Build failure: install race condition

Bug report

The generated Makefile for Python 3.11 has a race condition in its install target.

So far it triggers easiest with GNU Make 4.4 (I think they distribute more tasks breadth first instead of depth first compared to v4.3)

In short, this is a reproducer of the problem:

LIBDIR := $(CURDIR)/lib
INSTALL := /usr/bin/install -c

all: a b

a b:
	@for i in $(LIBDIR); do \
		if test ! -d $$i; then \
			echo "Creating directory $$i"; \
			$(INSTALL) -d -m 755 $$i; \
		else true; \
		fi \
	done

causing a race as follows:

% make -j2
Creating directory /private/var/folders/33/7njsb0_50dl7hnkr58nbnpb00000gn/T/tmp.TOdJ6wpw/lib
Creating directory /private/var/folders/33/7njsb0_50dl7hnkr58nbnpb00000gn/T/tmp.TOdJ6wpw/lib
install: mkdir /private/var/folders/33/7njsb0_50dl7hnkr58nbnpb00000gn/T/tmp.TOdJ6wpw/lib: File exists
make: *** [a] Error 71

This happens exactly in Python during make install -j$(nproc) as the commoninstall target has the prereqs altbininstall libinstall (among others) which both have a shell script loop over some directories they wanna make, and in particular it has:

altbininstall: $(BUILDPYTHON)
	@for i in $(BINDIR) $(LIBDIR); \
		... like example above (if dir not exists, run install)

libinstall: all $(srcdir)/Modules/xxmodule.c
	@for i in $(SCRIPTDIR) $(LIBDEST); \
		... like example above (if dir not exists, run install)

where SCRIPTDIR and LIBDIR in my case both point to <prefix>/lib.

Your environment

Python 3.11
GNU Make 4.4
macOS Ventura M1

Commencez par reproduire l’échec avec le Makefile fourni et make -j2, puis examinez les règles d’installation générées pour commoninstall, altbininstall et libinstall. La correction est terminée lorsque make install en parallèle ne provoque plus de conditions de concurrence lors de la création de répertoires partagés, y compris avec GNU Make 4.4 sur Python 3.11.