Opened 10 years ago
Closed 8 years ago
#22931 closed Bug (duplicate)
Migrations cannot rename intermediate models
Reported by: | JockeTF | Owned by: | nobody |
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Component: | Migrations | Version: | 1.7 |
Severity: | Normal | Keywords: | migrations migrate makemigrations rename intermediate model |
Cc: | eschler@…, info+coding@…, vytis.banaitis@… | Triage Stage: | Accepted |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
Due to a change in naming conventions I needed to rename an intermediate model. I renamed a model from Subscriber to Subscribe.
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')
Running makemigrations in Django 1.7c1 results in an exception.
0002_auto_20140701_0817.py: - Create model Subscribe - Alter unique_together for subscribe (1 constraints) 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/makemigrations.py", line 115, in handle self.write_migration_files(changes) File "/usr/local/lib/python3.4/dist-packages/django/core/management/commands/makemigrations.py", line 131, in write_migration_files self.stdout.write(" - %s\n" % operation.describe()) File "/usr/local/lib/python3.4/dist-packages/django/db/migrations/operations/models.py", line 251, in describe return "Alter %s for %s (%s constraints)" % (self.option_name, self.name, len(self.unique_together)) TypeError: object of type 'NoneType' has no len()
In Django 1.7b3 makemigrations actually worked.
from django.db import models, migrations from django.conf import settings class Migration(migrations.Migration): dependencies = [ ('api', '0002_auto_20140630_1443'), ] operations = [ migrations.RenameModel( old_name='Subscriber', new_name='Subscribe', ), migrations.AlterField( model_name='channel', name='subscribers', field=models.ManyToManyField(through='api.Subscribe', to=settings.AUTH_USER_MODEL), ), ]
However, running migrate in Django 1.7b3 results in another exception.
Running migrations: Applying api.0013_subscriber_renamed...Traceback (most recent call last): File "/usr/local/lib/python3.4/dist-packages/django/apps/config.py", line 152, 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 78, 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 190, 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 155, in get_model "App '%s' doesn't have a '%s' model." % (self.label, model_name)) LookupError: App 'api' 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 146, 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 62, in migrate self.apply_migration(migration, fake=fake) File "/usr/local/lib/python3.4/dist-packages/django/db/migrations/executor.py", line 96, 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 88, in render model=lookup_model, ValueError: Lookup failed for model referenced by field api.Channel.subscribers: api.Subscriber
The same exception is thrown if I move the migration generated in Django 1.7b3 to Django 1.7c1.
Change History (13)
comment:1 by , 10 years ago
comment:2 by , 10 years ago
Not sure why it's saying that I've unset various flags (Needs documentation etc). It wasn't deliberate!
comment:3 by , 10 years ago
Triage Stage: | Unreviewed → Accepted |
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comment:4 by , 10 years ago
Cc: | added |
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Component: | Database layer (models, ORM) → Migrations |
comment:5 by , 10 years ago
Resolution: | → worksforme |
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Status: | new → closed |
I haven't been able to reproduce the error neither renaming te model or removing the unique_together constraint. Tested against https://github.com/django/django/tree/d1c08d4758998318eb1a881a3963b63bc89435b8 with the tests submitted by the creator of the ticket and those in the first comment.
I guess it has been fixed...
comment:6 by , 10 years ago
Resolution: | worksforme → fixed |
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comment:7 by , 10 years ago
Resolution: | fixed |
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Status: | closed → new |
Version: | 1.7-rc-1 → 1.7-rc-2 |
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.
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.
$ 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.
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.
$ 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.
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.
$ python3 manage.py makemigrations No changes detected
Migrate.
$ 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.
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.
$ 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
comment:8 by , 10 years ago
On the detecting of the rename: Django does not guarantee to detect renames, it's just a courtesy we offer if we can, so that in itself is not a bug. It can probably be improved, sure, but it's unrelated to this issue.
It looks to me that the likely cause is RenameModel not taking care of all the state changes on related fields - notably, it fixes all "to" references, but no "through" references, so making it do that will likely fix this.
comment:9 by , 10 years ago
Cc: | added |
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I'm not sure why there is no stable sorting on the fields in model states, but this fix makes rename detection more reliable:
-
django/db/migrations/autodetector.py
diff --git a/django/db/migrations/autodetector.py b/django/db/migrations/autodetector.py index c8b7db7..441a453 100644
a b class MigrationAutodetector(object): 73 73 change during renames) 74 74 """ 75 75 fields_def = [] 76 for name, field in fields:76 for name, field in sorted(fields): 77 77 deconstruction = self.deep_deconstruct(field) 78 78 if field.rel and field.rel.to: 79 79 del deconstruction[2]['to']
I cannot reproduce the renaming problem on stable/1.7.x or master.
comment:10 by , 10 years ago
Version: | 1.7-rc-2 → 1.7 |
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comment:11 by , 8 years ago
comment:12 by , 8 years ago
Cc: | added |
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comment:13 by , 8 years ago
Resolution: | → duplicate |
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Status: | new → closed |
Let's close this ticket as a duplicate in this case.
Hi. I'm getting the same bug. I've done some digging and have some more details on the exact conditions that cause it.
First of all, a minimal reproduction. Create a project with an app and add this to the models.py. Run makemigrations, then rename the class ModelToBeRenamed, then run it again.
Interesting notes: