From ddd4f5cb010a63b04328515ef84fa771c5a15505 Mon Sep 17 00:00:00 2001 From: Chris Lalancette Date: Tue, 13 Feb 2024 21:39:50 +0000 Subject: [PATCH] Set hints to find the python version we actually want. The comment in the commit explains the reasoning behind it. Signed-off-by: Chris Lalancette --- ...osidl_typesupport_c_generate_interfaces.cmake | 16 ++++++++++++++++ ...idl_typesupport_cpp_generate_interfaces.cmake | 16 ++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/rosidl_typesupport_c/cmake/rosidl_typesupport_c_generate_interfaces.cmake b/rosidl_typesupport_c/cmake/rosidl_typesupport_c_generate_interfaces.cmake index 52c38ae3..c48eda56 100644 --- a/rosidl_typesupport_c/cmake/rosidl_typesupport_c_generate_interfaces.cmake +++ b/rosidl_typesupport_c/cmake/rosidl_typesupport_c_generate_interfaces.cmake @@ -71,6 +71,22 @@ rosidl_write_generator_arguments( TARGET_DEPENDENCIES ${target_dependencies} ) +# By default, without the settings below, find_package(Python3) will attempt +# to find the newest python version it can, and additionally will find the +# most specific version. For instance, on a system that has +# /usr/bin/python3.10, /usr/bin/python3.11, and /usr/bin/python3, it will find +# /usr/bin/python3.11, even if /usr/bin/python3 points to /usr/bin/python3.10. +# The behavior we want is to prefer the "system" installed version unless the +# user specifically tells us othewise through the Python3_EXECUTABLE hint. +# Setting CMP0094 to NEW means that the search will stop after the first +# python version is found. Setting Python3_FIND_UNVERSIONED_NAMES means that +# the search will prefer /usr/bin/python3 over /usr/bin/python3.11. And that +# latter functionality is only available in CMake 3.20 or later, so we need +# at least that version. +cmake_minimum_required(VERSION 3.20) +cmake_policy(SET CMP0094 NEW) +set(Python3_FIND_UNVERSIONED_NAMES FIRST) + find_package(Python3 REQUIRED COMPONENTS Interpreter) get_used_typesupports(typesupports "rosidl_typesupport_c") diff --git a/rosidl_typesupport_cpp/cmake/rosidl_typesupport_cpp_generate_interfaces.cmake b/rosidl_typesupport_cpp/cmake/rosidl_typesupport_cpp_generate_interfaces.cmake index 132f33b0..94c7105b 100644 --- a/rosidl_typesupport_cpp/cmake/rosidl_typesupport_cpp_generate_interfaces.cmake +++ b/rosidl_typesupport_cpp/cmake/rosidl_typesupport_cpp_generate_interfaces.cmake @@ -68,6 +68,22 @@ rosidl_write_generator_arguments( TARGET_DEPENDENCIES ${target_dependencies} ) +# By default, without the settings below, find_package(Python3) will attempt +# to find the newest python version it can, and additionally will find the +# most specific version. For instance, on a system that has +# /usr/bin/python3.10, /usr/bin/python3.11, and /usr/bin/python3, it will find +# /usr/bin/python3.11, even if /usr/bin/python3 points to /usr/bin/python3.10. +# The behavior we want is to prefer the "system" installed version unless the +# user specifically tells us othewise through the Python3_EXECUTABLE hint. +# Setting CMP0094 to NEW means that the search will stop after the first +# python version is found. Setting Python3_FIND_UNVERSIONED_NAMES means that +# the search will prefer /usr/bin/python3 over /usr/bin/python3.11. And that +# latter functionality is only available in CMake 3.20 or later, so we need +# at least that version. +cmake_minimum_required(VERSION 3.20) +cmake_policy(SET CMP0094 NEW) +set(Python3_FIND_UNVERSIONED_NAMES FIRST) + find_package(Python3 REQUIRED COMPONENTS Interpreter) get_used_typesupports(typesupports "rosidl_typesupport_cpp")