras/tests/JsonArray/remove.cpp

@@ -68,6 +68,12 @@ TEST_CASE("JsonArray::remove()") {
     REQUIRE(array[1] == 2);
   }
 
+  SECTION("remove end()") {
+    array.remove(array.end());
+
+    REQUIRE(3 == array.size());
+  }
+
   SECTION("In a loop") {
     for (JsonArray::iterator it = array.begin(); it != array.end(); ++it) {
       if (*it == 2)
@@ -88,6 +94,15 @@ TEST_CASE("JsonArray::remove()") {
     JsonArray unboundArray;
     unboundArray.remove(unboundArray.begin());
   }
+
+  SECTION("use JsonVariant as index") {
+    array.remove(array[3]);  // no effect with null variant
+    array.remove(array[0]);  // remove element at index 1
+
+    REQUIRE(2 == array.size());
+    REQUIRE(array[0] == 1);
+    REQUIRE(array[1] == 3);
+  }
 }
 
 TEST_CASE("Removed elements are recycled") {

extras/tests/JsonArray/std_string.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 static void eraseString(std::string& str) {
   char* p = const_cast<char*>(str.c_str());
   while (*p)
@@ -19,7 +21,7 @@ TEST_CASE("std::string") {
     std::string value("hello");
     array.add(value);
     eraseString(value);
-    REQUIRE(std::string("hello") == array[0]);
+    REQUIRE("hello"_s == array[0]);
   }
 
   SECTION("operator[]") {
@@ -27,6 +29,6 @@ TEST_CASE("std::string") {
     array.add("hello");
     array[0] = value;
     eraseString(value);
-    REQUIRE(std::string("world") == array[0]);
+    REQUIRE("world"_s == array[0]);
   }
 }

extras/tests/JsonArray/subscript.cpp

@@ -7,6 +7,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("JsonArray::operator[]") {
   SpyingAllocator spy;
@@ -129,7 +130,7 @@ TEST_CASE("JsonArray::operator[]") {
   }
 
   SECTION("should duplicate std::string") {
-    array[0] = std::string("world");
+    array[0] = "world"_s;
     REQUIRE(spy.log() == AllocatorLog{
                              Allocate(sizeofPool()),
                              Allocate(sizeofString("world")),
@@ -150,7 +151,7 @@ TEST_CASE("JsonArray::operator[]") {
     array.add("hello");
     array[0].set(vla);
 
-    REQUIRE(std::string("world") == array[0]);
+    REQUIRE("world"_s == array[0]);
   }
 
   SECTION("operator=(VLA)") {
@@ -161,7 +162,16 @@ TEST_CASE("JsonArray::operator[]") {
     array.add("hello");
     array[0] = vla;
 
-    REQUIRE(std::string("world") == array[0]);
+    REQUIRE("world"_s == array[0]);
   }
 #endif
+
+  SECTION("Use a JsonVariant as index") {
+    array[0] = 1;
+    array[1] = 2;
+    array[2] = 3;
+
+    REQUIRE(array[array[1]] == 3);
+    REQUIRE(array[array[3]] == nullptr);
+  }
 }

extras/tests/JsonArrayConst/subscript.cpp

@@ -13,8 +13,15 @@ TEST_CASE("JsonArrayConst::operator[]") {
   doc.add(2);
   doc.add(3);
 
-  REQUIRE(1 == arr[0].as<int>());
-  REQUIRE(2 == arr[1].as<int>());
-  REQUIRE(3 == arr[2].as<int>());
-  REQUIRE(0 == arr[3].as<int>());
+  SECTION("int") {
+    REQUIRE(1 == arr[0].as<int>());
+    REQUIRE(2 == arr[1].as<int>());
+    REQUIRE(3 == arr[2].as<int>());
+    REQUIRE(0 == arr[3].as<int>());
+  }
+
+  SECTION("JsonVariant") {
+    REQUIRE(2 == arr[arr[0]].as<int>());
+    REQUIRE(0 == arr[arr[3]].as<int>());
+  }
 }

extras/tests/JsonDeserializer/array.cpp

@@ -69,14 +69,32 @@ TEST_CASE("deserialize JSON array") {
       REQUIRE(arr[1] == 84);
     }
 
-    SECTION("Double") {
+    SECTION("Float") {
       DeserializationError err = deserializeJson(doc, "[4.2,1e2]");
       JsonArray arr = doc.as<JsonArray>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(2 == arr.size());
-      REQUIRE(arr[0] == 4.2);
-      REQUIRE(arr[1] == 1e2);
+      REQUIRE(arr[0].as<float>() == Approx(4.2f));
+      REQUIRE(arr[1] == 1e2f);
+      REQUIRE(spy.log() == AllocatorLog{
+                               Allocate(sizeofPool()),
+                               Reallocate(sizeofPool(), sizeofPool(2)),
+                           });
+    }
+
+    SECTION("Double") {
+      DeserializationError err = deserializeJson(doc, "[4.2123456,-7E89]");
+      JsonArray arr = doc.as<JsonArray>();
+
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(2 == arr.size());
+      REQUIRE(arr[0].as<double>() == Approx(4.2123456));
+      REQUIRE(arr[1] == -7E89);
+      REQUIRE(spy.log() == AllocatorLog{
+                               Allocate(sizeofPool()),
+                               Reallocate(sizeofPool(), sizeofPool(4)),
+                           });
     }
 
     SECTION("Unsigned long") {

extras/tests/JsonDeserializer/destination_types.cpp

@@ -8,6 +8,7 @@
 #include <string>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofArray;
 using ArduinoJson::detail::sizeofObject;
@@ -15,7 +16,7 @@ using ArduinoJson::detail::sizeofObject;
 TEST_CASE("deserializeJson(JsonDocument&)") {
   SpyingAllocator spy;
   JsonDocument doc(&spy);
-  doc.add(std::string("hello"));
+  doc.add("hello"_s);
   spy.clearLog();
 
   auto err = deserializeJson(doc, "[42]");
@@ -34,7 +35,7 @@ TEST_CASE("deserializeJson(JsonVariant)") {
   SECTION("variant is bound") {
     SpyingAllocator spy;
     JsonDocument doc(&spy);
-    doc.add(std::string("hello"));
+    doc.add("hello"_s);
     spy.clearLog();
 
     JsonVariant variant = doc[0];
@@ -60,7 +61,7 @@ TEST_CASE("deserializeJson(JsonVariant)") {
 TEST_CASE("deserializeJson(ElementProxy)") {
   SpyingAllocator spy;
   JsonDocument doc(&spy);
-  doc.add(std::string("hello"));
+  doc.add("hello"_s);
   spy.clearLog();
 
   SECTION("element already exists") {
@@ -85,7 +86,7 @@ TEST_CASE("deserializeJson(ElementProxy)") {
 TEST_CASE("deserializeJson(MemberProxy)") {
   SpyingAllocator spy;
   JsonDocument doc(&spy);
-  doc[std::string("hello")] = std::string("world");
+  doc["hello"_s] = "world"_s;
   spy.clearLog();
 
   SECTION("member already exists") {

extras/tests/JsonDeserializer/errors.cpp

@@ -6,6 +6,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Allocators.hpp"
+
 TEST_CASE("deserializeJson() returns IncompleteInput") {
   const char* testCases[] = {
       // strings
@@ -118,3 +120,43 @@ TEST_CASE("deserializeJson() returns NoMemory if string length overflows") {
     REQUIRE(err == DeserializationError::NoMemory);
   }
 }
+
+TEST_CASE("deserializeJson() returns NoMemory if extension allocation fails") {
+  JsonDocument doc(FailingAllocator::instance());
+
+  SECTION("uint32_t should pass") {
+    auto err = deserializeJson(doc, "4294967295");
+
+    REQUIRE(err == DeserializationError::Ok);
+  }
+
+  SECTION("uint64_t should fail") {
+    auto err = deserializeJson(doc, "18446744073709551615");
+
+    REQUIRE(err == DeserializationError::NoMemory);
+  }
+
+  SECTION("int32_t should pass") {
+    auto err = deserializeJson(doc, "-2147483648");
+
+    REQUIRE(err == DeserializationError::Ok);
+  }
+
+  SECTION("int64_t should fail") {
+    auto err = deserializeJson(doc, "-9223372036854775808");
+
+    REQUIRE(err == DeserializationError::NoMemory);
+  }
+
+  SECTION("float should pass") {
+    auto err = deserializeJson(doc, "3.402823e38");
+
+    REQUIRE(err == DeserializationError::Ok);
+  }
+
+  SECTION("double should fail") {
+    auto err = deserializeJson(doc, "1.7976931348623157e308");
+
+    REQUIRE(err == DeserializationError::NoMemory);
+  }
+}

extras/tests/JsonDeserializer/filter.cpp

@@ -10,6 +10,7 @@
 #include <string>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofArray;
 using ArduinoJson::detail::sizeofObject;
@@ -732,7 +733,7 @@ TEST_CASE("Overloads") {
   }
 
   SECTION("const std::string&, Filter") {
-    deserializeJson(doc, std::string("{}"), Filter(filter));
+    deserializeJson(doc, "{}"_s, Filter(filter));
   }
 
   SECTION("std::istream&, Filter") {
@@ -760,7 +761,7 @@ TEST_CASE("Overloads") {
   }
 
   SECTION("const std::string&, Filter, NestingLimit") {
-    deserializeJson(doc, std::string("{}"), Filter(filter), NestingLimit(5));
+    deserializeJson(doc, "{}"_s, Filter(filter), NestingLimit(5));
   }
 
   SECTION("std::istream&, Filter, NestingLimit") {
@@ -788,7 +789,7 @@ TEST_CASE("Overloads") {
   }
 
   SECTION("const std::string&, NestingLimit, Filter") {
-    deserializeJson(doc, std::string("{}"), NestingLimit(5), Filter(filter));
+    deserializeJson(doc, "{}"_s, NestingLimit(5), Filter(filter));
   }
 
   SECTION("std::istream&, NestingLimit, Filter") {

extras/tests/JsonDeserializer/input_types.cpp

@@ -9,6 +9,7 @@
 
 #include "Allocators.hpp"
 #include "CustomReader.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofObject;
 
@@ -69,7 +70,7 @@ TEST_CASE("deserializeJson(const std::string&)") {
   }
 
   SECTION("should accept temporary string") {
-    DeserializationError err = deserializeJson(doc, std::string("[42]"));
+    DeserializationError err = deserializeJson(doc, "[42]"_s);
 
     REQUIRE(err == DeserializationError::Ok);
   }
@@ -82,7 +83,7 @@ TEST_CASE("deserializeJson(const std::string&)") {
 
     JsonArray array = doc.as<JsonArray>();
     REQUIRE(err == DeserializationError::Ok);
-    REQUIRE(std::string("hello") == array[0]);
+    REQUIRE("hello"_s == array[0]);
   }
 }
 
@@ -108,7 +109,7 @@ TEST_CASE("deserializeJson(std::istream&)") {
 
     REQUIRE(err == DeserializationError::Ok);
     REQUIRE(1 == obj.size());
-    REQUIRE(std::string("world") == obj["hello"]);
+    REQUIRE("world"_s == obj["hello"]);
   }
 
   SECTION("Should not read after the closing brace of an empty object") {

extras/tests/JsonDeserializer/nestingLimit.cpp

@@ -7,6 +7,8 @@
 
 #include <sstream>
 
+#include "Literals.hpp"
+
 #define SHOULD_WORK(expression) REQUIRE(DeserializationError::Ok == expression);
 #define SHOULD_FAIL(expression) \
   REQUIRE(DeserializationError::TooDeep == expression);
@@ -63,23 +65,23 @@ TEST_CASE("JsonDeserializer nesting") {
   SECTION("Input = std::string") {
     SECTION("limit = 0") {
       DeserializationOption::NestingLimit nesting(0);
-      SHOULD_WORK(deserializeJson(doc, std::string("\"toto\""), nesting));
-      SHOULD_WORK(deserializeJson(doc, std::string("123"), nesting));
-      SHOULD_WORK(deserializeJson(doc, std::string("true"), nesting));
-      SHOULD_FAIL(deserializeJson(doc, std::string("[]"), nesting));
-      SHOULD_FAIL(deserializeJson(doc, std::string("{}"), nesting));
-      SHOULD_FAIL(deserializeJson(doc, std::string("[\"toto\"]"), nesting));
-      SHOULD_FAIL(deserializeJson(doc, std::string("{\"toto\":1}"), nesting));
+      SHOULD_WORK(deserializeJson(doc, "\"toto\""_s, nesting));
+      SHOULD_WORK(deserializeJson(doc, "123"_s, nesting));
+      SHOULD_WORK(deserializeJson(doc, "true"_s, nesting));
+      SHOULD_FAIL(deserializeJson(doc, "[]"_s, nesting));
+      SHOULD_FAIL(deserializeJson(doc, "{}"_s, nesting));
+      SHOULD_FAIL(deserializeJson(doc, "[\"toto\"]"_s, nesting));
+      SHOULD_FAIL(deserializeJson(doc, "{\"toto\":1}"_s, nesting));
     }
 
     SECTION("limit = 1") {
       DeserializationOption::NestingLimit nesting(1);
-      SHOULD_WORK(deserializeJson(doc, std::string("[\"toto\"]"), nesting));
-      SHOULD_WORK(deserializeJson(doc, std::string("{\"toto\":1}"), nesting));
-      SHOULD_FAIL(deserializeJson(doc, std::string("{\"toto\":{}}"), nesting));
-      SHOULD_FAIL(deserializeJson(doc, std::string("{\"toto\":[]}"), nesting));
-      SHOULD_FAIL(deserializeJson(doc, std::string("[[\"toto\"]]"), nesting));
-      SHOULD_FAIL(deserializeJson(doc, std::string("[{\"toto\":1}]"), nesting));
+      SHOULD_WORK(deserializeJson(doc, "[\"toto\"]"_s, nesting));
+      SHOULD_WORK(deserializeJson(doc, "{\"toto\":1}"_s, nesting));
+      SHOULD_FAIL(deserializeJson(doc, "{\"toto\":{}}"_s, nesting));
+      SHOULD_FAIL(deserializeJson(doc, "{\"toto\":[]}"_s, nesting));
+      SHOULD_FAIL(deserializeJson(doc, "[[\"toto\"]]"_s, nesting));
+      SHOULD_FAIL(deserializeJson(doc, "[{\"toto\":1}]"_s, nesting));
     }
   }
 

extras/tests/JsonDeserializer/object.cpp

@@ -155,15 +155,27 @@ TEST_CASE("deserialize JSON object") {
       REQUIRE(obj["key2"] == -42);
     }
 
-    SECTION("Double") {
+    SECTION("Float") {
       DeserializationError err =
-          deserializeJson(doc, "{\"key1\":12.345,\"key2\":-7E89}");
+          deserializeJson(doc, "{\"key1\":12.345,\"key2\":-7E3}");
       JsonObject obj = doc.as<JsonObject>();
 
       REQUIRE(err == DeserializationError::Ok);
       REQUIRE(doc.is<JsonObject>());
       REQUIRE(obj.size() == 2);
-      REQUIRE(obj["key1"] == 12.345);
+      REQUIRE(obj["key1"].as<float>() == Approx(12.345f));
+      REQUIRE(obj["key2"] == -7E3f);
+    }
+
+    SECTION("Double") {
+      DeserializationError err =
+          deserializeJson(doc, "{\"key1\":12.3456789,\"key2\":-7E89}");
+      JsonObject obj = doc.as<JsonObject>();
+
+      REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc.is<JsonObject>());
+      REQUIRE(obj.size() == 2);
+      REQUIRE(obj["key1"].as<double>() == Approx(12.3456789));
       REQUIRE(obj["key2"] == -7E89);
     }
 
