JsonObject: replace ObjectData* member with VariantData*

This new pool replaced the "extension" slot where a secondary variant slot was used to store 8-byte values.

.devcontainer/clang10/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "Clang 10",
+	"image": "conanio/clang10",
+	"runArgs": [
+		"--name=ArduinoJson-clang10"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.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"
+			}
+		}
+	}
+}

.devcontainer/clang5/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "Clang 5",
+	"image": "conanio/clang50",
+	"runArgs": [
+		"--name=ArduinoJson-clang5"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang6/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "Clang 6",
+	"image": "conanio/clang60",
+	"runArgs": [
+		"--name=ArduinoJson-clang6"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang7/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "Clang 7",
+	"image": "conanio/clang7",
+	"runArgs": [
+		"--name=ArduinoJson-clang7"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang8/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "Clang 8",
+	"image": "conanio/clang8",
+	"runArgs": [
+		"--name=ArduinoJson-clang8"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/clang9/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "Clang 9",
+	"image": "conanio/clang9",
+	"runArgs": [
+		"--name=ArduinoJson-clang9"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc10/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "GCC 10",
+	"image": "conanio/gcc10",
+	"runArgs": [
+		"--name=ArduinoJson-gcc10"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc11/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "GCC 11",
+	"image": "conanio/gcc11",
+	"runArgs": [
+		"--name=ArduinoJson-gcc11"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc12/Dockerfile

@@ -0,0 +1,4 @@
+FROM ubuntu:22.04
+
+RUN apt-get update
+RUN apt-get install -y cmake git g++-12

.devcontainer/gcc12/devcontainer.json

@@ -0,0 +1,20 @@
+{
+	"name": "GCC 12",
+	"build": {
+		"dockerfile": "Dockerfile",
+	},
+	"runArgs": [
+		"--name=ArduinoJson-gcc12"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc48/devcontainer.json

@@ -0,0 +1,20 @@
+{
+	"name": "GCC 4.8",
+	"image": "conanio/gcc48",
+	"runArgs": [
+		"--name=ArduinoJson-gcc48"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools",
+				"josetr.cmake-language-support-vscode",
+				"ms-vscode.cpptools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc5/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "GCC 5",
+	"image": "conanio/gcc5",
+	"runArgs": [
+		"--name=ArduinoJson-gcc5"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc6/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "GCC 6",
+	"image": "conanio/gcc6",
+	"runArgs": [
+		"--name=ArduinoJson-gcc6"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc7/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "GCC 7",
+	"image": "conanio/gcc7",
+	"runArgs": [
+		"--name=ArduinoJson-gcc7"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc8/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "GCC 8",
+	"image": "conanio/gcc8",
+	"runArgs": [
+		"--name=ArduinoJson-gcc8"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.devcontainer/gcc9/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "GCC 9",
+	"image": "conanio/gcc9",
+	"runArgs": [
+		"--name=ArduinoJson-gcc9"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-vscode.cmake-tools"
+			],
+			"settings": {
+				"cmake.generator": "Unix Makefiles",
+				"cmake.buildDirectory": "/tmp/build"
+			}
+		}
+	}
+}

.gitattributes

@@ -1 +1,2 @@
-*.sh text eol=lf
+* text=auto
+*.sh text eol=lf

.github/ISSUE_TEMPLATE/bug_report.md

@@ -14,7 +14,7 @@ Before opening a bug report, please use the ArduinoJson Troubleshooter as it may
 A clear and concise description of what the bug is.
 
 **Troubleshooter report**  
-Here is the report generated by the [ArduinoJson Troubleshooter](https://arduinojson.org/v6/troubleshooter/):  
+Here is the report generated by the [ArduinoJson Troubleshooter](https://arduinojson.org/v7/troubleshooter/):  
 [Paste the report here]
 
 **Environment**  
@@ -27,7 +27,7 @@ Here is the environment that I used:
 Here is a small snippet that reproduces the issue.
 
 ```c++
-JsonDocument doc(1024);
+JsonDocument doc;
 
 DeserializationError error = deserializeJson(doc, "{\"hello\":\"world\"}");
 

.github/ISSUE_TEMPLATE/config.yml

@@ -1,8 +1,8 @@
 blank_issues_enabled: true
 contact_links:
   - name: 👨‍🏫 ArduinoJson Assistant
-    url: https://arduinojson.org/v6/assistant/
+    url: https://arduinojson.org/v7/assistant/
     about: An online tool that computes memory requirements and generates scaffolding code for your project.
   - name: 👨‍⚕️ ArduinoJson Troubleshooter
-    url: https://arduinojson.org/v6/troubleshooter/
+    url: https://arduinojson.org/v7/troubleshooter/
     about: An online tool that helps you diagnose the most common issues with ArduinoJson.

.github/ISSUE_TEMPLATE/help.md

@@ -15,7 +15,7 @@ A clear and concise description of what you're trying to do.
 You don't need to explain every aspect of your project: focus on the problem you're having.
 
 **Troubleshooter report**  
-Here is the report generated by the [ArduinoJson Troubleshooter](https://arduinojson.org/v6/troubleshooter/):  
+Here is the report generated by the [ArduinoJson Troubleshooter](https://arduinojson.org/v7/troubleshooter/):  
 [Paste the report here]
 
 **Environment**  
@@ -28,7 +28,7 @@ Here is the environment that I'm using':
 Here is a small snippet that demonstrate the problem.
 
 ```c++
-JsonDocument doc(1024);
+JsonDocument doc;
 
 DeserializationError error = deserializeJson(doc, "{\"hello\":\"world\"}");
 

.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
@@ -33,6 +37,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - gcc: "4.8"
           - gcc: "5"
           - gcc: "6"
           - gcc: "7"
@@ -44,67 +49,97 @@ jobs:
           - gcc: "10"
             cxxflags: -funsigned-char # Issue #1715
           - 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
+          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial main universe'
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic main universe'
           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
     needs: lint
-    runs-on: ubuntu-20.04
     strategy:
       fail-fast: false
       matrix:
         include:
-          - clang: "3.8"
-            cxxflags: "-stdlib=libc++"
-          - clang: "3.9"
-            cxxflags: "-stdlib=libc++"
-          - clang: "4.0"
-            cxxflags: "-stdlib=libc++"
-          - clang: "5.0"
-          - clang: "6.0"
           - clang: "7"
+            runner: ubuntu-22.04
+            archive: focal
           - clang: "8"
             cxxflags: -fsanitize=leak -fno-sanitize-recover=all
+            runner: ubuntu-22.04
+            archive: focal
           - clang: "9"
             cxxflags: -fsanitize=undefined -fno-sanitize-recover=all
+            runner: ubuntu-22.04
+            archive: focal
           - clang: "10"
             cxxflags: -fsanitize=address -fno-sanitize-recover=all
+            runner: ubuntu-22.04
+            archive: focal
+          - clang: "11"
+            runner: ubuntu-22.04
+          - clang: "12"
+            runner: ubuntu-22.04
+          - clang: "13"
+            runner: ubuntu-22.04
+          - clang: 14
+          - clang: 15
+          - clang: 16
+          - clang: 17
+          - clang: 18
+          - clang: 19
+    runs-on: ${{ matrix.runner || 'ubuntu-latest' }}
     steps:
-      - name: Install
+      - name: Add archive repositories
+        if: matrix.archive
+        run: |
+          sudo gpg --keyserver keyserver.ubuntu.com --recv-keys 3B4FE6ACC0B21F32
+          sudo gpg --export 3B4FE6ACC0B21F32 | sudo tee /etc/apt/trusted.gpg.d/ubuntu-keyring.gpg > /dev/null
+          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ ${{ matrix.archive }} main'
+          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ ${{ matrix.archive }} universe'
+      - name: Install Clang ${{ matrix.clang }}
         run: |
-          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial main'
-          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial universe'
-          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic main'
-          sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic universe'
           sudo apt-get update
           sudo apt-get install -y clang-${{ matrix.clang }}
+      - name: Install libc++ ${{ matrix.clang }}
+        run: sudo apt-get install -y libc++-${{ matrix.clang }}-dev libc++abi-${{ matrix.clang }}-dev
+      - name: Install libunwind ${{ matrix.clang }}
+        if: matrix.clang == 12 # dependency is missing in Ubuntu 22.04
+        run: sudo apt-get install -y libunwind-${{ matrix.clang }}-dev
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Configure
         run: cmake -DCMAKE_BUILD_TYPE=Debug .
         env:
@@ -112,29 +147,25 @@ jobs:
           CXX: clang++-${{ matrix.clang }}
           CXXFLAGS: >-
             ${{ matrix.cxxflags }}
-            ${{ contains(matrix.cxxflags, 'libc++') && '-I/usr/lib/llvm-10/include/c++/v1/' || '' }}
+            ${{ matrix.clang < 11 && '-I/usr/lib/llvm-10/include/c++/v1/' || '' }}
       - 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
 
   conf_test:
     name: Test configuration on Linux
     needs: [gcc, clang]
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Install
         run: |
           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
@@ -152,7 +183,7 @@ 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"
@@ -167,17 +198,20 @@ 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
@@ -199,7 +233,7 @@ 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
@@ -218,10 +252,10 @@ jobs:
             board: arduino:avr:uno
           - core: arduino:samd
             board: arduino:samd:mkr1000
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     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
@@ -294,14 +328,14 @@ 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
@@ -313,7 +347,7 @@ 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 }}
@@ -362,7 +396,7 @@ 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
@@ -373,14 +407,14 @@ jobs:
   arm:
     name: GCC for ARM processor
     needs: gcc
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Install
         run: |
           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:
@@ -392,18 +426,18 @@ jobs:
   coverage:
     needs: gcc
     name: Coverage
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - 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
         run: ninja
       - name: Test
-        run: ctest -LE 'WillFail|Fuzzing' -T test
+        run: ctest --output-on-failure -LE 'WillFail|Fuzzing' -T test
       - name: lcov --capture
         run: lcov --capture --no-external --directory . --output-file coverage.info
       - name: lcov --remove
@@ -411,12 +445,12 @@ 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
@@ -424,109 +458,87 @@ jobs:
   valgrind:
     needs: gcc
     name: Valgrind
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Install
         run: |
           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
         run: ninja
       - name: Memcheck
-        run: ctest -LE WillFail -T memcheck
+        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:
     needs: clang
     name: Clang-Tidy
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - name: Install
-        run: sudo apt-get install -y clang-tidy cmake ninja-build
+        run: sudo apt-get install -y clang-tidy libc++-dev libc++abi-dev
       - 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 .
+        run: cmake -G Ninja -DCMAKE_CXX_CLANG_TIDY="clang-tidy;--warnings-as-errors=*" -DCMAKE_BUILD_TYPE=Debug .
         env:
-          CC: clang-10
-          CXX: clang++-10
+          CC: clang
+          CXX: clang++
       - name: Check
         run: cmake --build . -- -k 0
 
-  amalgamate-h:
+  amalgamate:
     needs: gcc
     name: Amalgamate ArduinoJson.h
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     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(300);
+            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(300);
+            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
@@ -534,14 +546,14 @@ 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
@@ -561,7 +573,7 @@ jobs:
 
   codeql:
     name: CodeQL
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     needs: gcc
 
     permissions:
@@ -570,20 +582,20 @@ jobs:
       security-events: write
 
     steps:
-    - name: Checkout repository
-      uses: actions/checkout@v3
+      - name: Checkout repository
+        uses: actions/checkout@v4
 
-    - name: Initialize CodeQL
-      uses: github/codeql-action/init@v2
-      with:
-        languages: cpp
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: cpp
 
-    - name: Build
-      run: |
-        cmake -DCMAKE_BUILD_TYPE=Debug .
-        cmake --build .
+      - name: Build
+        run: |
+          cmake -DCMAKE_BUILD_TYPE=Debug .
+          cmake --build .
 
