#22931: Migrations cannot rename intermediate models
-------------------------------------+-------------------------------------
Reporter: JockeTF | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7-rc-2
Severity: Normal | Resolution:
Keywords: migrations migrate | Triage Stage: Accepted
makemigrations rename | Needs documentation: 0
intermediate model | Patch needs improvement: 0
Has patch: 0 | UI/UX: 0
Needs tests: 0 |
Easy pickings: 0 |
-------------------------------------+-------------------------------------
Changes (by JockeTF):
* status: closed => new
* version: 1.7-rc-1 => 1.7-rc-2
* resolution: fixed =>
Comment:
I am still affected by this issue. It appears to affect 1.7c2, 1.7.x,
master, commit 015496539247b24c73b163f279ae8c8d3ccefc4c, and commit
d1c08d4758998318eb1a881a3963b63bc89435b8. I have included the steps I took
to reproduce the issue.
Start a new application called 'rename' in Django 1.7c2 with two models.
{{{#!python
from django.db import models
from django.conf import settings
class Channel(models.Model):
name = models.CharField(max_length=128)
subscribers = models.ManyToManyField(settings.AUTH_USER_MODEL,
through='Subscriber', related_name='subscriptions')
date_created = models.DateTimeField(auto_now_add=True)
class Subscriber(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL)
channel = models.ForeignKey(Channel)
date_subscribed = models.DateTimeField(auto_now_add=True)
class Meta():
unique_together = ('user', 'channel')
}}}
Make migrations.
{{{#!python
$ python3 manage.py makemigrations
Migrations for 'rename':
0001_initial.py:
- Create model Channel
- Create model Subscriber
- Add field subscribers to channel
- Add field channel to subscriber
- Add field user to subscriber
- Alter unique_together for subscriber (1 constraint(s))
}}}
Change the name of the subscriber model. Make sure to also update the
subscribers field to reflect the change.
{{{#!python
from django.db import models
from django.conf import settings
class Channel(models.Model):
name = models.CharField(max_length=128)
subscribers = models.ManyToManyField(settings.AUTH_USER_MODEL,
through='Subscribe', related_name='subscriptions')
date_created = models.DateTimeField(auto_now_add=True)
class Subscribe(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL)
channel = models.ForeignKey(Channel)
date_subscribed = models.DateTimeField(auto_now_add=True)
class Meta():
unique_together = ('user', 'channel')
}}}
Make migrations.
{{{#!python
$ python3 manage.py makemigrations
Migrations for 'rename':
0002_auto_20140729_0822.py:
- Create model Subscribe
- Alter unique_together for subscribe (1 constraint(s))
- Alter unique_together for subscriber (0 constraint(s))
- Remove field channel from subscriber
- Remove field user from subscriber
- Delete model Subscriber
- Alter field subscribers on channel
}}}
Django failed to detect the rename (perhaps due to some other bug).
Replace the automatically generated migration with one generated by Django
1.7b4. I cannot say whether or not this migration would still be valid,
but I have no other way of generating a proper migration at the moment.
{{{#!python
from django.db import models, migrations
from django.conf import settings
class Migration(migrations.Migration):
dependencies = [
('rename', '0001_initial'),
]
operations = [
migrations.RenameModel(
old_name='Subscriber',
new_name='Subscribe',
),
migrations.AlterField(
model_name='channel',
name='subscribers',
field=models.ManyToManyField(through='rename.Subscribe',
to=settings.AUTH_USER_MODEL),
),
]
}}}
Make migrations detects no further changes.
{{{#!python
$ python3 manage.py makemigrations
No changes detected
}}}
Migrate.