@@ -308,12 +320,12 @@ TEST_CASE("deserialize JSON object") {
       REQUIRE(doc["a"] == 2);
     }
 
-    SECTION("NUL in keys") {  // we don't support NULs in keys
+    SECTION("NUL in keys") {
       DeserializationError err =
           deserializeJson(doc, "{\"x\\u0000a\":1,\"x\\u0000b\":2}");
 
       REQUIRE(err == DeserializationError::Ok);
-      REQUIRE(doc.as<std::string>() == "{\"x\":2}");
+      REQUIRE(doc.as<std::string>() == "{\"x\\u0000a\":1,\"x\\u0000b\":2}");
     }
   }
 

extras/tests/JsonDeserializer/string.cpp

@@ -83,6 +83,22 @@ TEST_CASE("Truncated JSON string") {
   }
 }
 
+TEST_CASE("Escape single quote in single quoted string") {
+  JsonDocument doc;
+
+  DeserializationError err = deserializeJson(doc, "'ab\\\'cd'");
+  REQUIRE(err == DeserializationError::Ok);
+  CHECK(doc.as<std::string>() == "ab\'cd");
+}
+
+TEST_CASE("Escape double quote in double quoted string") {
+  JsonDocument doc;
+
+  DeserializationError err = deserializeJson(doc, "'ab\\\"cd'");
+  REQUIRE(err == DeserializationError::Ok);
+  CHECK(doc.as<std::string>() == "ab\"cd");
+}
+
 TEST_CASE("Invalid JSON string") {
   const char* testCases[] = {"'\\u'",     "'\\u000g'", "'\\u000'",
                              "'\\u000G'", "'\\u000/'", "'\\x1234'"};

extras/tests/JsonDocument/CMakeLists.txt

@@ -9,7 +9,6 @@ add_executable(JsonDocumentTests
 	clear.cpp
 	compare.cpp
 	constructor.cpp
-	containsKey.cpp
 	ElementProxy.cpp
 	isNull.cpp
 	issue1120.cpp
@@ -17,6 +16,7 @@ add_executable(JsonDocumentTests
 	nesting.cpp
 	overflowed.cpp
 	remove.cpp
+	set.cpp
 	shrinkToFit.cpp
 	size.cpp
 	subscript.cpp

extras/tests/JsonDocument/ElementProxy.cpp

@@ -5,7 +5,9 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-typedef ArduinoJson::detail::ElementProxy<JsonDocument&> ElementProxy;
+#include "Literals.hpp"
+
+using ElementProxy = ArduinoJson::detail::ElementProxy<JsonDocument&>;
 
 TEST_CASE("ElementProxy::add()") {
   JsonDocument doc;
@@ -24,13 +26,25 @@ TEST_CASE("ElementProxy::add()") {
     REQUIRE(doc.as<std::string>() == "[[\"world\"]]");
   }
 
-  SECTION("set(char[])") {
+  SECTION("add(char[])") {
     char s[] = "world";
     ep.add(s);
     strcpy(s, "!!!!!");
 
     REQUIRE(doc.as<std::string>() == "[[\"world\"]]");
   }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("set(vla)") {
+    size_t i = 8;
+    char vla[i];
+    strcpy(vla, "world");
+
+    ep.add(vla);
+
+    REQUIRE(doc.as<std::string>() == "[[\"world\"]]");
+  }
+#endif
 }
 
 TEST_CASE("ElementProxy::clear()") {
@@ -121,7 +135,7 @@ TEST_CASE("ElementProxy::remove()") {
     ep["a"] = 1;
     ep["b"] = 2;
 
-    ep.remove(std::string("b"));
+    ep.remove("b"_s);
 
     REQUIRE(ep.as<std::string>() == "{\"a\":1}");
   }
@@ -164,6 +178,18 @@ TEST_CASE("ElementProxy::set()") {
 
     REQUIRE(doc.as<std::string>() == "[\"world\"]");
   }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("set(VLA)") {
+    size_t i = 8;
+    char vla[i];
+    strcpy(vla, "world");
+
+    ep.set(vla);
+
+    REQUIRE(doc.as<std::string>() == "[\"world\"]");
+  }
+#endif
 }
 
 TEST_CASE("ElementProxy::size()") {
@@ -203,6 +229,18 @@ TEST_CASE("ElementProxy::operator[]") {
 
     REQUIRE(doc.as<std::string>() == "[null,[null,null,42]]");
   }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("set VLA") {
+    size_t i = 8;
+    char vla[i];
+    strcpy(vla, "world");
+
+    ep[0] = vla;
+
+    REQUIRE(doc.as<std::string>() == "[null,[\"world\"]]");
+  }
+#endif
 }
 
 TEST_CASE("ElementProxy cast to JsonVariantConst") {

extras/tests/JsonDocument/MemberProxy.cpp

@@ -9,12 +9,13 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofArray;
 using ArduinoJson::detail::sizeofObject;
 
-typedef ArduinoJson::detail::MemberProxy<JsonDocument&, const char*>
-    MemberProxy;
+using MemberProxy =
+    ArduinoJson::detail::MemberProxy<JsonDocument&, const char*>;
 
 TEST_CASE("MemberProxy::add()") {
   JsonDocument doc;
@@ -31,6 +32,18 @@ TEST_CASE("MemberProxy::add()") {
 
     REQUIRE(doc.as<std::string>() == "{\"hello\":[\"world\"]}");
   }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("add(vla)") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "world");
+
+    mp.add(vla);
+
+    REQUIRE(doc.as<std::string>() == "{\"hello\":[\"world\"]}");
+  }
+#endif
 }
 
 TEST_CASE("MemberProxy::clear()") {
@@ -92,33 +105,14 @@ TEST_CASE("MemberProxy::operator==()") {
   }
 }
 
-TEST_CASE("MemberProxy::containsKey()") {
-  JsonDocument doc;
-  MemberProxy mp = doc["hello"];
-
-  SECTION("containsKey(const char*)") {
-    mp["key"] = "value";
-
-    REQUIRE(mp.containsKey("key") == true);
-    REQUIRE(mp.containsKey("key") == true);
-  }
-
-  SECTION("containsKey(std::string)") {
-    mp["key"] = "value";
-
-    REQUIRE(mp.containsKey(std::string("key")) == true);
-    REQUIRE(mp.containsKey(std::string("key")) == true);
-  }
-}
-
 TEST_CASE("MemberProxy::operator|()") {
   JsonDocument doc;
 
   SECTION("const char*") {
     doc["a"] = "hello";
 
-    REQUIRE((doc["a"] | "world") == std::string("hello"));
-    REQUIRE((doc["b"] | "world") == std::string("world"));
+    REQUIRE((doc["a"] | "world") == "hello"_s);
+    REQUIRE((doc["b"] | "world") == "world"_s);
   }
 
   SECTION("Issue #1411") {
@@ -128,7 +122,7 @@ TEST_CASE("MemberProxy::operator|()") {
                                 // to trigger the bug
     const char* sensor = doc["sensor"] | test;  // "gps"
 
-    REQUIRE(sensor == std::string("gps"));
+    REQUIRE(sensor == "gps"_s);
   }
 
   SECTION("Issue #1415") {
@@ -170,7 +164,7 @@ TEST_CASE("MemberProxy::remove()") {
     mp["a"] = 1;
     mp["b"] = 2;
 
-    mp.remove(std::string("b"));
+    mp.remove("b"_s);
 
     REQUIRE(mp.as<std::string>() == "{\"a\":1}");
   }
@@ -213,6 +207,18 @@ TEST_CASE("MemberProxy::set()") {
 
     REQUIRE(doc.as<std::string>() == "{\"hello\":\"world\"}");
   }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("set(vla)") {
+    size_t i = 8;
+    char vla[i];
+    strcpy(vla, "world");
+
+    mp.set(vla);
+
+    REQUIRE(doc.as<std::string>() == "{\"hello\":\"world\"}");
+  }
+#endif
 }
 
 TEST_CASE("MemberProxy::size()") {
@@ -286,8 +292,8 @@ TEST_CASE("Deduplicate keys") {
   JsonDocument doc(&spy);
 
   SECTION("std::string") {
-    doc[0][std::string("example")] = 1;
-    doc[1][std::string("example")] = 2;
+    doc[0]["example"_s] = 1;
+    doc[1]["example"_s] = 2;
 
     const char* key1 = doc[0].as<JsonObject>().begin()->key().c_str();
     const char* key2 = doc[1].as<JsonObject>().begin()->key().c_str();
@@ -344,19 +350,51 @@ TEST_CASE("Deduplicate keys") {
 }
 
 TEST_CASE("MemberProxy under memory constraints") {
-  KillswitchAllocator killswitch;
-  SpyingAllocator spy(&killswitch);
+  TimebombAllocator timebomb(1);
+  SpyingAllocator spy(&timebomb);
   JsonDocument doc(&spy);
 
-  SECTION("key allocation fails") {
-    killswitch.on();
+  SECTION("key slot allocation fails") {
+    timebomb.setCountdown(0);
 
-    doc[std::string("hello")] = "world";
+    doc["hello"_s] = "world";
 
     REQUIRE(doc.is<JsonObject>());
     REQUIRE(doc.size() == 0);
     REQUIRE(doc.overflowed() == true);
     REQUIRE(spy.log() == AllocatorLog{
+                             AllocateFail(sizeofPool()),
+                         });
+  }
+
+  SECTION("value slot allocation fails") {
+    timebomb.setCountdown(1);
+
+    // fill the pool entirely, but leave one slot for the key
+    doc["foo"][ARDUINOJSON_POOL_CAPACITY - 4] = 1;
+    REQUIRE(doc.overflowed() == false);
+
+    doc["hello"_s] = "world";
+
+    REQUIRE(doc.is<JsonObject>());
+    REQUIRE(doc.size() == 1);
+    REQUIRE(doc.overflowed() == true);
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             AllocateFail(sizeofPool()),
+                         });
+  }
+
+  SECTION("key string allocation fails") {
+    timebomb.setCountdown(1);
+
+    doc["hello"_s] = "world";
+
+    REQUIRE(doc.is<JsonObject>());
+    REQUIRE(doc.size() == 0);
+    REQUIRE(doc.overflowed() == true);
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
                              AllocateFail(sizeofString("hello")),
                          });
   }

extras/tests/JsonDocument/add.cpp

@@ -9,6 +9,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofArray;
 
@@ -35,8 +36,8 @@ TEST_CASE("JsonDocument::add(T)") {
   }
 
   SECTION("std::string") {
-    doc.add(std::string("example"));
-    doc.add(std::string("example"));
+    doc.add("example"_s);
+    doc.add("example"_s);
 
     CHECK(doc[0].as<const char*>() == doc[1].as<const char*>());
     REQUIRE(spy.log() == AllocatorLog{
@@ -78,6 +79,24 @@ TEST_CASE("JsonDocument::add(T)") {
                              Allocate(sizeofString("example")),
                          });
   }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("VLA") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "example");
+
+    doc.add(vla);
+    doc.add(vla);
+
+    CHECK(doc[0].as<const char*>() == doc[1].as<const char*>());
+    REQUIRE("example"_s == doc[0]);
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             Allocate(sizeofString("example")),
+                         });
+  }
+#endif
 }
 
 TEST_CASE("JsonDocument::add<T>()") {
@@ -90,15 +109,57 @@ TEST_CASE("JsonDocument::add<T>()") {
     REQUIRE(doc.as<std::string>() == "[[1,2]]");
   }
 
-  SECTION("JsonObject") {
-    JsonObject object = doc.add<JsonObject>();
-    object["hello"] = "world";
-    REQUIRE(doc.as<std::string>() == "[{\"hello\":\"world\"}]");
-  }
-
   SECTION("JsonVariant") {
     JsonVariant variant = doc.add<JsonVariant>();
     variant.set(42);
     REQUIRE(doc.as<std::string>() == "[42]");
   }
 }
+
+TEST_CASE("JsonObject::add(JsonObject) ") {
+  JsonDocument doc1;
+  doc1["hello"_s] = "world"_s;
+
+  TimebombAllocator allocator(10);
+  SpyingAllocator spy(&allocator);
+  JsonDocument doc2(&spy);
+
+  SECTION("success") {
+    bool result = doc2.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == true);
+    REQUIRE(doc2.as<std::string>() == "[{\"hello\":\"world\"}]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
+                             Allocate(sizeofString("world")),
+                         });
+  }
+
+  SECTION("partial failure") {  // issue #2081
+    allocator.setCountdown(2);
+
+    bool result = doc2.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == false);
+    REQUIRE(doc2.as<std::string>() == "[]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
+                             AllocateFail(sizeofString("world")),
+                             Deallocate(sizeofString("hello")),
+                         });
+  }
+
+  SECTION("complete failure") {
+    allocator.setCountdown(0);
+
+    bool result = doc2.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == false);
+    REQUIRE(doc2.as<std::string>() == "[]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             AllocateFail(sizeofPool()),
+                         });
+  }
+}

extras/tests/JsonDocument/assignment.cpp

@@ -6,6 +6,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("JsonDocument assignment") {
   SpyingAllocator spyingAllocator;
@@ -21,8 +22,8 @@ TEST_CASE("JsonDocument assignment") {
     REQUIRE(doc2.as<std::string>() == "{\"hello\":\"world\"}");
 
     REQUIRE(spyingAllocator.log() == AllocatorLog{
-                                         Allocate(sizeofString("hello")),
                                          Allocate(sizeofPool()),
+                                         Allocate(sizeofString("hello")),
                                          Allocate(sizeofString("world")),
                                      });
   }
@@ -53,8 +54,8 @@ TEST_CASE("JsonDocument assignment") {
 
     REQUIRE(doc2.as<std::string>() == "{\"hello\":\"world\"}");
     REQUIRE(spyingAllocator.log() == AllocatorLog{
-                                         Allocate(sizeofString("hello")),
                                          Allocate(sizeofPool()),
+                                         Allocate(sizeofString("hello")),
                                          Allocate(sizeofString("world")),
                                      });
   }
@@ -62,7 +63,7 @@ TEST_CASE("JsonDocument assignment") {
   SECTION("Move assign") {
     {
       JsonDocument doc1(&spyingAllocator);
-      doc1[std::string("hello")] = std::string("world");
+      doc1["hello"_s] = "world"_s;
       JsonDocument doc2(&spyingAllocator);
 
       doc2 = std::move(doc1);
@@ -71,8 +72,8 @@ TEST_CASE("JsonDocument assignment") {
       REQUIRE(doc1.as<std::string>() == "null");
     }
     REQUIRE(spyingAllocator.log() == AllocatorLog{
-                                         Allocate(sizeofString("hello")),
                                          Allocate(sizeofPool()),
+                                         Allocate(sizeofString("hello")),
                                          Allocate(sizeofString("world")),
                                          Deallocate(sizeofString("hello")),
                                          Deallocate(sizeofString("world")),

extras/tests/JsonDocument/clear.cpp

@@ -9,6 +9,7 @@
 #include <string>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("JsonDocument::clear()") {
   SpyingAllocator spy;
@@ -22,7 +23,7 @@ TEST_CASE("JsonDocument::clear()") {
   }
 
   SECTION("releases resources") {
-    doc[std::string("hello")] = std::string("world");
+    doc["hello"_s] = "world"_s;
     spy.clearLog();
 
     doc.clear();

extras/tests/JsonDocument/constructor.cpp

@@ -6,6 +6,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::addPadding;
 
