Python test suite (test_ntpath?) tries to removes system directories in the volume root directory ("System Volume Information")

[vstinner]

A test creating testjunc junction on Windows (test_ntpath?) tries to remove system directories such as "\System Volume Information".

AMD64 Windows11 Non-Debug 3.14: https://buildbot.python.org/#/builders/1684/builds/823

Warning -- regrtest worker thread failed: Traceback (most recent call last):
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\__init__.py", line 211, in _force_run
Warning --     return func(*args)
Warning -- PermissionError: [WinError 5] Access is denied: 'b:\\uildworker_temp\\test_python_f3pmns6d\\tmpfeb_loxl\\testjunc\\System Volume Information'
Warning -- 
Warning -- During handling of the above exception, another exception occurred:
Warning -- 
Warning -- Traceback (most recent call last):
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\libregrtest\run_workers.py", line 407, in run
Warning --     mp_result = self._runtest(test_name)
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\libregrtest\run_workers.py", line 366, in _runtest
Warning --     retcode, tmp_files = self.run_tmp_files(worker_runtests,
Warning --                          ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
Warning --                                             stdout_file.fileno())
Warning --                                             ^^^^^^^^^^^^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\libregrtest\run_workers.py", line 306, in run_tmp_files
Warning --     os_helper.rmtree(tmp_dir)
Warning --     ~~~~~~~~~~~~~~~~^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 508, in rmtree
Warning --     _rmtree(path)
Warning --     ~~~~~~~^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 440, in _rmtree
Warning --     _waitfor(_rmtree_inner, path, waitall=True)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 381, in _waitfor
Warning --     func(pathname)
Warning --     ~~~~^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 436, in _rmtree_inner
Warning --     _waitfor(_rmtree_inner, fullname, waitall=True)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 381, in _waitfor
Warning --     func(pathname)
Warning --     ~~~~^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 436, in _rmtree_inner
Warning --     _waitfor(_rmtree_inner, fullname, waitall=True)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 381, in _waitfor
Warning --     func(pathname)
Warning --     ~~~~^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 436, in _rmtree_inner
Warning --     _waitfor(_rmtree_inner, fullname, waitall=True)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 381, in _waitfor
Warning --     func(pathname)
Warning --     ~~~~^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\os_helper.py", line 426, in _rmtree_inner
Warning --     for name in _force_run(path, os.listdir, path):
Warning --                 ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "b:\uildarea\3.14.ware-win11.nondebug\build\Lib\test\support\__init__.py", line 221, in _force_run
Warning --     os.chmod(path, stat.S_IRWXU)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^
Warning -- PermissionError: [WinError 5] Access is denied: 'b:\\uildworker_temp\\test_python_f3pmns6d\\tmpfeb_loxl\\testjunc\\System Volume Information'

Linked PRs

• gh-156707: Remove the junction created in test_realpath_volume_guid_path() #156709
• gh-156707: Do not follow junctions in os_helper.rmtree() on Windows #156710
• [3.15] gh-156707: Do not follow junctions in os_helper.rmtree() on Windows (GH-156710) #156714
• [3.14] gh-156707: Do not follow junctions in os_helper.rmtree() on Windows (GH-156710) #156715
• [3.13] gh-156707: Do not follow junctions in os_helper.rmtree() on Windows (GH-156710) #156716

[vstinner]

Another example trying to remove $WINRE_BACKUP_PARTITION.MARKER marker file.

AMD64 Windows Server 2025 Refleaks 3.13: https://buildbot.python.org/#/builders/2266/builds/92

Warning -- regrtest worker thread failed: Traceback (most recent call last):
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\__init__.py", line 205, in _force_run
Warning --     return func(*args)
Warning -- PermissionError: [WinError 5] Access is denied: 'B:\\tmpdir\\test_python_7gdw7rsn\\tmpze_w2zie\\testjunc\\$WINRE_BACKUP_PARTITION.MARKER'
Warning -- 
Warning -- During handling of the above exception, another exception occurred:
Warning -- 
Warning -- Traceback (most recent call last):
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\libregrtest\run_workers.py", line 398, in run
Warning --     mp_result = self._runtest(test_name)
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\libregrtest\run_workers.py", line 357, in _runtest
Warning --     retcode, tmp_files = self.run_tmp_files(worker_runtests,
Warning --                          ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
Warning --                                             stdout_file.fileno())
Warning --                                             ^^^^^^^^^^^^^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\libregrtest\run_workers.py", line 297, in run_tmp_files
Warning --     os_helper.rmtree(tmp_dir)
Warning --     ~~~~~~~~~~~~~~~~^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\os_helper.py", line 481, in rmtree
Warning --     _rmtree(path)
Warning --     ~~~~~~~^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\os_helper.py", line 413, in _rmtree
Warning --     _waitfor(_rmtree_inner, path, waitall=True)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\os_helper.py", line 354, in _waitfor
Warning --     func(pathname)
Warning --     ~~~~^^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\os_helper.py", line 409, in _rmtree_inner
Warning --     _waitfor(_rmtree_inner, fullname, waitall=True)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\os_helper.py", line 354, in _waitfor
Warning --     func(pathname)
Warning --     ~~~~^^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\os_helper.py", line 409, in _rmtree_inner
Warning --     _waitfor(_rmtree_inner, fullname, waitall=True)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\os_helper.py", line 354, in _waitfor
Warning --     func(pathname)
Warning --     ~~~~^^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\os_helper.py", line 412, in _rmtree_inner
Warning --     _force_run(fullname, os.unlink, fullname)
Warning --     ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning --   File "B:\uildarea\3.13.ware-ws2025.refleak\build\Lib\test\support\__init__.py", line 215, in _force_run
Warning --     os.chmod(path, stat.S_IRWXU)
Warning --     ~~~~~~~~^^^^^^^^^^^^^^^^^^^^
Warning -- PermissionError: [WinError 5] Access is denied: 'B:\\tmpdir\\test_python_7gdw7rsn\\tmpze_w2zie\\testjunc\\$WINRE_BACKUP_PARTITION.MARKER'

[vstinner]

@serhiy-storchaka @encukou: I suspect that it's a regression introduced by test_realpath_volume_guid_path() of test_ntpath, related to issue gh-89760.

[serhiy-storchaka]

Yes, this was my error. Thank you for catching it @vstinner.

Two solutions:

• gh-156707: Remove the junction created in test_realpath_volume_guid_path() #156709 fixes the test itself, it removes the junction explicitly, not leaving it to general cleanup.
• gh-156707: Do not follow junctions in os_helper.rmtree() on Windows #156710 fixes os_helper.rmtree() on Windows. This can help in future tests, and it can be backported independently from the new test. It seems that shutil.rmtree() and TemporaryDirectory already handle junctions correctly.

Any one of them fixes the issue, but it is better to apply both.