-    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v2
-      with:
-        category: "/language:cpp"
+      - name: Perform CodeQL Analysis
+        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

@@ -8,7 +8,7 @@ on:
 jobs:
   release:
     name: Create release
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       - name: Set variables
         id: init
@@ -16,12 +16,18 @@ 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: |
           FILENAME=RELEASE.md
-          extras/scripts/get-release-body.sh ${{ steps.init.outputs.tag }} CHANGELOG.md | tee $FILENAME
+          tee $FILENAME <<END
+          ## Changes
+
+          $(extras/scripts/extract_changes.awk CHANGELOG.md)
+
+          [View version history](https://github.com/bblanchon/ArduinoJson/blob/${{ steps.init.outputs.tag }}/CHANGELOG.md)
+          END
           echo "filename=$FILENAME" >> $GITHUB_OUTPUT
       - name: Amalgamate ArduinoJson.h
         id: amalgamate_h
@@ -35,18 +41,12 @@ jobs:
           FILENAME=ArduinoJson-${{ steps.init.outputs.tag }}.hpp
           extras/scripts/build-single-header.sh src/ArduinoJson.hpp "$FILENAME"
           echo "filename=$FILENAME" >> $GITHUB_OUTPUT
-      - name: Create Arduino package
-        id: arduino
-        run: |
-          FILENAME=ArduinoJson-${{ steps.init.outputs.tag }}.zip
-          extras/scripts/build-arduino-package.sh . "$FILENAME"
-          echo "filename=$FILENAME" >> $GITHUB_OUTPUT
       - name: Create release
         uses: ncipollo/release-action@v1
         with:
           bodyFile: ${{ steps.body.outputs.filename }}
           name: ArduinoJson ${{ steps.init.outputs.version }}
-          artifacts: ${{ steps.amalgamate_h.outputs.filename }},${{ steps.amalgamate_hpp.outputs.filename }},${{ steps.arduino.outputs.filename }}
+          artifacts: ${{ steps.amalgamate_h.outputs.filename }},${{ steps.amalgamate_hpp.outputs.filename }}
           token: ${{ secrets.GITHUB_TOKEN }}
 
   idf:
@@ -54,7 +54,7 @@ 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:
@@ -69,8 +69,25 @@ 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
         run: bash -eux extras/scripts/publish-particle-library.sh
+
+  platformio:
+    name: PlatformIO
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Python 3.x
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.x"
+      - name: Install PlatformIO
+        run: pip install platformio
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Publish
+        run: pio pkg publish --no-interactive --no-notify
+        env:
+          PLATFORMIO_AUTH_TOKEN: ${{ secrets.PLATFORMIO_AUTH_TOKEN }}

.mbedignore

@@ -1,3 +1,4 @@
+.devcontainer/
 .github/
 examples/
-extras/
+extras/

.vscode/settings.json

@@ -1,6 +1,5 @@
 {
   "C_Cpp.default.configurationProvider": "ms-vscode.cmake-tools",
-  "cmake.generator": "Ninja",
   "git.inputValidationLength": 80,
   "git.inputValidationSubjectLength": 72,
   "files.insertFinalNewline": true,

ArduinoJson.h

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #include "src/ArduinoJson.h"

CHANGELOG.md

@@ -4,14 +4,284 @@ ArduinoJson: change log
 HEAD
 ----
 
+* Optimize storage of static strings
+
+> ### BREAKING CHANGES
+>
+> Static string cannot contain NUL characters anymore (they could since 7.3.0).
+> This is an extremely rare case, so you probably won't be affected.
+>
+> For example, the following code produces different output in 7.3 and 7.4:
+>
+> ```cpp
+> JsonDocument doc;
+> doc["a\0b"] = "c\0d";
+> serializeJson(doc, Serial);
+> // With Arduino 7.3 -> {"a\u0000b":"c\u0000d"}
+> // With Arduino 7.4 -> {"a":"c"}
+> ```
+>
+> `JsonString` contructor now only accepts two arguments, not three.
+> If your code uses `JsonString` to store a string as a pointer, you must remove the size argument.
+>
+> For example, if you have something like this:
+>
+> ```cpp
+> doc["key"] = JsonString(str.c_str(), str.size(), true);
+> ```
+>
+> You must replace with either:
+>
+> ```cpp
+> doc["key"] = JsonString(str.c_str(), true);  // store as pointer, cannot contain NUL characters
+> doc["key"] = JsonString(str.c_str(), str.size()); // store by copy, NUL characters allowed
+> doc["key"] = str; // same as previous line for supported string classes (`String`, `std::string`, etc.)
+> ```
+
+v7.4.1 (2025-04-11)
+------
+
+* Fix crash with tiny Flash strings (issue #2170)
+
+v7.4.0 (2025-04-09)
+------
+
+* Optimize storage of tiny strings (up to 3 characters)
+* Fix support for `const char[]` (issue #2166)
+
+v7.3.1 (2025-02-27)
+------
+
+* Fix conversion from static string to number
+* Slightly reduce code size
+
+v7.3.0 (2024-12-29)
+------
+
+* Fix support for NUL characters in `deserializeJson()`
+* Make `ElementProxy` and `MemberProxy` non-copyable
+* Change string copy policy: only string literal are stored by pointer
+* `JsonString` is now stored by copy, unless specified otherwise
+* Replace undocumented `JsonString::Ownership` with `bool`
+* Rename undocumented `JsonString::isLinked()` to `isStatic()`
+* Move public facing SFINAEs to template declarations
+
+> ### BREAKING CHANGES
+>
+> In previous versions, `MemberProxy` (the class returned by `operator[]`) could lead to dangling pointers when used with a temporary string.
+> To prevent this issue, `MemberProxy` and `ElementProxy` are now non-copyable.
+>
+> Your code is likely to be affected if you use `auto` to store the result of `operator[]`. For example, the following line won't compile anymore:
+>
+> ```cpp
+> auto value = doc["key"];
+> ```
+>
+> To fix the issue, you must append either `.as<T>()` or `.to<T>()`, depending on the situation.
+>
+> For example, if you are extracting values from a JSON document, you should update like this:
+>
+> ```diff
+> - auto config = doc["config"];
+> + auto config = doc["config"].as<JsonObject>();
+> const char* name = config["name"];
+> ```
+>
+> However, if you are building a JSON document, you should update like this:
+>
+> ```diff
+> - auto config = doc["config"];
+> + auto config = doc["config"].to<JsonObject>();
+> config["name"] = "ArduinoJson";
+> ```
+
+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)
+------
+
+* Make `JSON_STRING_SIZE(N)` return `N+1` to fix third-party code (issue #2054)
+
+v7.0.3 (2024-02-05)
+------
+
+* Improve error messages when using `char` or `char*` (issue #2043)
+* Reduce stack consumption (issue #2046)
+* Fix compatibility with GCC 4.8 (issue #2045)
+
+v7.0.2 (2024-01-19)
+------
+
+* Fix assertion `poolIndex < count_` after `JsonDocument::clear()` (issue #2034)
+
+v7.0.1 (2024-01-10)
+------
+
+* Fix "no matching function" with `JsonObjectConst::operator[]` (issue #2019)
+* Remove unused files in the PlatformIO package
+* Fix `volatile bool` serialized as `1` or `0` instead of `true` or `false` (issue #2029)
+
+v7.0.0 (2024-01-03)
+------
+
 * Remove `BasicJsonDocument`
 * Remove `StaticJsonDocument`
 * Add abstract `Allocator` class
 * Merge `DynamicJsonDocument` with `JsonDocument`
 * Remove `JSON_ARRAY_SIZE()`, `JSON_OBJECT_SIZE()`, and `JSON_STRING_SIZE()`
-* Remove `ARDUINOJSON_ENABLE_STRING_DEDUPLICATION` (string deduplication cannot be enabled anymore)
+* Remove `ARDUINOJSON_ENABLE_STRING_DEDUPLICATION` (string deduplication cannot be disabled anymore)
 * Remove `JsonDocument::capacity()`
 * Store the strings in the heap
 * Reference-count shared strings
 * Always store `serialized("string")` by copy (#1915)
 * Remove the zero-copy mode of `deserializeJson()` and `deserializeMsgPack()`
+* Fix double lookup in `to<JsonVariant>()`
+* Fix double call to `size()` in `serializeMsgPack()`
+* Include `ARDUINOJSON_SLOT_OFFSET_SIZE` in the namespace name
+* Remove `JsonVariant::shallowCopy()`
+* `JsonDocument`'s capacity grows as needed, no need to pass it to the constructor anymore
+* `JsonDocument`'s allocator is not monotonic anymore, removed values get recycled
+* Show a link to the documentation when user passes an unsupported input type
+* Remove `JsonDocument::memoryUsage()`
+* Remove `JsonDocument::garbageCollect()`
+* Add `deserializeJson(JsonVariant, ...)` and `deserializeMsgPack(JsonVariant, ...)` (#1226)
+* Call `shrinkToFit()` in `deserializeJson()` and `deserializeMsgPack()`
+* `serializeJson()` and `serializeMsgPack()` replace the content of `std::string` and `String` instead of appending to it
+* Replace `add()` with `add<T>()` (`add(T)` is still supported)
+* Remove `createNestedArray()` and `createNestedObject()` (use `to<JsonArray>()` and `to<JsonObject>()` instead)
+
+> ### BREAKING CHANGES
+>
+> As every major release, ArduinoJson 7 introduces several breaking changes.
+> I added some stubs so that most existing programs should compile, but I highty recommend you upgrade your code.
+>
+> #### `JsonDocument`
+> 
+> In ArduinoJson 6, you could allocate the memory pool on the stack (with `StaticJsonDocument`) or in the heap (with `DynamicJsonDocument`).  
+> In ArduinoJson 7, the memory pool is always allocated in the heap, so `StaticJsonDocument` and `DynamicJsonDocument` have been merged into `JsonDocument`.
+>
+> In ArduinoJson 6, `JsonDocument` had a fixed capacity; in ArduinoJson 7, it has an elastic capacity that grows as needed.
+> Therefore, you don't need to specify the capacity anymore, so the macros `JSON_ARRAY_SIZE()`, `JSON_OBJECT_SIZE()`, and `JSON_STRING_SIZE()` have been removed.
+>
+> ```c++
+> // ArduinoJson 6
+> StaticJsonDocument<256> doc;
+> // or
+> DynamicJsonDocument doc(256);
+> 
+> // ArduinoJson 7
+> JsonDocument doc;
+> ```
+>
+> In ArduinoJson 7, `JsonDocument` reuses released memory, so `garbageCollect()` has been removed.  
+> `shrinkToFit()` is still available and releases the over-allocated memory.
+>
+> Due to a change in the implementation, it's not possible to store a pointer to a variant from another `JsonDocument`, so `shallowCopy()` has been removed.
+> 
+> In ArduinoJson 6, the meaning of `memoryUsage()` was clear: it returned the number of bytes used in the memory pool.  
+> In ArduinoJson 7, the meaning of `memoryUsage()` would be ambiguous, so it has been removed.
+>
+> #### Custom allocators
+>
+> In ArduinoJson 6, you could specify a custom allocator class as a template parameter of `BasicJsonDocument`.  
+> In ArduinoJson 7, you must inherit from `ArduinoJson::Allocator` and pass a pointer to an instance of your class to the constructor of `JsonDocument`.
+>
+> ```c++
+> // ArduinoJson 6
+> class MyAllocator {
+>   // ...
+> };
+> BasicJsonDocument<MyAllocator> doc(256);
+>
+> // ArduinoJson 7
+> class MyAllocator : public ArduinoJson::Allocator {
+>   // ...
+> };
+> MyAllocator myAllocator;
+> JsonDocument doc(&myAllocator);
+> ```
+>
+> #### `createNestedArray()` and `createNestedObject()`
+>
+> In ArduinoJson 6, you could create a nested array or object with `createNestedArray()` and `createNestedObject()`.  
+> In ArduinoJson 7, you must use `add<T>()` or `to<T>()` instead.
+>
+> For example, to create `[[],{}]`, you would write:
+>
+> ```c++
+> // ArduinoJson 6
+> arr.createNestedArray();
+> arr.createNestedObject();
+>
+> // ArduinoJson 7
+> arr.add<JsonArray>();
+> arr.add<JsonObject>();
+> ```
+>
+> And to create `{"array":[],"object":{}}`, you would write:
+>
+> ```c++
+> // ArduinoJson 6
+> obj.createNestedArray("array");
+> obj.createNestedObject("object");
+>
+> // ArduinoJson 7
+> obj["array"].to<JsonArray>();
+> obj["object"].to<JsonObject>();
+> ```

CMakeLists.txt

@@ -1,5 +1,5 @@
 # ArduinoJson - https://arduinojson.org
-# Copyright © 2014-2023, Benoit BLANCHON
+# Copyright © 2014-2025, Benoit BLANCHON
 # MIT License
 
 cmake_minimum_required(VERSION 3.15)
@@ -10,7 +10,7 @@ if(ESP_PLATFORM)
 	return()
 endif()
 
-project(ArduinoJson VERSION 7.0.0)
+project(ArduinoJson VERSION 7.4.1)
 
 if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
 	include(CTest)

LICENSE.txt

@@ -1,7 +1,7 @@
 The MIT License (MIT)
 ---------------------
 
-Copyright © 2014-2023, Benoit BLANCHON
+Copyright © 2014-2025, Benoit BLANCHON
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 

README.md

@@ -15,29 +15,28 @@ ArduinoJson is a C++ JSON library for Arduino and IoT (Internet Of Things).
 
