Build: Use the "new" FindPython mode and binary size optimizations (#104)

* Use "new" FindPython mode

- set explicit cmake versions
- Use of the "new" FindPython mode remove annoying CMP0148 warning
- Add INTERPROCEDURAL_OPTIMIZATION
  optimize binary size: libPythonRuntime.so is now 5M lighter (from 27M to 22M - Linux x64 gcc13)

* macos-12 fixes

* Fix GHA Windows build

* Windows port to new find_python

* Align python versions in CI

* Enhance macOS CI

* Use setup python for macOS

Author: rjanvier

.github/workflows/Build.yml

@@ -156,25 +156,32 @@ jobs:
         with:
           path: 'plugins/private/CloudCompare-PythonRuntime'
 
+      - name : setup-python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.8'
+          cache: 'pip'
+
+
       - name: Install Dependencies
         run: |
-          brew install qt@5 ninja pybind11
-          python3 -m pip install pytest
-          echo "CMAKE_PREFIX_PATH=/usr/local/opt/qt@5" >> $GITHUB_ENV
+          brew install qt@5 ninja
+          echo "CMAKE_PREFIX_PATH=$(brew --prefix qt@5)" >> $GITHUB_ENV
+          pip install --upgrade pip
+          pip install pytest pybind11
 
       - name: Configure CMake
-        shell: pwsh
         run: |
           mkdir build
-          cmake  `
-            --log-level=debug `
-            -G Ninja `
-            -B build `
-            -DCMAKE_BUILD_TYPE=Release `
-            -DOPTION_BUILD_CCVIEWER=OFF `
-            -DCMAKE_INSTALL_PREFIX=install `
-            -DPLUGIN_PYTHON=ON `
-            -DPLUGIN_STANDARD_QM3C2=ON `
+          cmake \
+            --log-level=debug \
+            -G Ninja \
+            -B build \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DOPTION_BUILD_CCVIEWER=OFF \
+            -DCMAKE_INSTALL_PREFIX=install \
+            -DPLUGIN_PYTHON=ON \
+            -DPLUGIN_STANDARD_QM3C2=ON \
             .
 
       - name: Build
@@ -184,7 +191,8 @@ jobs:
         run: sudo cmake --install build
 
       - name: Run Tests
-        run: cmake --build build --target pytest
+        run: |
+          cmake --build build --target pytest
 
 
   Windows-Wheels:
@@ -199,7 +207,7 @@ jobs:
         with:
           activate-environment: CloudCompareDev
           auto-activate-base: false
-          python-version: "3.7"
+          python-version: "3.8"
           miniconda-version: 'latest'
 
       - name: Install Dependencies
@@ -289,7 +297,7 @@ jobs:
           source venv/bin/activate
           python -m pip install --upgrade pip
           python -m pip install pytest
-          echo "CMAKE_PREFIX_PATH=/usr/local/opt/qt@5" >> $GITHUB_ENV
+          echo "CMAKE_PREFIX_PATH=$(brew --prefix qt@5)" >> $GITHUB_ENV
 
       - name: pip install cccorelib
         working-directory: "./wrapper"

CMakeLists.txt

@@ -1,3 +1,5 @@
+cmake_minimum_required(VERSION 3.15..3.27)
+
 include(cmake/Helpers.cmake)
 include(cmake/CompilerWarnings.cmake)
 include(cmake/PythonEnvHelper.cmake)
@@ -10,29 +12,23 @@ if(PLUGIN_PYTHON)
 
   addplugin(NAME ${PROJECT_NAME})
 
+  find_package(Python 3.8 COMPONENTS Interpreter Development REQUIRED)
+  ensure_pybind11_cmake_module_is_in_path()
+  find_package(pybind11 CONFIG REQUIRED)
+
   option(PLUGIN_PYTHON_USE_EMBEDDED_MODULES
          "Should the Python wrapper libs be embedded in the plugin" ON
   )
   mark_as_advanced(PLUGIN_PYTHON_USE_EMBEDDED_MODULES)
 
   if(WIN32)
     option(PLUGIN_PYTHON_COPY_ENV
-           "Should the content of the current python venv be copied on install"
+           "Should the content of the current python site-package be copied on install"
            ON
     )
     mark_as_advanced(PLUGIN_PYTHON_COPY_ENV)
   endif()
-
-  if(NOT PYTHON_EXECUTABLE)
-    set_python_executable_from_current_venv()
-  endif()
-
-  if(PYTHON_EXECUTABLE)
-    ensure_pybind11_cmake_module_is_in_path()
-  endif()
-
-  find_package(pybind11 CONFIG REQUIRED)
-
+  
   add_subdirectory(wrapper)
   add_subdirectory(src)
 