@@ -20,7 +21,7 @@ TEST_CASE("JsonDocument constructor") {
   SECTION("JsonDocument(const JsonDocument&)") {
     {
       JsonDocument doc1(&spyingAllocator);
-      doc1.set(std::string("The size of this string is 32!!"));
+      doc1.set("The size of this string is 32!!"_s);
 
       JsonDocument doc2(doc1);
 
@@ -38,7 +39,7 @@ TEST_CASE("JsonDocument constructor") {
   SECTION("JsonDocument(JsonDocument&&)") {
     {
       JsonDocument doc1(&spyingAllocator);
-      doc1.set(std::string("The size of this string is 32!!"));
+      doc1.set("The size of this string is 32!!"_s);
 
       JsonDocument doc2(std::move(doc1));
 
@@ -117,4 +118,31 @@ TEST_CASE("JsonDocument constructor") {
 
     REQUIRE(doc2.as<std::string>() == "hello");
   }
+
+  SECTION("JsonDocument(JsonVariantConst)") {
+    JsonDocument doc1;
+    deserializeJson(doc1, "\"hello\"");
+
+    JsonDocument doc2(doc1.as<JsonVariantConst>());
+
+    REQUIRE(doc2.as<std::string>() == "hello");
+  }
+
+  SECTION("JsonDocument(ElementProxy)") {
+    JsonDocument doc1;
+    deserializeJson(doc1, "[\"hello\",\"world\"]");
+
+    JsonDocument doc2(doc1[1]);
+
+    REQUIRE(doc2.as<std::string>() == "world");
+  }
+
+  SECTION("JsonDocument(MemberProxy)") {
+    JsonDocument doc1;
+    deserializeJson(doc1, "{\"hello\":\"world\"}");
+
+    JsonDocument doc2(doc1["hello"]);
+
+    REQUIRE(doc2.as<std::string>() == "world");
+  }
 }

extras/tests/JsonDocument/containsKey.cpp

@@ -1,44 +0,0 @@
-// ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2024, Benoit BLANCHON
-// MIT License
-
-#include <ArduinoJson.h>
-#include <catch.hpp>
-
-TEST_CASE("JsonDocument::containsKey()") {
-  JsonDocument doc;
-
-  SECTION("returns true on object") {
-    doc["hello"] = "world";
-
-    REQUIRE(doc.containsKey("hello") == true);
-  }
-
-  SECTION("returns true when value is null") {
-    doc["hello"] = static_cast<const char*>(0);
-
-    REQUIRE(doc.containsKey("hello") == true);
-  }
-
-  SECTION("returns true when key is a std::string") {
-    doc["hello"] = "world";
-
-    REQUIRE(doc.containsKey(std::string("hello")) == true);
-  }
-
-  SECTION("returns false  on object") {
-    doc["world"] = "hello";
-
-    REQUIRE(doc.containsKey("hello") == false);
-  }
-
-  SECTION("returns false on array") {
-    doc.add("hello");
-
-    REQUIRE(doc.containsKey("hello") == false);
-  }
-
-  SECTION("returns false on null") {
-    REQUIRE(doc.containsKey("hello") == false);
-  }
-}

extras/tests/JsonDocument/issue1120.cpp

@@ -2,6 +2,8 @@
 
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 TEST_CASE("Issue #1120") {
   JsonDocument doc;
   constexpr char str[] =
@@ -10,12 +12,12 @@ TEST_CASE("Issue #1120") {
 
   SECTION("MemberProxy<std::string>::isNull()") {
     SECTION("returns false") {
-      auto value = doc[std::string("contents")];
+      auto value = doc["contents"_s];
       CHECK(value.isNull() == false);
     }
 
     SECTION("returns true") {
-      auto value = doc[std::string("zontents")];
+      auto value = doc["zontents"_s];
       CHECK(value.isNull() == true);
     }
   }
@@ -46,12 +48,12 @@ TEST_CASE("Issue #1120") {
 
   SECTION("MemberProxy<ElementProxy<MemberProxy>, std::string>::isNull()") {
     SECTION("returns false") {
-      auto value = doc["contents"][1][std::string("module")];
+      auto value = doc["contents"][1]["module"_s];
       CHECK(value.isNull() == false);
     }
 
     SECTION("returns true") {
-      auto value = doc["contents"][1][std::string("zodule")];
+      auto value = doc["contents"][1]["zodule"_s];
       CHECK(value.isNull() == true);
     }
   }

extras/tests/JsonDocument/overflowed.cpp

@@ -6,6 +6,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("JsonDocument::overflowed()") {
   TimebombAllocator timebomb(10);
@@ -30,13 +31,13 @@ TEST_CASE("JsonDocument::overflowed()") {
 
   SECTION("returns true after a failed string copy") {
     timebomb.setCountdown(0);
-    doc.add(std::string("example"));
+    doc.add("example"_s);
     CHECK(doc.overflowed() == true);
   }
 
   SECTION("returns false after a successful string copy") {
     timebomb.setCountdown(3);
-    doc.add(std::string("example"));
+    doc.add("example"_s);
     CHECK(doc.overflowed() == false);
   }
 

extras/tests/JsonDocument/remove.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 TEST_CASE("JsonDocument::remove()") {
   JsonDocument doc;
 
@@ -31,7 +33,7 @@ TEST_CASE("JsonDocument::remove()") {
     doc["a"] = 1;
     doc["b"] = 2;
 
-    doc.remove(std::string("b"));
+    doc.remove("b"_s);
 
     REQUIRE(doc.as<std::string>() == "{\"a\":1}");
   }
@@ -49,4 +51,25 @@ TEST_CASE("JsonDocument::remove()") {
     REQUIRE(doc.as<std::string>() == "{\"a\":1}");
   }
 #endif
+
+  SECTION("remove(JsonVariant) from object") {
+    doc["a"] = 1;
+    doc["b"] = 2;
+    doc["c"] = "b";
+
+    doc.remove(doc["c"]);
+
+    REQUIRE(doc.as<std::string>() == "{\"a\":1,\"c\":\"b\"}");
+  }
+
+  SECTION("remove(JsonVariant) from array") {
+    doc[0] = 3;
+    doc[1] = 2;
+    doc[2] = 1;
+
+    doc.remove(doc[2]);
+    doc.remove(doc[3]);  // noop
+
+    REQUIRE(doc.as<std::string>() == "[3,1]");
+  }
 }

extras/tests/JsonDocument/set.cpp

@@ -0,0 +1,79 @@
+#define ARDUINOJSON_ENABLE_ARDUINO_STRING 1
+#define ARDUINOJSON_ENABLE_PROGMEM 1
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+#include "Allocators.hpp"
+#include "Literals.hpp"
+
+TEST_CASE("JsonDocument::set()") {
+  SpyingAllocator spy;
+  JsonDocument doc(&spy);
+
+  SECTION("integer") {
+    doc.set(42);
+
+    REQUIRE(doc.as<std::string>() == "42");
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+
+  SECTION("const char*") {
+    doc.set("example");
+
+    REQUIRE(doc.as<const char*>() == "example"_s);
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+
+  SECTION("std::string") {
+    doc.set("example"_s);
+
+    REQUIRE(doc.as<const char*>() == "example"_s);
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("example")),
+                         });
+  }
+
+  SECTION("char*") {
+    char value[] = "example";
+    doc.set(value);
+
+    REQUIRE(doc.as<const char*>() == "example"_s);
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("example")),
+                         });
+  }
+
+  SECTION("Arduino String") {
+    doc.set(String("example"));
+
+    REQUIRE(doc.as<const char*>() == "example"_s);
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("example")),
+                         });
+  }
+
+  SECTION("Flash string") {
+    doc.set(F("example"));
+
+    REQUIRE(doc.as<const char*>() == "example"_s);
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("example")),
+                         });
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("VLA") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "example");
+
+    doc.set(vla);
+
+    REQUIRE(doc.as<const char*>() == "example"_s);
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("example")),
+                         });
+  }
+#endif
+}

extras/tests/JsonDocument/shrinkToFit.cpp

@@ -9,6 +9,7 @@
 #include <string>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofArray;
 using ArduinoJson::detail::sizeofObject;
@@ -78,7 +79,7 @@ TEST_CASE("JsonDocument::shrinkToFit()") {
   }
 
   SECTION("owned string") {
-    doc.set(std::string("abcdefg"));
+    doc.set("abcdefg"_s);
     REQUIRE(doc.as<std::string>() == "abcdefg");
 
     doc.shrinkToFit();
@@ -114,15 +115,15 @@ TEST_CASE("JsonDocument::shrinkToFit()") {
   }
 
   SECTION("owned key") {
-    doc[std::string("abcdefg")] = 42;
+    doc["abcdefg"_s] = 42;
 
     doc.shrinkToFit();
 
     REQUIRE(doc.as<std::string>() == "{\"abcdefg\":42}");
     REQUIRE(spyingAllocator.log() ==
             AllocatorLog{
-                Allocate(sizeofString("abcdefg")),
                 Allocate(sizeofPool()),
+                Allocate(sizeofString("abcdefg")),
                 Reallocate(sizeofPool(), sizeofObject(1)),
             });
   }
@@ -141,7 +142,7 @@ TEST_CASE("JsonDocument::shrinkToFit()") {
   }
 
   SECTION("owned string in array") {
-    doc.add(std::string("abcdefg"));
+    doc.add("abcdefg"_s);
 
     doc.shrinkToFit();
 
@@ -168,7 +169,7 @@ TEST_CASE("JsonDocument::shrinkToFit()") {
   }
 
   SECTION("owned string in object") {
-    doc["key"] = std::string("abcdefg");
+    doc["key"] = "abcdefg"_s;
 
     doc.shrinkToFit();
 
@@ -177,7 +178,7 @@ TEST_CASE("JsonDocument::shrinkToFit()") {
             AllocatorLog{
                 Allocate(sizeofPool()),
                 Allocate(sizeofString("abcdefg")),
-                Reallocate(sizeofPool(), sizeofPool(1)),
+                Reallocate(sizeofPool(), sizeofPool(2)),
             });
   }
 }

extras/tests/JsonDocument/subscript.cpp

@@ -5,34 +5,77 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 TEST_CASE("JsonDocument::operator[]") {
   JsonDocument doc;
   const JsonDocument& cdoc = doc;
 
   SECTION("object") {
-    deserializeJson(doc, "{\"hello\":\"world\"}");
+    doc["abc"_s] = "ABC";
+    doc["abc\0d"_s] = "ABCD";
 
     SECTION("const char*") {
-      REQUIRE(doc["hello"] == "world");
-      REQUIRE(cdoc["hello"] == "world");
+      REQUIRE(doc["abc"] == "ABC");
+      REQUIRE(cdoc["abc"] == "ABC");
     }
 
     SECTION("std::string") {
-      REQUIRE(doc[std::string("hello")] == "world");
-      REQUIRE(cdoc[std::string("hello")] == "world");
+      REQUIRE(doc["abc"_s] == "ABC");
+      REQUIRE(cdoc["abc"_s] == "ABC");
+      REQUIRE(doc["abc\0d"_s] == "ABCD");
+      REQUIRE(cdoc["abc\0d"_s] == "ABCD");
+    }
+
+    SECTION("JsonVariant") {
+      doc["key1"] = "abc";
+      doc["key2"] = "abc\0d"_s;
+      doc["key3"] = "foo";
+
+      CHECK(doc[doc["key1"]] == "ABC");
+      CHECK(doc[doc["key2"]] == "ABCD");
+      CHECK(doc[doc["key3"]] == nullptr);
+      CHECK(doc[doc["key4"]] == nullptr);
+
+      CHECK(cdoc[cdoc["key1"]] == "ABC");
+      CHECK(cdoc[cdoc["key2"]] == "ABCD");
+      CHECK(cdoc[cdoc["key3"]] == nullptr);
+      CHECK(cdoc[cdoc["key4"]] == nullptr);
     }
 
     SECTION("supports operator|") {
-      REQUIRE((doc["hello"] | "nope") == std::string("world"));
-      REQUIRE((doc["world"] | "nope") == std::string("nope"));
+      REQUIRE((doc["abc"] | "nope") == "ABC"_s);
+      REQUIRE((doc["def"] | "nope") == "nope"_s);
     }
+
+#if defined(HAS_VARIABLE_LENGTH_ARRAY) && \
+    !defined(SUBSCRIPT_CONFLICTS_WITH_BUILTIN_OPERATOR)
+    SECTION("supports VLAs") {
+      size_t i = 16;
+      char vla[i];
+      strcpy(vla, "hello");
+
+      doc[vla] = "world";
+
+      REQUIRE(doc[vla] == "world");
+      REQUIRE(cdoc[vla] == "world");
+    }
+#endif
   }
 
   SECTION("array") {
     deserializeJson(doc, "[\"hello\",\"world\"]");
 
-    REQUIRE(doc[1] == "world");
-    REQUIRE(cdoc[1] == "world");
+    SECTION("int") {
+      REQUIRE(doc[1] == "world");
+      REQUIRE(cdoc[1] == "world");
+    }
+
+    SECTION("JsonVariant") {
+      doc[2] = 1;
+      REQUIRE(doc[doc[2]] == "world");
+      REQUIRE(cdoc[doc[2]] == "world");
+    }
   }
 }
 

extras/tests/JsonObject/CMakeLists.txt

@@ -5,13 +5,12 @@
 add_executable(JsonObjectTests
 	clear.cpp
 	compare.cpp
-	containsKey.cpp
-	copy.cpp
 	equals.cpp
 	isNull.cpp
 	iterator.cpp
 	nesting.cpp
 	remove.cpp
+	set.cpp
 	size.cpp
 	std_string.cpp
 	subscript.cpp

extras/tests/JsonObject/containsKey.cpp

@@ -1,33 +0,0 @@
-// ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2024, Benoit BLANCHON
-// MIT License
-
-#include <ArduinoJson.h>
-#include <catch.hpp>
-
-TEST_CASE("JsonObject::containsKey()") {
-  JsonDocument doc;
-  JsonObject obj = doc.to<JsonObject>();
-  obj["hello"] = 42;
-
-  SECTION("returns true only if key is present") {
-    REQUIRE(false == obj.containsKey("world"));
-    REQUIRE(true == obj.containsKey("hello"));
-  }
-
-  SECTION("returns false after remove()") {
-    obj.remove("hello");
-
-    REQUIRE(false == obj.containsKey("hello"));
-  }
-
-#ifdef HAS_VARIABLE_LENGTH_ARRAY
-  SECTION("key is a VLA") {
-    size_t i = 16;
-    char vla[i];
-    strcpy(vla, "hello");
-
-    REQUIRE(true == obj.containsKey(vla));
-  }
-#endif
-}

extras/tests/JsonObject/remove.cpp

@@ -80,4 +80,10 @@ TEST_CASE("JsonObject::remove()") {
     JsonObject unboundObject;
     unboundObject.remove(unboundObject.begin());
   }
+
+  SECTION("remove(JsonVariant)") {
+    obj["key"] = "b";
+    obj.remove(obj["key"]);
+    REQUIRE("{\"a\":0,\"c\":2,\"key\":\"b\"}" == doc.as<std::string>());
+  }
 }

extras/tests/JsonObject/set.cpp

@@ -6,6 +6,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("JsonObject::set()") {
   SpyingAllocator spy;
@@ -22,20 +23,20 @@ TEST_CASE("JsonObject::set()") {
     bool success = obj2.set(obj1);
 
