Adjust CMake minimal version (#4709)

* 🔧 adjust CMake versions Signed-off-by: Niels Lohmann <mail@nlohmann.me> * 🔧 install OpenSSL for CMake Signed-off-by: Niels Lohmann <mail@nlohmann.me> * 🔧 install OpenSSL for CMake Signed-off-by: Niels Lohmann <mail@nlohmann.me> * 🔧 install OpenSSL for CMake Signed-off-by: Niels Lohmann <mail@nlohmann.me> * 🔧 install OpenSSL for CMake Signed-off-by: Niels Lohmann <mail@nlohmann.me> * 🔧 install OpenSSL for CMake Signed-off-by: Niels Lohmann <mail@nlohmann.me> * 🔨 clean up Signed-off-by: Niels Lohmann <mail@nlohmann.me> * 📝 update documentation Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2025-08-06 20:16:33 +08:00 · 2025-04-01 14:42:08 +02:00 · 2025-04-01 14:42:08 +02:00 · d41ca94fa8
commit d41ca94fa8
parent 3a5703931a
12 changed files with 47 additions and 30 deletions
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@ -23,7 +23,7 @@ jobs:
    steps:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@56d043d188c3612951d8755da8f4b709ec951ad6 # v3.31.6
+        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@ -54,7 +54,7 @@ jobs:
        run: sudo apt-get update ; sudo apt-get install -y valgrind
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@56d043d188c3612951d8755da8f4b709ec951ad6 # v3.31.6
+        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@ -71,7 +71,7 @@ jobs:
        run: apt-get update ; apt-get install -y git clang-tools iwyu unzip
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@56d043d188c3612951d8755da8f4b709ec951ad6 # v3.31.6
+        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@ -85,10 +85,10 @@ jobs:
        target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls]
    steps:
      - name: Install build-essential
-        run: apt-get update ; apt-get install -y build-essential unzip wget git
+        run: apt-get update ; apt-get install -y build-essential unzip wget git libssl-dev
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@56d043d188c3612951d8755da8f4b709ec951ad6 # v3.31.6
+        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@ -148,7 +148,7 @@ jobs:
    steps:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@56d043d188c3612951d8755da8f4b709ec951ad6 # v3.31.6
+        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@ -165,7 +165,7 @@ jobs:
        run: apt-get update ; apt-get install -y unzip git
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@56d043d188c3612951d8755da8f4b709ec951ad6 # v3.31.6
+        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
      - name: Set env FORCE_STDCPPFS_FLAG for clang 7 / 8 / 9 / 10
        run: echo "JSON_FORCED_GLOBAL_COMPILE_OPTIONS=-DJSON_HAS_FILESYSTEM=0;-DJSON_HAS_EXPERIMENTAL_FILESYSTEM=0" >> "$GITHUB_ENV"
        if: ${{ matrix.compiler == '7' || matrix.compiler == '8' || matrix.compiler == '9' || matrix.compiler == '10' }}
@ -183,7 +183,7 @@ jobs:
    steps:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@56d043d188c3612951d8755da8f4b709ec951ad6 # v3.31.6
+        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@ -201,7 +201,7 @@ jobs:
        run: apt-get update ; apt-get install -y git unzip
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@56d043d188c3612951d8755da8f4b709ec951ad6 # v3.31.6
+        uses: lukka/get-cmake@28983e0d3955dba2bb0a6810caae0c6cf268ec0c # v4.0.0
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build with libc++
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.14)
+cmake_minimum_required(VERSION 3.5...4.0)

 ##
 ## PROJECT
--- a/README.md
+++ b/README.md
@ -1144,7 +1144,7 @@ The library is used in multiple projects, applications, operating systems, etc.
 Though it's 2025 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:

 - GCC 4.8 - 14.2 (and possibly later)
- Clang 3.4 - 20.0 (and possibly later)
+- Clang 3.4 - 21.0 (and possibly later)
 - Apple Clang 9.1 - 16.0 (and possibly later)
 - Intel C++ Compiler 17.0.2 (and possibly later)
 - Nvidia CUDA Compiler 11.0.221 (and possibly later)
--- a/cmake/ci.cmake
+++ b/cmake/ci.cmake
@ -541,6 +541,11 @@ add_custom_target(ci_benchmarks
 # CMake flags
 ###############################################################################