 ## Features
 
-* [JSON deserialization](https://arduinojson.org/v6/api/json/deserializejson/)
-    * [Optionally decodes UTF-16 escape sequences to UTF-8](https://arduinojson.org/v6/api/config/decode_unicode/)
-    * [Optionally stores links to the input buffer (zero-copy)](https://arduinojson.org/v6/api/json/deserializejson/)
-    * [Optionally supports comments in the input](https://arduinojson.org/v6/api/config/enable_comments/)
-    * [Optionally filters the input to keep only desired values](https://arduinojson.org/v6/api/json/deserializejson/#filtering)
+* [JSON deserialization](https://arduinojson.org/v7/api/json/deserializejson/)
+    * [Optionally decodes UTF-16 escape sequences to UTF-8](https://arduinojson.org/v7/api/config/decode_unicode/)
+    * [Optionally supports comments in the input](https://arduinojson.org/v7/api/config/enable_comments/)
+    * [Optionally filters the input to keep only desired values](https://arduinojson.org/v7/api/json/deserializejson/#filtering)
     * Supports single quotes as a string delimiter
     * Compatible with [NDJSON](http://ndjson.org/) and [JSON Lines](https://jsonlines.org/)
-* [JSON serialization](https://arduinojson.org/v6/api/json/serializejson/)
-    * [Can write to a buffer or a stream](https://arduinojson.org/v6/api/json/serializejson/)
-    * [Optionally indents the document (prettified JSON)](https://arduinojson.org/v6/api/json/serializejsonpretty/)
-* [MessagePack serialization](https://arduinojson.org/v6/api/msgpack/serializemsgpack/)
-* [MessagePack deserialization](https://arduinojson.org/v6/api/msgpack/deserializemsgpack/)
+* [JSON serialization](https://arduinojson.org/v7/api/json/serializejson/)
+    * [Can write to a buffer or a stream](https://arduinojson.org/v7/api/json/serializejson/)
+    * [Optionally indents the document (prettified JSON)](https://arduinojson.org/v7/api/json/serializejsonpretty/)
+* [MessagePack serialization](https://arduinojson.org/v7/api/msgpack/serializemsgpack/)
+* [MessagePack deserialization](https://arduinojson.org/v7/api/msgpack/deserializemsgpack/)
 * Efficient
     * [Twice smaller than the "official" Arduino_JSON library](https://arduinojson.org/2019/11/19/arduinojson-vs-arduino_json/)
     * [Almost 10% faster than the "official" Arduino_JSON library](https://arduinojson.org/2019/11/19/arduinojson-vs-arduino_json/)
     * [Consumes roughly 10% less RAM than the "official" Arduino_JSON library](https://arduinojson.org/2019/11/19/arduinojson-vs-arduino_json/)
     * [Deduplicates strings](https://arduinojson.org/news/2020/08/01/version-6-16-0/)
 * Versatile
-    * Supports [custom allocators (to use external RAM chip, for example)](https://arduinojson.org/v6/how-to/use-external-ram-on-esp32/)
-    * Supports [`String`](https://arduinojson.org/v6/api/config/enable_arduino_string/), [`std::string`](https://arduinojson.org/v6/api/config/enable_std_string/), and [`std::string_view`](https://arduinojson.org/v6/api/config/enable_string_view/)
-    * Supports [`Stream`](https://arduinojson.org/v6/api/config/enable_arduino_stream/) and [`std::istream`/`std::ostream`](https://arduinojson.org/v6/api/config/enable_std_stream/)
-    * Supports [Flash strings](https://arduinojson.org/v6/api/config/enable_progmem/)
-    * Supports [custom readers](https://arduinojson.org/v6/api/json/deserializejson/#custom-reader) and [custom writers](https://arduinojson.org/v6/api/json/serializejson/#custom-writer)
+    * Supports [custom allocators (to use external RAM chip, for example)](https://arduinojson.org/v7/how-to/use-external-ram-on-esp32/)
+    * Supports [`String`](https://arduinojson.org/v7/api/config/enable_arduino_string/), [`std::string`](https://arduinojson.org/v7/api/config/enable_std_string/), and [`std::string_view`](https://arduinojson.org/v7/api/config/enable_string_view/)
+    * Supports [`Stream`](https://arduinojson.org/v7/api/config/enable_arduino_stream/) and [`std::istream`/`std::ostream`](https://arduinojson.org/v7/api/config/enable_std_stream/)
+    * Supports [Flash strings](https://arduinojson.org/v7/api/config/enable_progmem/)
+    * Supports [custom readers](https://arduinojson.org/v7/api/json/deserializejson/#custom-reader) and [custom writers](https://arduinojson.org/v7/api/json/serializejson/#custom-writer)
     * Supports [custom converters](https://arduinojson.org/news/2021/05/04/version-6-18-0/)
 * Portable
     * Usable on any C++ project (not limited to Arduino)
@@ -67,29 +66,29 @@ ArduinoJson is a C++ JSON library for Arduino and IoT (Internet Of Things).
         * [Visual Micro](http://www.visualmicro.com/)
         * [Visual Studio](https://www.visualstudio.com/)
     * [Even works with online compilers like wandbox.org](https://wandbox.org/permlink/RlZSKy17DjJ6HcdN)
-    * [CMake friendly](https://arduinojson.org/v6/how-to/use-arduinojson-with-cmake/)
+    * [CMake friendly](https://arduinojson.org/v7/how-to/use-arduinojson-with-cmake/)
 * Well designed
-    * [Elegant API](http://arduinojson.org/v6/example/)
+    * [Elegant API](http://arduinojson.org/v7/example/)
     * [Thread-safe](https://en.wikipedia.org/wiki/Thread_safety)
     * Self-contained (no external dependency)
     * `const` friendly
-    * [`for` friendly](https://arduinojson.org/v6/api/jsonobject/begin_end/)
+    * [`for` friendly](https://arduinojson.org/v7/api/jsonobject/begin_end/)
     * [TMP friendly](https://en.wikipedia.org/wiki/Template_metaprogramming)
-    * Handles [integer overflows](https://arduinojson.org/v6/api/jsonvariant/as/#integer-overflows)
+    * Handles [integer overflows](https://arduinojson.org/v7/api/jsonvariant/as/#integer-overflows)
 * Well tested
     * [Unit test coverage close to 100%](https://coveralls.io/github/bblanchon/ArduinoJson?branch=7.x)
     * Continuously tested on
         * [Visual Studio 2017, 2019, 2022](https://ci.appveyor.com/project/bblanchon/arduinojson/branch/7.x)
-        * [GCC 5, 6, 7, 8, 9, 10, 11](https://github.com/bblanchon/ArduinoJson/actions?query=workflow%3A%22Continuous+Integration%22)
-        * [Clang 3.8, 3.9, 4.0, 5.0, 6.0, 7, 8, 9, 10](https://github.com/bblanchon/ArduinoJson/actions?query=workflow%3A%22Continuous+Integration%22)
+        * [GCC 4.8, 5, 6, 7, 8, 9, 10, 11, 12](https://github.com/bblanchon/ArduinoJson/actions?query=workflow%3A%22Continuous+Integration%22)
+        * [Clang 7 to 19](https://github.com/bblanchon/ArduinoJson/actions?query=workflow%3A%22Continuous+Integration%22)
     * [Continuously fuzzed with Google OSS Fuzz](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:arduinojson)
     * Passes all default checks of [clang-tidy](https://releases.llvm.org/10.0.0/tools/clang/tools/extra/docs/clang-tidy/)
 * Well documented
-    * [Tutorials](https://arduinojson.org/v6/doc/deserialization/)
-    * [Examples](https://arduinojson.org/v6/example/)
-    * [How-tos](https://arduinojson.org/v6/example/)
-    * [FAQ](https://arduinojson.org/v6/faq/)
-    * [Troubleshooter](https://arduinojson.org/v6/troubleshooter/)
+    * [Tutorials](https://arduinojson.org/v7/doc/deserialization/)
+    * [Examples](https://arduinojson.org/v7/example/)
+    * [How-tos](https://arduinojson.org/v7/example/)
+    * [FAQ](https://arduinojson.org/v7/faq/)
+    * [Troubleshooter](https://arduinojson.org/v7/troubleshooter/)
     * [Book](https://arduinojson.org/book/)
     * [Changelog](CHANGELOG.md)
 * Vibrant user community
@@ -104,9 +103,9 @@ ArduinoJson is a C++ JSON library for Arduino and IoT (Internet Of Things).
 Here is a program that parses a JSON document with ArduinoJson.
 
 ```c++
-char json[] = "{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";
+const char* json = "{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";
 
-JsonDocument doc(1024);
+JsonDocument doc;
 deserializeJson(doc, json);
 
 const char* sensor = doc["sensor"];
@@ -115,14 +114,14 @@ double latitude    = doc["data"][0];
 double longitude   = doc["data"][1];
 ```
 
-See the [tutorial on arduinojson.org](https://arduinojson.org/v6/doc/deserialization/)
+See the [tutorial on arduinojson.org](https://arduinojson.org/v7/doc/deserialization/)
 
 ### Serialization
 
 Here is a program that generates a JSON document with ArduinoJson:
 
 ```c++
-JsonDocument doc(1024);
+JsonDocument doc;
 
 doc["sensor"] = "gps";
 doc["time"]   = 1351824120;
@@ -134,7 +133,7 @@ serializeJson(doc, Serial);
 // {"sensor":"gps","time":1351824120,"data":[48.756080,2.302038]}
 ```
 
-See the [tutorial on arduinojson.org](https://arduinojson.org/v6/doc/serialization/)
+See the [tutorial on arduinojson.org](https://arduinojson.org/v7/doc/serialization/)
 
 ## Sponsors
 
@@ -149,6 +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: 7.0.0.{build}
+version: 7.4.1.{build}
 environment:
   matrix:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022

examples/JsonConfigFile/JsonConfigFile.ino

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to store your project configuration in a file.
@@ -17,18 +17,13 @@
 // * CLK  <-> pin 13
 // * CS   <-> pin 4
 //
-// https://arduinojson.org/v6/example/config/
+// https://arduinojson.org/v7/example/config/
 