     REQUIRE(success == true);
-    REQUIRE(obj2["hello"] == std::string("world"));
+    REQUIRE(obj2["hello"] == "world"_s);
     REQUIRE(spy.log() == AllocatorLog{
                              Allocate(sizeofPool()),
                          });
   }
 
   SECTION("copy local string value") {
-    obj1["hello"] = std::string("world");
+    obj1["hello"] = "world"_s;
     spy.clearLog();
 
     bool success = obj2.set(obj1);
 
     REQUIRE(success == true);
-    REQUIRE(obj2["hello"] == std::string("world"));
+    REQUIRE(obj2["hello"] == "world"_s);
     REQUIRE(spy.log() == AllocatorLog{
                              Allocate(sizeofPool()),
                              Allocate(sizeofString("world")),
@@ -43,16 +44,16 @@ TEST_CASE("JsonObject::set()") {
   }
 
   SECTION("copy local key") {
-    obj1[std::string("hello")] = "world";
+    obj1["hello"_s] = "world";
     spy.clearLog();
 
     bool success = obj2.set(obj1);
 
     REQUIRE(success == true);
-    REQUIRE(obj2["hello"] == std::string("world"));
+    REQUIRE(obj2["hello"] == "world"_s);
     REQUIRE(spy.log() == AllocatorLog{
-                             Allocate(sizeofString("hello")),
                              Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
                          });
   }
 
@@ -63,10 +64,10 @@ TEST_CASE("JsonObject::set()") {
     bool success = obj2.set(obj1);
 
     REQUIRE(success == true);
-    REQUIRE(obj2["hello"] == std::string("world"));
+    REQUIRE(obj2["hello"] == "world"_s);
     REQUIRE(spy.log() == AllocatorLog{
-                             Allocate(sizeofString("hello")),
                              Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
                              Allocate(sizeofString("world")),
                          });
   }
@@ -78,10 +79,10 @@ TEST_CASE("JsonObject::set()") {
     bool success = obj2.set(obj1);
 
     REQUIRE(success == true);
-    REQUIRE(obj2["hello"] == std::string("world"));
+    REQUIRE(obj2["hello"] == "world"_s);
     REQUIRE(spy.log() == AllocatorLog{
-                             Allocate(sizeofString("hello")),
                              Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
                              Allocate(sizeofString("world")),
                          });
   }
@@ -91,7 +92,7 @@ TEST_CASE("JsonObject::set()") {
 
     obj2.set(static_cast<JsonObjectConst>(obj1));
 
-    REQUIRE(obj2["hello"] == std::string("world"));
+    REQUIRE(obj2["hello"] == "world"_s);
   }
 
   SECTION("copy fails in the middle of an object") {
@@ -99,8 +100,8 @@ TEST_CASE("JsonObject::set()") {
     JsonDocument doc3(&timebomb);
     JsonObject obj3 = doc3.to<JsonObject>();
 
-    obj1[std::string("a")] = 1;
-    obj1[std::string("b")] = 2;
+    obj1["a"_s] = 1;
+    obj1["b"_s] = 2;
 
     bool success = obj3.set(obj1);
 
@@ -113,12 +114,12 @@ TEST_CASE("JsonObject::set()") {
     JsonDocument doc3(&timebomb);
     JsonObject obj3 = doc3.to<JsonObject>();
 
-    obj1["hello"][0] = std::string("world");
+    obj1["hello"][0] = "world"_s;
 
     bool success = obj3.set(obj1);
 
     REQUIRE(success == false);
-    REQUIRE(doc3.as<std::string>() == "{\"hello\":[null]}");
+    REQUIRE(doc3.as<std::string>() == "{\"hello\":[]}");
   }
 
   SECTION("destination is null") {

extras/tests/JsonObject/std_string.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 static void eraseString(std::string& str) {
   char* p = const_cast<char*>(str.c_str());
   while (*p)
@@ -20,7 +22,7 @@ TEST_CASE("std::string") {
     deserializeJson(doc, json);
     JsonObject obj = doc.as<JsonObject>();
 
-    REQUIRE(std::string("value") == obj[std::string("key")]);
+    REQUIRE("value"_s == obj["key"_s]);
   }
 
   SECTION("operator[] const") {
@@ -29,21 +31,14 @@ TEST_CASE("std::string") {
     deserializeJson(doc, json);
     JsonObject obj = doc.as<JsonObject>();
 
-    REQUIRE(std::string("value") == obj[std::string("key")]);
-  }
-
-  SECTION("containsKey()") {
-    char json[] = "{\"key\":\"value\"}";
-    deserializeJson(doc, json);
-    JsonObject obj = doc.as<JsonObject>();
-    REQUIRE(true == obj.containsKey(std::string("key")));
+    REQUIRE("value"_s == obj["key"_s]);
   }
 
   SECTION("remove()") {
     JsonObject obj = doc.to<JsonObject>();
     obj["key"] = "value";
 
-    obj.remove(std::string("key"));
+    obj.remove("key"_s);
 
     REQUIRE(0 == obj.size());
   }
@@ -53,7 +48,7 @@ TEST_CASE("std::string") {
     JsonObject obj = doc.to<JsonObject>();
     obj[key] = "world";
     eraseString(key);
-    REQUIRE(std::string("world") == obj["hello"]);
+    REQUIRE("world"_s == obj["hello"]);
   }
 
   SECTION("operator[], set value") {
@@ -61,6 +56,6 @@ TEST_CASE("std::string") {
     JsonObject obj = doc.to<JsonObject>();
     obj["hello"] = value;
     eraseString(value);
-    REQUIRE(std::string("world") == obj["hello"]);
+    REQUIRE("world"_s == obj["hello"]);
   }
 }

extras/tests/JsonObject/subscript.cpp

@@ -6,6 +6,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("JsonObject::operator[]") {
   SpyingAllocator spy;
@@ -50,7 +51,7 @@ TEST_CASE("JsonObject::operator[]") {
 
     REQUIRE(true == obj["hello"].is<const char*>());
     REQUIRE(false == obj["hello"].is<long>());
-    REQUIRE(std::string("h3110") == obj["hello"].as<const char*>());
+    REQUIRE("h3110"_s == obj["hello"].as<const char*>());
   }
 
   SECTION("array") {
@@ -117,22 +118,22 @@ TEST_CASE("JsonObject::operator[]") {
   SECTION("should duplicate char* key") {
     obj[const_cast<char*>("hello")] = "world";
     REQUIRE(spy.log() == AllocatorLog{
-                             Allocate(sizeofString("hello")),
                              Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
                          });
   }
 
   SECTION("should duplicate char* key&value") {
     obj[const_cast<char*>("hello")] = const_cast<char*>("world");
     REQUIRE(spy.log() == AllocatorLog{
-                             Allocate(sizeofString("hello")),
                              Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
                              Allocate(sizeofString("world")),
                          });
   }
 
   SECTION("should duplicate std::string value") {
-    obj["hello"] = std::string("world");
+    obj["hello"] = "world"_s;
     REQUIRE(spy.log() == AllocatorLog{
                              Allocate(sizeofPool()),
                              Allocate(sizeofString("world")),
@@ -140,18 +141,18 @@ TEST_CASE("JsonObject::operator[]") {
   }
 
   SECTION("should duplicate std::string key") {
-    obj[std::string("hello")] = "world";
+    obj["hello"_s] = "world";
     REQUIRE(spy.log() == AllocatorLog{
-                             Allocate(sizeofString("hello")),
                              Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
                          });
   }
 
   SECTION("should duplicate std::string key&value") {
-    obj[std::string("hello")] = std::string("world");
+    obj["hello"_s] = "world"_s;
     REQUIRE(spy.log() == AllocatorLog{
-                             Allocate(sizeofString("hello")),
                              Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
                              Allocate(sizeofString("world")),
                          });
   }
@@ -159,8 +160,8 @@ TEST_CASE("JsonObject::operator[]") {
   SECTION("should duplicate a non-static JsonString key") {
     obj[JsonString("hello", JsonString::Copied)] = "world";
     REQUIRE(spy.log() == AllocatorLog{
-                             Allocate(sizeofString("hello")),
                              Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
                          });
   }
 
@@ -197,7 +198,7 @@ TEST_CASE("JsonObject::operator[]") {
 
     obj[vla] = "world";
 
-    REQUIRE(std::string("world") == obj["hello"]);
+    REQUIRE("world"_s == obj["hello"]);
   }
 
   SECTION("obj[str] = VLA") {  // issue #416
@@ -207,7 +208,7 @@ TEST_CASE("JsonObject::operator[]") {
 
     obj["hello"] = vla;
 
-    REQUIRE(std::string("world") == obj["hello"].as<const char*>());
+    REQUIRE("world"_s == obj["hello"].as<const char*>());
   }
 
   SECTION("obj.set(VLA, str)") {
@@ -217,7 +218,7 @@ TEST_CASE("JsonObject::operator[]") {
 
     obj[vla] = "world";
 
-    REQUIRE(std::string("world") == obj["hello"]);
+    REQUIRE("world"_s == obj["hello"]);
   }
 
   SECTION("obj.set(str, VLA)") {
@@ -227,7 +228,7 @@ TEST_CASE("JsonObject::operator[]") {
 
     obj["hello"].set(vla);
 
-    REQUIRE(std::string("world") == obj["hello"].as<const char*>());
+    REQUIRE("world"_s == obj["hello"].as<const char*>());
   }
 
   SECTION("obj[VLA]") {
@@ -238,7 +239,7 @@ TEST_CASE("JsonObject::operator[]") {
     deserializeJson(doc, "{\"hello\":\"world\"}");
 
     obj = doc.as<JsonObject>();
-    REQUIRE(std::string("world") == obj[vla]);
+    REQUIRE("world"_s == obj[vla]);
   }
 #endif
 
@@ -249,4 +250,18 @@ TEST_CASE("JsonObject::operator[]") {
     REQUIRE(true == obj["hello"]["world"].is<int>());
     REQUIRE(false == obj["hello"]["world"].is<bool>());
   }
+
+  SECTION("JsonVariant") {
+    obj["hello"] = "world";
+    obj["a\0b"_s] = "ABC";
+
+    doc["key1"] = "hello";
+    doc["key2"] = "a\0b"_s;
+    doc["key3"] = "foo";
+
+    REQUIRE(obj[obj["key1"]] == "world");
+    REQUIRE(obj[obj["key2"]] == "ABC");
+    REQUIRE(obj[obj["key3"]] == nullptr);
+    REQUIRE(obj[obj["key4"]] == nullptr);
+  }
 }

extras/tests/JsonObjectConst/CMakeLists.txt

@@ -3,7 +3,6 @@
 # MIT License
 
 add_executable(JsonObjectConstTests
-	containsKey.cpp
 	equals.cpp
 	isNull.cpp
 	iterator.cpp

extras/tests/JsonObjectConst/containsKey.cpp

@@ -1,32 +0,0 @@
-// ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2024, Benoit BLANCHON
-// MIT License
-
-#include <ArduinoJson.h>
-#include <catch.hpp>
-
-TEST_CASE("JsonObjectConst::containsKey()") {
-  JsonDocument doc;
-  doc["hello"] = 42;
-  auto obj = doc.as<JsonObjectConst>();
-
-  SECTION("supports const char*") {
-    REQUIRE(false == obj.containsKey("world"));
-    REQUIRE(true == obj.containsKey("hello"));
-  }
-
-  SECTION("supports std::string") {
-    REQUIRE(false == obj.containsKey(std::string("world")));
-    REQUIRE(true == obj.containsKey(std::string("hello")));
-  }
-
-#ifdef HAS_VARIABLE_LENGTH_ARRAY
-  SECTION("supports VLA") {
-    size_t i = 16;
-    char vla[i];
-    strcpy(vla, "hello");
-
-    REQUIRE(true == obj.containsKey(vla));
-  }
-#endif
-}

extras/tests/JsonObjectConst/subscript.cpp

@@ -6,10 +6,12 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("JsonObjectConst::operator[]") {
   JsonDocument doc;
   doc["hello"] = "world";
+  doc["a\0b"_s] = "ABC";
   JsonObjectConst obj = doc.as<JsonObjectConst>();
 
   SECTION("supports const char*") {
@@ -17,7 +19,8 @@ TEST_CASE("JsonObjectConst::operator[]") {
   }
 
   SECTION("supports std::string") {
-    REQUIRE(obj[std::string("hello")] == "world");  // issue #2019
+    REQUIRE(obj["hello"_s] == "world");  // issue #2019
+    REQUIRE(obj["a\0b"_s] == "ABC");
   }
 
 #if defined(HAS_VARIABLE_LENGTH_ARRAY) && \
@@ -27,7 +30,17 @@ TEST_CASE("JsonObjectConst::operator[]") {
     char vla[i];
     strcpy(vla, "hello");
 
-    REQUIRE(std::string("world") == obj[vla]);
+    REQUIRE(obj[vla] == "world"_s);
   }
 #endif
+
+  SECTION("supports JsonVariant") {
+    doc["key1"] = "hello";
+    doc["key2"] = "a\0b"_s;
+    doc["key3"] = "foo";
+    REQUIRE(obj[obj["key1"]] == "world");
+    REQUIRE(obj[obj["key2"]] == "ABC");
+    REQUIRE(obj[obj["key3"]] == nullptr);
+    REQUIRE(obj[obj["key4"]] == nullptr);
+  }
 }

extras/tests/JsonSerializer/JsonVariant.cpp

@@ -6,6 +6,8 @@
 #include <catch.hpp>
 #include <limits>
 
+#include "Literals.hpp"
+
 template <typename T>
 void check(T value, const std::string& expected) {
   JsonDocument doc;
@@ -30,42 +32,46 @@ TEST_CASE("serializeJson(JsonVariant)") {
   }
 
   SECTION("string") {
-    check(std::string("hello"), "\"hello\"");
+    check("hello"_s, "\"hello\"");
 
     SECTION("Escape quotation mark") {
-      check(std::string("hello \"world\""), "\"hello \\\"world\\\"\"");
+      check("hello \"world\""_s, "\"hello \\\"world\\\"\"");
     }
 
     SECTION("Escape reverse solidus") {
-      check(std::string("hello\\world"), "\"hello\\\\world\"");
+      check("hello\\world"_s, "\"hello\\\\world\"");
     }
 
     SECTION("Don't escape solidus") {
-      check(std::string("fifty/fifty"), "\"fifty/fifty\"");
+      check("fifty/fifty"_s, "\"fifty/fifty\"");
+    }
+
+    SECTION("Don't escape single quote") {
+      check("hello'world"_s, "\"hello'world\"");
     }
 
     SECTION("Escape backspace") {
-      check(std::string("hello\bworld"), "\"hello\\bworld\"");
+      check("hello\bworld"_s, "\"hello\\bworld\"");
     }
 
     SECTION("Escape formfeed") {
-      check(std::string("hello\fworld"), "\"hello\\fworld\"");
+      check("hello\fworld"_s, "\"hello\\fworld\"");
     }
 
     SECTION("Escape linefeed") {
-      check(std::string("hello\nworld"), "\"hello\\nworld\"");
+      check("hello\nworld"_s, "\"hello\\nworld\"");
     }
 
     SECTION("Escape carriage return") {
-      check(std::string("hello\rworld"), "\"hello\\rworld\"");
+      check("hello\rworld"_s, "\"hello\\rworld\"");
     }
 
     SECTION("Escape tab") {
-      check(std::string("hello\tworld"), "\"hello\\tworld\"");
+      check("hello\tworld"_s, "\"hello\\tworld\"");
     }
 
