COMP: Update to find_package(Python3)

.github/workflows/ci.yml

@@ -41,6 +41,7 @@ jobs:
         if: ${{ matrix.qt-major-version == 5 }}
         run: |
           sudo apt-get install -y \
+            python3-dev \
             qtbase5-dev \
             qtmultimedia5-dev \
             qttools5-dev \

CMake/ctkBlockCheckDependencies.cmake

@@ -90,7 +90,7 @@ set(${Log4Qt_enabling_variable}_INCLUDE_DIRS Log4Qt_INCLUDE_DIRS)
 set(${Log4Qt_enabling_variable}_FIND_PACKAGE_CMD Log4Qt)
 
 set(PythonQt_enabling_variable PYTHONQT_LIBRARIES)
-set(${PythonQt_enabling_variable}_INCLUDE_DIRS PYTHONQT_INCLUDE_DIR PYTHON_INCLUDE_DIRS)
+set(${PythonQt_enabling_variable}_INCLUDE_DIRS PYTHONQT_INCLUDE_DIR Python3_INCLUDE_DIRS)
 set(${PythonQt_enabling_variable}_FIND_PACKAGE_CMD PythonQt)
 
 set(QtSOAP_enabling_variable QtSOAP_LIBRARIES)

CMake/ctkMacroBuildLibWrapper.cmake

@@ -95,8 +95,8 @@ macro(ctkMacroBuildLibWrapper)
   # Since the PythonQt decorator depends on PythonQt, Python and VTK, let's link against
   # these ones to avoid complaints of MSVC
   # Note: "LINK_DIRECTORIES" has to be invoked before "ADD_LIBRARY"
-  ctkFunctionExtractOptimizedLibrary(PYTHON_LIBRARIES PYTHON_LIBRARY)
-  set(my_EXTRA_PYTHON_LIBRARIES ${PYTHON_LIBRARY} ${PYTHONQT_LIBRARIES})
+  ctkFunctionExtractOptimizedLibrary(Python3_LIBRARIES PYTHON_LIBRARY)
+  set(my_EXTRA_Python3_LIBRARIES ${PYTHON_LIBRARY} ${PYTHONQT_LIBRARIES})
 
   # Does a header having the expected filename exists ?
   string(REGEX REPLACE "^CTK" "ctk" lib_name_lc_ctk ${lib_name})
@@ -122,7 +122,7 @@ macro(ctkMacroBuildLibWrapper)
     list(APPEND KIT_PYTHONQT_SRCS ${DECORATOR_HEADER})
   endif()
   add_library(${lib_name}PythonQt ${MY_WRAPPER_LIBRARY_TYPE} ${KIT_PYTHONQT_SRCS})
-  target_link_libraries(${lib_name}PythonQt ${lib_name} ${my_EXTRA_PYTHON_LIBRARIES})
+  target_link_libraries(${lib_name}PythonQt ${lib_name} ${my_EXTRA_Python3_LIBRARIES})
   if(MY_WRAPPER_LIBRARY_TYPE STREQUAL "STATIC")
     if(CMAKE_SIZEOF_VOID_P EQUAL 8) # 64-bit
       set_target_properties(${lib_name}PythonQt PROPERTIES COMPILE_FLAGS "-fPIC")

CMake/ctkMacroCompilePythonScript.cmake

@@ -164,15 +164,15 @@ function(_ctk_add_compile_python_directories_target target keep_only_pyc)
       endif()
     endforeach()
 
-    if(NOT PYTHONINTERP_FOUND)
-      find_package(PythonInterp REQUIRED)
+    if(NOT Python3_Interpreter_FOUND)
+      find_package(Python3 COMPONENTS Interpreter REQUIRED)
     endif()
-    if(NOT PYTHONLIBS_FOUND)
-      find_package(PythonLibs REQUIRED)
+    if(NOT Python3_Development_FOUND)
+      find_package(Python3 COMPONENTS Development REQUIRED)
     endif()
 
     # Extract python lib path
-    ctkFunctionExtractOptimizedLibrary(PYTHON_LIBRARIES PYTHON_LIBRARY)
+    ctkFunctionExtractOptimizedLibrary(Python3_LIBRARIES PYTHON_LIBRARY)
     get_filename_component(PYTHON_LIBRARY_PATH "${PYTHON_LIBRARY}" PATH)
 
