Unable to use pytest from mapped network drive

[abhilash1in]

• a detailed description of the bug or suggestion
  Running pyest --version using PowerShell displays the pytest version when I'm in my home directory or any other local directory on my Windows machine. When I cd into a mapped network drive (Q:\) and run pyest --version, I get PermissionError: [WinError 5] Access is denied: '.'. I get the same error when I run pyest --version inside as well as outside a virtual environment when I'm in a mapped network drive.
• output of pip list from the virtual environment you are using

(env) PS Q:\Projects\Abhilash\Feeds> pip list
Package            Version
------------------ -------
asn1crypto         0.24.0
astroid            2.2.5
atomicwrites       1.3.0
attrs              19.1.0
bcrypt             3.1.7
cffi               1.12.3
colorama           0.4.1
coverage           4.5.4
cryptography       2.7
importlib-metadata 0.20
isort              4.3.21
lazy-object-proxy  1.4.2
mccabe             0.6.1
more-itertools     7.2.0
packaging          19.1
paramiko           2.6.0
pip                19.0.3
pluggy             0.12.0
py                 1.8.0
pycparser          2.19
pylint             2.3.1
pymssql            2.1.4
PyNaCl             1.3.0
pyparsing          2.4.2
pytest             5.1.2
pytest-cov         2.7.1
setuptools         40.8.0
six                1.12.0
typed-ast          1.4.0
wcwidth            0.1.7
wrapt              1.11.2
zipp               0.6.0
You are using pip version 19.0.3, however version 19.2.3 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip'
command.

• pytest and operating system versions

PS C:\Users\kishorea> pytest --version
This is pytest version 5.1.2, imported from c:\users\kishorea\appdata\local\programs\python\python37\lib\site-packages\pytest.py
setuptools registered plugins:
  pytest-cov-2.7.1 at c:\users\kishorea\appdata\local\programs\python\python37\lib\site-packages\pytest_cov\plugin.py
PS C:\Users\kishorea>

PS C:\Users\kishorea> (Get-WMIObject win32_operatingsystem).name
Microsoft Windows 10 Enterprise|C:\WINDOWS|\Device\Harddisk0\Partition4

• minimal example if possible

PS C:\Users\kishorea> pytest --version
This is pytest version 5.1.2, imported from c:\users\kishorea\appdata\local\programs\python\python37\lib\site-packages\pytest.py
setuptools registered plugins:
  pytest-cov-2.7.1 at c:\users\kishorea\appdata\local\programs\python\python37\lib\site-packages\pytest_cov\plugin.py
PS C:\Users\kishorea> q:
PS Q:\> pytest --version
Traceback (most recent call last):
  File "c:\users\kishorea\appdata\local\programs\python\python37\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "c:\users\kishorea\appdata\local\programs\python\python37\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Users\kishorea\AppData\Local\Programs\Python\Python37\Scripts\pytest.exe\__main__.py", line 9, in <module>
  File "c:\users\kishorea\appdata\local\programs\python\python37\lib\site-packages\_pytest\config\__init__.py", line 59, in main
    config = _prepareconfig(args, plugins)
  File "c:\users\kishorea\appdata\local\programs\python\python37\lib\site-packages\_pytest\config\__init__.py", line 195, in _prepareconfig
    config = get_config(args, plugins)
  File "c:\users\kishorea\appdata\local\programs\python\python37\lib\site-packages\_pytest\config\__init__.py", line 160, in get_config
    args=args, plugins=plugins, dir=Path().resolve()
  File "c:\users\kishorea\appdata\local\programs\python\python37\lib\pathlib.py", line 1151, in resolve
    s = self._flavour.resolve(self, strict=strict)
  File "c:\users\kishorea\appdata\local\programs\python\python37\lib\pathlib.py", line 202, in resolve
    s = self._ext_to_normal(_getfinalpathname(s))
PermissionError: [WinError 5] Access is denied: '.'
PS Q:\>

[blueyed]

Is this a regression? (i.e. did it work in older versions? (which?))
If so, can you git-bisect it?

[abhilash1in]

I've not used pytest before, so I'm not sure if this is a regression.

[RonnyPfannschmidt]

at first glance this looks like a windows issue of python, as it happens in the resolve method of pathlib

[dr-1]

I get the same issue and for me it worked in previous versions. I git-bisected it and it appears that 6a9bf28 is the first bad commit.

Edit: Sorry, wrong reference. Updated.

[dr-1]

Also, agreed that the issue comes from Python on Windows, as pathlib.Path().resolve() does not seem to be able to handle network drives. After a bit of research I'm not sure how to solve that, other than using the os module instead to get the current directory.

[adamkerz]

Another issue related to Path().resolve() - #5905
Can Path().absolute() be used instead?

[Thibuko]

Also, agreed that the issue comes from Python on Windows, as pathlib.Path().resolve() does not seem to be able to handle network drives. After a bit of research I'm not sure how to solve that, other than using the os module instead to get the current directory.

Seems that Python will not change anything and pytest should do the work: https://bugs.python.org/issue37993 resolution: not a bug

[RonnyPfannschmidt]

@abhilash1in can you (or another windows user) verify if the issue disappears if Path().resolve() is repalced by Path.cwd() or Path.cwd().resolve()

[RonnyPfannschmidt]

@Thibuko it seems that the issue that pops up in the python bug also means that pytest has to replace py.path.local.pyimport with a pathlib one as its no longer functional on windows

thanks for bringing the python issue to attention

[manum45]

A similar issue occurs on RAM disks (O:\ in this case):

O:\>C:\ProgramData\Anaconda3\python.exe -m pytest --version
Traceback (most recent call last):
  File "C:\ProgramData\Anaconda3\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "C:\ProgramData\Anaconda3\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\ProgramData\Anaconda3\lib\site-packages\pytest.py", line 101, in <module>
    raise SystemExit(pytest.main())
  File "C:\ProgramData\Anaconda3\lib\site-packages\_pytest\config\__init__.py", line 71, in main
    config = _prepareconfig(args, plugins)
  File "C:\ProgramData\Anaconda3\lib\site-packages\_pytest\config\__init__.py", line 207, in _prepareconfig
    config = get_config(args, plugins)
  File "C:\ProgramData\Anaconda3\lib\site-packages\_pytest\config\__init__.py", line 172, in get_config
    args=args, plugins=plugins, dir=Path().resolve()
  File "C:\ProgramData\Anaconda3\lib\pathlib.py", line 1151, in resolve
    s = self._flavour.resolve(self, strict=strict)
  File "C:\ProgramData\Anaconda3\lib\pathlib.py", line 202, in resolve
    s = self._ext_to_normal(_getfinalpathname(s))
OSError: [WinError 1] Incorrect function: '.'

This behavior seems to be described here: https://bugs.python.org/issue31842

Edit:
Error occurs with:

Python 3.7.4 (default, Aug  9 2019, 18:34:13) [MSC v.1915 64 bit (AMD64)] :: Anaconda, Inc. on win32

pytest                             5.2.1
pytest-arraydiff                   0.3
pytest-astropy                     0.5.0
pytest-doctestplus                 0.4.0
pytest-openfiles                   0.4.0
pytest-remotedata                  0.3.2
python-dateutil                    2.8.0

[nicoddemus]

This will be fixed in pytest 6.0 because we are no longer resolving paths. 👍