+# we test the project with different CMake versions:
+# - CMake 3.5 (the earliest supported)
+# - CMake 3.31.6 (the latest 3.x release)
+# - CMake 4.0.0 (the latest release)
+
 function(ci_get_cmake version var)
    set(${var} ${PROJECT_BINARY_DIR}/cmake-${version}/bin/cmake)
    add_custom_command(
@ -548,26 +553,30 @@ function(ci_get_cmake version var)
        COMMAND wget -nc https://github.com/Kitware/CMake/releases/download/v${version}/cmake-${version}.tar.gz
        COMMAND tar xfz cmake-${version}.tar.gz
        COMMAND rm cmake-${version}.tar.gz
-        COMMAND ${CMAKE_COMMAND} -S cmake-${version} -B cmake-${version}
-        COMMAND ${CMAKE_COMMAND} --build cmake-${version} --parallel 10
+        # -DCMAKE_POLICY_VERSION_MINIMUM=3.5 required to compile older CMake versions with CMake 4.0.0
+        COMMAND cmake -S cmake-${version} -B cmake-${version} -DCMAKE_POLICY_VERSION_MINIMUM=3.5
+        COMMAND cmake --build cmake-${version} --parallel 10
        WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
        COMMENT "Download CMake ${version}"
    )
    set(${var} ${${var}} PARENT_SCOPE)
 endfunction()

-ci_get_cmake(3.1.0 CMAKE_3_1_0_BINARY)
-ci_get_cmake(3.13.0 CMAKE_3_13_0_BINARY)
+ci_get_cmake(3.5.0  CMAKE_3_5_0_BINARY)
+ci_get_cmake(3.31.6 CMAKE_3_31_6_BINARY)
+ci_get_cmake(4.0.0  CMAKE_4_0_0_BINARY)

-set(JSON_CMAKE_FLAGS_3_1_0 JSON_Diagnostics JSON_Diagnostic_Positions JSON_GlobalUDLs JSON_ImplicitConversions JSON_DisableEnumSerialization
+# the tests require CMake 3.13 or later, so they are excluded for CMake 3.5.0
+set(JSON_CMAKE_FLAGS_3_5_0 JSON_Diagnostics JSON_Diagnostic_Positions JSON_GlobalUDLs JSON_ImplicitConversions JSON_DisableEnumSerialization
    JSON_LegacyDiscardedValueComparison JSON_Install JSON_MultipleHeaders JSON_SystemInclude JSON_Valgrind)
-set(JSON_CMAKE_FLAGS_3_13_0 JSON_BuildTests)
+set(JSON_CMAKE_FLAGS_3_31_6 JSON_BuildTests ${JSON_CMAKE_FLAGS_3_31_6})
+set(JSON_CMAKE_FLAGS_4_0_0 JSON_BuildTests ${JSON_CMAKE_FLAGS_3_5_0})

 function(ci_add_cmake_flags_targets flag min_version)
    string(TOLOWER "ci_cmake_flag_${flag}" flag_target)
    string(REPLACE . _ min_version_var ${min_version})
    set(cmake_binary ${CMAKE_${min_version_var}_BINARY})
-    add_custom_target(${flag_target}
+    add_custom_target(${flag_target}_${min_version}_2
        COMMENT "Check CMake flag ${flag} (CMake ${CMAKE_VERSION})"
        COMMAND ${CMAKE_COMMAND}
            -Werror=dev
@ -587,12 +596,16 @@ function(ci_add_cmake_flags_targets flag min_version)
    set(JSON_CMAKE_FLAG_BUILD_DIRS ${JSON_CMAKE_FLAG_BUILD_DIRS} PARENT_SCOPE)
 endfunction()

-foreach(JSON_CMAKE_FLAG ${JSON_CMAKE_FLAGS_3_1_0})
-    ci_add_cmake_flags_targets(${JSON_CMAKE_FLAG} 3.1.0)
+foreach(JSON_CMAKE_FLAG ${JSON_CMAKE_FLAGS_3_5_0})
+    ci_add_cmake_flags_targets(${JSON_CMAKE_FLAG} 3.5.0)
 endforeach()

-foreach(JSON_CMAKE_FLAG ${JSON_CMAKE_FLAGS_3_13_0})
-    ci_add_cmake_flags_targets(${JSON_CMAKE_FLAG} 3.13.0)
+foreach(JSON_CMAKE_FLAG ${JSON_CMAKE_FLAGS_3_31_6})
+    ci_add_cmake_flags_targets(${JSON_CMAKE_FLAG} 3.31.6)
+endforeach()
+
+foreach(JSON_CMAKE_FLAG ${JSON_CMAKE_FLAGS_4_0_0})
+    ci_add_cmake_flags_targets(${JSON_CMAKE_FLAG} 4.0.0)
 endforeach()

 add_custom_target(ci_cmake_flags
@ -695,6 +708,6 @@ add_custom_target(ci_test_build_documentation
 ###############################################################################

 add_custom_target(ci_clean
-    COMMAND rm -fr ${PROJECT_BINARY_DIR}/build_* cmake-3.1.0-Darwin64 ${JSON_CMAKE_FLAG_BUILD_DIRS} ${single_binaries}
+    COMMAND rm -fr ${PROJECT_BINARY_DIR}/build_* cmake-3.5.0-Darwin64 ${JSON_CMAKE_FLAG_BUILD_DIRS} ${single_binaries}
    COMMENT "Clean generated directories"
 )
--- a/docs/mkdocs/docs/community/quality_assurance.md
+++ b/docs/mkdocs/docs/community/quality_assurance.md
@ -208,4 +208,7 @@ violations will result in a failed build.
    All library functions are exposed and usable by CMake.

