`test_py_info_cache_invalidation_on_py_info_change` alters `py_info.py`, invalidating `.pyc` files

[mgorny]

Issue

The following test alters py_info.py on installed virtualenv. While it restores the original content afterwards, the operation changes mtime and therefore invalidates .pyc files.

virtualenv/tests/unit/discovery/py_info/test_py_info.py

Lines 158 to 185 in 08e5dfa

	def test_py_info_cache_invalidation_on_py_info_change(mocker, session_app_data):
	# 1. Get a PythonInfo object for the current executable, this will cache it.
	PythonInfo.from_exe(sys.executable, session_app_data)
	# 2. Spy on _run_subprocess
	spy = mocker.spy(cached_py_info, "_run_subprocess")
	# 3. Modify the content of py_info.py
	py_info_script = Path(cached_py_info.__file__).parent / "py_info.py"
	original_content = py_info_script.read_text(encoding="utf-8")
	try:
	# 4. Clear the in-memory cache
	mocker.patch.dict(cached_py_info._CACHE, {}, clear=True) # noqa: SLF001
	py_info_script.write_text(original_content + "\n# a comment", encoding="utf-8")
	# 5. Get the PythonInfo object again
	info = PythonInfo.from_exe(sys.executable, session_app_data)
	# 6. Assert that _run_subprocess was called again
	if is_macos_brew(info):
	assert spy.call_count in {2, 3}
	else:
	assert spy.call_count == 2
	finally:
	# Restore the original content
	py_info_script.write_text(original_content, encoding="utf-8")

 * QA Notice: This package installs one or more compiled Python modules whose
 * .py files have different timestamps than recorded:
 * 
 *   /usr/lib/pypy3.11/site-packages/virtualenv/discovery/__pycache__/py_info.pypy311.opt-1.pyc
 *   /usr/lib/pypy3.11/site-packages/virtualenv/discovery/__pycache__/py_info.pypy311.opt-2.pyc
 *   /usr/lib/pypy3.11/site-packages/virtualenv/discovery/__pycache__/py_info.pypy311.pyc
 *   /usr/lib/python3.11/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-311.opt-1.pyc
 *   /usr/lib/python3.11/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-311.opt-2.pyc
 *   /usr/lib/python3.11/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-311.pyc
 *   /usr/lib/python3.12/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-312.opt-1.pyc
 *   /usr/lib/python3.12/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-312.opt-2.pyc
 *   /usr/lib/python3.12/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-312.pyc
 *   /usr/lib/python3.13/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-313.opt-1.pyc
 *   /usr/lib/python3.13/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-313.opt-2.pyc
 *   /usr/lib/python3.13/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-313.pyc
 *   /usr/lib/python3.14/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-314.opt-1.pyc
 *   /usr/lib/python3.14/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-314.opt-2.pyc
 *   /usr/lib/python3.14/site-packages/virtualenv/discovery/__pycache__/py_info.cpython-314.pyc

Environment

Provide at least:

• OS: Gentoo Linux amd64
• pip list of the host python where virtualenv is installed: n/a (very long)

Output of the virtual environment creation

n/a

[gaborbernat]

cc @esafak

[mgorny]

Thank you!