#35359 closed Bug (fixed)
Got `django.core.exceptions.FieldError` when adding GeneratedField
Reported by: | wd0517 | Owned by: | Bhuvnesh |
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Component: | Migrations | Version: | 5.0 |
Severity: | Release blocker | Keywords: | GeneratedField |
Cc: | David Sanders, Simon Charette | 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
Here is an exists model
class Foo1(models.Model): age = models.IntegerField()
Then adding GeneratedField
class Foo1(models.Model): age = models.IntegerField() name = models.CharField(max_length=10) lower_name = models.GeneratedField( expression=Lower("name"), output_field=models.CharField(max_length=11), db_persist=True, )
Run makemigrations get below file
class Migration(migrations.Migration): dependencies = [ ('temp_django_test', '0006_foo1'), ] operations = [ migrations.AddField( model_name='foo1', name='lower_name', field=models.GeneratedField(db_persist=True, expression=django.db.models.functions.text.Lower('name'), output_field=models.CharField(max_length=11)), ), migrations.AddField( model_name='foo1', name='name', field=models.CharField(default='a', max_length=10), preserve_default=False, ), ]
Then run migrate, will got error
temp-django-5.0 ❯ python manage.py migrate Operations to perform: Apply all migrations: admin, auth, contenttypes, sessions, temp_django_test Running migrations: Applying temp_django_test.0007_foo1_lower_name_foo1_name...Traceback (most recent call last): File "/Users/wangdi/Desktop/test_scripts.nosync/temp-django-5.0/manage.py", line 22, in <module> main() File "/Users/wangdi/Desktop/test_scripts.nosync/temp-django-5.0/manage.py", line 18, in main execute_from_command_line(sys.argv) File "/Users/wangdi/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/core/management/__init__.py", line 442, in execute_from_command_line utility.execute() File "/Users/wangdi/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/core/management/__init__.py", line 436, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/Users/wangdi/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/core/management/base.py", line 413, in run_from_argv self.execute(*args, **cmd_options) File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/core/management/base.py", line 459, in execute output = self.handle(*args, **options) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/core/management/base.py", line 107, in wrapper res = handle_func(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/core/management/commands/migrate.py", line 356, in handle post_migrate_state = executor.migrate( ^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/migrations/executor.py", line 135, in migrate state = self._migrate_all_forwards( ^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/migrations/executor.py", line 167, in _migrate_all_forwards state = self.apply_migration( ^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/migrations/executor.py", line 252, in apply_migration state = migration.apply(state, schema_editor) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/migrations/migration.py", line 132, in apply operation.database_forwards( File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/migrations/operations/fields.py", line 108, in database_forwards schema_editor.add_field( File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/backends/mysql/schema.py", line 103, in add_field super().add_field(model, field) File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/backends/base/schema.py", line 709, in add_field definition, params = self.column_sql(model, field, include_default=True) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/backends/base/schema.py", line 369, in column_sql " ".join( File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/backends/base/schema.py", line 336, in _iter_column_sql generated_sql, generated_params = self._column_generated_sql(field) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/backends/base/schema.py", line 434, in _column_generated_sql expression_sql, params = field.generated_sql(self.connection) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/models/fields/generated.py", line 58, in generated_sql resolved_expression = self.expression.resolve_expression( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/models/expressions.py", line 975, in resolve_expression c.source_expressions[pos] = arg.resolve_expression( ^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/models/expressions.py", line 854, in resolve_expression return query.resolve_ref(self.name, allow_joins, reuse, summarize) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/models/sql/query.py", line 2014, in resolve_ref join_info = self.setup_joins( ^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/models/sql/query.py", line 1867, in setup_joins path, final_field, targets, rest = self.names_to_path( ^^^^^^^^^^^^^^^^^^^ File "/Users/wd0517/Desktop/test_scripts.nosync/temp-django-5.0/.venv/lib/python3.11/site-packages/django/db/models/sql/query.py", line 1772, in names_to_path raise FieldError( django.core.exceptions.FieldError: Cannot resolve keyword 'name' into field. Choices are: age, id, lower_name
Environment:
- Python 3.11.8
- Django 5.0.4
- MySQL 8.0.34
I think the bug is caused by the order of operations in Migration, after adjusting it, then can be migrate successfully
Change History (13)
comment:1 by , 6 months ago
Severity: | Normal → Release blocker |
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Triage Stage: | Unreviewed → Accepted |
comment:2 by , 6 months ago
For anyone picking up this ticket: Simon & I were discussing ways to get fields from expressions in this PR: https://github.com/django/django/pull/16054
comment:3 by , 6 months ago
Cc: | added |
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comment:4 by , 6 months ago
Cc: | added |
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Thanks David, I knew this was implemented somewhere but I lost track of where exactly!
I think that relying on this property once it lands is definitely the way to go so it's reused by multiple code paths but in the case of stable/5.x we might be better off by always adding them last. Thoughts?
comment:5 by , 6 months ago
I think that relying on this property once it lands is definitely the way to go so it's reused by multiple code paths but in the case of stable/5.x we might be better off by always adding them last. Thoughts?
Hm can't fks depend on these though because the constraints for those are also grouped together last. 🤔
comment:6 by , 6 months ago
Hm can't fks depend on these though because the constraints for those are also grouped together last. 🤔
Right. Since GeneratedField
cannot be foreign keys though it should still allow for the following grouping of fields?
non_fk_non_generated_field | fk_fields | generated_fields
comment:10 by , 5 months ago
Triage Stage: | Accepted → Ready for checkin |
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The auto-detector has to be adapted to make the
AddField
of generated field depend on any otherAddField
orAlterField
of field it references through.expression
. SinceGeneratedField
cannot depend on otherGeneratedField
the easier way of doing to avoid introspecting.expression
is likely to make them depend on all other non-GeneratedField
fields being added per model so they are always last.