#23916 closed Bug (fixed)
makemigrations does not detect/like model name case changes
Reported by: | Sven Coenye | Owned by: | Adam Johnson |
---|---|---|---|
Component: | Migrations | Version: | dev |
Severity: | Normal | Keywords: | |
Cc: | info+coding@… | Triage Stage: | Ready for checkin |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
Starting with
class Evidence(models.Model): rubrictype = models.ForeignKey('Rubrictype') class Rubrictype(models.Model): type_code = models.CharField(max_length=1)
Make the initial migration:
$ ./manage.py makemigrations Migrations for 'as_migrations': 0001_initial.py: - Create model Evidence - Create model Rubrictype - Add field rubrictype to evidence
Change the name of Rubrictype to RubricType:
class Evidence(models.Model): rubrictype = models.ForeignKey('RubricType') class RubricType(models.Model): type_code = models.CharField(max_length=1)
Generate the migration:
$ ./manage.py makemigrations Migrations for 'as_migrations': 0002_auto_20141125_1930.py: - Alter field rubrictype on evidence
Django does not detect the name change on the RubricType model itself. No confirmation is requested for the name change and no operation is generated. The problem is that any subsequent makemigrations run will generate the same operation ad infinitum:
$ ./manage.py makemigrations Migrations for 'as_migrations': 0003_auto_20141125_1930.py: - Alter field rubrictype on evidence
If instead the name is changed to RubricXype:
class Evidence(models.Model): rubrictype = models.ForeignKey('RubricXype') class RubricXype(models.Model): type_code = models.CharField(max_length=1)
the corresponding migration becomes
$ ./manage.py makemigrations Did you rename the as_migrations.Rubrictype model to RubricXype? [y/N] y Migrations for 'as_migrations': 0002_auto_20141125_1956.py: - Rename model Rubrictype to RubricXype
This migration generates a RenameModel operation only and any subsequent makemigrations runs will properly report "No changes detected". So it appears the change detector does not pick up on capitalization changes in model names.
Trying to work around by adding a
migrations.RenameModel( old_name='Rubrictype', new_name='RubricType', )
to the auto generated operations results in a ValueError exception when makemigrations is run again:
$ ./manage.py makemigrations Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "/home/svencoenye/developer/django_test/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line utility.execute() File "/home/svencoenye/developer/django_test/lib/python2.7/site-packages/django/core/management/__init__.py", line 377, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/home/svencoenye/developer/django_test/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv self.execute(*args, **options.__dict__) File "/home/svencoenye/developer/django_test/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute output = self.handle(*args, **options) File "/home/svencoenye/developer/django_test/lib/python2.7/site-packages/django/core/management/commands/makemigrations.py", line 111, in handle convert_apps=app_labels or None, File "/home/svencoenye/developer/django_test/lib/python2.7/site-packages/django/db/migrations/autodetector.py", line 42, in changes changes = self._detect_changes(convert_apps, graph) File "/home/svencoenye/developer/django_test/lib/python2.7/site-packages/django/db/migrations/autodetector.py", line 109, in _detect_changes self.old_apps = self.from_state.render(ignore_swappable=True) File "/home/svencoenye/developer/django_test/lib/python2.7/site-packages/django/db/migrations/state.py", line 89, in render model=lookup_model, ValueError: Lookup failed for model referenced by field as_migrations.Evidence.rubrictype: as_migrations.RubricType
The sequence of the operations does not matter. Neither does substituting the RenameModel operation for the AlterField operation.
(Looking at the next to last entry in the traceback, the autodetector seems to be looking for the new name in the old_apps state?)
It is possible, however, to go the long way around and use two separate migrations: Rubrictype -> RubricXype. RubricXype -> RubricType works without getting the migration state stuck and does not throw an exception.
Change History (16)
comment:1 by , 10 years ago
Triage Stage: | Unreviewed → Accepted |
---|
comment:2 by , 10 years ago
Cc: | added |
---|
comment:3 by , 10 years ago
Sorry for the delayed response. I did not realize my e-mail address was missing from the preferences.
Is there anything I can do to provide more info on the RenameModel failure?
comment:4 by , 9 years ago
See #25429 for a probable duplicate (but please check when this is fixed and reopen it if not).
comment:5 by , 8 years ago
#26752 seems to be another symptom (closed as duplicate, but reopen if not).
comment:7 by , 5 years ago
Has patch: | set |
---|---|
Owner: | changed from | to
Status: | new → assigned |
follow-up: 9 comment:8 by , 5 years ago
Needs tests: | set |
---|---|
Version: | 1.7 → master |
comment:9 by , 5 years ago
Pardon my ignorance, but does this recent activity mean something is being done about this bug? I've only just run into it (changed a model name in casing only and now have infinite migration detection), so I'd be interested in finding a workaround. Replying to felixxm:
comment:10 by , 5 years ago
Yes, there's a pull request - see the "Pull Requests" row in the table at the top describing the issue.
comment:11 by , 5 years ago
I hit this issue with Django 2.2.11.
- Renamed several models with a case change only
- Generated a migration with
makemigrations
- Subsequent migrations would always detect a change.
- Ported Adam's patch to 2.2.12
makemigrations
no longer detects changes
There were no conflicts in the patch.
comment:12 by , 5 years ago
Needs tests: | unset |
---|
comment:13 by , 5 years ago
Triage Stage: | Accepted → Ready for checkin |
---|
Thank you for the report. The problem you ran into relates to the fact that the migration internally don't care about case sensitivity of model names (
ProjectState.models
has a dictionary whose keys are(app_label, model_name)
where the latter is lower cased).Your work around seems to be valid. I'd need more info to figure out why adding the RenameModel manually fails.