isort pre-commit hook does not skip text files

[mathause]

MCVE Code Sample

Add arbitrary change to the file doc/pandas.rst

git add doc/pandas.rst
git commit -m "test"

The pre-commit hook will fail.

Expected Output

the pre-commit hook to pass

Problem Description

running isort -rc doc/* will change the following files:

        modified:   contributing.rst
        modified:   howdoi.rst
        modified:   internals.rst
        modified:   io.rst
        modified:   pandas.rst
        modified:   quick-overview.rst

unfortunately it does not behave properly and deletes/ changes arbitrary lines. Can the pre-commit hook be told to only run on *.py files? On the command line this would be isort -rc *.py

[keewis]

pre-commit allows filtering the files passed to a hook using regular expressions:

   - repo: https://github.com/timothycrosley/isort
     rev: 4.3.21-2
     hooks:
       - id: isort
+        files: ".+[.]py"
   # https://github.com/python/black#version-control-integration
   - repo: https://github.com/python/black

Not sure if this regex is the one we should use, but it does seem to work.

[mathause]

You can tell isort to skip files in the setup.cfg but this seems to be ignored when doing isort file (which is what happens in the pre-commit hook) - see pre-commit/mirrors-isort#9 (comment)

So I think adapting .pre-commit-config.yaml is the way to go at the moment. (Maybe adapt setup.cfg anyway to ensure it does not happen when isort is called with isort -rc .).

[keewis]

actually, isort does support filtering using --filter-files -sg '*.rst' which would blacklist rst files. Since we don't have just rst files, I think that whitelisting is a better approach. Maybe we should use files: .\.py$?

[asottile]

fwiw, the problem here is the -2 tag of isort is broken -- you want 4.3.21 which properly specifies types: [python]