 #include <ArduinoJson.h>
 #include <SD.h>
 #include <SPI.h>
 
 // Our configuration structure.
-//
-// Never use a JsonDocument to store the configuration!
-// A JsonDocument is *not* a permanent storage; it's only a temporary storage
-// used during the serialization phase. See:
-// https://arduinojson.org/v6/faq/why-must-i-create-a-separate-config-object/
 struct Config {
   char hostname[64];
   int port;
@@ -43,9 +38,7 @@ void loadConfiguration(const char* filename, Config& config) {
   File file = SD.open(filename);
 
   // Allocate a temporary JsonDocument
-  // Don't forget to change the capacity to match your requirements.
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(512);
+  JsonDocument doc;
 
   // Deserialize the JSON document
   DeserializationError error = deserializeJson(doc, file);
@@ -75,9 +68,7 @@ void saveConfiguration(const char* filename, const Config& config) {
   }
 
   // Allocate a temporary JsonDocument
-  // Don't forget to change the capacity to match your requirements.
-  // Use https://arduinojson.org/assistant to compute the capacity.
-  JsonDocument doc(256);
+  JsonDocument doc;
 
   // Set the values in the document
   doc["hostname"] = config.hostname;
@@ -145,7 +136,7 @@ void loop() {
 // ------------------
 //
 // File is an unbuffered stream, which is not optimal for ArduinoJson.
-// See: https://arduinojson.org/v6/how-to/improve-speed/
+// See: https://arduinojson.org/v7/how-to/improve-speed/
 
 // See also
 // --------

examples/JsonFilterExample/JsonFilterExample.ino

@@ -1,10 +1,10 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to use DeserializationOption::Filter
 //
-// https://arduinojson.org/v6/example/filter/
+// https://arduinojson.org/v7/example/filter/
 
 #include <ArduinoJson.h>
 
@@ -34,12 +34,12 @@ void setup() {
       "1000000,\"timezone\":0,\"sunrise\":1581492085,\"sunset\":1581527294}}");
 
   // The filter: it contains "true" for each value we want to keep
-  JsonDocument filter(200);
+  JsonDocument filter;
   filter["list"][0]["dt"] = true;
   filter["list"][0]["main"]["temp"] = true;
 
   // Deserialize the document
-  JsonDocument doc(400);
+  JsonDocument doc;
   deserializeJson(doc, input_json, DeserializationOption::Filter(filter));
 
   // Print the result

examples/JsonGeneratorExample/JsonGeneratorExample.ino

@@ -1,10 +1,10 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to generate a JSON document with ArduinoJson.
 //
-// https://arduinojson.org/v6/example/generator/
+// https://arduinojson.org/v7/example/generator/
 
 #include <ArduinoJson.h>
 
@@ -15,25 +15,18 @@ void setup() {
     continue;
 
   // Allocate the JSON document
-  //
-  // Inside the parentheses, 200 is the RAM allocated to this document.
-  // Don't forget to change this value to match your requirement.
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(200);
+  JsonDocument doc;
 
   // Add values in the document
-  //
   doc["sensor"] = "gps";
   doc["time"] = 1351824120;
 
-  // Add an array.
-  //
-  JsonArray data = doc.createNestedArray("data");
+  // Add an array
+  JsonArray data = doc["data"].to<JsonArray>();
   data.add(48.756080);
   data.add(2.302038);
 
-  // Generate the minified JSON and send it to the Serial port.
-  //
+  // Generate the minified JSON and send it to the Serial port
   serializeJson(doc, Serial);
   // The above line prints:
   // {"sensor":"gps","time":1351824120,"data":[48.756080,2.302038]}
@@ -41,8 +34,7 @@ void setup() {
   // Start a new line
   Serial.println();
 
-  // Generate the prettified JSON and send it to the Serial port.
-  //
+  // Generate the prettified JSON and send it to the Serial port
   serializeJsonPretty(doc, Serial);
   // The above line prints:
   // {

examples/JsonHttpClient/JsonHttpClient.ino

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to parse a JSON document in an HTTP response.
@@ -16,7 +16,7 @@
 //   ]
 // }
 //
-// https://arduinojson.org/v6/example/http-client/
+// https://arduinojson.org/v7/example/http-client/
 
 #include <ArduinoJson.h>
 #include <Ethernet.h>
@@ -25,7 +25,8 @@
 void setup() {
   // Initialize Serial port
   Serial.begin(9600);
-  while (!Serial) continue;
+  while (!Serial)
+    continue;
 
   // Initialize Ethernet library
   byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
@@ -77,8 +78,7 @@ void setup() {
   }
 
   // Allocate the JSON document
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(256);
+  JsonDocument doc;
 
   // Parse JSON object
   DeserializationError error = deserializeJson(doc, client);
@@ -108,7 +108,7 @@ void loop() {
 // ------------------
 //
 // EthernetClient is an unbuffered stream, which is not optimal for ArduinoJson.
-// See: https://arduinojson.org/v6/how-to/improve-speed/
+// See: https://arduinojson.org/v7/how-to/improve-speed/
 
 // See also
 // --------

examples/JsonParserExample/JsonParserExample.ino

@@ -1,10 +1,10 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to deserialize a JSON document with ArduinoJson.
 //
-// https://arduinojson.org/v6/example/parser/
+// https://arduinojson.org/v7/example/parser/
 
 #include <ArduinoJson.h>
 
@@ -15,34 +15,23 @@ void setup() {
     continue;
 
   // Allocate the JSON document
-  //
-  // Inside the parentheses, 200 is the capacity of the memory pool in bytes.
-  // Don't forget to change this value to match your JSON document.
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(200);
+  JsonDocument doc;
 
   // JSON input string.
-  //
-  // Using a char[], as shown here, enables the "zero-copy" mode. This mode uses
-  // the minimal amount of memory because the JsonDocument stores pointers to
-  // the input buffer.
-  // If you use another type of input, ArduinoJson must copy the strings from
-  // the input to the JsonDocument, so you need to increase the capacity of the
-  // JsonDocument.
-  char json[] =
+  const char* json =
       "{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";
 
   // Deserialize the JSON document
   DeserializationError error = deserializeJson(doc, json);
 
-  // Test if parsing succeeds.
+  // Test if parsing succeeds
   if (error) {
     Serial.print(F("deserializeJson() failed: "));
     Serial.println(error.f_str());
     return;
   }
 
-  // Fetch values.
+  // Fetch the values
   //
   // Most of the time, you can rely on the implicit casts.
   // In other case, you can do doc["time"].as<long>();
@@ -51,7 +40,7 @@ void setup() {
   double latitude = doc["data"][0];
   double longitude = doc["data"][1];
 
-  // Print values.
+  // Print the values
   Serial.println(sensor);
   Serial.println(time);
   Serial.println(latitude, 6);

examples/JsonServer/JsonServer.ino

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to implement an HTTP server that sends a JSON document
@@ -13,7 +13,7 @@
 //   "digital": [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0]
 // }
 //
-// https://arduinojson.org/v6/example/http-server/
+// https://arduinojson.org/v7/example/http-server/
 
 #include <ArduinoJson.h>
 #include <Ethernet.h>
@@ -57,11 +57,10 @@ void loop() {
     client.read();
 
   // Allocate a temporary JsonDocument
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(500);
+  JsonDocument doc;
 
   // Create the "analog" array
-  JsonArray analogValues = doc.createNestedArray("analog");
+  JsonArray analogValues = doc["analog"].to<JsonArray>();
   for (int pin = 0; pin < 6; pin++) {
     // Read the analog input
     int value = analogRead(pin);
@@ -71,7 +70,7 @@ void loop() {
   }
 
   // Create the "digital" array
-  JsonArray digitalValues = doc.createNestedArray("digital");
+  JsonArray digitalValues = doc["digital"].to<JsonArray>();
   for (int pin = 0; pin < 14; pin++) {
     // Read the digital input
     int value = digitalRead(pin);
@@ -103,7 +102,7 @@ void loop() {
 // ------------------
 //
 // EthernetClient is an unbuffered stream, which is not optimal for ArduinoJson.
-// See: https://arduinojson.org/v6/how-to/improve-speed/
+// See: https://arduinojson.org/v7/how-to/improve-speed/
 
 // See also
 // --------

examples/JsonUdpBeacon/JsonUdpBeacon.ino

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to send a JSON document to a UDP socket.
@@ -17,7 +17,7 @@
 // $ ncat -ulp 8888
 // See https://nmap.org/ncat/
 //
-// https://arduinojson.org/v6/example/udp-beacon/
+// https://arduinojson.org/v7/example/udp-beacon/
 
 #include <ArduinoJson.h>
 #include <Ethernet.h>
@@ -47,11 +47,10 @@ void setup() {
 
 void loop() {
   // Allocate a temporary JsonDocument
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(500);
+  JsonDocument doc;
 
   // Create the "analog" array
-  JsonArray analogValues = doc.createNestedArray("analog");
+  JsonArray analogValues = doc["analog"].to<JsonArray>();
   for (int pin = 0; pin < 6; pin++) {
     // Read the analog input
     int value = analogRead(pin);
@@ -61,7 +60,7 @@ void loop() {
   }
 
   // Create the "digital" array
-  JsonArray digitalValues = doc.createNestedArray("digital");
+  JsonArray digitalValues = doc["digital"].to<JsonArray>();
   for (int pin = 0; pin < 14; pin++) {
     // Read the digital input
     int value = digitalRead(pin);
@@ -91,7 +90,7 @@ void loop() {
 // ------------------
 //
 // EthernetUDP is an unbuffered stream, which is not optimal for ArduinoJson.
-// See: https://arduinojson.org/v6/how-to/improve-speed/
+// See: https://arduinojson.org/v7/how-to/improve-speed/
 
 // See also
 // --------

examples/MsgPackParser/MsgPackParser.ino

@@ -1,11 +1,11 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to deserialize a MessagePack document with
 // ArduinoJson.
 //
-// https://arduinojson.org/v6/example/msgpack-parser/
+// https://arduinojson.org/v7/example/msgpack-parser/
 
 #include <ArduinoJson.h>
 
@@ -16,20 +16,9 @@ void setup() {
     continue;
 
   // Allocate the JSON document
-  //
-  // Inside the parentheses, 200 is the capacity of the memory pool in bytes.
-  // Don't forget to change this value to match your JSON document.
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(200);
+  JsonDocument doc;
 
-  // MessagePack input string.
-  //
-  // Using a char[], as shown here, enables the "zero-copy" mode. This mode uses
-  // the minimal amount of memory because the JsonDocument stores pointers to
-  // the input buffer.
-  // If you use another type of input, ArduinoJson must copy the strings from
-  // the input to the JsonDocument, so you need to increase the capacity of the
-  // JsonDocument.
+  // The MessagePack input string
   uint8_t input[] = {131, 166, 115, 101, 110, 115, 111, 114, 163, 103, 112, 115,
                      164, 116, 105, 109, 101, 206, 80,  147, 50,  248, 164, 100,
                      97,  116, 97,  146, 203, 64,  72,  96,  199, 58,  188, 148,
@@ -41,16 +30,17 @@ void setup() {
   //   "data": [48.75608, 2.302038]
   // }
 
+  // Parse the input
   DeserializationError error = deserializeMsgPack(doc, input);
 
-  // Test if parsing succeeded.
+  // Test if parsing succeeded
   if (error) {
     Serial.print("deserializeMsgPack() failed: ");
     Serial.println(error.f_str());
     return;
   }
 
-  // Fetch values.
+  // Fetch the values
   //
   // Most of the time, you can rely on the implicit casts.
   // In other case, you can do doc["time"].as<long>();
@@ -59,7 +49,7 @@ void setup() {
   double latitude = doc["data"][0];
   double longitude = doc["data"][1];
 
