`test_peg_generator` failures on some buildbots

[picnixz]

Bug report

Bug description:

One of those PRs made the test_peg_generator tests fail (see https://buildbot.python.org/#/builders/469):

• sysconfig --generate-posix-vars can hang on cyclic variable definitions #136097: Fix sysconfig._parse_makefile() (gh-136097: Fix sysconfig._parse_makefile() #136166) by @serhiy-storchaka
• test_venv.test_special_chars_csh fails on NetBSD #139308: Skip test_special_chars_csh on NetBSD due to csh variable expansion issue (gh-139308: Skip test_special_chars_csh on NetBSD due to csh variable expansion issue #139341) by @furkanonder (I don't think it's the case here).
• creating venv Python3.13 on CIFS mounted drive fails ENODATA #133951: Remove lib64->lib symlink in venv creation (gh-133951: Remove lib64->lib symlink in venv creation #137139) by @Cycloctane (cc @FFY00)
• Remove deprecated parameter alias for importlib.resources.files #138044: Remove deprecated parameter alias for importlib.resources.files (gh-138044: Remove deprecated parameter alias for importlib.resources.files #138059) @donbarbos

The failure seems to be setuptools being not present and I don't know why. It could be the lib64->lib symlink that is no more here or the change in importlib.resources.files. I don't have time now to investigate.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-139604: Test reverting a7a485558c05a59665d24f9bc048db8a41daf532. #139605
• gh-133951: Fix purelib packages not found in test_peg_generator TestCParser #139607

[StanFromIreland]

It could be the lib64->lib symlink that is no more

It seems most likely, the test creates a venv.

Testing it here.

[StanFromIreland]

Yep, in the run (There are several other failures, but they seem to be unrelated) the failing test_peg_generator tests pass, therefore, it is a7a4855 / #133951.

[Cycloctane]

pr #137139 does have a breaking change. I think the root cause of the failing test is here:

cpython/Lib/test/test_peg_generator/test_c_parser.py

Lines 101 to 108 in 13dc2fd

	with contextlib.ExitStack() as stack:
	python_exe = stack.enter_context(support.setup_venv_with_pip_setuptools("venv"))
	sitepackages = subprocess.check_output(
	[python_exe, "-c", "import sysconfig; print(sysconfig.get_path('platlib'))"],
	text=True,
	).strip()
	stack.enter_context(import_helper.DirsOnSysPath(sitepackages))
	cls.addClassCleanup(stack.pop_all().close)

Only platlib is added to syspath. Also adding purelib should fix the problem. I'm now testing and working on a pr for it.

[StanFromIreland]

Should this be closed as a duplicate of #133951 since it is still open?

[picnixz]

I wasn't sure which one was the faulty commit but now I can indeed close it as a duplicate.