zephyr/cmake/python.cmake
Torsten Rasmussen 3a2f8349fd cmake: find python3 on windows when multiarch are installed
Fixes: #24692

This commit fixes an issue where FindPython3 could wrongly select the
Python version not in environment path.

If user installed both 32 and 64 bit versions of the same Python, for
example 3.7.x, the current search would only specify that 3.7 is needed.

In some cases, FindPython3 could select the 32 bit version, even if the
64 bit version is the one on %PATH%.

This is fixed, by setting Python3_ROOT_DIR to point to the tested Python
in %PATH%.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
2020-05-13 12:13:36 +02:00

46 lines
2 KiB
CMake

# SPDX-License-Identifier: Apache-2.0
# On Windows, instruct Python to output UTF-8 even when not
# interacting with a terminal. This is required since Python scripts
# are invoked by CMake code and, on Windows, standard I/O encoding defaults
# to the current code page if not connected to a terminal, which is often
# not what we want.
if (WIN32)
set(ENV{PYTHONIOENCODING} "utf-8")
endif()
set(PYTHON_MINIMUM_REQUIRED 3.6)
# We are using foreach here, instead of find_program(PYTHON_EXECUTABLE_SYSTEM_DEFAULT "python" "python3")
# cause just using find_program directly could result in a python2.7 as python, and not finding a valid python3.
foreach(PYTHON_PREFER ${PYTHON_PREFER} "python" "python3")
find_program(PYTHON_PREFER_EXECUTABLE ${PYTHON_PREFER})
if(PYTHON_PREFER_EXECUTABLE)
execute_process (COMMAND "${PYTHON_PREFER_EXECUTABLE}" -c
"import sys; sys.stdout.write('.'.join([str(x) for x in sys.version_info[:2]]))"
RESULT_VARIABLE result
OUTPUT_VARIABLE version
ERROR_QUIET
OUTPUT_STRIP_TRAILING_WHITESPACE)
if(version VERSION_LESS PYTHON_MINIMUM_REQUIRED)
set(PYTHON_PREFER_EXECUTABLE "PYTHON_PREFER_EXECUTABLE-NOTFOUND")
else()
set(PYTHON_MINIMUM_REQUIRED ${version})
set(PYTHON_EXACT EXACT)
# Python3_ROOT_DIR ensures that location will be preferred by FindPython3.
# On Linux, this has no impact as it will usually be /usr/bin
# but on Windows it solve issues when both 32 and 64 bit versions are
# installed, as version is not enough and FindPython3 might pick the
# version not on %PATH%. Setting Python3_ROOT_DIR ensures we are using
# the version we just tested.
get_filename_component(PYTHON_PATH ${PYTHON_PREFER_EXECUTABLE} DIRECTORY)
set(Python3_ROOT_DIR ${PYTHON_PATH})
break()
endif()
endif()
endforeach()
find_package(Python3 ${PYTHON_MINIMUM_REQUIRED} REQUIRED ${PYTHON_EXACT})
set(PYTHON_EXECUTABLE ${Python3_EXECUTABLE})