-  // Print values.
+  // Print the values
   Serial.println(sensor);
   Serial.println(time);
   Serial.println(latitude, 6);

examples/ProgmemExample/ProgmemExample.ino

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows the different ways you can use Flash strings with
@@ -9,12 +9,12 @@
 // JsonDocument. Prefer plain old char*, as they are more efficient in term of
 // code size, speed, and memory usage.
 //
-// https://arduinojson.org/v6/example/progmem/
+// https://arduinojson.org/v7/example/progmem/
 
 #include <ArduinoJson.h>
 
 void setup() {
-  JsonDocument doc(1024);
+  JsonDocument doc;
 
   // You can use a Flash String as your JSON input.
   // WARNING: the strings in the input will be duplicated in the JsonDocument.

examples/StringExample/StringExample.ino

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows the different ways you can use String with ArduinoJson.
@@ -8,12 +8,12 @@
 // JsonDocument. Prefer plain old char[], as they are more efficient in term of
 // code size, speed, and memory usage.
 //
-// https://arduinojson.org/v6/example/string/
+// https://arduinojson.org/v7/example/string/
 
 #include <ArduinoJson.h>
 
 void setup() {
-  JsonDocument doc(1024);
+  JsonDocument doc;
 
   // You can use a String as your JSON input.
   // WARNING: the string in the input  will be duplicated in the JsonDocument.
@@ -55,7 +55,6 @@ void setup() {
   }
 
   // Lastly, you can print the resulting JSON to a String
-  // WARNING: it doesn't replace the content but appends to it
   String output;
   serializeJson(doc, output);
 }

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
@@ -30,10 +34,20 @@ 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()
-		add_compile_options(-g -O0)
+	else() # GCC 4.8
+		add_compile_options(
+			-g
+			-O0 # GCC 4.8 doesn't support -Og
+			-Wno-shadow  # allow the same name for a function parameter and a member functions
+			-Wp,-w  # Disable preprocessing warnings (see below)
+		)
+		# GCC 4.8 doesn't support __has_include, so we need to help him
+		add_definitions(
+			-DARDUINOJSON_ENABLE_STD_STRING=1
+			-DARDUINOJSON_ENABLE_STD_STREAM=1
+		)
 	endif()
 
 	add_compile_options(
@@ -64,6 +78,9 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 endif()
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+	add_compile_options(-stdlib=libc++)
+	link_libraries(c++ m)
+
 	if((CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.0) AND(NOT ${COVERAGE}))
 		add_compile_options(-g -Og)
 	else()

extras/ci/espidf/CMakeLists.txt

@@ -1,5 +1,5 @@
 # ArduinoJson - https://arduinojson.org
-# Copyright © 2014-2023, Benoit BLANCHON
+# Copyright © 2014-2025, Benoit BLANCHON
 # MIT License
 
 cmake_minimum_required(VERSION 3.5)

extras/ci/espidf/main/CMakeLists.txt

@@ -1,5 +1,5 @@
 # ArduinoJson - https://arduinojson.org
-# Copyright © 2014-2023, Benoit BLANCHON
+# Copyright © 2014-2025, Benoit BLANCHON
 # MIT License
 
 idf_component_register(

extras/ci/espidf/main/main.cpp

@@ -1,12 +1,12 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #include <ArduinoJson.h>
 
 extern "C" void app_main() {
   char buffer[256];
-  JsonDocument doc(200);
+  JsonDocument doc;
 
   doc["hello"] = "world";
   serializeJson(doc, buffer);

extras/conf_test/avr.cpp

@@ -4,15 +4,15 @@ static_assert(ARDUINOJSON_ENABLE_PROGMEM == 1, "ARDUINOJSON_ENABLE_PROGMEM");
 
 static_assert(ARDUINOJSON_USE_LONG_LONG == 0, "ARDUINOJSON_USE_LONG_LONG");
 
-static_assert(ARDUINOJSON_SLOT_OFFSET_SIZE == 1,
-              "ARDUINOJSON_SLOT_OFFSET_SIZE");
+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(sizeof(ArduinoJson::detail::VariantData) == 6, "slot size");
 
 void setup() {}
 void loop() {}

extras/conf_test/esp8266.cpp

@@ -2,15 +2,15 @@
 
 static_assert(ARDUINOJSON_USE_LONG_LONG == 1, "ARDUINOJSON_USE_LONG_LONG");
 
-static_assert(ARDUINOJSON_SLOT_OFFSET_SIZE == 2,
-              "ARDUINOJSON_SLOT_OFFSET_SIZE");
+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(sizeof(ArduinoJson::detail::VariantData) == 8, "slot size");
 
 void setup() {}
 void loop() {}

extras/conf_test/x64.cpp

@@ -2,14 +2,14 @@
 
 static_assert(ARDUINOJSON_USE_LONG_LONG == 1, "ARDUINOJSON_USE_LONG_LONG");
 
-static_assert(ARDUINOJSON_SLOT_OFFSET_SIZE == 4,
-              "ARDUINOJSON_SLOT_OFFSET_SIZE");
+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) == 32,
-              "sizeof(VariantSlot)");
+static_assert(sizeof(ArduinoJson::detail::VariantData) == 16, "slot size");
 
 int main() {}

extras/conf_test/x86.cpp

@@ -2,14 +2,14 @@
 
 static_assert(ARDUINOJSON_USE_LONG_LONG == 1, "ARDUINOJSON_USE_LONG_LONG");
 
-static_assert(ARDUINOJSON_SLOT_OFFSET_SIZE == 2,
-              "ARDUINOJSON_SLOT_OFFSET_SIZE");
+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(sizeof(ArduinoJson::detail::VariantData) == 8, "slot size");
 
 int main() {}

extras/fuzzing/CMakeLists.txt

@@ -1,5 +1,5 @@
 # ArduinoJson - https://arduinojson.org
-# Copyright © 2014-2023, Benoit BLANCHON
+# Copyright © 2014-2025, Benoit BLANCHON
 # MIT License
 
 set(CMAKE_CXX_STANDARD 11)
@@ -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/fuzzing/json_fuzzer.cpp

@@ -1,7 +1,7 @@
 #include <ArduinoJson.h>
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  JsonDocument doc(4096);
+  JsonDocument doc;
   DeserializationError error = deserializeJson(doc, data, size);
   if (!error) {
     std::string json;

extras/fuzzing/msgpack_fuzzer.cpp

@@ -1,7 +1,7 @@
 #include <ArduinoJson.h>
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  JsonDocument doc(4096);
+  JsonDocument doc;
   DeserializationError error = deserializeMsgPack(doc, data, size);
   if (!error) {
     std::string json;

extras/fuzzing/reproducer.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 // This file is NOT use by Google's OSS fuzz

extras/scripts/build-arduino-package.sh

@@ -1,23 +0,0 @@
-#!/bin/bash
-
-set -eu
-
-INPUT=$1
-OUTPUT=$2
-
-cd "$INPUT"
-
-# remove existing file
-rm -f "$OUTPUT"
-
-# create zip
-7z a "$OUTPUT" \
-	-xr!.vs \
-	CHANGELOG.md \
-	examples \
-	src \
-	keywords.txt \
-	library.properties \
-	LICENSE.txt \
-	README.md \
-	ArduinoJson.h

extras/scripts/extract_changes.awk

@@ -0,0 +1,29 @@
+#!/usr/bin/awk -f
+
+# Start echoing after the first list item
+/\* / {
+    STARTED=1
+    EMPTY_LINE=0
+}
+
+# Remember if we have seen an empty line
+/^[[:space:]]*$/ {
+    EMPTY_LINE=1
+}
+
+# Exit when seeing a new version number
+/^v[[:digit:]]/ {
+    if (STARTED) exit
+}
+
+# Print if the line is not empty
+# and restore the empty line we have skipped
+!/^[[:space:]]*$/ {
+    if (STARTED) {
+        if (EMPTY_LINE) {
+            print ""
+            EMPTY_LINE=0
+        }
+        print
+    }
+}

extras/scripts/get-release-body.sh

@@ -1,14 +0,0 @@
-#!/bin/bash
-
-set -eu
-
-TAG="$1"
-CHANGELOG="$2"
-
-cat << END
-## Changes
-
-$(awk '/\* /{ FOUND=1 } /^[[:space:]]*$/ { if(FOUND) exit } { if(FOUND) print }' "$CHANGELOG")
-
-[View version history](https://github.com/bblanchon/ArduinoJson/blob/$TAG/CHANGELOG.md)
-END

extras/scripts/get-release-page.sh

@@ -4,15 +4,15 @@ set -eu
 
 VERSION="$1"
 CHANGELOG="$2"
-FRONTMATTER="$3"
+ARDUINOJSON_H="$3"
 
 cat << END
 ---
-branch: v6
+branch: v7
 version: $VERSION
 date: '$(date +'%Y-%m-%d')'
-$(cat "$FRONTMATTER")
+$(extras/scripts/wandbox/publish.sh "$ARDUINOJSON_H")
 ---
 
-$(awk '/\* /{ FOUND=1; print; next } { if (FOUND) exit}' "$CHANGELOG")
+$(extras/scripts/extract_changes.awk "$CHANGELOG")
 END

extras/scripts/publish.sh

@@ -2,7 +2,7 @@
 
 set -eu
 
-which awk sed jq 7z curl perl >/dev/null
+which awk sed jq curl perl >/dev/null
 
 cd "$(dirname "$0")/../.."
 
@@ -15,6 +15,7 @@ VERSION="$1"
 DATE=$(date +%F)
 TAG="v$VERSION"
 VERSION_REGEX='[0-9]+\.[0-9]+\.[0-9]+(-[a-z0-9]+)?'
+STARS=$(curl -s https://api.github.com/repos/bblanchon/ArduinoJson | jq '.stargazers_count')
 
 update_version_in_source () {
 	IFS=".-" read MAJOR MINOR REVISION EXTRA < <(echo "$VERSION")
@@ -29,16 +30,25 @@ update_version_in_source () {
 	sed -i~ -bE "s/(project\\s*\\(ArduinoJson\\s+VERSION\\s+).*?\\)/\\1$MAJOR.$MINOR.$REVISION)/" CMakeLists.txt
 	rm CMakeLists.txt~
 
-	sed -i~ -bE "s/\"version\":.*$/\"version\": \"$VERSION\",/" library.json
+	sed -i~ -bE \
+		-e "s/\"version\":.*$/\"version\": \"$VERSION\",/" \
+		-e "s/[0-9]+ stars/$STARS stars/" \
+		library.json
 	rm library.json~
 
-	sed -i~ -bE "s/version=.*$/version=$VERSION/" library.properties
+	sed -i~ -bE \
+		-e "s/version=.*$/version=$VERSION/" \
+		-e "s/[0-9]+ stars/$STARS stars/" \
+		library.properties
 	rm library.properties~
 
 	sed -i~ -bE "s/version: .*$/version: $VERSION.{build}/" appveyor.yml
 	rm appveyor.yml~
 
-	sed -i~ -bE "s/^version: .*$/version: \"$VERSION\"/" idf_component.yml
+	sed -i~ -bE \
+		-e "s/^version: .*$/version: \"$VERSION\"/" \
+		-e "s/[0-9]+ stars/$STARS stars/" \
+		idf_component.yml
 	rm idf_component.yml~
 
 	sed -i~ -bE \
@@ -70,10 +80,8 @@ commit_new_version
 add_tag
 push
 
-extras/scripts/build-arduino-package.sh . "../ArduinoJson-$TAG.zip"
 extras/scripts/build-single-header.sh "src/ArduinoJson.h" "../ArduinoJson-$TAG.h"
 extras/scripts/build-single-header.sh "src/ArduinoJson.hpp" "../ArduinoJson-$TAG.hpp"
-extras/scripts/wandbox/publish.sh "../ArduinoJson-$TAG.h" > "../ArduinoJson-$TAG-wandbox.txt" || echo "Wandbox failed!"
-extras/scripts/get-release-page.sh "$VERSION" "CHANGELOG.md" "../ArduinoJson-$TAG-wandbox.txt" > "../ArduinoJson-$TAG.md"
+extras/scripts/get-release-page.sh "$VERSION" "CHANGELOG.md" "../ArduinoJson-$TAG.h" > "../ArduinoJson-$TAG.md"
 
 echo "You can now copy ../ArduinoJson-$TAG.md into arduinojson.org/collections/_versions/$VERSION.md"

extras/scripts/wandbox/JsonGeneratorExample.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to generate a JSON document with ArduinoJson.
@@ -9,25 +9,18 @@
 
 int main() {
   // Allocate the JSON document
-  //
-  // Inside the parentheses, 200 is the RAM allocated to this document.
-  // Don't forget to change this value to match your requirement.
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(200);
+  JsonDocument doc;
 
