pre-commit hook to check django migrations

Question

I'm trying to write a pre-commit hook to my Django project that checks for missing migrations. That is, it ensures all changes are reflected in a migrations file.

One way to implement this is to PASS the pre-commit hook if the makemigrations command returns no changes.

$ ./manage.py makemigrations --dry-run
No changes detected

And to FAIL the pre-commit hook if it returns something:

$ ./manage.py makemigrations --dry-run
Migrations for 'myapp':
  myapp/migrations/0003_auto_20201213_2233.py
    - Alter field type on event

How can I write this pre-commit hook? Is there a better approach than using makemigrations? This is what I have so far but it always passes (I think I need to parse the response):

repos:
  - repo: local
    hooks:
      - id: pre-commit-django-migrations
        name: Check django migrations
        entry: ./manage.py makemigrations --dry-run
        language: system
        types: [python]
        pass_filenames: false

Answer 1

From Django makemigrations documentation

--check

Makes makemigrations exit with a non-zero status when model changes without migrations are detected.

So you can use --check instead

  entry: python manage.py makemigrations --check