@@ -44,7 +40,7 @@ if(PLUGIN_PYTHON)
   endif()
 
   target_link_libraries(${PROJECT_NAME} pybind11::embed)
-  set_target_properties(${PROJECT_NAME} PROPERTIES CXX_VISIBILITY_PRESET hidden)
+  set_target_properties(${PROJECT_NAME} PROPERTIES INTERPROCEDURAL_OPTIMIZATION ON CXX_VISIBILITY_PRESET hidden)
 
   add_subdirectory(tests)
   add_subdirectory(docs)

cmake/Helpers.cmake

@@ -1,9 +1,7 @@
-# PYTHON_PREFIX & PYTHON_LIBRARY_SUFFIX come from pybind11 cmake
-
 # This function sets a global PYTHON_BASE_PREFIX cache variable
 function(getset_python_base_prefix)
   execute_process(
-    COMMAND "${PYTHON_EXECUTABLE}" "-c"
+    COMMAND "${Python_EXECUTABLE}" "-c"
             "import sys;print(sys.base_prefix.replace('\\\\', '/'), end='')"
     OUTPUT_VARIABLE PYTHON_BASE_PREFIX
   )
@@ -13,34 +11,34 @@ function(getset_python_base_prefix)
   )
 endfunction()
 
-function(copy_python_venv INSTALL_DIR)
+function(copy_python_env INSTALL_DIR)
   message(
     DEBUG
-    "Venv copy:
+    "ENV copy:
         PYTHON_BASE_PREFIX: ${PYTHON_BASE_PREFIX}
-        PYTHON_PREFIX:      ${PYTHON_PREFIX}
-        INSTALL_DIR:        ${INSTALL_DIR}"
+        PYTHON_SITELIB:     ${Python_SITELIB}
+        PYTHON_STDARCH:     ${Python_STDARCH}
+        PYTHON_STDLIB:      ${Python_STDLIB}
+        PYTHON_LIBRARIES:   ${Python_RUNTIME_LIBRARY_DIRS}"
   )
-  message(DEBUG "COPYING venv from ${PYTHON_BASE_PREFIX} to ${INSTALL_DIR}")
+  message(DEBUG "COPYING venv from ${Python_SITELIB}/ to ${INSTALL_DIR}/Lib/site-packages/")
   install(DIRECTORY "${PYTHON_BASE_PREFIX}/" DESTINATION "${INSTALL_DIR}")
 
-  if(NOT "${PYTHON_BASE_PREFIX}" STREQUAL "${PYTHON_PREFIX}")
-    install(DIRECTORY "${PYTHON_PREFIX}/Lib/site-packages/"
-            DESTINATION "${INSTALL_DIR}/Lib/site-packages/"
-    )
-  endif()
+  install(DIRECTORY "${Python_SITELIB}/"
+        DESTINATION "${INSTALL_DIR}/Lib/site-packages/"
+  )
 endfunction()
 
 function(copy_python_dll)
   message(
     DEBUG
-    "Python DLL: = ${PYTHON_BASE_PREFIX}/python${PYTHON_LIBRARY_SUFFIX}.dll"
+    "Python DLL: = ${Python_RUNTIME_LIBRARY_DIRS}/python${Python_VERSION_MAJOR}${Python_VERSION_MINOR}.dll"
   )
   install(
-    FILES "${PYTHON_BASE_PREFIX}/python${PYTHON_LIBRARY_SUFFIX}.dll"
+    FILES "${Python_RUNTIME_LIBRARY_DIRS}/python${Python_VERSION_MAJOR}${Python_VERSION_MINOR}.dll"
           # install the python3 base dll as well because some libs will try to
           # find it (PySide and PyQT for example)
-          "${PYTHON_BASE_PREFIX}/python3.dll"
+          "${Python_RUNTIME_LIBRARY_DIRS}/python${Python_VERSION_MAJOR}.dll"
     DESTINATION ${CLOUDCOMPARE_DEST_FOLDER}
   )
 endfunction()
@@ -50,7 +48,7 @@ function(manage_windows_install)
   getset_python_base_prefix()
 
   if(PLUGIN_PYTHON_COPY_ENV)
-    copy_python_venv(${CC_PYTHON_INSTALL_DIR})
+    copy_python_env(${CC_PYTHON_INSTALL_DIR})
   endif()
 
   copy_python_dll()