     # Configure cmake script associated with the custom command

CMake/ctkMacroWrapPythonQt.cmake

@@ -62,10 +62,10 @@ macro(ctkMacroWrapPythonQt WRAPPING_NAMESPACE TARGET SRCS_LIST_NAME SOURCES IS_W
   # TODO: this find package seems not to work when called form a superbuild, but the call is needed
   # in general to find the python interpreter.  In CTK, the toplevel CMakeLists.txt does the find
   # package so this is a no-op.  Other uses of this file may need to have this call so it is still enabled.
-  if(NOT PYTHONINTERP_FOUND)
-    find_package(PythonInterp)
-    if(NOT PYTHONINTERP_FOUND)
-      message(FATAL_ERROR "PYTHON_EXECUTABLE not specified or inexistent when calling ctkMacroWrapPythonQt")
+  if(NOT Python3_Interpreter_FOUND)
+    find_package(Python3 COMPONENTS Interpreter)
+    if(NOT Python3_Interpreter_FOUND)
+      message(FATAL_ERROR "Python3_EXECUTABLE not specified or inexistent when calling ctkMacroWrapPythonQt")
     endif()
   endif()
 
@@ -157,7 +157,7 @@ macro(ctkMacroWrapPythonQt WRAPPING_NAMESPACE TARGET SRCS_LIST_NAME SOURCES IS_W
     DEPENDS
       ${SOURCES_TO_WRAP}
       ${CTK_CMAKE_DIR}/ctkWrapPythonQt.py
-    COMMAND ${PYTHON_EXECUTABLE} ${CTK_CMAKE_DIR}/ctkWrapPythonQt.py
+    COMMAND ${Python3_EXECUTABLE} ${CTK_CMAKE_DIR}/ctkWrapPythonQt.py
       --target=${TARGET}
       --namespace=${WRAPPING_NAMESPACE}
       --output-dir=${CMAKE_CURRENT_BINARY_DIR}/${wrap_int_dir} ${extra_args}
@@ -188,6 +188,6 @@ macro(ctkMacroWrapPythonQt WRAPPING_NAMESPACE TARGET SRCS_LIST_NAME SOURCES IS_W
   if(NOT PYTHONQT_FOUND)
     message(FATAL_ERROR "error: PythonQt package is required to build ${TARGET}PythonQt")
   endif()
-  include_directories(${PYTHON_INCLUDE_DIRS} ${PYTHONQT_INCLUDE_DIR})
+  include_directories(${Python3_INCLUDE_DIRS} ${PYTHONQT_INCLUDE_DIR})
 
 endmacro()

CMake/ctk_compile_python_scripts.cmake.in

@@ -95,7 +95,7 @@ else()
 endif()
 
 execute_process(
-  COMMAND "@PYTHON_EXECUTABLE@" "@compile_all_script@"
+  COMMAND "@Python3_EXECUTABLE@" "@compile_all_script@"
   RESULT_VARIABLE result_var
   )
 if(NOT result_var STREQUAL 0)

CMakeExternals/PythonQt.cmake

@@ -75,9 +75,9 @@ if(NOT DEFINED PYTHONQT_INSTALL_DIR)
   endif()
 
   # Python is required
-  if(NOT PYTHONLIBS_FOUND)
-    find_package(PythonLibs)
-    if(NOT PYTHONLIBS_FOUND)
+  if(NOT Python3_Development_FOUND)
+    find_package(Python3 COMPONENTS Development)
+    if(NOT Python3_Development_FOUND)
       message(FATAL_ERROR "error: Python is required to build ${PROJECT_NAME}")
     endif()
   endif()
@@ -89,7 +89,7 @@ if(NOT DEFINED PYTHONQT_INSTALL_DIR)
   set(Python3_LIBRARY_RELEASE ${PYTHON_LIBRARY})
   find_package(Python3 COMPONENTS Development REQUIRED)
 
-  ctkFunctionExtractOptimizedLibrary(PYTHON_LIBRARIES PYTHON_LIBRARY)
+  ctkFunctionExtractOptimizedLibrary(Python3_LIBRARY PYTHON_LIBRARY)
 
   set(revision_tag 74dcd675e1515324cd7467a328d63dd25d263679) # patched-v4.1.0-2026-06-05-9992368e9
   if(${proj}_REVISION_TAG)
@@ -299,7 +299,7 @@ set(PythonQt_DIR ${PYTHONQT_INSTALL_DIR})
 mark_as_superbuild(
   VARS
     PYTHONQT_INSTALL_DIR:PATH
-    PYTHON_EXECUTABLE:FILEPATH # FindPythonInterp expects PYTHON_EXECUTABLE variable to be defined
+    Python3_EXECUTABLE:FILEPATH # FindPythonInterp expects Python3_EXECUTABLE variable to be defined
     PYTHON_INCLUDE_DIR:PATH # FindPythonQt expects PYTHON_INCLUDE_DIR variable to be defined
     PYTHON_INCLUDE_DIR2:PATH
     PYTHON_LIBRARY:FILEPATH # FindPythonQt expects PYTHON_LIBRARY variable to be defined