{{{#!python
$ python3 manage.py migrate
Operations to perform:
Apply all migrations: sessions, contenttypes, admin, auth, rename
Running migrations:
Applying contenttypes.0001_initial... OK
Applying auth.0001_initial... OK
Applying admin.0001_initial... OK
Applying rename.0001_initial... OK
Applying rename.0002_auto_20140729_0822...Traceback (most recent call
last):
File "/usr/local/lib/python3.4/dist-packages/django/apps/config.py",
line 158, in get_model
return self.models[model_name.lower()]
KeyError: 'subscriber'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/state.py", line 79, in render
model = self.apps.get_model(lookup_model[0], lookup_model[1])
File "/usr/local/lib/python3.4/dist-packages/django/apps/registry.py",
line 202, in get_model
return self.get_app_config(app_label).get_model(model_name.lower())
File "/usr/local/lib/python3.4/dist-packages/django/apps/config.py",
line 161, in get_model
"App '%s' doesn't have a '%s' model." % (self.label, model_name))
LookupError: App 'rename' doesn't have a 'subscriber' 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 "/usr/local/lib/python3.4/dist-
packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.4/dist-
packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python3.4/dist-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/usr/local/lib/python3.4/dist-
packages/django/core/management/base.py", line 337, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python3.4/dist-
packages/django/core/management/commands/migrate.py", line 160, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/executor.py", line 63, in migrate
self.apply_migration(migration, fake=fake)
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/executor.py", line 97, in apply_migration
migration.apply(project_state, schema_editor)
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/migration.py", line 107, in apply
operation.database_forwards(self.app_label, schema_editor,
project_state, new_state)
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/operations/models.py", line 141, in
database_forwards
new_apps = to_state.render()
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/state.py", line 89, in render
model=lookup_model,
ValueError: Lookup failed for model referenced by field
rename.Channel.subscribers: rename.Subscriber
}}}
I also tried to change the order of the operations.
{{{#!python
from django.db import models, migrations
from django.conf import settings
class Migration(migrations.Migration):
dependencies = [
('rename', '0001_initial'),
]
operations = [
migrations.AlterField(
model_name='channel',
name='subscribers',
field=models.ManyToManyField(through='rename.Subscribe',
to=settings.AUTH_USER_MODEL),
),
migrations.RenameModel(
old_name='Subscriber',
new_name='Subscribe',
),
]
}}}
This results in a slightly different exception.
{{{#!python
$ rm db.sqlite3
$ python3 manage.py migrate
Operations to perform:
Apply all migrations: rename, admin, auth, contenttypes, sessions
Running migrations:
Applying contenttypes.0001_initial... OK
Applying auth.0001_initial... OK
Applying admin.0001_initial... OK
Applying rename.0001_initial... OK
Applying rename.0002_auto_20140729_0822...Traceback (most recent call
last):
File "/usr/local/lib/python3.4/dist-packages/django/apps/config.py",
line 158, in get_model
return self.models[model_name.lower()]
KeyError: 'subscribe'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/state.py", line 79, in render
model = self.apps.get_model(lookup_model[0], lookup_model[1])
File "/usr/local/lib/python3.4/dist-packages/django/apps/registry.py",
line 202, in get_model
return self.get_app_config(app_label).get_model(model_name.lower())
File "/usr/local/lib/python3.4/dist-packages/django/apps/config.py",
line 161, in get_model
"App '%s' doesn't have a '%s' model." % (self.label, model_name))
LookupError: App 'rename' doesn't have a 'subscribe' 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 "/usr/local/lib/python3.4/dist-
packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.4/dist-
packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python3.4/dist-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/usr/local/lib/python3.4/dist-
packages/django/core/management/base.py", line 337, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python3.4/dist-
packages/django/core/management/commands/migrate.py", line 160, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/executor.py", line 63, in migrate
self.apply_migration(migration, fake=fake)
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/executor.py", line 91, in apply_migration
if self.detect_soft_applied(migration):
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/executor.py", line 134, in
detect_soft_applied
project_state = self.loader.project_state((migration.app_label,
migration.name), at_end=True)
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/loader.py", line 268, in project_state
return self.graph.make_state(nodes=nodes, at_end=at_end,
real_apps=list(self.unmigrated_apps))
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/graph.py", line 147, in make_state
project_state = self.nodes[node].mutate_state(project_state)
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/migration.py", line 76, in mutate_state
operation.state_forwards(self.app_label, new_state)
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/operations/models.py", line 117, in
state_forwards
apps = state.render(skip_cache=True)
File "/usr/local/lib/python3.4/dist-
packages/django/db/migrations/state.py", line 89, in render
model=lookup_model,
ValueError: Lookup failed for model referenced by field
rename.Channel.subscribers: rename.Subscribe
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/22931#comment:7>
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