Using Python in CMake script
Finding Python is made more robust in CMake >= 3.15, which prioritizes location over version number.
Prior to CMake 3.15, even specifying Python3_ROOT
could be overridden if the other Python was a higher version.
Using the Python interpreter in CMake should generally be via ${PYTHON3_EXECUTABLE}
and not Python3::Interpreter
.
CMake provides the imported target
Python3::Interpreter
only when the
CMAKE_ROLE
is PROJECT
.
This means that Python3::Interpreter
is not available when using CTest, which is often when using the Python3 interpreter is desired.
Normally, to use Python interpreter from a CMake script, including in
execute_process
or
add_test,
use PYTHON3_EXECUTABLE
.
If the project must support CMake older than 3.15, you can still get the benefits of better Python3_ROOT
behavior by using CMake maximum version policy like:
cmake_minimum_required(VERSION 3.13...3.15)
The “3.15” can be set to even newer versions of CMake as well. As long as the user is using CMake ≥ 3.15, you’ll get the modern FindPython3 behavior. The “3.13” is arbitrary, it’s whatever old CMake version your project must support.
then do like:
find_package(Python3 COMPONENTS Interpreter REQUIRED)
add_test(NAME Foo COMMAND ${PYTHON3_EXECUTABLE} myscript.py -arg1 value)