     SECTION("NUL char") {
-      check(std::string("hello\0world", 11), "\"hello\\u0000world\"");
+      check("hello\0world"_s, "\"hello\\u0000world\"");
     }
   }
 
@@ -74,13 +80,18 @@ TEST_CASE("serializeJson(JsonVariant)") {
   }
 
   SECTION("SerializedValue<std::string>") {
-    check(serialized(std::string("[1,2]")), "[1,2]");
+    check(serialized("[1,2]"_s), "[1,2]");
   }
 
   SECTION("Double") {
     check(3.1415927, "3.1415927");
   }
 
+  SECTION("Float") {
+    REQUIRE(sizeof(float) == 4);
+    check(3.1415927f, "3.141593");
+  }
+
   SECTION("Zero") {
     check(0, "0");
   }

extras/tests/JsonSerializer/std_string.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 TEST_CASE("serialize JsonArray to std::string") {
   JsonDocument doc;
   JsonArray array = doc.to<JsonArray>();
@@ -48,7 +50,7 @@ TEST_CASE("serialize JsonObject to std::string") {
 
 TEST_CASE("serialize an std::string containing a NUL") {
   JsonDocument doc;
-  doc.set(std::string("hello\0world", 11));
+  doc.set("hello\0world"_s);
 
   std::string json = "erase me";
   serializeJson(doc, json);

extras/tests/JsonVariant/CMakeLists.txt

@@ -7,7 +7,6 @@ add_executable(JsonVariantTests
 	as.cpp
 	clear.cpp
 	compare.cpp
-	containsKey.cpp
 	converters.cpp
 	copy.cpp
 	is.cpp

extras/tests/JsonVariant/add.cpp

@@ -6,6 +6,9 @@
 #include <stdint.h>
 #include <catch.hpp>
 
+#include "Allocators.hpp"
+#include "Literals.hpp"
+
 TEST_CASE("JsonVariant::add(T)") {
   JsonDocument doc;
   JsonVariant var = doc.to<JsonVariant>();
@@ -23,7 +26,7 @@ TEST_CASE("JsonVariant::add(T)") {
   }
 
   SECTION("add std::string to new variant") {
-    var.add(std::string("hello"));
+    var.add("hello"_s);
 
     REQUIRE(var.as<std::string>() == "[\"hello\"]");
   }
@@ -43,6 +46,18 @@ TEST_CASE("JsonVariant::add(T)") {
 
     REQUIRE(var.as<std::string>() == "{\"val\":123}");
   }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("supports VLAs") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "hello");
+
+    var.add(vla);
+
+    REQUIRE(var.as<std::string>() == "[\"hello\"]");
+  }
+#endif
 }
 
 TEST_CASE("JsonVariant::add<T>()") {
@@ -56,15 +71,58 @@ TEST_CASE("JsonVariant::add<T>()") {
     REQUIRE(doc.as<std::string>() == "[[1,2]]");
   }
 
-  SECTION("JsonObject") {
-    JsonObject object = var.add<JsonObject>();
-    object["hello"] = "world";
-    REQUIRE(doc.as<std::string>() == "[{\"hello\":\"world\"}]");
-  }
-
   SECTION("JsonVariant") {
     JsonVariant variant = var.add<JsonVariant>();
     variant.set(42);
     REQUIRE(doc.as<std::string>() == "[42]");
   }
 }
+
+TEST_CASE("JsonObject::add(JsonObject) ") {
+  JsonDocument doc1;
+  doc1["hello"_s] = "world"_s;
+
+  TimebombAllocator allocator(10);
+  SpyingAllocator spy(&allocator);
+  JsonDocument doc2(&spy);
+  JsonVariant variant = doc2.to<JsonVariant>();
+
+  SECTION("success") {
+    bool result = variant.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == true);
+    REQUIRE(doc2.as<std::string>() == "[{\"hello\":\"world\"}]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
+                             Allocate(sizeofString("world")),
+                         });
+  }
+
+  SECTION("partial failure") {  // issue #2081
+    allocator.setCountdown(2);
+
+    bool result = variant.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == false);
+    REQUIRE(doc2.as<std::string>() == "[]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             Allocate(sizeofString("hello")),
+                             AllocateFail(sizeofString("world")),
+                             Deallocate(sizeofString("hello")),
+                         });
+  }
+
+  SECTION("complete failure") {
+    allocator.setCountdown(0);
+
+    bool result = variant.add(doc1.as<JsonObject>());
+
+    REQUIRE(result == false);
+    REQUIRE(doc2.as<std::string>() == "[]");
+    REQUIRE(spy.log() == AllocatorLog{
+                             AllocateFail(sizeofPool()),
+                         });
+  }
+}

extras/tests/JsonVariant/as.cpp

@@ -6,6 +6,8 @@
 #include <stdint.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 namespace my {
 using ArduinoJson::detail::isinf;
 }  // namespace my
@@ -25,17 +27,36 @@ TEST_CASE("JsonVariant::as()") {
     REQUIRE(0 == variant.as<const char*>());
     REQUIRE("null" == variant.as<std::string>());
     REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
   }
 
-  SECTION("set(4.2)") {
+  SECTION("set(float)") {
+    variant.set(4.2f);
+
+    REQUIRE(variant.as<bool>());
+    REQUIRE(0 == variant.as<const char*>());
+    REQUIRE(variant.as<std::string>() == "4.2");
+    REQUIRE(variant.as<long>() == 4L);
+    REQUIRE(variant.as<float>() == 4.2f);
+    REQUIRE(variant.as<unsigned>() == 4U);
+    REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
+  }
+
+  SECTION("set(double)") {
     variant.set(4.2);
 
     REQUIRE(variant.as<bool>());
     REQUIRE(0 == variant.as<const char*>());
     REQUIRE(variant.as<std::string>() == "4.2");
     REQUIRE(variant.as<long>() == 4L);
+    REQUIRE(variant.as<double>() == 4.2);
     REQUIRE(variant.as<unsigned>() == 4U);
     REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
   }
 
   SECTION("set(0.0)") {
@@ -44,6 +65,8 @@ TEST_CASE("JsonVariant::as()") {
     REQUIRE(variant.as<bool>() == false);
     REQUIRE(variant.as<long>() == 0L);
     REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
   }
 
   SECTION("set(false)") {
@@ -54,6 +77,8 @@ TEST_CASE("JsonVariant::as()") {
     REQUIRE(variant.as<long>() == 0L);
     REQUIRE(variant.as<std::string>() == "false");
     REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
   }
 
   SECTION("set(true)") {
@@ -64,43 +89,66 @@ TEST_CASE("JsonVariant::as()") {
     REQUIRE(variant.as<long>() == 1L);
     REQUIRE(variant.as<std::string>() == "true");
     REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
   }
 
-  SECTION("set(42)") {
-    variant.set(42);
+  SECTION("set(uint32_t)") {
+    variant.set(4294967295U);
 
     REQUIRE(variant.as<bool>() == true);
-    REQUIRE(variant.as<double>() == 42.0);
-    REQUIRE(variant.as<int>() == 42);
-    REQUIRE(variant.as<unsigned int>() == 42U);  // issue #1601
-    REQUIRE(variant.as<std::string>() == "42");
+    REQUIRE(variant.as<double>() == 4294967295.0);
+    REQUIRE(variant.as<int32_t>() == 0);
+    REQUIRE(variant.as<uint32_t>() == 4294967295U);
+    REQUIRE(variant.as<uint64_t>() == 4294967295U);
+    REQUIRE(variant.as<std::string>() == "4294967295");
     REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
   }
 
-  SECTION("set(42L)") {
-    variant.set(42L);
+  SECTION("set(int32_t)") {
+    variant.set(-2147483648LL);
 
     REQUIRE(variant.as<bool>() == true);
-    REQUIRE(variant.as<double>() == 42.0);
-    REQUIRE(variant.as<std::string>() == "42");
+    REQUIRE(variant.as<double>() == -2147483648LL);
+    REQUIRE(variant.as<int32_t>() == -2147483648LL);
+    REQUIRE(variant.as<int64_t>() == -2147483648LL);
+    REQUIRE(variant.as<uint32_t>() == 0);
+    REQUIRE(variant.as<uint64_t>() == 0);
+    REQUIRE(variant.as<std::string>() == "-2147483648");
     REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
   }
 
-  SECTION("set(-42L)") {
-    variant.set(-42L);
-
-    REQUIRE(variant.as<double>() == -42.0);
-    REQUIRE(variant.as<std::string>() == "-42");
-    REQUIRE(variant.as<JsonString>().isNull());
-  }
-
-  SECTION("set(42UL)") {
-    variant.set(42UL);
+  SECTION("set(uint64_t)") {
+    variant.set(4294967296U);
 
     REQUIRE(variant.as<bool>() == true);
-    REQUIRE(variant.as<double>() == 42.0);
-    REQUIRE(variant.as<std::string>() == "42");
+    REQUIRE(variant.as<double>() == 4294967296.0);
+    REQUIRE(variant.as<int32_t>() == 0);
+    REQUIRE(variant.as<uint32_t>() == 0);
+    REQUIRE(variant.as<uint64_t>() == 4294967296U);
+    REQUIRE(variant.as<std::string>() == "4294967296");
     REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
+  }
+
+  SECTION("set(int64_t)") {
+    variant.set(-2147483649LL);
+
+    REQUIRE(variant.as<bool>() == true);
+    REQUIRE(variant.as<double>() == -2147483649LL);
+    REQUIRE(variant.as<int32_t>() == 0);
+    REQUIRE(variant.as<int64_t>() == -2147483649LL);
+    REQUIRE(variant.as<uint32_t>() == 0);
+    REQUIRE(variant.as<uint64_t>() == 0);
+    REQUIRE(variant.as<std::string>() == "-2147483649");
+    REQUIRE(variant.as<JsonString>().isNull());
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
   }
 
   SECTION("set(0L)") {
@@ -144,20 +192,20 @@ TEST_CASE("JsonVariant::as()") {
 
     REQUIRE(variant.as<bool>() == true);
     REQUIRE(variant.as<long>() == 0L);
-    REQUIRE(variant.as<const char*>() == std::string("hello"));
-    REQUIRE(variant.as<const char*>() == std::string("hello"));
-    REQUIRE(variant.as<std::string>() == std::string("hello"));
+    REQUIRE(variant.as<const char*>() == "hello"_s);
+    REQUIRE(variant.as<const char*>() == "hello"_s);
+    REQUIRE(variant.as<std::string>() == "hello"_s);
     REQUIRE(variant.as<JsonString>() == "hello");
   }
 
   SECTION("set(std::string(\"4.2\"))") {
-    variant.set(std::string("4.2"));
+    variant.set("4.2"_s);
 
     REQUIRE(variant.as<bool>() == true);
     REQUIRE(variant.as<long>() == 4L);
-    REQUIRE(variant.as<double>() == 4.2);
-    REQUIRE(variant.as<const char*>() == std::string("4.2"));
-    REQUIRE(variant.as<std::string>() == std::string("4.2"));
+    REQUIRE(variant.as<double>() == Approx(4.2));
+    REQUIRE(variant.as<const char*>() == "4.2"_s);
+    REQUIRE(variant.as<std::string>() == "4.2"_s);
     REQUIRE(variant.as<JsonString>() == "4.2");
     REQUIRE(variant.as<JsonString>().isLinked() == false);
   }
@@ -199,6 +247,13 @@ TEST_CASE("JsonVariant::as()") {
     REQUIRE(variant.as<JsonString>().isNull());
   }
 
+  SECTION("set(serialized(\"hello\"))") {
+    variant.set(serialized("hello"));
+
+    REQUIRE(variant.as<MsgPackBinary>().data() == nullptr);
+    REQUIRE(variant.as<MsgPackExtension>().data() == nullptr);
+  }
+
   SECTION("to<JsonObject>()") {
     JsonObject obj = variant.to<JsonObject>();
     obj["key"] = "value";
@@ -208,13 +263,13 @@ TEST_CASE("JsonVariant::as()") {
     }
 
     SECTION("as<std::string>()") {
-      REQUIRE(variant.as<std::string>() == std::string("{\"key\":\"value\"}"));
+      REQUIRE(variant.as<std::string>() == "{\"key\":\"value\"}"_s);
     }
 
     SECTION("ObjectAsJsonObject") {
       JsonObject o = variant.as<JsonObject>();
       REQUIRE(o.size() == 1);
-      REQUIRE(o["key"] == std::string("value"));
+      REQUIRE(o["key"] == "value"_s);
     }
   }
 
@@ -228,7 +283,7 @@ TEST_CASE("JsonVariant::as()") {
     }
 
     SECTION("as<std::string>()") {
-      REQUIRE(variant.as<std::string>() == std::string("[4,2]"));
+      REQUIRE(variant.as<std::string>() == "[4,2]"_s);
     }
 
     SECTION("as<JsonArray>()") {
@@ -245,7 +300,7 @@ TEST_CASE("JsonVariant::as()") {
     REQUIRE(variant.as<long long>() == -9223372036854775807 - 1);
   }
 
-  SECTION("Biggerst int64 positive") {
+  SECTION("Biggest int64 positive") {
     variant.set("9223372036854775807");
     REQUIRE(variant.as<long long>() == 9223372036854775807);
   }

extras/tests/JsonVariant/clear.cpp

@@ -7,6 +7,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 TEST_CASE("JsonVariant::clear()") {
   SpyingAllocator spy;
@@ -28,7 +29,7 @@ TEST_CASE("JsonVariant::clear()") {
   }
 
   SECTION("releases owned string") {
-    var.set(std::string("hello"));
+    var.set("hello"_s);
     var.clear();
 
     REQUIRE(spy.log() == AllocatorLog{

extras/tests/JsonVariant/compare.cpp

@@ -113,6 +113,42 @@ TEST_CASE("Compare JsonVariant with JsonVariant") {
     CHECK_FALSE(a == b);
   }
 
+  SECTION("MsgPackBinary('abc') vs MsgPackBinary('abc')") {
+    a.set(MsgPackBinary("abc", 4));
+    b.set(MsgPackBinary("abc", 4));
+
+    CHECK(a == b);
+    CHECK(a <= b);
+    CHECK(a >= b);
+    CHECK_FALSE(a != b);
+    CHECK_FALSE(a < b);
+    CHECK_FALSE(a > b);
+  }
+
+  SECTION("MsgPackBinary('abc') vs MsgPackBinary('bcd')") {
+    a.set(MsgPackBinary("abc", 4));
+    b.set(MsgPackBinary("bcd", 4));
+
+    CHECK(a != b);
+    CHECK(a < b);
+    CHECK(a <= b);
+    CHECK_FALSE(a == b);
+    CHECK_FALSE(a > b);
+    CHECK_FALSE(a >= b);
+  }
+
+  SECTION("MsgPackBinary('bcd') vs MsgPackBinary('abc')") {
+    a.set(MsgPackBinary("bcd", 4));
+    b.set(MsgPackBinary("abc", 4));
+
+    CHECK(a != b);
+    CHECK(a > b);
+    CHECK(a >= b);
+    CHECK_FALSE(a < b);
+    CHECK_FALSE(a <= b);
+    CHECK_FALSE(a == b);
+  }
+
   SECTION("false vs true") {
     a.set(false);
     b.set(true);

extras/tests/JsonVariant/containsKey.cpp

@@ -1,26 +0,0 @@
-// ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2024, Benoit BLANCHON
-// MIT License
-
-#include <ArduinoJson.h>
-#include <stdint.h>
-#include <catch.hpp>
-
-TEST_CASE("JsonVariant::containsKey()") {
-  JsonDocument doc;
-  JsonVariant var = doc.to<JsonVariant>();
-
-  SECTION("containsKey(const char*)") {
-    var["hello"] = "world";
-
-    REQUIRE(var.containsKey("hello") == true);
-    REQUIRE(var.containsKey("world") == false);
-  }
-
-  SECTION("containsKey(std::string)") {
-    var["hello"] = "world";
-
-    REQUIRE(var.containsKey(std::string("hello")) == true);
-    REQUIRE(var.containsKey(std::string("world")) == false);
-  }
-}

extras/tests/JsonVariant/converters.cpp

@@ -140,15 +140,3 @@ TEST_CASE("Custom converter with specialization") {
     REQUIRE(doc["value"]["imag"] == 3);
   }
 }
-
-TEST_CASE("ConverterNeedsWriteableRef") {
-  using namespace ArduinoJson::detail;
-  CHECK(ConverterNeedsWriteableRef<int>::value == false);
-  CHECK(ConverterNeedsWriteableRef<float>::value == false);
-  CHECK(ConverterNeedsWriteableRef<JsonVariant>::value == true);
-  CHECK(ConverterNeedsWriteableRef<JsonVariantConst>::value == false);
-  CHECK(ConverterNeedsWriteableRef<JsonObject>::value == true);
-  CHECK(ConverterNeedsWriteableRef<JsonObjectConst>::value == false);
-  CHECK(ConverterNeedsWriteableRef<JsonArray>::value == true);
-  CHECK(ConverterNeedsWriteableRef<JsonArrayConst>::value == false);
-}

extras/tests/JsonVariant/copy.cpp

@@ -6,6 +6,8 @@
 #include <catch.hpp>
 #include "Allocators.hpp"
 
