Hello, I'm struggling with migrations when trying to add a m2m between two apps in Django dev. I don't know if this is a bug or if I'm doing it wrong but basically, if main.models is:
from django.conf import settings
> from django.db import models
>
> class Restaurant(models.Model):
> name = models.CharField(max_length = 80)
>
> class UserRestaurant(models.Model):
> restaurant = models.ForeignKey(Restaurant)
> user = models.ForeignKey('custom_auth.User')
>
And custom_auth.models is:
from django.db import models
>
> class User(models.Model):
> address = models.CharField(max_length=100, blank=True)
>
Then adding the following field to custom_auth.models.User (that cannot be
done in one migration because of a CircularDependency exception):
restaurants = models.ManyToManyField('main.Restaurant')
>
Will raise the following exception when migrating (makemigrations is fine):
$ python3 manage.py migrate
> Operations to perform:
> Synchronize unmigrated apps: admin, sessions, auth, contenttypes
> Apply all migrations: custom_auth, main
> Synchronizing apps without migrations:
> Creating tables...
> Installing custom SQL...
> Installing indexes...
> Running migrations:
> Applying custom_auth.0002_user_restaurants...Traceback (most recent call
> last):
> File "manage.py", line 10, in <module>
> execute_from_command_line(sys.argv)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/core/management/__init__.py",
>
> line 427, in execute_from_command_line
> utility.execute()
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/core/management/__init__.py",
>
> line 419, in execute
> self.fetch_command(subcommand).run_from_argv(self.argv)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/core/management/base.py",
>
> line 287, in run_from_argv
> self.execute(*args, **options.__dict__)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/core/management/base.py",
>
> line 336, in execute
> output = self.handle(*args, **options)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/core/management/commands/migrate.py",
>
> line 145, in handle
> executor.migrate(targets, plan, fake=options.get("fake", False))
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/migrations/executor.py",
>
> line 60, in migrate
> self.apply_migration(migration, fake=fake)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/migrations/executor.py",
>
> line 94, in apply_migration
> migration.apply(project_state, schema_editor)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/migrations/migration.py",
>
> line 97, in apply
> operation.database_forwards(self.app_label, schema_editor,
> project_state, new_state)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/migrations/operations/fields.py",
>
> line 35, in database_forwards
> field,
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/backends/sqlite3/schema.py",
>
> line 110, in add_field
> return self.create_model(field.rel.through)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/backends/schema.py",
>
> line 191, in create_model
> definition, extra_params = self.column_sql(model, field)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/backends/schema.py",
>
> line 108, in column_sql
> db_params = field.db_parameters(connection=self.connection)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/models/fields/related.py",
>
> line 1754, in db_parameters
> return {"type": self.db_type(connection), "check": []}
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/models/fields/related.py",
>
> line 1745, in db_type
> rel_field = self.related_field
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/models/fields/related.py",
>
> line 1651, in related_field
> return self.foreign_related_fields[0]
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/models/fields/related.py",
>
> line 1410, in foreign_related_fields
> return tuple(rhs_field for lhs_field, rhs_field in self.related_fields)
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/models/fields/related.py",
>
> line 1397, in related_fields
> self._related_fields = self.resolve_related_fields()
> File
> "/usr/local/lib/python3.3/dist-packages/Django-1.7a2-py3.3.egg/django/db/models/fields/related.py",
>
> line 1382, in resolve_related_fields
> raise ValueError('Related model %r cannot be resolved' % self.rel.to)
> ValueError: Related model 'main.Restaurant' cannot be resolved
>
I'm attaching this test project to the email, you'll see that the last
migration will fail.
Am I missing something obvious here? The FK in main.UserRestaurant is
working fine but I don't know what can't Django resolve main.Restaurant in
custom_auth.User...
Thank you for your help
Baptiste
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