[Django] #22777: Foreignkey does (sometimes) not get added to migration of M2M with a through model
Django
through model
----------------------------+--------------------
Reporter: valberg | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: master
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------+--------------------
The following models:
{{{
from django.conf import settings
from django.db import models
class Event(models.Model):
participants = models.ManyToManyField(
settings.AUTH_USER_MODEL,
through='testapp.Participant',
related_name='events'
)
class Participant(models.Model):
event = models.ForeignKey(
'testapp.Event',
related_name='associations',
)
user = models.ForeignKey(
settings.AUTH_USER_MODEL
)
}}}
Result in the following migration
{{{
$ ./manage.py makemigrations
Migrations for 'testapp':
0001_initial.py:
- Create model Event
- Create model Participant
$ cat testapp/migrations/0001_initial.py
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models, migrations
from django.conf import settings
class Migration(migrations.Migration):
dependencies = [
migrations.swappable_dependency(settings.AUTH_USER_MODEL),
]
operations = [
migrations.CreateModel(
name='Event',
fields=[
('id', models.AutoField(serialize=False,
auto_created=True, primary_key=True, verbose_name='ID')),
('participants',
models.ManyToManyField(through='testapp.Participant',
to=settings.AUTH_USER_MODEL)),
],
options={
},
bases=(models.Model,),
),
migrations.CreateModel(
name='Participant',
fields=[
('id', models.AutoField(serialize=False,
auto_created=True, primary_key=True, verbose_name='ID')),
('event', models.ForeignKey(to_field='id',
to='testapp.Event')),
('user', models.ForeignKey(to_field='id',
to=settings.AUTH_USER_MODEL)),
],
options={
},
bases=(models.Model,),
),
]
}}}
When migrating the following error occurs:
{{{
$ ./manage.py migrate
Operations to perform:
Synchronize unmigrated apps: sessions, auth, admin, contenttypes
Apply all migrations: testapp
Synchronizing apps without migrations:
Creating tables...
Creating table django_admin_log
Creating table auth_permission
Creating table auth_group_permissions
Creating table auth_group
Creating table auth_user_groups
Creating table auth_user_user_permissions
Creating table auth_user
Creating table django_content_type
Creating table django_session
Installing custom SQL...
Installing indexes...
Running migrations:
Applying testapp.0001_initial...Traceback (most recent call last):
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/apps/config.py", line 152, in get_model
return self.models[model_name.lower()]
KeyError: 'participant'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/db/migrations/state.py", line 76, in render
model = self.apps.get_model(lookup_model[0], lookup_model[1])
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/apps/registry.py", line 190, in get_model
return self.get_app_config(app_label).get_model(model_name.lower())
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/apps/config.py", line 155, in get_model
"App '%s' doesn't have a '%s' model." % (self.label, model_name))
LookupError: App 'testapp' doesn't have a 'participant' model.
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "./manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/core/management/base.py", line 337, in execute
output = self.handle(*args, **options)
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/core/management/commands/migrate.py", line 146, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/db/migrations/executor.py", line 62, in migrate
self.apply_migration(migration, fake=fake)
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/db/migrations/executor.py", line 96, in apply_migration
migration.apply(project_state, schema_editor)
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/db/migrations/migration.py", line 107, in apply
operation.database_forwards(self.app_label, schema_editor,
project_state, new_state)
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/db/migrations/operations/models.py", line 33, in
database_forwards
apps = to_state.render()
File "/home/valberg/.virtualenvs/django/lib/python3.3/site-
packages/django/db/migrations/state.py", line 86, in render
model=lookup_model,
ValueError: Lookup failed for model referenced by field
testapp.Event.participants: testapp.Participant
}}}
The odd thing is that the following models (same structure as above, just
different names):
{{{
from django.conf import settings
from django.db import models
# Same as Event above
class Foo(models.Model):
users = models.ManyToManyField(