+#include "Literals.hpp"
+
 TEST_CASE("JsonVariant::set(JsonVariant)") {
   KillswitchAllocator killswitch;
   SpyingAllocator spyingAllocator(&killswitch);
@@ -72,7 +74,7 @@ TEST_CASE("JsonVariant::set(JsonVariant)") {
   }
 
   SECTION("stores std::string by copy") {
-    var1.set(std::string("hello!!"));
+    var1.set("hello!!"_s);
     spyingAllocator.clearLog();
 
     var2.set(var1);
@@ -106,7 +108,7 @@ TEST_CASE("JsonVariant::set(JsonVariant)") {
   }
 
   SECTION("stores Serialized<std::string> by copy") {
-    var1.set(serialized(std::string("hello!!")));
+    var1.set(serialized("hello!!"_s));
     spyingAllocator.clearLog();
 
     var2.set(var1);
@@ -117,7 +119,7 @@ TEST_CASE("JsonVariant::set(JsonVariant)") {
   }
 
   SECTION("fails gracefully if raw string allocation fails") {
-    var1.set(serialized(std::string("hello!!")));
+    var1.set(serialized("hello!!"_s));
     killswitch.on();
     spyingAllocator.clearLog();
 

extras/tests/JsonVariant/remove.cpp

@@ -7,6 +7,7 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofArray;
 
@@ -15,9 +16,9 @@ TEST_CASE("JsonVariant::remove(int)") {
   JsonDocument doc(&spy);
 
   SECTION("release top level strings") {
-    doc.add(std::string("hello"));
-    doc.add(std::string("hello"));
-    doc.add(std::string("world"));
+    doc.add("hello"_s);
+    doc.add("hello"_s);
+    doc.add("world"_s);
 
     JsonVariant var = doc.as<JsonVariant>();
     REQUIRE(var.as<std::string>() == "[\"hello\",\"hello\",\"world\"]");
@@ -43,7 +44,7 @@ TEST_CASE("JsonVariant::remove(int)") {
   }
 
   SECTION("release strings in nested array") {
-    doc[0][0] = std::string("hello");
+    doc[0][0] = "hello"_s;
 
     JsonVariant var = doc.as<JsonVariant>();
     REQUIRE(var.as<std::string>() == "[[\"hello\"]]");
@@ -77,7 +78,51 @@ TEST_CASE("JsonVariant::remove(std::string)") {
   var["a"] = 1;
   var["b"] = 2;
 
-  var.remove(std::string("b"));
+  var.remove("b"_s);
 
   REQUIRE(var.as<std::string>() == "{\"a\":1}");
 }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+TEST_CASE("JsonVariant::remove(VLA)") {
+  JsonDocument doc;
+  JsonVariant var = doc.to<JsonVariant>();
+
+  var["a"] = 1;
+  var["b"] = 2;
+  size_t i = 16;
+  char vla[i];
+  strcpy(vla, "b");
+
+  var.remove("b"_s);
+
+  REQUIRE(var.as<std::string>() == "{\"a\":1}");
+}
+#endif
+
+TEST_CASE("JsonVariant::remove(JsonVariant) from object") {
+  JsonDocument doc;
+  JsonVariant var = doc.to<JsonVariant>();
+
+  var["a"] = "a";
+  var["b"] = 2;
+  var["c"] = "b";
+
+  var.remove(var["c"]);
+
+  REQUIRE(var.as<std::string>() == "{\"a\":\"a\",\"c\":\"b\"}");
+}
+
+TEST_CASE("JsonVariant::remove(JsonVariant) from array") {
+  JsonDocument doc;
+  JsonVariant var = doc.to<JsonVariant>();
+
+  var[0] = 3;
+  var[1] = 2;
+  var[2] = 1;
+
+  var.remove(var[2]);
+  var.remove(var[3]);  // noop
+
+  REQUIRE(var.as<std::string>() == "[3,1]");
+}

extras/tests/JsonVariant/set.cpp

@@ -6,13 +6,15 @@
 #include <catch.hpp>
 
 #include "Allocators.hpp"
+#include "Literals.hpp"
 
 using ArduinoJson::detail::sizeofObject;
 
 enum ErrorCode { ERROR_01 = 1, ERROR_10 = 10 };
 
 TEST_CASE("JsonVariant::set() when there is enough memory") {
-  JsonDocument doc;
+  SpyingAllocator spy;
+  JsonDocument doc(&spy);
   JsonVariant variant = doc.to<JsonVariant>();
 
   SECTION("const char*") {
@@ -24,6 +26,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant == "world");  // stores by pointer
+    REQUIRE(spy.log() == AllocatorLog{});
   }
 
   SECTION("(const char*)0") {
@@ -31,6 +34,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant.isNull());
+    REQUIRE(spy.log() == AllocatorLog{});
   }
 
   SECTION("char*") {
@@ -42,6 +46,9 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant == "hello");  // stores by copy
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("hello")),
+                         });
   }
 
   SECTION("(char*)0") {
@@ -49,6 +56,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant.isNull());
+    REQUIRE(spy.log() == AllocatorLog{});
   }
 
   SECTION("unsigned char*") {
@@ -60,6 +68,9 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant == "hello");  // stores by copy
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("hello")),
+                         });
   }
 
   SECTION("signed char*") {
@@ -71,6 +82,9 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant == "hello");  // stores by copy
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("hello")),
+                         });
   }
 
 #ifdef HAS_VARIABLE_LENGTH_ARRAY
@@ -84,6 +98,9 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant == "hello");  // stores by copy
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("hello")),
+                         });
   }
 #endif
 
@@ -96,6 +113,9 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant == "hello");  // stores by copy
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("hello")),
+                         });
   }
 
   SECTION("static JsonString") {
@@ -107,6 +127,7 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant == "world");  // stores by pointer
+    REQUIRE(spy.log() == AllocatorLog{});
   }
 
   SECTION("non-static JsonString") {
@@ -118,6 +139,9 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
 
     REQUIRE(result == true);
     REQUIRE(variant == "hello");  // stores by copy
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofString("hello")),
+                         });
   }
 
   SECTION("enum") {
@@ -128,6 +152,89 @@ TEST_CASE("JsonVariant::set() when there is enough memory") {
     REQUIRE(result == true);
     REQUIRE(variant.is<int>() == true);
     REQUIRE(variant.as<int>() == 10);
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+
+  SECTION("float") {
+    bool result = variant.set(1.2f);
+
+    REQUIRE(result == true);
+    REQUIRE(variant.is<float>() == true);
+    REQUIRE(variant.as<float>() == 1.2f);
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+
+  SECTION("double") {
+    bool result = variant.set(1.2);
+    doc.shrinkToFit();
+
+    REQUIRE(result == true);
+    REQUIRE(variant.is<double>() == true);
+    REQUIRE(variant.as<double>() == 1.2);
+    REQUIRE(spy.log() ==
+            AllocatorLog{
+                Allocate(sizeofPool()),
+                Reallocate(sizeofPool(), sizeofPool(1)),  // one extension slot
+            });
+  }
+
+  SECTION("int32_t") {
+    bool result = variant.set(int32_t(42));
+
+    REQUIRE(result == true);
+    REQUIRE(variant.is<int32_t>() == true);
+    REQUIRE(variant.as<int32_t>() == 42);
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+
+  SECTION("int64_t") {
+    bool result = variant.set(int64_t(-2147483649LL));
+    doc.shrinkToFit();
+
+    REQUIRE(result == true);
+    REQUIRE(variant.is<int64_t>() == true);
+    REQUIRE(variant.as<int64_t>() == -2147483649LL);
+    REQUIRE(spy.log() ==
+            AllocatorLog{
+                Allocate(sizeofPool()),
+                Reallocate(sizeofPool(), sizeofPool(1)),  // one extension slot
+            });
+  }
+
+  SECTION("uint32_t") {
+    bool result = variant.set(uint32_t(42));
+
+    REQUIRE(result == true);
+    REQUIRE(variant.is<uint32_t>() == true);
+    REQUIRE(variant.as<uint32_t>() == 42);
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+
+  SECTION("uint64_t") {
+    bool result = variant.set(uint64_t(4294967296));
+    doc.shrinkToFit();
+
+    REQUIRE(result == true);
+    REQUIRE(variant.is<uint64_t>() == true);
+    REQUIRE(variant.as<uint64_t>() == 4294967296);
+    REQUIRE(spy.log() ==
+            AllocatorLog{
+                Allocate(sizeofPool()),
+                Reallocate(sizeofPool(), sizeofPool(1)),  // one extension slot
+            });
+  }
+
+  SECTION("JsonDocument") {
+    JsonDocument doc1;
+    doc1["hello"] = "world";
+
+    // Should copy the doc
+    variant.set(doc1);
+    doc1.clear();
+
+    std::string json;
+    serializeJson(doc, json);
+    REQUIRE(json == "{\"hello\":\"world\"}");
   }
 }
 
@@ -137,14 +244,14 @@ TEST_CASE("JsonVariant::set() with not enough memory") {
   JsonVariant v = doc.to<JsonVariant>();
 
   SECTION("std::string") {
-    bool result = v.set(std::string("hello world!!"));
+    bool result = v.set("hello world!!"_s);
 
     REQUIRE(result == false);
     REQUIRE(v.isNull());
   }
 
   SECTION("Serialized<std::string>") {
-    bool result = v.set(serialized(std::string("hello world!!")));
+    bool result = v.set(serialized("hello world!!"_s));
 
     REQUIRE(result == false);
     REQUIRE(v.isNull());
@@ -157,28 +264,54 @@ TEST_CASE("JsonVariant::set() with not enough memory") {
     REQUIRE(result == false);
     REQUIRE(v.isNull());
   }
-}
 
-TEST_CASE("JsonVariant::set(JsonDocument)") {
-  JsonDocument doc1;
-  doc1["hello"] = "world";
+  SECTION("float") {
+    bool result = v.set(1.2f);
 
-  JsonDocument doc2;
-  JsonVariant v = doc2.to<JsonVariant>();
+    REQUIRE(result == true);
+    REQUIRE(v.is<float>());
+  }
 
-  // Should copy the doc
-  v.set(doc1);
-  doc1.clear();
+  SECTION("double") {
+    bool result = v.set(1.2);
 
-  std::string json;
-  serializeJson(doc2, json);
-  REQUIRE(json == "{\"hello\":\"world\"}");
+    REQUIRE(result == false);
+    REQUIRE(v.isNull());
+  }
+
+  SECTION("int32_t") {
+    bool result = v.set(-42);
+
+    REQUIRE(result == true);
+    REQUIRE(v.is<int32_t>());
+  }
+
+  SECTION("int64_t") {
+    bool result = v.set(-2147483649LL);
+
+    REQUIRE(result == false);
+    REQUIRE(v.isNull());
+  }
+
+  SECTION("uint32_t") {
+    bool result = v.set(42);
+
+    REQUIRE(result == true);
+    REQUIRE(v.is<uint32_t>());
+  }
+
+  SECTION("uint64_t") {
+    bool result = v.set(4294967296U);
+
+    REQUIRE(result == false);
+    REQUIRE(v.isNull());
+  }
 }
 
 TEST_CASE("JsonVariant::set() releases the previous value") {
   SpyingAllocator spy;
   JsonDocument doc(&spy);
-  doc["hello"] = std::string("world");
+  doc["hello"] = "world"_s;
   spy.clearLog();
 
   JsonVariant v = doc["hello"];
@@ -219,3 +352,34 @@ TEST_CASE("JsonVariant::set() releases the previous value") {
                          });
   }
 }
+
+TEST_CASE("JsonVariant::set() reuses extension slot") {
+  SpyingAllocator spy;
+  JsonDocument doc(&spy);
+  JsonVariant variant = doc.to<JsonVariant>();
+
+  variant.set(1.2);
+  doc.shrinkToFit();
+  spy.clearLog();
+
+  SECTION("double") {
+    bool result = variant.set(3.4);
+
+    REQUIRE(result == true);
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+
+  SECTION("int64_t") {
+    bool result = variant.set(-2147483649LL);
+
+    REQUIRE(result == true);
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+
+  SECTION("uint64_t") {
+    bool result = variant.set(4294967296U);
+
+    REQUIRE(result == true);
+    REQUIRE(spy.log() == AllocatorLog{});
+  }
+}

extras/tests/JsonVariant/stl_containers.cpp

@@ -99,7 +99,7 @@ TEST_CASE("vector<int>") {
 }
 
 TEST_CASE("array<int, 2>") {
-  typedef std::array<int, 2> array_type;
+  using array_type = std::array<int, 2>;
 
   SECTION("toJson") {
     array_type v;

extras/tests/JsonVariant/subscript.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 TEST_CASE("JsonVariant::operator[]") {
   JsonDocument doc;
   JsonVariant var = doc.to<JsonVariant>();
@@ -31,9 +33,9 @@ TEST_CASE("JsonVariant::operator[]") {
 
       REQUIRE(2 == var.size());
       var[0].as<std::string>();
-      // REQUIRE(std::string("element at index 0") == );
-      REQUIRE(std::string("element at index 1") == var[1]);
-      REQUIRE(std::string("element at index 0") ==
+      // REQUIRE("element at index 0"_s == );
+      REQUIRE("element at index 1"_s == var[1]);
+      REQUIRE("element at index 0"_s ==
               var[static_cast<unsigned char>(0)]);  // issue #381
       REQUIRE(var[666].isNull());
       REQUIRE(var[3].isNull());
@@ -46,7 +48,7 @@ TEST_CASE("JsonVariant::operator[]") {
       var[1] = "world";
 
       REQUIRE(var.size() == 2);
-      REQUIRE(std::string("world") == var[1]);
+      REQUIRE("world"_s == var[1]);
     }
 
     SECTION("set value in a nested object") {
@@ -56,7 +58,7 @@ TEST_CASE("JsonVariant::operator[]") {
 
