Pre-commit install fails on Windows network mount drive

Hi, I’m trying to help some team members set up pre-commit on a Windows network mount drive, and they’re encountering an issue with paths. Seems related to this comment in #1610, which seems to be a different issue than the one the original issue, as we are on the most recent version of pre-commit and git, and the fix that was merged in #1727 for that doesn’t seem to address this issue. I also tried other versions of Git for Windows <2.25, and the issue still seemed to persist.

I tested the solution that @christopherdoyle proposed, and that does seems to fix this issue with network mount drives, though I saw that @asottile would prefer not to use pathlib. I am not able to propose a fix right now, but I wanted to raise this as an issue that still exists.

Full error below:

    ### version information
    
    ```
    pre-commit version: 2.10.1
    sys.version:
        3.9.1 | packaged by conda-forge | (default, Jan 26 2021, 01:29:07) [MSC v.1916 64 bit (AMD64)]
    sys.executable: C:\Users\roderick\.conda\envs\nmt\python.exe
    os.name: nt
    sys.platform: win32
    ```
    
    ### error information
    
    ```
    An unexpected error has occurred: ValueError: path is on mount 'S:', start on mount '\\\\MyServer\Directory'
    ```
    
    ```
    Traceback (most recent call last):
      File "C:\Users\roderick\.conda\envs\nmt\lib\site-packages\pre_commit\error_handler.py", line 65, in error_handler
        yield
      File "C:\Users\roderick\.conda\envs\nmt\lib\site-packages\pre_commit\main.py", line 333, in main
        _adjust_args_and_chdir(args)
      File "C:\Users\roderick\.conda\envs\nmt\lib\site-packages\pre_commit\main.py", line 153, in _adjust_args_and_chdir
        args.config = os.path.relpath(args.config)
      File "C:\Users\roderick\.conda\envs\nmt\lib\ntpath.py", line 703, in relpath
        raise ValueError("path is on mount %r, start on mount %r" % (
    ValueError: path is on mount 'S:', start on mount '\\\\MyServer\Directory'

[faph]

From the docs (https://docs.python.org/3/library/os.path.html#os.path.realpath):

os.path.realpath(path) Return the canonical path of the specified filename, eliminating any symbolic links encountered in the path (if they are supported by the operating system).

Note When symbolic link cycles occur, the returned path will be one member of the cycle, but no guarantee is made about which member that will be. Changed in version 3.6: Accepts a path-like object.

Changed in version 3.8: Symbolic links and junctions are now resolved on Windows.

[goroderickgo]

Yep, also works for me. Thanks for the quick fix!