From 02f4d62bbf95ae12eb0cc2cbf7ecbcdb1ab8c9fe Mon Sep 17 00:00:00 2001 From: Arnout Vandecappelle Date: Fri, 29 Aug 2025 11:20:55 +0200 Subject: [PATCH] package/python3: do build-time detection of non-working toolchain Since the bump to Python 3.13.2 in commit d63e207eb869063f82c867658676c2903beb08cb, there is a runtime assertion in Python when the toolchain doesn't support time64 [1]. The only such toolchain is one with uClibc and linux headers < 5.1. Encoding this dependency in Config.in was deemed to complicated (cfr. commit ffd00280315e60908d0d317b1dfb4c714590a03e). Instead, do a build-time check of the same condition. The check itself is a bit complicated, but it is localized to python3.mk and doesn't need to be propagated to all reverse dependencies. Testing such a corner case toolchain is a bit complicated. It can be done with the following configuration. BR2_arm=y BR2_cortex_a9=y BR2_ARM_ENABLE_VFP=y BR2_TOOLCHAIN_EXTERNAL=y BR2_TOOLCHAIN_EXTERNAL_CUSTOM=y BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD=y BR2_TOOLCHAIN_EXTERNAL_URL="http://toolchains.bootlin.com/downloads/releases/toolchains/armv7-eabihf/tarballs/armv7-eabihf--uclibc--stable-2018.02-1.tar.bz2" BR2_TOOLCHAIN_EXTERNAL_GCC_6=y BR2_TOOLCHAIN_EXTERNAL_HEADERS_4_1=y BR2_TOOLCHAIN_EXTERNAL_LOCALE=y BR2_TOOLCHAIN_EXTERNAL_CXX=y BR2_PACKAGE_PYTHON3=y It needs to be built in an environment that has libmpfr.so.4 installed as the pre-built toolchain from that era did not include it. An easy way to achieve this is to build this configuration under an old Buildroot Docker container: IMAGE=buildroot/base:20180205.0730 ./utils/docker-run make python3 With a build-time check, the autobuilders could get build failures when generating such a config. However, the autobuilders cannot use a toolchain with this configuration (they only use more recent toolchains). Therefore, no update to genrandconfig is needed. [1] https://gitlab.com/buildroot.org/buildroot/-/issues/95#note_2348479811 Cc: Vincent Fazio Cc: James Hilliard Signed-off-by: Arnout Vandecappelle Signed-off-by: Julien Olivain (cherry picked from commit b45400dad416d174459ccafc1ec223b984434a5b) Signed-off-by: Thomas Perale --- package/python3/python3.mk | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/package/python3/python3.mk b/package/python3/python3.mk index 082dd69bf1..a54170b8ec 100644 --- a/package/python3/python3.mk +++ b/package/python3/python3.mk @@ -318,3 +318,11 @@ define PYTHON3_REMOVE_OPTIMIZED_PYC_FILES xargs -0 --no-run-if-empty rm -f endef PYTHON3_TARGET_FINALIZE_HOOKS += PYTHON3_REMOVE_OPTIMIZED_PYC_FILES + +# uClibc without time64 support (i.e. when linux headers < 5.1) causes +# a runtime assertion in Python. Encoding this as a dependency in Config.in +# causes too many problems for propagating reverse dependencies. Therefore +# instead we do a build time check. +ifeq ($(BR_BUILDING)$(BR2_PACKAGE_PYTHON3)$(BR2_TOOLCHAIN_USES_UCLIBC)-$(BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_1),yyy-) +$(error Python3 doesn't work with uClibc and kernel headers < 5.1. Please use a different toolchain or unselect Python3.) +endif