       REQUIRE(1 == var.size());
       REQUIRE(1 == var[0].size());
-      REQUIRE(std::string("world") == var[0]["hello"]);
+      REQUIRE("world"_s == var[0]["hello"]);
     }
 
     SECTION("variant[0] when variant contains an integer") {
@@ -67,6 +69,15 @@ TEST_CASE("JsonVariant::operator[]") {
       REQUIRE(var.is<int>());
       REQUIRE(var.as<int>() == 123);
     }
+
+    SECTION("use JsonVariant as index") {
+      array.add("A");
+      array.add("B");
+      array.add(1);
+
+      REQUIRE(var[var[2]] == "B");
+      REQUIRE(var[var[3]].isNull());
+    }
   }
 
   SECTION("The JsonVariant is a JsonObject") {
@@ -77,8 +88,8 @@ TEST_CASE("JsonVariant::operator[]") {
       object["b"] = "element at key \"b\"";
 
       REQUIRE(2 == var.size());
-      REQUIRE(std::string("element at key \"a\"") == var["a"]);
-      REQUIRE(std::string("element at key \"b\"") == var["b"]);
+      REQUIRE("element at key \"a\""_s == var["a"]);
+      REQUIRE("element at key \"b\""_s == var["b"]);
       REQUIRE(var["c"].isNull());
       REQUIRE(var[0].isNull());
     }
@@ -87,7 +98,7 @@ TEST_CASE("JsonVariant::operator[]") {
       var["hello"] = "world";
 
       REQUIRE(1 == var.size());
-      REQUIRE(std::string("world") == var["hello"]);
+      REQUIRE("world"_s == var["hello"]);
     }
 
     SECTION("set value, key is a char[]") {
@@ -96,13 +107,29 @@ TEST_CASE("JsonVariant::operator[]") {
       key[0] = '!';  // make sure the key is duplicated
 
       REQUIRE(1 == var.size());
-      REQUIRE(std::string("world") == var["hello"]);
+      REQUIRE("world"_s == var["hello"]);
     }
 
     SECTION("var[key].to<JsonArray>()") {
       JsonArray arr = var["hello"].to<JsonArray>();
       REQUIRE(arr.isNull() == false);
     }
+
+    SECTION("use JsonVariant as key") {
+      object["a"] = "A";
+      object["ab"] = "AB";
+      object["ab\0c"_s] = "ABC";
+      object["key1"] = "a";
+      object["key2"] = "ab";
+      object["key3"] = "ab\0c"_s;
+      object["key4"] = "foo";
+
+      REQUIRE(var[var["key1"]] == "A");
+      REQUIRE(var[var["key2"]] == "AB");
+      REQUIRE(var[var["key3"]] == "ABC");
+      REQUIRE(var[var["key4"]].isNull());
+      REQUIRE(var[var["key5"]].isNull());
+    }
   }
 
 #if defined(HAS_VARIABLE_LENGTH_ARRAY) && \
@@ -115,7 +142,7 @@ TEST_CASE("JsonVariant::operator[]") {
     deserializeJson(doc, "{\"hello\":\"world\"}");
     JsonVariant variant = doc.as<JsonVariant>();
 
-    REQUIRE(std::string("world") == variant[vla]);
+    REQUIRE("world"_s == variant[vla]);
   }
 
   SECTION("key is a VLA, const JsonVariant") {
@@ -126,7 +153,7 @@ TEST_CASE("JsonVariant::operator[]") {
     deserializeJson(doc, "{\"hello\":\"world\"}");
     const JsonVariant variant = doc.as<JsonVariant>();
 
-    REQUIRE(std::string("world") == variant[vla]);
+    REQUIRE("world"_s == variant[vla]);
   }
 #endif
 }

extras/tests/JsonVariant/unbound.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 TEST_CASE("Unbound JsonVariant") {
   JsonVariant variant;
 
@@ -21,6 +23,10 @@ TEST_CASE("Unbound JsonVariant") {
     CHECK(variant.as<JsonObject>().isNull());
     CHECK(variant.as<JsonObjectConst>().isNull());
     CHECK(variant.as<JsonString>().isNull());
+    CHECK(variant.as<MsgPackBinary>().data() == nullptr);
+    CHECK(variant.as<MsgPackBinary>().size() == 0);
+    CHECK(variant.as<MsgPackExtension>().data() == nullptr);
+    CHECK(variant.as<MsgPackExtension>().size() == 0);
   }
 
   SECTION("is<T>()") {
@@ -44,8 +50,10 @@ TEST_CASE("Unbound JsonVariant") {
     CHECK_FALSE(variant.set(42L));
     CHECK_FALSE(variant.set(42U));
     CHECK_FALSE(variant.set(serialized("42")));
-    CHECK_FALSE(variant.set(serialized(std::string("42"))));
+    CHECK_FALSE(variant.set(serialized("42"_s)));
     CHECK_FALSE(variant.set(true));
+    CHECK_FALSE(variant.set(MsgPackBinary("hello", 5)));
+    CHECK_FALSE(variant.set(MsgPackExtension(1, "hello", 5)));
   }
 
   SECTION("add()") {
@@ -62,11 +70,7 @@ TEST_CASE("Unbound JsonVariant") {
     CHECK(variant["key"].isNull());
     CHECK_FALSE(variant[0].set(1));
     CHECK_FALSE(variant["key"].set(1));
-    CHECK_FALSE(variant[std::string("key")].set(1));
-  }
-
-  SECTION("containsKey()") {
-    CHECK_FALSE(variant.containsKey("hello"));
+    CHECK_FALSE(variant["key"_s].set(1));
   }
 
   SECTION("remove()") {

extras/tests/JsonVariantConst/CMakeLists.txt

@@ -4,7 +4,6 @@
 
 add_executable(JsonVariantConstTests
 	as.cpp
-	containsKey.cpp
 	is.cpp
 	isnull.cpp
 	nesting.cpp

extras/tests/JsonVariantConst/as.cpp

@@ -6,6 +6,8 @@
 #include <stdint.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 TEST_CASE("JsonVariantConst::as<T>()") {
   JsonDocument doc;
   JsonVariantConst var = doc.to<JsonVariant>();
@@ -14,6 +16,27 @@ TEST_CASE("JsonVariantConst::as<T>()") {
 
   REQUIRE(var.as<bool>() == true);
   REQUIRE(var.as<long>() == 0L);
-  REQUIRE(var.as<const char*>() == std::string("hello"));
-  REQUIRE(var.as<std::string>() == std::string("hello"));
+  REQUIRE(var.as<const char*>() == "hello"_s);
+  REQUIRE(var.as<std::string>() == "hello"_s);
+}
+
+TEST_CASE("Invalid conversions") {
+  using namespace ArduinoJson::detail;
+
+  JsonVariantConst variant;
+
+  CHECK(is_same<decltype(variant.as<int>()), int>::value);
+  CHECK(is_same<decltype(variant.as<float>()), float>::value);
+  CHECK(is_same<decltype(variant.as<JsonVariantConst>()),
+                JsonVariantConst>::value);
+  CHECK(
+      is_same<decltype(variant.as<JsonObjectConst>()), JsonObjectConst>::value);
+  CHECK(is_same<decltype(variant.as<JsonArrayConst>()), JsonArrayConst>::value);
+
+  CHECK(is_same<decltype(variant.as<JsonVariant>()),
+                InvalidConversion<JsonVariantConst, JsonVariant>>::value);
+  CHECK(is_same<decltype(variant.as<JsonObject>()),
+                InvalidConversion<JsonVariantConst, JsonObject>>::value);
+  CHECK(is_same<decltype(variant.as<JsonArray>()),
+                InvalidConversion<JsonVariantConst, JsonArray>>::value);
 }

extras/tests/JsonVariantConst/containsKey.cpp

@@ -1,33 +0,0 @@
-// ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2024, Benoit BLANCHON
-// MIT License
-
-#include <ArduinoJson.h>
-#include <stdint.h>
-#include <catch.hpp>
-
-TEST_CASE("JsonVariantConst::containsKey()") {
-  JsonDocument doc;
-  doc["hello"] = "world";
-  JsonVariantConst var = doc.as<JsonVariant>();
-
-  SECTION("support const char*") {
-    REQUIRE(var.containsKey("hello") == true);
-    REQUIRE(var.containsKey("world") == false);
-  }
-
-  SECTION("support std::string") {
-    REQUIRE(var.containsKey(std::string("hello")) == true);
-    REQUIRE(var.containsKey(std::string("world")) == false);
-  }
-
-#ifdef HAS_VARIABLE_LENGTH_ARRAY
-  SECTION("supports VLA") {
-    size_t i = 16;
-    char vla[i];
-    strcpy(vla, "hello");
-
-    REQUIRE(true == var.containsKey(vla));
-  }
-#endif
-}

extras/tests/JsonVariantConst/subscript.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 TEST_CASE("JsonVariantConst::operator[]") {
   JsonDocument doc;
   JsonVariantConst var = doc.to<JsonVariant>();
@@ -27,31 +29,43 @@ TEST_CASE("JsonVariantConst::operator[]") {
     array.add("A");
     array.add("B");
 
-    REQUIRE(std::string("A") == var[0]);
-    REQUIRE(std::string("B") == var[1]);
-    REQUIRE(std::string("A") ==
-            var[static_cast<unsigned char>(0)]);  // issue #381
-    REQUIRE(var[666].isNull());
-    REQUIRE(var[3].isNull());
-    REQUIRE(var["0"].isNull());
+    SECTION("int") {
+      REQUIRE("A"_s == var[0]);
+      REQUIRE("B"_s == var[1]);
+      REQUIRE("A"_s == var[static_cast<unsigned char>(0)]);  // issue #381
+      REQUIRE(var[666].isNull());
+      REQUIRE(var[3].isNull());
+    }
+
+    SECTION("const char*") {
+      REQUIRE(var["0"].isNull());
+    }
+
+    SECTION("JsonVariant") {
+      array.add(1);
+      REQUIRE(var[var[2]] == "B"_s);
+      REQUIRE(var[var[3]].isNull());
+    }
   }
 
   SECTION("object") {
     JsonObject object = doc.to<JsonObject>();
-    object["a"] = "A";
-    object["b"] = "B";
+    object["ab"_s] = "AB";
+    object["abc"_s] = "ABC";
+    object["abc\0d"_s] = "ABCD";
 
     SECTION("supports const char*") {
-      REQUIRE(std::string("A") == var["a"]);
-      REQUIRE(std::string("B") == var["b"]);
-      REQUIRE(var["c"].isNull());
+      REQUIRE(var["ab"] == "AB"_s);
+      REQUIRE(var["abc"] == "ABC"_s);
+      REQUIRE(var["def"].isNull());
       REQUIRE(var[0].isNull());
     }
 
     SECTION("supports std::string") {
-      REQUIRE(std::string("A") == var[std::string("a")]);
-      REQUIRE(std::string("B") == var[std::string("b")]);
-      REQUIRE(var[std::string("c")].isNull());
+      REQUIRE(var["ab"_s] == "AB"_s);
+      REQUIRE(var["abc"_s] == "ABC"_s);
+      REQUIRE(var["abc\0d"_s] == "ABCD"_s);
+      REQUIRE(var["def"_s].isNull());
     }
 
 #if defined(HAS_VARIABLE_LENGTH_ARRAY) && \
@@ -59,10 +73,23 @@ TEST_CASE("JsonVariantConst::operator[]") {
     SECTION("supports VLA") {
       size_t i = 16;
       char vla[i];
-      strcpy(vla, "a");
+      strcpy(vla, "abc");
 
-      REQUIRE(std::string("A") == var[vla]);
+      REQUIRE(var[vla] == "ABC"_s);
     }
 #endif
+
+    SECTION("supports JsonVariant") {
+      object["key1"] = "ab";
+      object["key2"] = "abc";
+      object["key3"] = "abc\0d"_s;
+      object["key4"] = "foo";
+
+      REQUIRE(var[var["key1"]] == "AB"_s);
+      REQUIRE(var[var["key2"]] == "ABC"_s);
+      REQUIRE(var[var["key3"]] == "ABCD"_s);
+      REQUIRE(var[var["key4"]].isNull());
+      REQUIRE(var[var["key5"]].isNull());
+    }
   }
 }

extras/tests/Misc/CMakeLists.txt

@@ -5,8 +5,8 @@
 add_executable(MiscTests
 	arithmeticCompare.cpp
 	conflicts.cpp
-	FloatParts.cpp
 	issue1967.cpp
+	issue2129.cpp
 	JsonString.cpp
 	NoArduinoHeader.cpp
 	printable.cpp

extras/tests/Misc/StringAdapters.cpp

@@ -12,77 +12,101 @@
 #include "custom_string.hpp"
 #include "weird_strcmp.hpp"
 
+using ArduinoJson::JsonString;
 using namespace ArduinoJson::detail;
 
-TEST_CASE("ZeroTerminatedRamString") {
-  SECTION("null") {
-    ZeroTerminatedRamString s = adaptString(static_cast<const char*>(0));
+TEST_CASE("adaptString()") {
+  SECTION("null const char*") {
+    auto s = adaptString(static_cast<const char*>(0));
 
     CHECK(s.isNull() == true);
     CHECK(s.size() == 0);
+    CHECK(s.isLinked() == true);
   }
 
-  SECTION("non-null") {
-    ZeroTerminatedRamString s = adaptString("bravo");
+  SECTION("non-null const char*") {
+    auto s = adaptString("bravo");
 
     CHECK(s.isNull() == false);
     CHECK(s.size() == 5);
+    CHECK(s.isLinked() == true);
   }
-}
 
-TEST_CASE("SizedRamString") {
-  SECTION("null") {
-    SizedRamString s = adaptString(static_cast<const char*>(0), 10);
+  SECTION("null const char* + size") {
+    auto s = adaptString(static_cast<const char*>(0), 10);
 
     CHECK(s.isNull() == true);
+    CHECK(s.isLinked() == false);
   }
 
-  SECTION("non-null") {
-    SizedRamString s = adaptString("bravo", 5);
+  SECTION("non-null const char* + size") {
+    auto s = adaptString("bravo", 5);
 
     CHECK(s.isNull() == false);
     CHECK(s.size() == 5);
+    CHECK(s.isLinked() == false);
   }
-}
 
-TEST_CASE("FlashString") {
-  SECTION("null") {
-    FlashString s = adaptString(static_cast<const __FlashStringHelper*>(0));
+  SECTION("null Flash string") {
+    auto s = adaptString(static_cast<const __FlashStringHelper*>(0));
 
     CHECK(s.isNull() == true);
     CHECK(s.size() == 0);
+    CHECK(s.isLinked() == false);
   }
 
-  SECTION("non-null") {
-    FlashString s = adaptString(F("bravo"));
+  SECTION("non-null Flash string") {
+    auto s = adaptString(F("bravo"));
 
     CHECK(s.isNull() == false);
     CHECK(s.size() == 5);
+    CHECK(s.isLinked() == false);
   }
-}
 
-TEST_CASE("std::string") {
-  std::string orig("bravo");
-  SizedRamString s = adaptString(orig);
+  SECTION("std::string") {
+    std::string orig("bravo");
+    auto s = adaptString(orig);
 
-  CHECK(s.isNull() == false);
-  CHECK(s.size() == 5);
-}
+    CHECK(s.isNull() == false);
+    CHECK(s.size() == 5);
+    CHECK(s.isLinked() == false);
+  }
 
-TEST_CASE("Arduino String") {
-  ::String orig("bravo");
-  SizedRamString s = adaptString(orig);
+  SECTION("Arduino String") {
+    ::String orig("bravo");
+    auto s = adaptString(orig);
 
