Use CMake features to find NumPy (#333)

The current CMake script that is used to find NumPy does not always work
for me, and sometimes causes problems on the different systems I build
on. Given we have recently updated the minimum CMake version and the
minimum pybind11 version, these changes now use the standard CMake tools
to find Python3 and NumPy, and makes the links with the standard CMake
targets. I specifically use Python3 in the CMake as the indicated
pybind11 version no longer supports Python 2.7.

Author: HunterBelanger

CMakeLists.txt

@@ -10,7 +10,6 @@
 cmake_minimum_required(VERSION 3.29)
 project(xtensor-python)
 
-set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
 set(XTENSOR_PYTHON_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/include)
 
 # Versioning
@@ -46,7 +45,7 @@ else()
     message(STATUS "Found xtensor: ${xtensor_INCLUDE_DIRS}/xtensor")
 endif()
 
-find_package(Python COMPONENTS Interpreter REQUIRED)
+find_package(Python3 COMPONENTS Development.Embed NumPy REQUIRED)
 
 set(pybind11_REQUIRED_VERSION 3.0.0)
 if (NOT TARGET pybind11::headers)
@@ -60,14 +59,6 @@ else ()
     message(STATUS "Found pybind11 v${pybind11_VERSION}")
 endif ()
 
-# Look for NumPy headers, except if NUMPY_INCLUDE_DIRS is passed,
-# which is required under some circumstances (such as wasm, where
-# there is no real python executable)
-if(NOT NUMPY_INCLUDE_DIRS)
-    find_package(NumPy REQUIRED)
-endif()
-message(STATUS "Found numpy: ${NUMPY_INCLUDE_DIRS}")
-
 # Build
 # =====
 
@@ -84,10 +75,8 @@ set(XTENSOR_PYTHON_HEADERS
         )
 
 add_library(xtensor-python INTERFACE)
-target_include_directories(xtensor-python INTERFACE
-    "$<BUILD_INTERFACE:${XTENSOR_PYTHON_INCLUDE_DIR};${pybind11_INCLUDE_DIRS};${NUMPY_INCLUDE_DIRS}>"
-    $<INSTALL_INTERFACE:include>)
-target_link_libraries(xtensor-python INTERFACE xtensor)
+target_include_directories(xtensor-python INTERFACE "$<BUILD_INTERFACE:${XTENSOR_PYTHON_INCLUDE_DIR}>" $<INSTALL_INTERFACE:include>)
+target_link_libraries(xtensor-python INTERFACE xtensor pybind11::pybind11 Python3::NumPy)
 get_target_property(inc_dir xtensor-python INTERFACE_INCLUDE_DIRECTORIES)
 
 OPTION(BUILD_TESTS "xtensor test suite" OFF)

cmake/FindNumPy.cmake

@@ -5,9 +5,9 @@ project(mymodule)
 find_package(pybind11 CONFIG REQUIRED)
 find_package(xtensor REQUIRED)
 find_package(xtensor-python REQUIRED)
-find_package(Python REQUIRED COMPONENTS NumPy)
+find_package(Python3 REQUIRED COMPONENTS NumPy)
 
 pybind11_add_module(mymodule main.cpp)
-target_link_libraries(mymodule PUBLIC pybind11::module xtensor-python Python::NumPy)
+target_link_libraries(mymodule PUBLIC pybind11::module xtensor-python Python3::NumPy)
 
 target_compile_definitions(mymodule PRIVATE VERSION_INFO=0.1.0)

docs/source/examples/copy_cast/CMakeLists.txt

@@ -2,12 +2,12 @@ cmake_minimum_required(VERSION 3.29)
 
 project(mymodule)
 
-find_package(Python REQUIRED COMPONENTS Interpreter Development NumPy)
+find_package(Python3 REQUIRED COMPONENTS Interpreter Development NumPy)
 find_package(pybind11 REQUIRED CONFIG)
 find_package(xtensor REQUIRED)
 find_package(xtensor-python REQUIRED)
 
 pybind11_add_module(mymodule main.cpp)
-target_link_libraries(mymodule PUBLIC pybind11::module xtensor-python Python::NumPy)
+target_link_libraries(mymodule PUBLIC pybind11::module xtensor-python Python3::NumPy)
 
 target_compile_definitions(mymodule PRIVATE VERSION_INFO=0.1.0)

docs/source/examples/readme_example_1/CMakeLists.txt

@@ -2,13 +2,13 @@ cmake_minimum_required(VERSION 3.29)
 
 project(mymodule)
 
-find_package(Python REQUIRED COMPONENTS Interpreter Development NumPy)
+find_package(Python3 REQUIRED COMPONENTS Interpreter Development NumPy)
 find_package(pybind11 REQUIRED CONFIG)
 find_package(xtensor REQUIRED)
 find_package(xtensor-python REQUIRED)
 
 pybind11_add_module(mymodule python.cpp)
-target_link_libraries(mymodule PUBLIC pybind11::module xtensor-python Python::NumPy)
+target_link_libraries(mymodule PUBLIC pybind11::module xtensor-python Python3::NumPy)
 
 target_compile_definitions(mymodule PRIVATE VERSION_INFO=0.1.0)
 

docs/source/examples/sfinae/CMakeLists.txt

@@ -84,7 +84,7 @@ set(XTENSOR_PYTHON_TESTS
 )
 
 add_executable(test_xtensor_python ${XTENSOR_PYTHON_TESTS} ${XTENSOR_PYTHON_HEADERS})
-target_link_libraries(test_xtensor_python xtensor-python ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT} ${PYTHON_LIBRARIES})
+target_link_libraries(test_xtensor_python xtensor-python ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT} Python3::Python)
 
 if(DOWNLOAD_GTEST OR GTEST_SRC_DIR)
     add_dependencies(test_xtensor_python gtest_main)