id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 34985 Migrations raise AppRegistryNotReady when GeneratedField references incorrect fields. Paolo Melchiorre Mariusz Felisiak "''**Note**: In my experiments, I am sure I have encountered similar errors even in cases that are simpler to reproduce, without models with multi-table inheritance to clarify, but in this case, I cannot find the example code of the field generated to reproduce it, so I report below the example that certainly allows you to reproduce the error.'' ---- I tried to test the behavior of the generated fields in the case of multi-table inheritance. I was expecting an error since the documentation specifies that: > The expressions should be deterministic and only reference fields within the model (in the same database table). The generation of migrations of two inheritance models occurs successfully (without generated fields) {{{ #!python from django.db import models class Person(models.Model): first_name = models.CharField(max_length=150) last_name = models.CharField(max_length=150) class Profile(Person): email = models.EmailField() }}} {{{ #!console $ python3 -m manage makemigrations Migrations for 'samples': samples/migrations/0010_person_profile.py - Create model Person - Create model Profile $ python3 -m manage sqlmigrate samples 0010 }}} {{{ #!sql BEGIN; -- -- Create model Person -- CREATE TABLE ""samples_person"" (""id"" integer NOT NULL PRIMARY KEY AUTOINCREMENT, ""first_name"" varchar(150) NOT NULL, ""last_name"" varchar(150) NOT NULL); -- -- Create model Profile -- CREATE TABLE ""samples_profile"" (""person_ptr_id"" bigint NOT NULL PRIMARY KEY REFERENCES ""samples_person"" (""id"") DEFERRABLE INITIALLY DEFERRED, ""email"" varchar(254) NOT NULL); COMMIT; }}} Instead, if in the second model, I create a generated field that references the fields in the first model I get a very unclear error that perhaps we could make more clear. {{{ #!python from django.db import models from django.db.models import Value from django.db.models.functions import ( Concat, ) class Person(models.Model): first_name = models.CharField(max_length=150) last_name = models.CharField(max_length=150) class Profile(Person): email = models.EmailField() display_name = models.GeneratedField( expression=Concat(""first_name"", Value("" ""), ""last_name"", Value("" ""), ""email"",), db_persist=True, output_field=models.TextField(), ) }}} {{{ #!console $ python3 -m manage makemigrations }}} {{{ #!pycon Traceback (most recent call last): File """", line 198, in _run_module_as_main File """", line 88, in _run_code File ""/home/paulox/Projects/generatedfields/manage.py"", line 22, in main() File ""/home/paulox/Projects/generatedfields/manage.py"", line 18, in main execute_from_command_line(sys.argv) File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/core/management/__init__.py"", line 442, in execute_from_command_line utility.execute() File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/core/management/__init__.py"", line 416, in execute django.setup() File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/__init__.py"", line 24, in setup apps.populate(settings.INSTALLED_APPS) File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/apps/registry.py"", line 116, in populate app_config.import_models() File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/apps/config.py"", line 269, in import_models self.models_module = import_module(models_module_name) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ""/usr/lib/python3.12/importlib/__init__.py"", line 90, in import_module return _bootstrap._gcd_import(name[level:], package, level) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File """", line 1381, in _gcd_import File """", line 1354, in _find_and_load File """", line 1325, in _find_and_load_unlocked File """", line 929, in _load_unlocked File """", line 994, in exec_module File """", line 488, in _call_with_frames_removed File ""/home/paulox/Projects/generatedfields/samples/models.py"", line 233, in class Profile(User): File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/base.py"", line 194, in __new__ new_class.add_to_class(obj_name, obj) File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/base.py"", line 371, in add_to_class value.contribute_to_class(cls, name) File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/fields/generated.py"", line 51, in contribute_to_class self._resolved_expression = self.expression.resolve_expression( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/expressions.py"", line 975, in resolve_expression c.source_expressions[pos] = arg.resolve_expression( ^^^^^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/expressions.py"", line 975, in resolve_expression c.source_expressions[pos] = arg.resolve_expression( ^^^^^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/expressions.py"", line 854, in resolve_expression return query.resolve_ref(self.name, allow_joins, reuse, summarize) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/sql/query.py"", line 2001, in resolve_ref join_info = self.setup_joins( ^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/sql/query.py"", line 1854, in setup_joins path, final_field, targets, rest = self.names_to_path( ^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/sql/query.py"", line 1754, in names_to_path *get_field_names_from_opts(opts), ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/sql/query.py"", line 63, in get_field_names_from_opts (f.name, f.attname) if f.concrete else (f.name,) for f in opts.get_fields() ^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/options.py"", line 858, in get_fields return self._get_fields( ^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/options.py"", line 931, in _get_fields all_fields = self._relation_tree ^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/utils/functional.py"", line 47, in __get__ res = instance.__dict__[self.name] = self.func(instance) ^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/options.py"", line 831, in _relation_tree return self._populate_directed_relation_graph() ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/db/models/options.py"", line 798, in _populate_directed_relation_graph all_models = self.apps.get_models(include_auto_created=True) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/apps/registry.py"", line 181, in get_models self.check_models_ready() File ""/home/paulox/.virtualenvs/generatedfields/lib/python3.12/site-packages/django/apps/registry.py"", line 143, in check_models_ready raise AppRegistryNotReady(""Models aren't loaded yet."") django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet. }}}" Bug closed Database layer (models, ORM) 5.0 Release blocker fixed field, database, generated, output_field Lily Foote Accepted 1 0 0 0 0 0