Empty file path with custom local hook

Hi there, I’m trying to setup pre-commit for a mono-repo (backend and frontend of an app I’m using) and I’m encountering an “error” where the path passed to the hook is empty, here’s an example of hook:

repos:
  - repo: local
    hooks:
      - id: example
        name: run example
        language: system
        entry: bash -c 'cd backend && echo hello && echo $@ && echo "${@/backend\//./}" && exit 1'
        types: [python]
        files: ^backend/

The idea is to run hooks from the correct folder so they find the right configuration files 😃

This is my stage:

❯ git status
On branch main
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	modified:   .pre-commit-config.yaml
	modified:   backend/api/schema.py
	modified:   frontend/components/activate-screen/modal.tsx
	modified:   frontend/components/add-media-card/modal.tsx
	new file:   frontend/components/loading.tsx

And this is the output:

❯ git commit
run example..............................................................Failed
- hook id: example
- exit code: 1

hello

Am I doing something wrong with using “$@”? Let me know if you need more information 😊

[asottile]

I think if you’re trying to do it inline if you add -- to the end it’ll work (that’ll be the “program name”) – that way your first filename doesn’t get gobbled:

    entry: bash -c '...' --

[paulhfischer]

• bash -c shifts the arguments. thus, if pre-commit passes foo1 foo2 foo3 as arguments, $@ will expand to foo2 foo3
• you have types: [python], thus only backend/api/schema.py will be matched. this means, that $@ expands to an empty string

you can see which arguments are passed if you use entry: echo and set verbose: true