Cannot run --files on Windows

[harrybiddle]

(pre-commit version 2.4.0) We're running in to an odd issue on Windows

$ pre-commit run --files my_file.py
black................................................(no files to check)Skipped

However, running pre-commit run --all-files will correctly format the file. Equally, running pre-commit run --files my_file.py in the same repository on a Mac works fine.

It's like the file is somehow not being read in Windows... Has anybody else encountered this?

[asottile]

please share your configuration -- I suspect you've got an exclude: or types: which is causing that file to be skipped

[harrybiddle]

Hey @asottile ,

Here are the configuration files. The file we were trying to format was ./trase/supplychain/test/test_supplychain.py.

However, I thought that we had ruled out this being a configuration issue, for two reasons:

1. Running pre-commit run --all-files does format the file, so it must be correct in the configuration
2. Running the same command on a Mac works

Thank you for any help!

• .pre-commit-config.yaml:

  exclude: '^(?!trase/).*$'
  repos:
  -   repo: https://github.com/ambv/black
      rev: 19.10b0
      hooks:
      - id: black
        language_version: python3.6
  -   repo: https://github.com/timothycrosley/isort
      rev: 4.3.21
      hooks:
      -   id: isort

• .gitignore:

  __pycache__/
  .ipynb_checkpoints/
  .vscode/
  .venv/
  ORI/
  IN/
  PRE/
  OUT/
  POST/
  *.pyc
  *.mps
  *.lp
  *.txt
  .DS_Store
  poetry.toml
  .pytest_cache
  Tutorial_1/
  Tutorial_2/
  Tutorial_3/
  result.log
  main.py
  **/*.idea*
  .idea/*
  **/*~
  **/*#
  **/.#*
  

[asottile]

can you show the exact command you ran?

[harrybiddle]

On Windows:

$ pre-commit run --files trase/supplychain/test/test_supplychain.py
black................................................(no files to check)Skipped
isort................................................(no files to check)Skipped

On Mac:

$ pre-commit run --files trase/supplychain/test/test_supplychain.py
black....................................................................Passed
isort....................................................................Passed

I'm wondering if it is something odd about passing the file path on Windows. I've noticed that I get "skipped" on a Mac with pre-commit run --files this-file-does-not-exist. We did try changing to a backslash but still no joy...

[asottile]

ok, I can now reproduce this, it seems that when I switched everything to use forward slashes for the regexes, I forgot to handle global files / exclude (by the way, your configuration can be a little bit simpler by doing files: ^trase/ (this still doesn't work until I fix this bug though!))

thanks for the report! (I'm working on this on stream right now https://twitch.tv/anthonywritescode)

[harrybiddle]

Amazing - I love the twitch livestream. Thank you for the fix!

By the way, Python's stdlib has a great module for converting the a file path to posix-style, maybe it will catch some odd edge cases that aren't covered in your f.replace(os.sep, os.altsep) code?

https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.as_posix

[asottile]

yeah it's literally the same thing:

    def as_posix(self):
        """Return the string representation of the path with forward (/)
        slashes."""
        f = self._flavour
        return str(self).replace(f.sep, '/')