-  // Add values in the document
-  //
+  // Add values in the document.
   doc["sensor"] = "gps";
   doc["time"] = 1351824120;
 
-  // Add an array.
-  //
-  JsonArray data = doc.createNestedArray("data");
+  // Add an array
+  JsonArray data = doc["data"].to<JsonArray>();
   data.add(48.756080);
   data.add(2.302038);
 
   // Generate the minified JSON and send it to STDOUT
-  //
   serializeJson(doc, std::cout);
   // The above line prints:
   // {"sensor":"gps","time":1351824120,"data":[48.756080,2.302038]}
@@ -36,7 +29,6 @@ int main() {
   std::cout << std::endl;
 
   // Generate the prettified JSON and send it to STDOUT
-  //
   serializeJsonPretty(doc, std::cout);
   // The above line prints:
   // {

extras/scripts/wandbox/JsonParserExample.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to deserialize a JSON document with ArduinoJson.
@@ -9,33 +9,22 @@
 
 int main() {
   // Allocate the JSON document
-  //
-  // Inside the parentheses, 200 is the capacity of the memory pool in bytes.
-  // Don't forget to change this value to match your JSON document.
-  // Use https://arduinojson.org/v6/assistant to compute the capacity.
-  JsonDocument doc(300);
+  JsonDocument doc;
 
-  // JSON input string.
-  //
-  // Using a char[], as shown here, enables the "zero-copy" mode. This mode uses
-  // the minimal amount of memory because the JsonDocument stores pointers to
-  // the input buffer.
-  // If you use another type of input, ArduinoJson must copy the strings from
-  // the input to the JsonDocument, so you need to increase the capacity of the
-  // JsonDocument.
-  char json[] =
+  // JSON input string
+  const char* json =
       "{\"sensor\":\"gps\",\"time\":1351824120,\"data\":[48.756080,2.302038]}";
 
   // Deserialize the JSON document
   DeserializationError error = deserializeJson(doc, json);
 
-  // Test if parsing succeeds.
+  // Test if parsing succeeds
   if (error) {
     std::cerr << "deserializeJson() failed: " << error.c_str() << std::endl;
     return 1;
   }
 
-  // Fetch values.
+  // Fetch the values
   //
   // Most of the time, you can rely on the implicit casts.
   // In other case, you can do doc["time"].as<long>();
@@ -44,7 +33,7 @@ int main() {
   double latitude = doc["data"][0];
   double longitude = doc["data"][1];
 
-  // Print values.
+  // Print the values
   std::cout << sensor << std::endl;
   std::cout << time << std::endl;
   std::cout << latitude << std::endl;

extras/scripts/wandbox/MsgPackParserExample.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 //
 // This example shows how to generate a JSON document with ArduinoJson.
@@ -9,17 +9,9 @@
 
 int main() {
   // Allocate the JSON document
-  //
-  // Inside the parentheses, 300 is the size of the memory pool in bytes.
-  // Don't forget to change this value to match your JSON document.
-  // Use https://arduinojson.org/assistant to compute the capacity.
-  JsonDocument doc(300);
+  JsonDocument doc;
 
-  // MessagePack input string.
-  //
-  // It's better to use a char[] as shown here.
-  // If you use a const char* or a String, ArduinoJson will
-  // have to make a copy of the input in the JsonBuffer.
+  // The MessagePack input string
   uint8_t input[] = {131, 166, 115, 101, 110, 115, 111, 114, 163, 103, 112, 115,
                      164, 116, 105, 109, 101, 206, 80,  147, 50,  248, 164, 100,
                      97,  116, 97,  146, 203, 64,  72,  96,  199, 58,  188, 148,
@@ -31,20 +23,16 @@ int main() {
   //   "data": [48.75608, 2.302038]
   // }
 
-  // doc of the object tree.
-  //
-  // It's a reference to the JsonObject, the actual bytes are inside the
-  // JsonBuffer with all the other nodes of the object tree.
-  // Memory is freed when jsonBuffer goes out of scope.
+  // Parse the input
   DeserializationError error = deserializeMsgPack(doc, input);
 
-  // Test if parsing succeeds.
+  // Test if parsing succeeds
   if (error) {
     std::cerr << "deserializeMsgPack() failed: " << error.c_str() << std::endl;
     return 1;
   }
 
-  // Fetch values.
+  // Fetch the values
   //
   // Most of the time, you can rely on the implicit casts.
   // In other case, you can do doc["time"].as<long>();
@@ -53,7 +41,7 @@ int main() {
   double latitude = doc["data"][0];
   double longitude = doc["data"][1];
 
-  // Print values.
+  // Print the values
   std::cout << sensor << std::endl;
   std::cout << time << std::endl;
   std::cout << latitude << std::endl;

extras/scripts/wandbox/publish.sh

@@ -15,7 +15,7 @@ compile() {
   "code":$(read_string "$FILE_PATH"),
   "codes": [{"file":"ArduinoJson.h","code":$(read_string "$ARDUINOJSON_H")}],
   "options": "warning,c++11",
-  "compiler": "gcc-5.5.0",
+  "compiler": "gcc-head",
   "save": true
 }
 END

extras/tests/CMakeLists.txt

@@ -1,25 +1,32 @@
 # ArduinoJson - https://arduinojson.org
-# Copyright © 2014-2023, Benoit BLANCHON
+# Copyright © 2014-2025, Benoit BLANCHON
 # MIT License
 
 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(FailingBuilds)
+add_subdirectory(Deprecated)
 add_subdirectory(IntegrationTests)
 add_subdirectory(JsonArray)
+add_subdirectory(JsonArrayConst)
 add_subdirectory(JsonDeserializer)
 add_subdirectory(JsonDocument)
 add_subdirectory(JsonObject)
+add_subdirectory(JsonObjectConst)
 add_subdirectory(JsonSerializer)
 add_subdirectory(JsonVariant)
+add_subdirectory(JsonVariantConst)
 add_subdirectory(ResourceManager)
 add_subdirectory(Misc)
 add_subdirectory(MixedConfiguration)

extras/tests/Cpp17/CMakeLists.txt

@@ -1,5 +1,5 @@
 # ArduinoJson - https://arduinojson.org
-# Copyright © 2014-2023, Benoit BLANCHON
+# Copyright © 2014-2025, Benoit BLANCHON
 # MIT License
 
 if(MSVC_VERSION LESS 1910)

extras/tests/Cpp17/string_view.cpp

@@ -1,17 +1,28 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+// we expect ArduinoJson.h to include <string_view>
+// but we don't want it to included accidentally
+#undef ARDUINO
+#define ARDUINOJSON_ENABLE_STD_STREAM 0
+#define ARDUINOJSON_ENABLE_STD_STRING 0
+
 #include <ArduinoJson.h>
 #include <catch.hpp>
 
-#include <string_view>
+#include "Allocators.hpp"
+#include "Literals.hpp"
 
 #if !ARDUINOJSON_ENABLE_STRING_VIEW
 #  error ARDUINOJSON_ENABLE_STRING_VIEW must be set to 1
 #endif
 
 using ArduinoJson::detail::sizeofArray;
-using ArduinoJson::detail::sizeofString;
 
 TEST_CASE("string_view") {
-  JsonDocument doc(256);
+  SpyingAllocator spy;
+  JsonDocument doc(&spy);
   JsonVariant variant = doc.to<JsonVariant>();
 
   SECTION("deserializeJson()") {
@@ -22,7 +33,7 @@ TEST_CASE("string_view") {
 
   SECTION("JsonDocument::set()") {
     doc.set(std::string_view("123", 2));
-    REQUIRE(doc.as<std::string>() == "12");
+    REQUIRE(doc.as<std::string_view>() == "12");
   }
 
   SECTION("JsonDocument::operator[]() const") {
@@ -56,18 +67,15 @@ TEST_CASE("string_view") {
 
   SECTION("String deduplication") {
     doc.add(std::string_view("example one", 7));
-    REQUIRE(doc.memoryUsage() == sizeofArray(1) + sizeofString(7));
-
     doc.add(std::string_view("example two", 7));
-    REQUIRE(doc.memoryUsage() == sizeofArray(2) + sizeofString(7));
-
     doc.add(std::string_view("example\0tree", 12));
-    REQUIRE(doc.memoryUsage() ==
-            sizeofArray(3) + sizeofString(7) + sizeofString(12));
-
     doc.add(std::string_view("example\0tree and a half", 12));
-    REQUIRE(doc.memoryUsage() ==
-            sizeofArray(4) + sizeofString(7) + sizeofString(12));
+
+    REQUIRE(spy.log() == AllocatorLog{
+                             Allocate(sizeofPool()),
+                             Allocate(sizeofString("example")),
+                             Allocate(sizeofString("example tree")),
+                         });
   }
 
   SECTION("as<std::string_view>()") {
@@ -85,7 +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/Cpp20/CMakeLists.txt

@@ -1,5 +1,5 @@
 # ArduinoJson - https://arduinojson.org
-# Copyright © 2014-2023, Benoit BLANCHON
+# Copyright © 2014-2025, Benoit BLANCHON
 # MIT License
 
 if(MSVC_VERSION LESS 1910)

extras/tests/Cpp20/smoke_test.cpp

@@ -4,7 +4,7 @@
 #include <string>
 
 TEST_CASE("C++20 smoke test") {
-  JsonDocument doc(128);
+  JsonDocument doc;
 
   deserializeJson(doc, "{\"hello\":\"world\"}");
   REQUIRE(doc["hello"] == "world");

extras/tests/Deprecated/BasicJsonDocument.cpp

@@ -0,0 +1,69 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+#include <string>
+
+using ArduinoJson::detail::is_base_of;
+
+static std::string allocatorLog;
+
+struct CustomAllocator {
+  CustomAllocator() {
+    allocatorLog = "";
+  }
+
+  void* allocate(size_t n) {
+    allocatorLog += "A";
+    return malloc(n);
+  }
+
+  void deallocate(void* p) {
+    free(p);
+    allocatorLog += "D";
+  }
+
+  void* reallocate(void* p, size_t n) {
+    allocatorLog += "R";
+    return realloc(p, n);
+  }
+};
+
+TEST_CASE("BasicJsonDocument") {
+  allocatorLog.clear();
+
+  SECTION("is a JsonDocument") {
+    REQUIRE(
+        is_base_of<JsonDocument, BasicJsonDocument<CustomAllocator>>::value ==
+        true);
+  }
+
+  SECTION("deserialize / serialize") {
+    BasicJsonDocument<CustomAllocator> doc(256);
+    deserializeJson(doc, "{\"hello\":\"world\"}");
+    REQUIRE(doc.as<std::string>() == "{\"hello\":\"world\"}");
+    doc.clear();
+    REQUIRE(allocatorLog == "AARARDDD");
+  }
+
+  SECTION("copy") {
+    BasicJsonDocument<CustomAllocator> doc(256);
+    doc["hello"] = "world";
+    auto copy = doc;
+    REQUIRE(copy.as<std::string>() == "{\"hello\":\"world\"}");
+    REQUIRE(allocatorLog == "AAAA");
+  }
+
+  SECTION("capacity") {
+    BasicJsonDocument<CustomAllocator> doc(256);
+    REQUIRE(doc.capacity() == 256);
+  }
+
+  SECTION("garbageCollect()") {
+    BasicJsonDocument<CustomAllocator> doc(256);
+    doc.garbageCollect();
+  }
+}