-  CHECK(s.isNull() == false);
-  CHECK(s.size() == 5);
-}
+    CHECK(s.isNull() == false);
+    CHECK(s.size() == 5);
+    CHECK(s.isLinked() == false);
+  }
 
-TEST_CASE("custom_string") {
-  custom_string orig("bravo");
-  SizedRamString s = adaptString(orig);
+  SECTION("custom_string") {
+    custom_string orig("bravo");
+    auto s = adaptString(orig);
 
-  CHECK(s.isNull() == false);
-  CHECK(s.size() == 5);
+    CHECK(s.isNull() == false);
+    CHECK(s.size() == 5);
+    CHECK(s.isLinked() == false);
+  }
+
+  SECTION("JsonString linked") {
+    JsonString orig("hello", JsonString::Ownership::Linked);
+    auto s = adaptString(orig);
+
+    CHECK(s.isNull() == false);
+    CHECK(s.size() == 5);
+    CHECK(s.isLinked() == true);
+  }
+
+  SECTION("JsonString copied") {
+    JsonString orig("hello", JsonString::Ownership::Copied);
+    auto s = adaptString(orig);
+
+    CHECK(s.isNull() == false);
+    CHECK(s.size() == 5);
+    CHECK(s.isLinked() == false);
+  }
 }
 
 struct EmptyStruct {};
@@ -97,6 +121,7 @@ TEST_CASE("IsString<T>") {
   CHECK(IsString<::String>::value == true);
   CHECK(IsString<::StringSumHelper>::value == true);
   CHECK(IsString<const EmptyStruct*>::value == false);
+  CHECK(IsString<JsonString>::value == true);
 }
 
 TEST_CASE("stringCompare") {

extras/tests/Misc/StringWriter.cpp

@@ -9,6 +9,7 @@
 
 #include <catch.hpp>
 
+#include "Literals.hpp"
 #include "custom_string.hpp"
 
 using namespace ArduinoJson::detail;
@@ -36,13 +37,13 @@ void common_tests(StringWriter& writer, const String& output) {
 
   SECTION("OneString") {
     REQUIRE(4 == print(writer, "ABCD"));
-    REQUIRE(std::string("ABCD") == output);
+    REQUIRE("ABCD"_s == output);
   }
 
   SECTION("TwoStrings") {
     REQUIRE(4 == print(writer, "ABCD"));
     REQUIRE(4 == print(writer, "EFGH"));
-    REQUIRE(std::string("ABCDEFGH") == output);
+    REQUIRE("ABCDEFGH"_s == output);
   }
 }
 

extras/tests/Misc/conflicts.cpp

@@ -58,5 +58,10 @@
 // issue #1914
 #define V7 7
 
+// STM32, Mbed, Particle
+#define A0 16
+#define A1 17
+#define A2 18
+
 // catch.hpp mutes several warnings, this file also allows to detect them
 #include "ArduinoJson.h"

extras/tests/Misc/custom_string.hpp

@@ -7,6 +7,5 @@
 #include <string>
 
 struct custom_char_traits : std::char_traits<char> {};
-struct custom_allocator : std::allocator<char> {};
-typedef std::basic_string<char, custom_char_traits, custom_allocator>
-    custom_string;
+
+using custom_string = std::basic_string<char, custom_char_traits>;

extras/tests/Misc/issue2129.cpp

@@ -0,0 +1,55 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2024, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+template <typename T>
+class Nullable {
+ public:
+  Nullable() : value_{} {}
+  Nullable(T value) : value_{value} {}
+
+  operator T() const {
+    return value_;
+  }
+
+  operator T&() {
+    return value_;
+  }
+
+  bool is_valid() const {
+    return value_ != invalid_value_;
+  }
+
+  T value() const {
+    return value_;
+  }
+
+ private:
+  T value_;
+  static T invalid_value_;
+};
+
+template <>
+float Nullable<float>::invalid_value_ = std::numeric_limits<float>::lowest();
+
+template <typename T>
+void convertToJson(const Nullable<T>& src, JsonVariant dst) {
+  if (src.is_valid()) {
+    dst.set(src.value());
+  } else {
+    dst.clear();
+  }
+}
+
+TEST_CASE("Issue #2129") {
+  Nullable<float> nullable_value = Nullable<float>{123.4f};
+
+  JsonDocument doc;
+
+  doc["value"] = nullable_value;
+
+  REQUIRE(doc["value"].as<float>() == Approx(123.4f));
+}

extras/tests/Misc/unsigned_char.cpp

@@ -5,6 +5,8 @@
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
+#include "Literals.hpp"
+
 #if defined(__clang__)
 #  define CONFLICTS_WITH_BUILTIN_OPERATOR
 #endif
@@ -111,7 +113,7 @@ TEST_CASE("unsigned char[]") {
       deserializeJson(doc, "{\"hello\":\"world\"}");
       JsonVariant variant = doc.as<JsonVariant>();
 
-      REQUIRE(std::string("world") == variant[key]);
+      REQUIRE("world"_s == variant[key]);
     }
 #endif
 
@@ -122,7 +124,7 @@ TEST_CASE("unsigned char[]") {
       deserializeJson(doc, "{\"hello\":\"world\"}");
       const JsonVariant variant = doc.as<JsonVariant>();
 
-      REQUIRE(std::string("world") == variant[key]);
+      REQUIRE("world"_s == variant[key]);
     }
 #endif
 
@@ -160,7 +162,7 @@ TEST_CASE("unsigned char[]") {
       JsonObject obj = doc.to<JsonObject>();
       obj[key] = "world";
 
-      REQUIRE(std::string("world") == obj["hello"]);
+      REQUIRE("world"_s == obj["hello"]);
     }
 
     SECTION("JsonObject::operator[] const") {
@@ -170,19 +172,10 @@ TEST_CASE("unsigned char[]") {
       deserializeJson(doc, "{\"hello\":\"world\"}");
 
       JsonObject obj = doc.as<JsonObject>();
-      REQUIRE(std::string("world") == obj[key]);
+      REQUIRE("world"_s == obj[key]);
     }
 #endif
 
-    SECTION("containsKey()") {
-      unsigned char key[] = "hello";
-
-      JsonDocument doc;
-      deserializeJson(doc, "{\"hello\":\"world\"}");
-      JsonObject obj = doc.as<JsonObject>();
-      REQUIRE(true == obj.containsKey(key));
-    }
-
     SECTION("remove()") {
       unsigned char key[] = "hello";
 
@@ -203,7 +196,7 @@ TEST_CASE("unsigned char[]") {
       JsonObject obj = doc.to<JsonObject>();
       obj["hello"] = value;
 
-      REQUIRE(std::string("world") == obj["hello"]);
+      REQUIRE("world"_s == obj["hello"]);
     }
 
     SECTION("set()") {
@@ -213,7 +206,7 @@ TEST_CASE("unsigned char[]") {
       JsonObject obj = doc.to<JsonObject>();
       obj["hello"].set(value);
 
-      REQUIRE(std::string("world") == obj["hello"]);
+      REQUIRE("world"_s == obj["hello"]);
     }
   }
 
@@ -225,7 +218,7 @@ TEST_CASE("unsigned char[]") {
       JsonArray arr = doc.to<JsonArray>();
       arr.add(value);
 
-      REQUIRE(std::string("world") == arr[0]);
+      REQUIRE("world"_s == arr[0]);
     }
   }
 
@@ -238,7 +231,7 @@ TEST_CASE("unsigned char[]") {
       arr.add("hello");
       arr[0].set(value);
 
-      REQUIRE(std::string("world") == arr[0]);
+      REQUIRE("world"_s == arr[0]);
     }
 
     SECTION("operator=") {
@@ -249,7 +242,7 @@ TEST_CASE("unsigned char[]") {
       arr.add("hello");
       arr[0] = value;
 
-      REQUIRE(std::string("world") == arr[0]);
+      REQUIRE("world"_s == arr[0]);
     }
   }
 }

extras/tests/MixedConfiguration/CMakeLists.txt

@@ -15,6 +15,9 @@ add_executable(MixedConfigurationTests
 	enable_nan_1.cpp
 	enable_progmem_1.cpp
 	issue1707.cpp
+	string_length_size_1.cpp
+	string_length_size_2.cpp
+	string_length_size_4.cpp
 	use_double_0.cpp
 	use_double_1.cpp
 	use_long_long_0.cpp

extras/tests/MixedConfiguration/string_length_size_1.cpp

@@ -0,0 +1,131 @@
+#define ARDUINOJSON_STRING_LENGTH_SIZE 1
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+#include <string>
+
+#include "Literals.hpp"
+
+TEST_CASE("ARDUINOJSON_STRING_LENGTH_SIZE == 1") {
+  JsonDocument doc;
+
+  SECTION("set(std::string)") {
+    SECTION("returns true if len <= 255") {
+      auto result = doc.set(std::string(255, '?'));
+
+      REQUIRE(result == true);
+      REQUIRE(doc.overflowed() == false);
+    }
+
+    SECTION("returns false if len >= 256") {
+      auto result = doc.set(std::string(256, '?'));
+
+      REQUIRE(result == false);
+      REQUIRE(doc.overflowed() == true);
+    }
+  }
+
+  SECTION("set(MsgPackBinary)") {
+    SECTION("returns true if size <= 253") {
+      auto str = std::string(253, '?');
+      auto result = doc.set(MsgPackBinary(str.data(), str.size()));
+
+      REQUIRE(result == true);
+      REQUIRE(doc.overflowed() == false);
+    }
+
+    SECTION("returns false if size >= 254") {
+      auto str = std::string(254, '?');
+      auto result = doc.set(MsgPackBinary(str.data(), str.size()));
+
+      REQUIRE(result == false);
+      REQUIRE(doc.overflowed() == true);
+    }
+  }
+
+  SECTION("set(MsgPackExtension)") {
+    SECTION("returns true if size <= 252") {
+      auto str = std::string(252, '?');
+      auto result = doc.set(MsgPackExtension(1, str.data(), str.size()));
+
+      REQUIRE(result == true);
+      REQUIRE(doc.overflowed() == false);
+    }
+
+    SECTION("returns false if size >= 253") {
+      auto str = std::string(253, '?');
+      auto result = doc.set(MsgPackExtension(1, str.data(), str.size()));
+
+      REQUIRE(result == false);
+      REQUIRE(doc.overflowed() == true);
+    }
+  }
+
+  SECTION("deserializeJson()") {
+    SECTION("returns Ok if string length <= 255") {
+      auto input = "\"" + std::string(255, '?') + "\"";
+
+      auto err = deserializeJson(doc, input);
+
+      REQUIRE(err == DeserializationError::Ok);
+    }
+
+    SECTION("returns NoMemory if string length >= 256") {
+      auto input = "\"" + std::string(256, '?') + "\"";
+
+      auto err = deserializeJson(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+  }
+
+  SECTION("deserializeMsgPack()") {
+    SECTION("returns Ok if string length <= 255") {
+      auto input = "\xd9\xff" + std::string(255, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::Ok);
+    }
+
+    SECTION("returns NoMemory if string length >= 256") {
+      auto input = "\xda\x01\x00"_s + std::string(256, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+
+    SECTION("returns Ok if binary size <= 253") {
+      auto input = "\xc4\xfd" + std::string(253, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::Ok);
+    }
+
+    SECTION("returns NoMemory if binary size >= 254") {
+      auto input = "\xc4\xfe" + std::string(254, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+
+    SECTION("returns Ok if extension size <= 252") {
+      auto input = "\xc7\xfc\x01" + std::string(252, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::Ok);
+    }
+
+    SECTION("returns NoMemory if binary size >= 253") {
+      auto input = "\xc7\xfd\x01" + std::string(253, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+  }
+}

extras/tests/MixedConfiguration/string_length_size_2.cpp

@@ -0,0 +1,140 @@
+#define ARDUINOJSON_STRING_LENGTH_SIZE 2
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+#include <string>
+
+#include "Literals.hpp"
+
+TEST_CASE("ARDUINOJSON_STRING_LENGTH_SIZE == 2") {
+  JsonDocument doc;
+
+  SECTION("set(std::string)") {
+    SECTION("returns true if len <= 65535") {
+      auto result = doc.set(std::string(65535, '?'));
+
+      REQUIRE(result == true);
+      REQUIRE(doc.overflowed() == false);
+    }
+
+    SECTION("returns false if len >= 65536") {
+      auto result = doc.set(std::string(65536, '?'));
+
+      REQUIRE(result == false);
+      REQUIRE(doc.overflowed() == true);
+    }
+  }
+
+  SECTION("set(MsgPackBinary)") {
+    SECTION("returns true if size <= 65532") {
+      auto str = std::string(65532, '?');
+      auto result = doc.set(MsgPackBinary(str.data(), str.size()));
+
+      REQUIRE(result == true);
+      REQUIRE(doc.overflowed() == false);
+    }
+
+    SECTION("returns false if size >= 65533") {
+      auto str = std::string(65533, '?');
+      auto result = doc.set(MsgPackBinary(str.data(), str.size()));
+
+      REQUIRE(result == false);
+      REQUIRE(doc.overflowed() == true);
+    }
+  }
+
+  SECTION("set(MsgPackExtension)") {
+    SECTION("returns true if size <= 65531") {
+      auto str = std::string(65531, '?');
+      auto result = doc.set(MsgPackExtension(1, str.data(), str.size()));
+
+      REQUIRE(result == true);
+      REQUIRE(doc.overflowed() == false);
+    }
+
+    SECTION("returns false if size >= 65532") {
+      auto str = std::string(65532, '?');
+      auto result = doc.set(MsgPackExtension(1, str.data(), str.size()));
+
+      REQUIRE(result == false);
+      REQUIRE(doc.overflowed() == true);
+    }
+  }
+
+  SECTION("deserializeJson()") {
+    SECTION("returns Ok if string length <= 65535") {
+      auto input = "\"" + std::string(65535, '?') + "\"";
+
+      auto err = deserializeJson(doc, input);
+
+      REQUIRE(err == DeserializationError::Ok);
+    }
+
+    SECTION("returns NoMemory if string length >= 65536") {
+      auto input = "\"" + std::string(65536, '?') + "\"";
+
+      auto err = deserializeJson(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+  }
+
+  SECTION("deserializeMsgPack()") {
+    SECTION("returns Ok if string length <= 65535") {
+      auto input = "\xda\xff\xff" + std::string(65535, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::Ok);
+    }
+
+    SECTION("returns NoMemory if string length >= 65536") {
+      auto input = "\xdb\x00\x01\x00\x00"_s + std::string(65536, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+
+    SECTION("returns Ok if binary size <= 65532") {
+      auto input = "\xc5\xff\xfc" + std::string(65532, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::Ok);
+    }
+
+    SECTION("returns NoMemory if binary size >= 65534") {
+      auto input = "\xc5\xff\xfd" + std::string(65534, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+
+    // https://oss-fuzz.com/testcase?key=5354792971993088
+    SECTION("doesn't overflow if binary size == 0xFFFF") {
+      auto input = "\xc5\xff\xff"_s;
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+
+    SECTION("returns Ok if extension size <= 65531") {
+      auto input = "\xc8\xff\xfb\x01" + std::string(65531, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::Ok);
+    }
+
+    SECTION("returns NoMemory if extension size >= 65532") {
+      auto input = "\xc8\xff\xfc\x01" + std::string(65532, '?');
+
+      auto err = deserializeMsgPack(doc, input);
+
+      REQUIRE(err == DeserializationError::NoMemory);
+    }
+  }
+}