(Flaky) test failure: OSError via PosixPath.glob

testing/test_assertrewrite.py::test_try_makedirs failed with "OSError: [Errno
22]" via pathlib.Path.glob:

py38-xdist run-test: commands[0] | coverage run -m pytest -n auto
============================= test session starts ==============================
platform darwin -- Python 3.8.1, pytest-5.3.5.dev396+gc0826bc8d, py-1.8.1, pluggy-0.13.1
cachedir: .tox/py38-xdist/.pytest_cache
rootdir: /Users/runner/runners/2.165.2/work/pytest/pytest, inifile: tox.ini, testpaths: testing
plugins: hypothesis-5.5.4, xdist-1.31.0, forked-1.1.3
gw0 I / gw1 I / gw2 I / gw3 I
gw0 [2686] / gw1 [2686] / gw2 [2686] / gw3 [2686]

.....ss...............................s................................. [  2%]
..............E...............................................s.......... [  5%]
…
==================================== ERRORS ====================================
_____________________ ERROR at setup of test_try_makedirs ______________________
[gw3] darwin -- Python 3.8.1 /Users/runner/runners/2.165.2/work/pytest/pytest/.tox/py38-xdist/bin/python

self = PosixPath('/private/var/folders/24/8k48jl6d249_n_qfxwsl6xvm0000gn/T/pytest-of-runner')
pattern = 'garbage-*'

    def glob(self, pattern):
        """Iterate over this subtree and yield all existing files (of any
        kind, including directories) matching the given relative pattern.
        """
        if not pattern:
            raise ValueError("Unacceptable pattern: {!r}".format(pattern))
        drv, root, pattern_parts = self._flavour.parse_parts((pattern,))
        if drv or root:
            raise NotImplementedError("Non-relative patterns are unsupported")
        selector = _make_selector(tuple(pattern_parts), self._flavour)
>       for p in selector.select_from(self):

/Users/runner/hostedtoolcache/Python/3.8.1/x64/lib/python3.8/pathlib.py:1133: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <pathlib._WildcardSelector object at 0x1125354f0>
parent_path = PosixPath('/private/var/folders/24/8k48jl6d249_n_qfxwsl6xvm0000gn/T/pytest-of-runner')
is_dir = <function Path.is_dir at 0x10f54f5e0>
exists = <function Path.exists at 0x10f54f550>
scandir = <built-in function scandir>

    def _select_from(self, parent_path, is_dir, exists, scandir):
        try:
            entries = list(scandir(parent_path))
            for entry in entries:
                entry_is_dir = False
                try:
>                   entry_is_dir = entry.is_dir()
E                   OSError: [Errno 22] Invalid argument: '/private/var/folders/24/8k48jl6d249_n_qfxwsl6xvm0000gn/T/pytest-of-runner/pytest-current'

/Users/runner/hostedtoolcache/Python/3.8.1/x64/lib/python3.8/pathlib.py:536: OSError
=============================== warnings summary ===============================
testing/test_cacheprovider.py:40
  /Users/runner/runners/2.165.2/work/pytest/pytest/testing/test_cacheprovider.py:40: PytestCacheWarning: could not create cache path /private/var/folders/24/8k48jl6d249_n_qfxwsl6xvm0000gn/T/pytest-of-runner/pytest-1/test_cache_writefail_cachfile_silent0/.pytest_cache/v/test/broken
    cache.set("test/broken", [])

-- Docs: https://docs.pytest.org/en/latest/warnings.html
=========================== short test summary info ============================
ERROR testing/test_assertrewrite.py::test_try_makedirs - OSError: [Errno 22] ...
= 2591 passed, 84 skipped, 10 xfailed, 1 warning, 1 error in 101.45s (0:01:41) =
ERROR: InvocationError for command /Users/runner/runners/2.165.2/work/pytest/pytest/.tox/py38-xdist/bin/coverage run -m pytest -n auto (exited with code 1)
___________________________________ summary ____________________________________
ERROR:   py38-xdist: commands failed

As mentioned earlier it is bad that the exception context is lost here.

Code ref: https://github.com/pytest-dev/pytest/blob/d98dca33b5770d68f8b43e30aea4351dd176fe71/testing/test_assertrewrite.py#L1567-L1604

Build: https://github.com/pytest-dev/pytest/pull/6808/checks?check_run_id=464820845

Start with testing/test_assertrewrite.py around test_try_makedirs, then run that test on the affected macOS/Python 3.8 configuration. Investigate the pathlib.Path.glob OSError and the lost exception context described in the report; the work is done when the test no longer flakes and the relevant failure context is retained.