extras/tests/Deprecated/CMakeLists.txt

@@ -0,0 +1,35 @@
+# ArduinoJson - https://arduinojson.org
+# Copyright © 2014-2025, Benoit BLANCHON
+# MIT License
+
+if(CMAKE_CXX_COMPILER_ID MATCHES "(GNU|Clang)")
+	add_compile_options(
+		-w
+	)
+endif()
+
+if(MSVC)
+	add_compile_options(
+		/wd4996
+	)
+endif()
+
+add_executable(DeprecatedTests
+	add.cpp
+	BasicJsonDocument.cpp
+	containsKey.cpp
+	createNestedArray.cpp
+	createNestedObject.cpp
+	DynamicJsonDocument.cpp
+	macros.cpp
+	memoryUsage.cpp
+	shallowCopy.cpp
+	StaticJsonDocument.cpp
+)
+
+add_test(Deprecated DeprecatedTests)
+
+set_tests_properties(Deprecated
+	PROPERTIES
+	LABELS "Catch"
+)

extras/tests/Deprecated/DynamicJsonDocument.cpp

@@ -0,0 +1,37 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using ArduinoJson::detail::is_base_of;
+
+TEST_CASE("DynamicJsonDocument") {
+  SECTION("is a JsonDocument") {
+    REQUIRE(is_base_of<JsonDocument, DynamicJsonDocument>::value == true);
+  }
+
+  SECTION("deserialize / serialize") {
+    DynamicJsonDocument doc(256);
+    deserializeJson(doc, "{\"hello\":\"world\"}");
+    REQUIRE(doc.as<std::string>() == "{\"hello\":\"world\"}");
+  }
+
+  SECTION("copy") {
+    DynamicJsonDocument doc(256);
+    doc["hello"] = "world";
+    auto copy = doc;
+    REQUIRE(copy.as<std::string>() == "{\"hello\":\"world\"}");
+  }
+
+  SECTION("capacity") {
+    DynamicJsonDocument doc(256);
+    REQUIRE(doc.capacity() == 256);
+  }
+
+  SECTION("garbageCollect()") {
+    DynamicJsonDocument doc(256);
+    doc.garbageCollect();
+  }
+}

extras/tests/Deprecated/StaticJsonDocument.cpp

@@ -0,0 +1,32 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using ArduinoJson::detail::is_base_of;
+
+TEST_CASE("StaticJsonDocument") {
+  SECTION("is a JsonDocument") {
+    REQUIRE(is_base_of<JsonDocument, StaticJsonDocument<256>>::value == true);
+  }
+
+  SECTION("deserialize / serialize") {
+    StaticJsonDocument<256> doc;
+    deserializeJson(doc, "{\"hello\":\"world\"}");
+    REQUIRE(doc.as<std::string>() == "{\"hello\":\"world\"}");
+  }
+
+  SECTION("copy") {
+    StaticJsonDocument<256> doc;
+    doc["hello"] = "world";
+    auto copy = doc;
+    REQUIRE(copy.as<std::string>() == "{\"hello\":\"world\"}");
+  }
+
+  SECTION("capacity") {
+    StaticJsonDocument<256> doc;
+    REQUIRE(doc.capacity() == 256);
+  }
+}

extras/tests/Deprecated/add.cpp

@@ -0,0 +1,38 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonArray::add()") {
+  JsonDocument doc;
+  JsonArray array = doc.to<JsonArray>();
+  array.add().set(42);
+  REQUIRE(doc.as<std::string>() == "[42]");
+}
+
+TEST_CASE("JsonDocument::add()") {
+  JsonDocument doc;
+  doc.add().set(42);
+  REQUIRE(doc.as<std::string>() == "[42]");
+}
+
+TEST_CASE("ElementProxy::add()") {
+  JsonDocument doc;
+  doc[0].add().set(42);
+  REQUIRE(doc.as<std::string>() == "[[42]]");
+}
+
+TEST_CASE("MemberProxy::add()") {
+  JsonDocument doc;
+  doc["x"].add().set(42);
+  REQUIRE(doc.as<std::string>() == "{\"x\":[42]}");
+}
+
+TEST_CASE("JsonVariant::add()") {
+  JsonDocument doc;
+  JsonVariant v = doc.add();
+  v.add().set(42);
+  REQUIRE(doc.as<std::string>() == "[[42]]");
+}

extras/tests/Deprecated/containsKey.cpp

@@ -0,0 +1,246 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, 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;
+  const 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

@@ -0,0 +1,113 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+#include <string>
+
+#include "Literals.hpp"
+
+TEST_CASE("JsonDocument::createNestedArray()") {
+  JsonDocument doc;
+
+  SECTION("createNestedArray()") {
+    JsonArray array = doc.createNestedArray();
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "[[42]]");
+  }
+
+  SECTION("createNestedArray(const char*)") {
+    JsonArray array = doc.createNestedArray("key");
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+
+  SECTION("createNestedArray(std::string)") {
+    JsonArray array = doc.createNestedArray("key"_s);
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("createNestedArray(VLA)") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "key");
+    JsonArray array = doc.createNestedArray(vla);
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+#endif
+}
+
+TEST_CASE("JsonArray::createNestedArray()") {
+  JsonDocument doc;
+  JsonArray array = doc.to<JsonArray>();
+  JsonArray nestedArray = array.createNestedArray();
+  nestedArray.add(42);
+  REQUIRE(doc.as<std::string>() == "[[42]]");
+}
+
+TEST_CASE("JsonObject::createNestedArray()") {
+  JsonDocument doc;
+  JsonObject object = doc.to<JsonObject>();
+
+  SECTION("createNestedArray(const char*)") {
+    JsonArray array = object.createNestedArray("key");
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+
+  SECTION("createNestedArray(std::string)") {
+    JsonArray array = object.createNestedArray("key"_s);
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("createNestedArray(VLA)") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "key");
+    JsonArray array = object.createNestedArray(vla);
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+#endif
+}
+
+TEST_CASE("JsonVariant::createNestedArray()") {
+  JsonDocument doc;
+  JsonVariant variant = doc.to<JsonVariant>();
+
+  SECTION("createNestedArray()") {
+    JsonArray array = variant.createNestedArray();
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "[[42]]");
+  }
+
+  SECTION("createNestedArray(const char*)") {
+    JsonArray array = variant.createNestedArray("key");
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+
+  SECTION("createNestedArray(std::string)") {
+    JsonArray array = variant.createNestedArray("key"_s);
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("createNestedArray(VLA)") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "key");
+    JsonArray array = variant.createNestedArray(vla);
+    array.add(42);
+    REQUIRE(doc.as<std::string>() == "{\"key\":[42]}");
+  }
+#endif
+}

extras/tests/Deprecated/createNestedObject.cpp

@@ -0,0 +1,113 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+#include <string>
+
+#include "Literals.hpp"
+
+TEST_CASE("JsonDocument::createNestedObject()") {
+  JsonDocument doc;
+
+  SECTION("createNestedObject()") {
+    JsonObject object = doc.createNestedObject();
+    object["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "[{\"hello\":\"world\"}]");
+  }
+
+  SECTION("createNestedObject(const char*)") {
+    JsonObject object = doc.createNestedObject("key");
+    object["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+
+  SECTION("createNestedObject(std::string)") {
+    JsonObject object = doc.createNestedObject("key"_s);
+    object["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("createNestedObject(VLA)") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "key");
+    JsonObject object = doc.createNestedObject(vla);
+    object["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+#endif
+}
+
+TEST_CASE("JsonArray::createNestedObject()") {
+  JsonDocument doc;
+  JsonArray array = doc.to<JsonArray>();
+  JsonObject object = array.createNestedObject();
+  object["hello"] = "world";
+  REQUIRE(doc.as<std::string>() == "[{\"hello\":\"world\"}]");
+}
+
+TEST_CASE("JsonObject::createNestedObject()") {
+  JsonDocument doc;
+  JsonObject object = doc.to<JsonObject>();
+
+  SECTION("createNestedObject(const char*)") {
+    JsonObject nestedObject = object.createNestedObject("key");
+    nestedObject["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+
+  SECTION("createNestedObject(std::string)") {
+    JsonObject nestedObject = object.createNestedObject("key"_s);
+    nestedObject["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("createNestedObject(VLA)") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "key");
+    JsonObject nestedObject = object.createNestedObject(vla);
+    nestedObject["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+#endif
+}
+
+TEST_CASE("JsonVariant::createNestedObject()") {
+  JsonDocument doc;
+  JsonVariant variant = doc.to<JsonVariant>();
+
+  SECTION("createNestedObject()") {
+    JsonObject object = variant.createNestedObject();
+    object["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "[{\"hello\":\"world\"}]");
+  }
+
+  SECTION("createNestedObject(const char*)") {
+    JsonObject object = variant.createNestedObject("key");
+    object["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+
+  SECTION("createNestedObject(std::string)") {
+    JsonObject object = variant.createNestedObject("key"_s);
+    object["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("createNestedObject(VLA)") {
+    size_t i = 16;
+    char vla[i];
+    strcpy(vla, "key");
+    JsonObject object = variant.createNestedObject(vla);
+    object["hello"] = "world";
+    REQUIRE(doc.as<std::string>() == "{\"key\":{\"hello\":\"world\"}}");
+  }
+#endif
+}

extras/tests/Deprecated/macros.cpp

@@ -0,0 +1,18 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JSON_ARRAY_SIZE") {
+  REQUIRE(JSON_ARRAY_SIZE(10) == ArduinoJson::detail::sizeofArray(10));
+}
+
+TEST_CASE("JSON_OBJECT_SIZE") {
+  REQUIRE(JSON_OBJECT_SIZE(10) == ArduinoJson::detail::sizeofObject(10));
+}
+
+TEST_CASE("JSON_STRING_SIZE") {
+  REQUIRE(JSON_STRING_SIZE(10) == 11);  // issue #2054
+}

extras/tests/Deprecated/memoryUsage.cpp

@@ -0,0 +1,51 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonArray::memoryUsage()") {
+  JsonArray array;
+  REQUIRE(array.memoryUsage() == 0);
+}
+
+TEST_CASE("JsonArrayConst::memoryUsage()") {
+  JsonArrayConst array;
+  REQUIRE(array.memoryUsage() == 0);
+}
+
+TEST_CASE("JsonDocument::memoryUsage()") {
+  JsonDocument doc;
+  REQUIRE(doc.memoryUsage() == 0);
+}
+
+TEST_CASE("JsonObject::memoryUsage()") {
+  JsonObject array;
+  REQUIRE(array.memoryUsage() == 0);
+}
+
+TEST_CASE("JsonObjectConst::memoryUsage()") {
+  JsonObjectConst array;
+  REQUIRE(array.memoryUsage() == 0);
+}
+
+TEST_CASE("JsonVariant::memoryUsage()") {
+  JsonVariant doc;
+  REQUIRE(doc.memoryUsage() == 0);
+}
+
+TEST_CASE("JsonVariantConst::memoryUsage()") {
+  JsonVariantConst doc;
+  REQUIRE(doc.memoryUsage() == 0);
+}
+
+TEST_CASE("ElementProxy::memoryUsage()") {
+  JsonDocument doc;
+  REQUIRE(doc[0].memoryUsage() == 0);
+}
+
+TEST_CASE("MemberProxy::memoryUsage()") {
+  JsonDocument doc;
+  REQUIRE(doc["hello"].memoryUsage() == 0);
+}

extras/tests/Deprecated/shallowCopy.cpp

@@ -0,0 +1,14 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("shallowCopy()") {
+  JsonDocument doc1, doc2;
+  doc1["b"] = "c";
+  doc2["a"].shallowCopy(doc1);
+
+  REQUIRE(doc2.as<std::string>() == "{\"a\":{\"b\":\"c\"}}");
+}

extras/tests/FailingBuilds/CMakeLists.txt

@@ -1,8 +1,12 @@
 # ArduinoJson - https://arduinojson.org
-# Copyright © 2014-2023, Benoit BLANCHON
+# Copyright © 2014-2025, 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/Issue978.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #include <ArduinoJson.h>
@@ -8,6 +8,6 @@ struct Stream {};
 
 int main() {
   Stream* stream = 0;
-  JsonDocument doc(1024);
+  JsonDocument doc;
   deserializeJson(doc, stream);
 }

extras/tests/FailingBuilds/assign_char.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #include <ArduinoJson.h>
@@ -7,6 +7,6 @@
 // See issue #1498
 
 int main() {
-  JsonDocument doc(1024);
+  JsonDocument doc;
   doc["dummy"] = 'A';
 }

extras/tests/FailingBuilds/deserialize_object.cpp

@@ -0,0 +1,12 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+
+// See issue #2135
+
+int main() {
+  JsonObject obj;
+  deserializeJson(obj, "");
+}

extras/tests/FailingBuilds/read_long_long.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #define ARDUINOJSON_USE_LONG_LONG 0
@@ -11,6 +11,6 @@
 