cmake/PythonEnvHelper.cmake

@@ -1,6 +1,6 @@
 macro(ensure_pybind11_cmake_module_is_in_path)
   execute_process(
-    COMMAND "${PYTHON_EXECUTABLE}" "-m" "pybind11" "--cmake"
+    COMMAND "${Python_EXECUTABLE}" "-m" "pybind11" "--cmake"
     RESULT_VARIABLE _PYTHON_SUCCESS
     OUTPUT_VARIABLE PYBIND11_CMAKE_MODULES_PATH
   )
@@ -15,23 +15,4 @@ macro(ensure_pybind11_cmake_module_is_in_path)
       WARNING "Failed to get pybind11 cmake prefix path ${_PYTHON_SUCCESS}"
     )
   endif()
-endmacro()
-
-macro(set_python_executable_from_current_venv)
-  if(WIN32)
-    if(DEFINED ENV{CONDA_PREFIX})
-      list(INSERT CMAKE_PREFIX_PATH 0 "$ENV{CONDA_PREFIX}/Library/share/cmake")
-      set(PYTHON_EXECUTABLE "$ENV{CONDA_PREFIX}/python.exe")
-    elseif(DEFINED ENV{VIRTUAL_ENV})
-      set(PYTHON_EXECUTABLE "$ENV{VIRTUAL_ENV}/Scripts/python.exe")
-    endif()
-  else()
-    if(DEFINED ENV{CONDA_PREFIX})
-      set(PYTHON_EXECUTABLE "$ENV{CONDA_PREFIX}/bin/python")
-    elseif(DEFINED ENV{VIRTUAL_ENV})
-      set(PYTHON_EXECUTABLE "$ENV{VIRTUAL_ENV}/bin/python")
-    else()
-      set(PYTHON_EXECUTABLE "python3")
-    endif()
-  endif()
-endmacro()
+endmacro()

tests/CMakeLists.txt

@@ -1,15 +1,15 @@
 if(WIN32 OR APPLE)
   add_custom_target(
     pytest
-    COMMAND ${PYTHON_EXECUTABLE} -m pytest --verbose --cloudcompare_exe
+    COMMAND ${Python_EXECUTABLE} -m pytest --verbose --cloudcompare_exe
             ${CLOUDCOMPARE_EXECUTABLE_INSTALL_PATH} ${CMAKE_CURRENT_LIST_DIR}
   )
 else()
   add_custom_target(
     pytest
     COMMAND
       ${CMAKE_COMMAND} -E env CC_PLUGIN_PATH=${CC_PLUGIN_PATH_VALUE}
-      ${PYTHON_EXECUTABLE} -m pytest --verbose --cloudcompare_exe
+      ${Python_EXECUTABLE} -m pytest --verbose --cloudcompare_exe
       ${CLOUDCOMPARE_EXECUTABLE_INSTALL_PATH} ${CMAKE_CURRENT_LIST_DIR}
   )
 endif()

wrapper/cccorelib/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.14)
+cmake_minimum_required(VERSION 3.15..3.27)
 project(pycccorelib LANGUAGES CXX)
 
 include("${CMAKE_CURRENT_LIST_DIR}/../../cmake/Helpers.cmake")
@@ -16,14 +16,6 @@ endif()
 add_subdirectory(src)
 
 if(CCCORELIB_PYTHON_IS_MASTER_PROJECT)
-  if(NOT PYTHON_EXECUTABLE)
-    set_python_executable_from_current_venv()
-  endif()
-
-  if(PYTHON_EXECUTABLE)
-    ensure_pybind11_cmake_module_is_in_path()
-  endif()
-
   include(FetchContent)
 
   set(FETCHCONTENT_QUIET OFF)
@@ -49,7 +41,10 @@ if(CCCORELIB_PYTHON_IS_MASTER_PROJECT)
 endif()
 
 if(CCCORELIB_PYTHON_IS_MASTER_PROJECT OR NOT PLUGIN_PYTHON_USE_EMBEDDED_MODULES)
+  find_package(Python 3.8 COMPONENTS Interpreter Development REQUIRED)
+  ensure_pybind11_cmake_module_is_in_path()
   find_package(pybind11 CONFIG REQUIRED)
+  
   pybind11_add_module(cccorelib ${cccorelib_sources})
   target_link_libraries(cccorelib PRIVATE CCCoreLib)
 

wrapper/pycc/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.14)
+cmake_minimum_required(VERSION 3.15..3.27)
 project(pycc LANGUAGES CXX)
 
 include("${CMAKE_CURRENT_LIST_DIR}/../../cmake/Helpers.cmake")
@@ -16,15 +16,11 @@ else()
 endif()
 
 if(PYCC_IS_MASTER_PROJECT)
-  message(DEBUG "PYTHON_EXECUTABLE: ${PYTHON_EXECUTABLE}")
-  if(NOT PYTHON_EXECUTABLE)
-    set_python_executable_from_current_venv()
-  endif()
+  message(DEBUG "Python_EXECUTABLE: ${Python_EXECUTABLE}")
 
-  message(DEBUG "PYTHON_EXECUTABLE: ${PYTHON_EXECUTABLE}")
-  if(PYTHON_EXECUTABLE)
-    ensure_pybind11_cmake_module_is_in_path()
-  endif()
+
+  message(DEBUG "Python_EXECUTABLE: ${Python_EXECUTABLE}")
+  ensure_pybind11_cmake_module_is_in_path()
 
   include(FetchContent)
 
@@ -51,6 +47,8 @@ if(PYCC_IS_MASTER_PROJECT)
   endif()
 endif()
 
+find_package(Python 3.8 COMPONENTS Interpreter Development REQUIRED)
+ensure_pybind11_cmake_module_is_in_path()
 find_package(pybind11 CONFIG REQUIRED)
 
 add_subdirectory(src)