pre-commit for local hook gives error: "unrecognized arguments: .pre-commit-config.yaml" - continuous-integration

Question

I have the following repo in pre-commit file .pre-commit-config.yaml
- repo: local
hooks:
- id: check_pip
name: Check pip file
description: This hook checks if requirements-dev.txt is up to date.
language: system
entry: python -m scripts.check_pip_requirements
args: ["--compare"]
But it keeps giving me the error:
error: unrecognized arguments: .pre-commit-config.yaml
As it passes the filename as an argument to my python script. How can I prevent this?

Answer 1

to clean up your example a little bit -- and use files to only run when the necessary files change:
- repo: local
hooks:
- id: check_pip
name: Check pip file
description: This hook checks if requirements-dev.txt is up to date.
language: system
entry: python -m scripts.check_pip_requirements --compare
files: ^requirements-dev.txt$
pass_filenames: false
note that I did a couple things:
args doesn't really make sense for local hooks, you can just put that in entry
pass_filenames (as you did) -- pre-commit is a framework based on passing filenames to executables, but you can turn that off
files: this will make it so the hook only gets triggered if requirements-dev.txt changes
alternatively (if you expect changes outside requirements-dev.txt to need to run this hook) you can drop files and use always_run: true
disclaimer: I'm the author of pre-commit

Answer 2

I spent quite some time figuring out what caused this and how to solve this. It's not documented well, eventually I fixed it by trial and error. We have to use pass_filenames: false in our hook:
- repo: local
hooks:
- id: check_pip
name: Check pip file
description: This hook checks if requirements-dev.txt is up to date.
language: system
entry: python -m scripts.check_pip_requirements
pass_filenames: false
args: ["--compare"]