ENH: Update for ITK 5.1rc02

Author: hjmjohnson

CMakeLists.txt

@@ -154,6 +154,62 @@ if(PYTHON_EXECUTABLE AND NOT ITK_WRAP_PYTHON)
     set(ITK_WRAP_PYTHON 1)
   endif()
 endif()
+if(BUILD_TESTING OR ITK_BUILD_DOCUMENTATION OR ITK_WRAP_PYTHON)
+  # Prefer to use more robust FindPython3 module if greater than cmake 3.12.0
+  if("${CMAKE_VERSION}" VERSION_LESS_EQUAL "3.12.0")
+    # Use of PythonInterp and PythonLibs is deprecated since cmake version 3.12.0
+    # Only use deprecated mechanisms for older versions of cmake
+    set(Python_ADDITIONAL_VERSIONS 3.9 3.8 3.7 3.6 3.5)
+    find_package(PythonInterp)
+    if(ITK_WRAP_PYTHON)
+      find_package(PythonLibs REQUIRED)
+      # check for version mismatch.
+      if(PYTHONLIBS_FOUND AND PYTHONINTERP_FOUND
+          AND NOT(PYTHON_VERSION_STRING VERSION_EQUAL PYTHONLIBS_VERSION_STRING))
+        message(FATAL_ERROR "Python executable (\"${PYTHON_VERSION_STRING}\") and library (\"${PYTHONLIBS_VERSION_STRING}\") version mismatch.")
+      endif()
+    endif()
+    if(PYTHON_VERSION_STRING VERSION_LESS 3.5)
+      # if python version is less than 3.5, unset so that it appears that no python version is found.
+      # to emulate the same behavior as find(Python3 ..) from cmake 3.12.0+
+      unset(PYTHON_EXECUTABLE)
+      unset(PYTHONINTERP_FOUND)
+      unset(PYTHON_VERSION_STRING)
+      unset(PYTHON_INCLUDE_DIRS)
+    else()
+      ## For forward compatibility with cmake 3.12.0 or greater, emulate variable names from FindPython3.cmake
+      set(Python3_EXECUTABLE ${PYTHON_EXECUTABLE})
+      set(Python3_Interpreter_FOUND ${PYTHONINTERP_FOUND})
+      set(Python3_VERSION ${PYTHON_VERSION_STRING})
+
+      set(Python3_Development_FOUND ${PYTHONLIBS_FOUND})
+      set(Python3_INCLUDE_DIRS ${PYTHON_INCLUDE_DIRS})
+      set(Python3_LIBRARIES    ${PYTHON_LIBRARIES})
+    endif()
+  else()
+    if(ITK_WRAP_PYTHON)
+      if(DEFINED Python3_EXECUTABLE)
+        set(_specified_Python3_EXECUTABLE ${Python3_EXECUTABLE})
+      endif()
+      find_package(Python3 COMPONENTS Interpreter Development)
+      set(Python3_EXECUTABLE ${_specified_Python3_EXECUTABLE} CACHE INTERNAL
+        "Path to the Python interpreter" FORCE)
+    else()
+      find_package(Python3 COMPONENTS Interpreter)
+    endif()
+    if(NOT Python3_EXECUTABLE AND _Python3_EXECUTABLE)
+      set(Python3_EXECUTABLE ${_Python3_EXECUTABLE} CACHE INTERNAL
+        "Path to the Python interpreter" FORCE)
+    endif()
+  endif()
+
+  if(ITK_WRAP_PYTHON AND Python3_VERSION VERSION_LESS 3.5)
+    message(FATAL_ERROR "Python versions less than 3.5 are not supported for wrapping. Python version: \"${Python3_VERSION}\".")
+  endif()
+  if(ITK_WRAP_PYTHON AND NOT Python3_INCLUDE_DIRS)
+    message(FATAL_ERROR "Python version ${Python3_VERSION} development environment not found for wrapping.")
+  endif()
+endif()
 
 # Build the documentation?
 option(BUILD_DOCUMENTATION "Build the examples documentation." OFF)

Superbuild/External-ITK.cmake

@@ -30,11 +30,11 @@ endif()
 set(_wrap_python_args )
 if(ITKExamples_USE_WRAP_PYTHON)
   set(_python_depends)
-  if(NOT EXISTS PYTHON_EXECUTABLE)
+  if(NOT EXISTS Python3_EXECUTABLE)
     set(_python_depends ITKPython)
   endif()
   set(_wrap_python_args
-    "-DPYTHON_EXECUTABLE:FILEPATH=${ITKPYTHON_EXECUTABLE}"
+    "-DPython3_EXECUTABLE:FILEPATH=${ITKPython3_EXECUTABLE}"
     )
 endif()
 

itk-module.cmake

@@ -3,7 +3,7 @@ set(DOCUMENTATION "This module builds the examples found at https://github.com/I
 itk_module(SphinxExamples
   DEPENDS
     ITKCommon
-    EXCLUDE_FROM_DEFAULT
   DESCRIPTION
     "${DOCUMENTATION}"
-  )
+  EXCLUDE_FROM_DEFAULT
+)