CMakeExternals/VTK.cmake

@@ -62,17 +62,17 @@ if(NOT DEFINED VTK_DIR AND NOT ${CMAKE_PROJECT_NAME}_USE_SYSTEM_${proj})
 
   if(CTK_LIB_Scripting/Python/Core_PYTHONQT_USE_VTK)
 
-    set(Python3_EXECUTABLE ${PYTHON_EXECUTABLE})
+    set(Python3_EXECUTABLE ${Python3_EXECUTABLE})
     set(Python3_INCLUDE_DIR ${PYTHON_INCLUDE_DIR})
     set(Python3_LIBRARY ${PYTHON_LIBRARY})
     set(Python3_LIBRARY_DEBUG ${PYTHON_LIBRARY})
     set(Python3_LIBRARY_RELEASE ${PYTHON_LIBRARY})
     find_package(Python3 COMPONENTS Interpreter Development)
 
-    ctkFunctionExtractOptimizedLibrary(PYTHON_LIBRARIES PYTHON_LIBRARY)
+    ctkFunctionExtractOptimizedLibrary(Python3_LIBRARIES PYTHON_LIBRARY)
     list(APPEND additional_vtk_cmakevars
       # FindPythonInterp, FindPythonLibs
-      -DPYTHON_EXECUTABLE:PATH=${PYTHON_EXECUTABLE}
+      -DPython3_EXECUTABLE:PATH=${Python3_EXECUTABLE}
       -DPYTHON_INCLUDE_DIR:PATH=${PYTHON_INCLUDE_DIR}
       -DPYTHON_LIBRARY:FILEPATH=${PYTHON_LIBRARY}
       -DPYTHON_DEBUG_LIBRARIES:FILEPATH=${PYTHON_DEBUG_LIBRARIES}

CMakeLists.txt

@@ -965,16 +965,16 @@ endif()
 
 # Check if dependencies are satisfied
 if(CTK_LIB_Scripting/Python/Core)
-  if(NOT PYTHONINTERP_FOUND)
-    find_package(PythonInterp)
-    if(NOT PYTHONINTERP_FOUND)
-      message(FATAL_ERROR "PYTHON_EXECUTABLE variable should be set to build CTK_LIB_Scripting/Python")
+  if(NOT Python3_Interpreter_FOUND)
+    find_package(Python3 COMPONENTS Interpreter Development REQUIRED)
+    if(NOT Python3_Interpreter_FOUND)
+      message(FATAL_ERROR "Python3_EXECUTABLE variable should be set to build CTK_LIB_Scripting/Python")
     endif()
   endif()
-  if(NOT PYTHONLIBS_FOUND)
-    find_package(PythonLibs)
-    if(NOT PYTHONLIBS_FOUND)
-      message(FATAL_ERROR "PYTHON_LIBRARIES and PYTHON_INCLUDE_DIRS should be set to build CTK_LIB_Scripting/Python")
+  if(NOT Python3_Development_FOUND)
+    find_package(Python3 COMPONENTS Interpreter Development REQUIRED)
+    if(NOT Python3_Development_FOUND)
+      message(FATAL_ERROR "Python3_LIBRARIES and Python3_INCLUDE_DIRS should be set to build CTK_LIB_Scripting/Python")
     endif()
   endif()
 endif()

Libs/Scripting/Python/Core/CMakeLists.txt

@@ -36,7 +36,7 @@ configure_file(
 
 # Target libraries - See CMake/ctkFunctionGetTargetLibraries.cmake
 # The following macro will read the target libraries from the file 'target_libraries.cmake'
-ctkFunctionExtractOptimizedLibrary(PYTHON_LIBRARIES PYTHON_LIBRARY)
+ctkFunctionExtractOptimizedLibrary(Python3_LIBRARIES PYTHON_LIBRARY)
 ctkFunctionGetTargetLibraries(KIT_target_libraries)
 
 ctkMacroBuildLib(