Alembic migrations in "app/migrations" folder cause django development server to fail

[esquonk]

After setting up a django app and creating a migration using sorcery revision command, I get the following error when starting django dev server:

Exception in thread django-main-thread:
Traceback (most recent call last):
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\threading.py", line 917, in _bootstrap_inner
    self.run()
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\threading.py", line 865, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\site-packages\django\utils\autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\management\commands\runserver.py", line 120, in inner_run
    self.check_migrations()
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\site-packages\django\core\management\base.py", line 453, in check_migrations
    executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\executor.py", line 18, in __init__
    self.loader = MigrationLoader(self.connection)
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\loader.py", line 49, in __init__
    self.build_graph()
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\loader.py", line 206, in build_graph
    self.load_disk()
  File "C:\Users\mi\AppData\Local\Programs\Python\Python37\lib\site-packages\django\db\migrations\loader.py", line 119, in load_disk
    "Migration %s in app %s has no Migration class" % (migration_name, app_config.label)
django.db.migrations.exceptions.BadMigrationError: Migration 0001_test in app fares has no Migration class

It appears that the migration check wants all the files in migrations folders in apps to be valid django migrations. For now I work around this by manually adding a dummy django migration to alembic migration file:

from django.db import migrations


class Migration(migrations.Migration):
    dependencies = [
    ]

    operations = [
    ]

One alternative would be using a different folder, perhaps alembic_migrations or revisions to avoid confusion with django ORM migration system.

[shosca]

You can disable django migrations using MIGRATION_MODULES, just add a key with app label and with None value
https://docs.djangoproject.com/en/2.2/ref/settings/#migration-modules

[esquonk]

Thanks!
I think it would be nice to include this information in the tutorial.