#34928: makemigrations when adding a ForeignKey to a model with a
UniqueConstraint
must create the field before creating the constraint
------------------------------------------+------------------------
Reporter: yonatanramirez | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 4.2
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
------------------------------------------+------------------------
This issue looks like #25551 but with UniqueConstraint and not
unique_together.
{{{#!diff
from django.db import models
+class Author(models.Model):
+ name = models.CharField(max_length=255)
+
class Book(models.Model):
name = models.CharField(max_length=255)
+ author = models.ForeignKey(Author, on_delete=models.CASCADE,
null=True)
+
+ class Meta:
+ constraints = [
+ models.UniqueConstraint(
+ fields=['name', 'author'],
+ name='unique_book_name_author'
+ )
+ ]
}}}
This is the output of the makemigration command
{{{
Migrations for 'issue':
issue/migrations/0002_author_book_unique_book_name_author_book_author.py
- Create model Author
- Create constraint unique_book_name_author on model book
- Add field author to book
}}}
And the portion of the migration file:
{{{
operations = [
migrations.CreateModel(
name='Author',
fields=[
('id', models.BigAutoField(auto_created=True,
primary_key=True, serialize=False, verbose_name='ID')),
('name', models.CharField(max_length=255)),
],
),
migrations.AddConstraint(
model_name='book',
constraint=models.UniqueConstraint(fields=('name', 'author'),
name='unique_book_name_author'),
),
migrations.AddField(
model_name='book',
name='author',
field=models.ForeignKey(null=True,
on_delete=django.db.models.deletion.CASCADE, to='issue.author'),
),
]
}}}
The stacktrace:
{{{
Operations to perform:
Apply all migrations: admin, auth, contenttypes, issue, sessions
Running migrations:
Applying contenttypes.0001_initial... OK
Applying auth.0001_initial... OK
Applying admin.0001_initial... OK
Applying admin.0002_logentry_remove_auto_add... OK
Applying admin.0003_logentry_add_action_flag_choices... OK
Applying contenttypes.0002_remove_content_type_name... OK
Applying auth.0002_alter_permission_name_max_length... OK
Applying auth.0003_alter_user_email_max_length... OK
Applying auth.0004_alter_user_username_opts... OK
Applying auth.0005_alter_user_last_login_null... OK
Applying auth.0006_require_contenttypes_0002... OK
Applying auth.0007_alter_validators_add_error_messages... OK
Applying auth.0008_alter_user_username_max_length... OK
Applying auth.0009_alter_user_last_name_max_length... OK
Applying auth.0010_alter_group_name_max_length... OK
Applying auth.0011_update_proxy_permissions... OK
Applying auth.0012_alter_user_first_name_max_length... OK
Applying issue.0001_initial... OK
Applying
issue.0002_author_book_unique_book_name_author_book_author...Traceback
(most recent call last):
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/models/options.py", line 681, in get_field
return self.fields_map[field_name]
~~~~~~~~~~~~~~~^^^^^^^^^^^^
KeyError: 'author'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/yramirez/playground/django/essai/manage.py", line 22, in
<module>
main()
File "/home/yramirez/playground/django/essai/manage.py", line 18, in
main
execute_from_command_line(sys.argv)
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/core/management/__init__.py", line 442, in
execute_from_command_line
utility.execute()
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/core/management/__init__.py", line 436, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/core/management/base.py", line 412, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/core/management/base.py", line 458, in execute
output = self.handle(*args, **options)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/core/management/base.py", line 106, in wrapper
res = handle_func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/core/management/commands/migrate.py", line 356, in handle
post_migrate_state = executor.migrate(
^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/migrations/executor.py", line 135, in migrate
state = self._migrate_all_forwards(
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/migrations/executor.py", line 167, in
_migrate_all_forwards
state = self.apply_migration(
^^^^^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/migrations/executor.py", line 252, in apply_migration
state = migration.apply(state, schema_editor)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/migrations/migration.py", line 132, in apply
operation.database_forwards(
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/migrations/operations/models.py", line 1135, in
database_forwards
schema_editor.add_constraint(model, self.constraint)
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/backends/sqlite3/schema.py", line 562, in
add_constraint
self._remake_table(model)
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/backends/sqlite3/schema.py", line 331, in _remake_table
self.create_model(new_model)
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/backends/base/schema.py", line 448, in create_model
sql, params = self.table_sql(model)
^^^^^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/backends/base/schema.py", line 267, in table_sql
constraints = [
^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/backends/base/schema.py", line 268, in <listcomp>
constraint.constraint_sql(model, self)
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/models/constraints.py", line 216, in constraint_sql
fields = [model._meta.get_field(field_name) for field_name in
self.fields]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/models/constraints.py", line 216, in <listcomp>
fields = [model._meta.get_field(field_name) for field_name in
self.fields]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/yramirez/.pyenv/versions/django/lib/python3.11/site-
packages/django/db/models/options.py", line 683, in get_field
raise FieldDoesNotExist(
django.core.exceptions.FieldDoesNotExist: NewBook has no field named
'author'
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/34928>
Django <https://code.djangoproject.com/>
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