 - [x] All library options are exposed as [CMake options](https://json.nlohmann.me/integration/cmake/) and tested.
- [x] The library is tested against the earliest supported CMake version.
+- [x] The library is tested against relevant CMake versions:
+  - CMake 3.5 (the earliest supported)
+  - CMake 3.31.6 (the latest 3.x release)
+  - CMake 4.0.0 (a very recent release)
--- a/docs/mkdocs/docs/home/customers.md
+++ b/docs/mkdocs/docs/home/customers.md
@ -111,6 +111,7 @@ the result of an internet search. If you know further customers of the library,
 - [**Autodesk Desktop**](https://damassets.autodesk.net/content/dam/autodesk/www/Company/legal-notices-trademarks/autodesk-desktop-platform-components/internal-autodesk-components-web-page-2023.pdf), a software platform developed by Autodesk for creating and managing desktop applications and services
 - [**Check Point**](https://www.checkpoint.com/about-us/copyright-and-trademarks/): a cybersecurity company specializing in threat prevention and network security solutions, offering a range of products designed to protect enterprises from cyber threats and ensure data integrity
 - [**Microsoft Office for Mac**](https://officecdnmac.microsoft.com/pr/legal/mac/OfficeforMacAttributions.html), a suite of productivity applications developed by Microsoft for macOS, including tools for word processing, spreadsheets, and presentations
+- [**Microsoft Teams**](https://www.microsoft.com/microsoft-teams/), a team collaboration application offering workspace chat and video conferencing, file storage, and integration of proprietary and third-party applications and services
 - [**Nexthink Infinity**](https://docs.nexthink.com/legal/services-terms/experience-open-source-software-licenses/infinity-2022.8-software-licenses): a digital employee experience management platform for monitoring and improving IT performance
 - [**Sophos Connect Client**](https://docs.sophos.com/nsg/licenses/SophosConnect/SophosConnectAttribution.html): a secure VPN client from Sophos that allows remote users to connect to their corporate network, ensuring secure access to resources and data
 - [**Stonebranch**](https://stonebranchdocs.atlassian.net/wiki/spaces/UA77/pages/799545647/Licenses+for+Third-Party+Libraries): a cloud-based cybersecurity solution that integrates backup, disaster recovery, and cybersecurity features to protect data and ensure business continuity for organizations
--- a/docs/mkdocs/docs/images/customers.png
+++ b/docs/mkdocs/docs/images/customers.png
--- a/docs/mkdocs/docs/integration/cmake.md
+++ b/docs/mkdocs/docs/integration/cmake.md
@ -15,7 +15,7 @@ and use the namespaced imported target from the generated package configuration:
 !!! example

    ```cmake title="CMakeLists.txt"
-    cmake_minimum_required(VERSION 3.1)
+    cmake_minimum_required(VERSION 3.5)
    project(ExampleProject LANGUAGES CXX)
    
    find_package(nlohmann_json 3.11.3 REQUIRED)
@ -35,7 +35,7 @@ To embed the library directly into an existing CMake project, place the entire s
 !!! example

    ```cmake title="CMakeLists.txt"
-    cmake_minimum_required(VERSION 3.1)
+    cmake_minimum_required(VERSION 3.5)
    project(ExampleProject LANGUAGES CXX)

    # If you only include this third party in PRIVATE source files, you do not need to install it
--- a/tests/cmake_add_subdirectory/project/CMakeLists.txt
+++ b/tests/cmake_add_subdirectory/project/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.14)
+cmake_minimum_required(VERSION 3.5...3.14)

 project(DummyImport CXX)

--- a/tests/cmake_import/project/CMakeLists.txt
+++ b/tests/cmake_import/project/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.14)
+cmake_minimum_required(VERSION 3.5...3.14)

 project(DummyImport CXX)

--- a/tests/cmake_import_minver/project/CMakeLists.txt
+++ b/tests/cmake_import_minver/project/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.14)
+cmake_minimum_required(VERSION 3.5...3.14)

 project(DummyImportMinVer CXX)

--- a/tests/cmake_target_include_directories/project/CMakeLists.txt
+++ b/tests/cmake_target_include_directories/project/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1...3.14)
+cmake_minimum_required(VERSION 3.5...3.14)

 project(DummyImport CXX)