The issue didn't crop up, because there were no rows when you added the field, so default isn't called. If you had existing data, then it would've triggered.
What default should return for foreign keys is actually documented: > For fields like ForeignKey that map to model instances, defaults should be > the value of the field they reference (pk unless to_field is set) instead of > model instances. https://docs.djangoproject.com/en/1.11/ref/models/fields/#default On Wed, Sep 13, 2017 at 4:39 PM, Matthew Pava <matthew.p...@iss.com> wrote: > Okay, after much investigation, I found that the default value on this exact > field was actually a callable that returned an instance of DisplayName > rather than the pk. After changing that, the migrations ran successfully. > I wonder if Django could provide a better hint of such issues. It’s strange > because that default was on the previous migration file in the AddField > command, but the migrate command never threw an error. It only threw it on > AlterField, and the default didn’t even have to be specified in the > AlterField version. > > > > Thank you, > > Matthew > > > > From: django-users@googlegroups.com [mailto:django-users@googlegroups.com] > On Behalf Of Matthew Pava > Sent: Tuesday, September 12, 2017 4:09 PM > To: django-users@googlegroups.com > Subject: Migration Woes: TypeError: int() argument must be a string... on > ForeignKeys > > > > I’m trying to alter my foreign keys on my audit log models to allow for > null. Django creates a new migration file, with an operation something like > below: > > > > migrations.AlterField( > > model_name='checklistauditlogentry', > > name='usage', > > field=models.ForeignKey(null=True, > on_delete=django.db.models.deletion.CASCADE, > related_name='_auditlog_checklistusages', to='general.DisplayName'), > > ) > > > > Upon applying the migrations, I get this error (without full path shown): > > TypeError: int() argument must be a string, a bytes-like object or a number, > not 'DisplayName' > > > > I just can’t seem to figure this one out. I can’t just delete the > migrations and start over because I really need Django to modify the > database to remove the requirement on those fields. > > > > Full trace: > > Running migrations: > > Applying documents.0002_auto_20170912_1445...Traceback (most recent call > last): > > File "manage.py", line 10, in <module> > > execute_from_command_line(sys.argv) > > File "\lib\site-packages\django\core\management\__init__.py", line 364, in > execute_from_command_line > > utility.execute() > > File "\lib\site-packages\django\core\management\__init__.py", line 356, in > execute > > self.fetch_command(subcommand).run_from_argv(self.argv) > > File "\lib\site-packages\django\core\management\base.py", line 283, in > run_from_argv > > self.execute(*args, **cmd_options) > > File "\lib\site-packages\django\core\management\base.py", line 330, in > execute > > output = self.handle(*args, **options) > > File "\lib\site-packages\django\core\management\commands\migrate.py", line > 204, in handle > > fake_initial=fake_initial, > > File "\lib\site-packages\django\db\migrations\executor.py", line 115, in > migrate > > state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, > fake_initial=fake_initial) > > File "\lib\site-packages\django\db\migrations\executor.py", line 145, in > _migrate_all_forwards > > state = self.apply_migration(state, migration, fake=fake, > fake_initial=fake_initial) > > File "\lib\site-packages\django\db\migrations\executor.py", line 244, in > apply_migration > > state = migration.apply(state, schema_editor) > > File "\lib\site-packages\django\db\migrations\migration.py", line 129, in > apply > > operation.database_forwards(self.app_label, schema_editor, old_state, > project_state) > > File "\lib\site-packages\django\db\migrations\operations\fields.py", line > 216, in database_forwards > > schema_editor.alter_field(from_model, from_field, to_field) > > File "\lib\site-packages\django\db\backends\base\schema.py", line 515, in > alter_field > > old_db_params, new_db_params, strict) > > File "\lib\site-packages\django\db\backends\postgresql\schema.py", line > 112, in _alter_field > > new_db_params, strict, > > File "\lib\site-packages\django\db\backends\base\schema.py", line 612, in > _alter_field > > old_default = self.effective_default(old_field) > > File "\lib\site-packages\django\db\backends\base\schema.py", line 229, in > effective_default > > default = field.get_db_prep_save(default, self.connection) > > File "\lib\site-packages\django\db\models\fields\related.py", line 963, in > get_db_prep_save > > return self.target_field.get_db_prep_save(value, connection=connection) > > File "\lib\site-packages\django\db\models\fields\__init__.py", line 770, > in get_db_prep_save > > prepared=False) > > File "\lib\site-packages\django\db\models\fields\__init__.py", line 958, > in get_db_prep_value > > value = self.get_prep_value(value) > > File "\lib\site-packages\django\db\models\fields\__init__.py", line 966, > in get_prep_value > > return int(value) > > TypeError: int() argument must be a string, a bytes-like object or a number, > not 'DisplayName' > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to django-users+unsubscr...@googlegroups.com. > To post to this group, send email to django-users@googlegroups.com. > Visit this group at https://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/ab2c2b14c7a04e82835dd53fc58eef30%40ISS1.ISS.LOCAL. > For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to django-users+unsubscr...@googlegroups.com. > To post to this group, send email to django-users@googlegroups.com. > Visit this group at https://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/9cfb3dab4545461ea8e0964ea1be6ebc%40ISS1.ISS.LOCAL. > > For more options, visit https://groups.google.com/d/optout. -- Melvyn Sopacua -- You received this message because you are subscribed to the Google Groups "Django users" group. 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