settings.AUTH_USER_MODEL,
through='testapp.Bar',
related_name='foos'
)
# Same as Participant above
class Bar(models.Model):
foo = models.ForeignKey(
'testapp.Foo',
related_name='bars',
)
user = models.ForeignKey(
settings.AUTH_USER_MODEL
)
}}}
Result in the following:
{{{
$ ./manage.py makemigrations
Migrations for 'testapp':
0001_initial.py:
- Create model Bar
- Create model Foo
- Add field foo to bar
$ cat testapp/migrations/0001_initial.py
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models, migrations
from django.conf import settings
class Migration(migrations.Migration):
dependencies = [
migrations.swappable_dependency(settings.AUTH_USER_MODEL),
]
operations = [
migrations.CreateModel(
name='Bar',
fields=[
('id', models.AutoField(serialize=False, primary_key=True,
auto_created=True, verbose_name='ID')),
('user', models.ForeignKey(to_field='id',
to=settings.AUTH_USER_MODEL)),
],
options={
},
bases=(models.Model,),
),
migrations.CreateModel(
name='Foo',
fields=[
('id', models.AutoField(serialize=False, primary_key=True,
auto_created=True, verbose_name='ID')),
('users',
models.ManyToManyField(to=settings.AUTH_USER_MODEL,
through='testapp.Bar')),
],
options={
},
bases=(models.Model,),
),
migrations.AddField(
model_name='bar',
name='foo',
field=models.ForeignKey(to_field='id', to='testapp.Foo'),
preserve_default=True,
),
]
$ ./manage.py migrate
Operations to perform:
Synchronize unmigrated apps: admin, auth, sessions, contenttypes
Apply all migrations: testapp
Synchronizing apps without migrations:
Creating tables...
Creating table django_admin_log
Creating table auth_permission
Creating table auth_group_permissions
Creating table auth_group
Creating table auth_user_groups
Creating table auth_user_user_permissions
Creating table auth_user
Creating table django_content_type
Creating table django_session
Installing custom SQL...
Installing indexes...
Running migrations:
Applying testapp.0001_initial... OK
}}}
So somehow the naming of the models has a say in how the migrations are
made. In the failing example there is no creation of the FK from
Participant to Event as there is from Bar to Foo.
--
Ticket URL: <https://code.djangoproject.com/ticket/22777>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
through model
Reporter: valberg | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: master
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by bmispelon):
* needs_better_patch: => 0
* needs_docs: => 0
* severity: Normal => Release blocker
* needs_tests: => 0
* stage: Unreviewed => Accepted
Comment:
Hi,
I can reproduce your issue with this simplified models (no reference to
`settings.AUTH_USER_MODEL`):
{{{#!python
from django.db import models
class Foo(models.Model):
pass
class Bar(models.Model):
foos = models.ManyToManyField('Foo', through='FooBar')
class FooBar(models.Model):
foo = models.ForeignKey('Foo')
bar = models.ForeignKey('Bar')
}}}
As you mentionned, renaming `FooBar` to `AFooBar` (so that it appears
before when sorting alphabetically) makes everything work.
I'll upgrade the ticket to a release blocker.
Thanks.
--
Ticket URL: <https://code.djangoproject.com/ticket/22777#comment:1>
Django
through model
Reporter: valberg | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: master
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by andrewgodwin):
Looks like there's not enough dependency stuff set in the autodetector to
force the operation ordering. Hopefully an easy-ish fix.
--
Ticket URL: <https://code.djangoproject.com/ticket/22777#comment:2>
Django
through model
Reporter: valberg | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Release blocker | Resolution: fixed
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Andrew Godwin <andrew@…>):
* status: new => closed
* resolution: => fixed
Comment:
In [changeset:"3f91238adf819b1d86f800d6b535b3c04447dac2"]:
{{{
#!CommitTicketReference repository=""
revision="3f91238adf819b1d86f800d6b535b3c04447dac2"
Fixed #22777: Add dependency on through for autodetected M2M adds
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/22777#comment:3>
Django
through model
Reporter: valberg | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Release blocker | Resolution: fixed
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Andrew Godwin <andrew@…>):
In [changeset:"55fa4c2d3423b051fce5663b3efc13e458fbb777"]:
{{{
#!CommitTicketReference repository=""
revision="55fa4c2d3423b051fce5663b3efc13e458fbb777"
[1.7.x] Fixed #22777: Add dependency on through for autodetected M2M adds
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/22777#comment:4>