 ARDUINOJSON_ASSERT_INTEGER_TYPE_IS_SUPPORTED(long long)
 int main() {
-  JsonDocument doc(1024);
+  JsonDocument doc;
   doc["dummy"].as<long long>();
 }

extras/tests/FailingBuilds/variant_as_char.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #include <ArduinoJson.h>
@@ -7,6 +7,6 @@
 // See issue #1498
 
 int main() {
-  JsonDocument doc(1024);
+  JsonDocument doc;
   doc["dummy"].as<char>();
 }

extras/tests/FailingBuilds/write_long_long.cpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #define ARDUINOJSON_USE_LONG_LONG 0
@@ -10,6 +10,6 @@
 #endif
 
 int main() {
-  JsonDocument doc(1024);
+  JsonDocument doc;
   doc["dummy"] = static_cast<long long>(42);
 }

extras/tests/Helpers/Allocators.hpp

@@ -1,13 +1,17 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #pragma once
 
 #include <ArduinoJson/Memory/Allocator.hpp>
+#include <ArduinoJson/Memory/MemoryPool.hpp>
+#include <ArduinoJson/Memory/StringBuilder.hpp>
 
 #include <sstream>
 
+namespace {
+
 struct FailingAllocator : ArduinoJson::Allocator {
   static FailingAllocator* instance() {
     static FailingAllocator allocator;
@@ -29,41 +33,72 @@ struct FailingAllocator : ArduinoJson::Allocator {
   }
 };
 
+class AllocatorLogEntry {
+ public:
+  AllocatorLogEntry(std::string s, size_t n = 1) : str_(s), count_(n) {}
+
+  const std::string& str() const {
+    return str_;
+  }
+
+  size_t count() const {
+    return count_;
+  }
+
+  AllocatorLogEntry operator*(size_t n) const {
+    return AllocatorLogEntry(str_, n);
+  }
+
+ private:
+  std::string str_;
+  size_t count_;
+};
+
+inline AllocatorLogEntry Allocate(size_t s) {
+  char buffer[32];
+  snprintf(buffer, sizeof(buffer), "allocate(%zu)", s);
+  return AllocatorLogEntry(buffer);
+}
+
+inline AllocatorLogEntry AllocateFail(size_t s) {
+  char buffer[32];
+  snprintf(buffer, sizeof(buffer), "allocate(%zu) -> nullptr", s);
+  return AllocatorLogEntry(buffer);
+}
+
+inline AllocatorLogEntry Reallocate(size_t s1, size_t s2) {
+  char buffer[32];
+  snprintf(buffer, sizeof(buffer), "reallocate(%zu, %zu)", s1, s2);
+  return AllocatorLogEntry(buffer);
+}
+
+inline AllocatorLogEntry ReallocateFail(size_t s1, size_t s2) {
+  char buffer[32];
+  snprintf(buffer, sizeof(buffer), "reallocate(%zu, %zu) -> nullptr", s1, s2);
+  return AllocatorLogEntry(buffer);
+}
+
+inline AllocatorLogEntry Deallocate(size_t s) {
+  char buffer[32];
+  snprintf(buffer, sizeof(buffer), "deallocate(%zu)", s);
+  return AllocatorLogEntry(buffer);
+}
+
 class AllocatorLog {
  public:
-  static std::string Allocate(size_t s) {
-    char buffer[32];
-    sprintf(buffer, "allocate(%zu)", s);
-    return buffer;
+  AllocatorLog() = default;
+  AllocatorLog(std::initializer_list<AllocatorLogEntry> list) {
+    for (auto& entry : list)
+      append(entry);
   }
 
-  static std::string AllocateFail(size_t s) {
-    char buffer[32];
-    sprintf(buffer, "allocate(%zu) -> nullptr", s);
-    return buffer;
+  void clear() {
+    log_.str("");
   }
 
-  static std::string Reallocate(size_t s1, size_t s2) {
-    char buffer[32];
-    sprintf(buffer, "reallocate(%zu, %zu)", s1, s2);
-    return buffer;
-  };
-
-  static std::string ReallocateFail(size_t s1, size_t s2) {
-    char buffer[32];
-    sprintf(buffer, "reallocate(%zu, %zu) -> nullptr", s1, s2);
-    return buffer;
-  };
-
-  static std::string Deallocate(size_t s) {
-    char buffer[32];
-    sprintf(buffer, "deallocate(%zu)", s);
-    return buffer;
-  };
-
-  AllocatorLog& operator<<(const std::string& s) {
-    log_ << s << "\n";
-    return *this;
+  void append(const AllocatorLogEntry& entry) {
+    for (size_t i = 0; i < entry.count(); i++)
+      log_ << entry.str() << "\n";
   }
 
   std::string str() const {
@@ -94,43 +129,49 @@ class SpyingAllocator : public ArduinoJson::Allocator {
       : upstream_(upstream) {}
   virtual ~SpyingAllocator() {}
 
+  size_t allocatedBytes() const {
+    return allocatedBytes_;
+  }
+
   void* allocate(size_t n) override {
     auto block = reinterpret_cast<AllocatedBlock*>(
         upstream_->allocate(sizeof(AllocatedBlock) + n - 1));
     if (block) {
-      log_ << AllocatorLog::Allocate(n);
+      log_.append(Allocate(n));
+      allocatedBytes_ += n;
       block->size = n;
       return block->payload;
     } else {
-      log_ << AllocatorLog::AllocateFail(n);
+      log_.append(AllocateFail(n));
       return nullptr;
     }
   }
 
   void deallocate(void* p) override {
     auto block = AllocatedBlock::fromPayload(p);
-    log_ << AllocatorLog::Deallocate(block->size);
+    allocatedBytes_ -= block->size;
+    log_.append(Deallocate(block ? block->size : 0));
     upstream_->deallocate(block);
   }
 
   void* reallocate(void* p, size_t n) override {
     auto block = AllocatedBlock::fromPayload(p);
-    auto oldSize = block->size;
+    auto oldSize = block ? block->size : 0;
     block = reinterpret_cast<AllocatedBlock*>(
         upstream_->reallocate(block, sizeof(AllocatedBlock) + n - 1));
     if (block) {
-      log_ << AllocatorLog::Reallocate(oldSize, n);
-      ARDUINOJSON_ASSERT(block->size == oldSize);
+      log_.append(Reallocate(oldSize, n));
       block->size = n;
+      allocatedBytes_ += n - oldSize;
       return block->payload;
     } else {
-      log_ << AllocatorLog::ReallocateFail(oldSize, n);
+      log_.append(ReallocateFail(oldSize, n));
       return nullptr;
     }
   }
 
   void clearLog() {
-    log_ = AllocatorLog();
+    log_.clear();
   }
 
   const AllocatorLog& log() const {
@@ -143,6 +184,8 @@ class SpyingAllocator : public ArduinoJson::Allocator {
     char payload[1];
 
     static AllocatedBlock* fromPayload(void* p) {
+      if (!p)
+        return nullptr;
       return reinterpret_cast<AllocatedBlock*>(
           // Cast to void* to silence "cast increases required alignment of
           // target type [-Werror=cast-align]"
@@ -153,17 +196,18 @@ class SpyingAllocator : public ArduinoJson::Allocator {
 
   AllocatorLog log_;
   Allocator* upstream_;
+  size_t allocatedBytes_ = 0;
 };
 
-class ControllableAllocator : public ArduinoJson::Allocator {
+class KillswitchAllocator : public ArduinoJson::Allocator {
  public:
-  ControllableAllocator(
+  KillswitchAllocator(
       Allocator* upstream = ArduinoJson::detail::DefaultAllocator::instance())
-      : enabled_(true), upstream_(upstream) {}
-  virtual ~ControllableAllocator() {}
+      : working_(true), upstream_(upstream) {}
+  virtual ~KillswitchAllocator() {}
 
   void* allocate(size_t n) override {
-    return enabled_ ? upstream_->allocate(n) : 0;
+    return working_ ? upstream_->allocate(n) : 0;
   }
 
   void deallocate(void* p) override {
@@ -171,15 +215,16 @@ class ControllableAllocator : public ArduinoJson::Allocator {
   }
 
   void* reallocate(void* ptr, size_t n) override {
-    return enabled_ ? upstream_->reallocate(ptr, n) : 0;
+    return working_ ? upstream_->reallocate(ptr, n) : 0;
   }
 
-  void disable() {
-    enabled_ = false;
+  // Turn the killswitch on, so all allocation fail
+  void on() {
+    working_ = false;
   }
 
  private:
-  bool enabled_;
+  bool working_;
   Allocator* upstream_;
 };
 
@@ -217,3 +262,33 @@ class TimebombAllocator : public ArduinoJson::Allocator {
   size_t countdown_ = 0;
   Allocator* upstream_;
 };
+}  // namespace
+
+inline size_t sizeofPoolList(size_t n = ARDUINOJSON_INITIAL_POOL_COUNT) {
+  using namespace ArduinoJson::detail;
+  return sizeof(MemoryPool<VariantData>) * n;
+}
+
+template <typename T = ArduinoJson::detail::VariantData>
+inline size_t sizeofPool(
+    ArduinoJson::detail::SlotCount n = ARDUINOJSON_POOL_CAPACITY) {
+  return ArduinoJson::detail::MemoryPool<T>::slotsToBytes(n);
+}
+
+inline size_t sizeofStaticStringPool(
+    ArduinoJson::detail::SlotCount n = ARDUINOJSON_POOL_CAPACITY) {
+  using namespace ArduinoJson::detail;
+  return MemoryPool<const char*>::slotsToBytes(n);
+}
+
+inline size_t sizeofStringBuffer(size_t iteration = 1) {
+  // returns 31, 63, 127, 255, etc.
+  auto capacity = ArduinoJson::detail::StringBuilder::initialCapacity;
+  for (size_t i = 1; i < iteration; i++)
+    capacity = capacity * 2 + 1;
+  return ArduinoJson::detail::sizeofString(capacity);
+}
+
+inline size_t sizeofString(const char* s) {
+  return ArduinoJson::detail::sizeofString(strlen(s));
+}

extras/tests/Helpers/Arduino.h

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #pragma once

extras/tests/Helpers/CustomReader.hpp

@@ -1,5 +1,5 @@
 // ArduinoJson - https://arduinojson.org
-// Copyright © 2014-2023, Benoit BLANCHON
+// Copyright © 2014-2025, Benoit BLANCHON
 // MIT License
 
 #pragma once

extras/tests/Helpers/Literals.hpp

@@ -0,0 +1,12 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2025, 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);
+}