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 23956 makemigrations creates broken initial migration for models with multiple inheritance Kirill Gagarski nobody "Hello. I am trying to create models that use multiple inheritance and then use django migrations mechanism to migrate. But I have some problems with it. I have created simplest example to reproduce. = Steps to reproduce = 1. Create a `migrationstest` django app with following `models.py`: {{{ from django.db import models class A(models.Model): a_id = models.AutoField(primary_key=True) class B(models.Model): b_id = models.AutoField(primary_key=True) class C(A, B): pass class D(A, B): pass class E(A, B): pass }}} 2. run './manage.py makemigrations migrationstest' 3. run './manage.py migrate migrationstest' = Expected results = Fine migration = Actual results = Exception is thrown while running 'migrate': {{{ Traceback (most recent call last): File ""./manage.py"", line 10, in execute_from_command_line(sys.argv) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/core/management/__init__.py"", line 385, in execute_from_command_line utility.execute() File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/core/management/__init__.py"", line 377, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/core/management/base.py"", line 288, in run_from_argv self.execute(*args, **options.__dict__) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/core/management/base.py"", line 338, in execute output = self.handle(*args, **options) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/core/management/commands/migrate.py"", line 160, in handle executor.migrate(targets, plan, fake=options.get(""fake"", False)) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/migrations/executor.py"", line 63, in migrate self.apply_migration(migration, fake=fake) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/migrations/executor.py"", line 97, in apply_migration migration.apply(project_state, schema_editor) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/migrations/migration.py"", line 107, in apply operation.database_forwards(self.app_label, schema_editor, project_state, new_state) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/migrations/operations/fields.py"", line 37, in database_forwards field, File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/backends/schema.py"", line 390, in add_field self.execute(sql, params) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/backends/schema.py"", line 99, in execute cursor.execute(sql, params) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/backends/utils.py"", line 81, in execute return super(CursorDebugWrapper, self).execute(sql, params) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/backends/utils.py"", line 65, in execute return self.cursor.execute(sql, params) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/utils.py"", line 94, in __exit__ six.reraise(dj_exc_type, dj_exc_value, traceback) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/utils/six.py"", line 549, in reraise raise value.with_traceback(tb) File ""/home/gagarski/polyana-web/environment/lib/python3.4/site-packages/django/db/backends/utils.py"", line 65, in execute return self.cursor.execute(sql, params) django.db.utils.ProgrammingError: column ""b_ptr_id"" of relation ""migrationstest_d"" already exists }}} = More details = The generated initial migration: {{{ # -*- coding: utf-8 -*- from __future__ import unicode_literals from django.db import models, migrations class Migration(migrations.Migration): dependencies = [ ] operations = [ migrations.CreateModel( name='A', fields=[ ('a_id', models.IntegerField(serialize=False, primary_key=True)), ], options={ }, bases=(models.Model,), ), migrations.CreateModel( name='B', fields=[ ('b_id', models.IntegerField(serialize=False, primary_key=True)), ], options={ }, bases=(models.Model,), ), migrations.CreateModel( name='C', fields=[ ('a_ptr', models.OneToOneField(parent_link=True, serialize=False, primary_key=True, to='migrationstest.A', auto_created=True)), ], options={ }, bases=('migrationstest.a', 'migrationstest.b'), ), migrations.CreateModel( name='D', fields=[ ('a_ptr', models.OneToOneField(parent_link=True, serialize=False, primary_key=True, to='migrationstest.A', auto_created=True)), ], options={ }, bases=('migrationstest.a', 'migrationstest.b'), ), migrations.CreateModel( name='E', fields=[ ('a_ptr', models.OneToOneField(parent_link=True, serialize=False, primary_key=True, to='migrationstest.A', auto_created=True)), ('b_ptr', models.OneToOneField(parent_link=True, to='migrationstest.B', auto_created=True)), ], options={ }, bases=('migrationstest.a', 'migrationstest.b'), ), migrations.AddField( model_name='d', name='b_ptr', field=models.OneToOneField(parent_link=True, to='migrationstest.B', auto_created=True), preserve_default=True, ), migrations.AddField( model_name='c', name='b_ptr', field=models.OneToOneField(parent_link=True, to='migrationstest.B', auto_created=True), preserve_default=True, ), ] }}} As you can see `b_ptr` field is added in `CreateModel `only for the last model (`E`). For `D` and `C` it is added via `AddField`. But it seems that `b_ptr` is already added to them even without a field specified in `CreateModel`'s `fields` argument (with the help of `bases` argument, I think). == Output of `sqlmigrate` == {{{ BEGIN; CREATE TABLE ""migrationstest_a"" (""a_id"" integer NOT NULL PRIMARY KEY); CREATE TABLE ""migrationstest_b"" (""b_id"" integer NOT NULL PRIMARY KEY); CREATE TABLE ""migrationstest_c"" (""b_ptr_id"" integer NOT NULL UNIQUE, ""a_ptr_id"" integer NOT NULL PRIMARY KEY); CREATE TABLE ""migrationstest_d"" (""b_ptr_id"" integer NOT NULL UNIQUE, ""a_ptr_id"" integer NOT NULL PRIMARY KEY); CREATE TABLE ""migrationstest_e"" (""b_ptr_id"" integer NOT NULL UNIQUE, ""a_ptr_id"" integer NOT NULL PRIMARY KEY); ALTER TABLE ""migrationstest_d"" ADD COLUMN ""b_ptr_id"" integer NOT NULL UNIQUE; ALTER TABLE ""migrationstest_d"" ALTER COLUMN ""b_ptr_id"" DROP DEFAULT; ALTER TABLE ""migrationstest_c"" ADD COLUMN ""b_ptr_id"" integer NOT NULL UNIQUE; ALTER TABLE ""migrationstest_c"" ALTER COLUMN ""b_ptr_id"" DROP DEFAULT; ALTER TABLE ""migrationstest_c"" ADD CONSTRAINT ""migrationste_b_ptr_id_6684147e60c05d18_fk_migrationstest_b_b_id"" FOREIGN KEY (""b_ptr_id"") REFERENCES ""migrationstest_b"" (""b_id"") DEFERRABLE INITIALLY DEFERRED; ALTER TABLE ""migrationstest_c"" ADD CONSTRAINT ""migrationste_a_ptr_id_2670758b3e821055_fk_migrationstest_a_a_id"" FOREIGN KEY (""a_ptr_id"") REFERENCES ""migrationstest_a"" (""a_id"") DEFERRABLE INITIALLY DEFERRED; ALTER TABLE ""migrationstest_d"" ADD CONSTRAINT ""migrationste_b_ptr_id_2ed6e3025678dfb9_fk_migrationstest_b_b_id"" FOREIGN KEY (""b_ptr_id"") REFERENCES ""migrationstest_b"" (""b_id"") DEFERRABLE INITIALLY DEFERRED; ALTER TABLE ""migrationstest_d"" ADD CONSTRAINT ""migrationste_a_ptr_id_4d0009d1fad71dec_fk_migrationstest_a_a_id"" FOREIGN KEY (""a_ptr_id"") REFERENCES ""migrationstest_a"" (""a_id"") DEFERRABLE INITIALLY DEFERRED; ALTER TABLE ""migrationstest_e"" ADD CONSTRAINT ""migrationste_b_ptr_id_29d2159648c59c3e_fk_migrationstest_b_b_id"" FOREIGN KEY (""b_ptr_id"") REFERENCES ""migrationstest_b"" (""b_id"") DEFERRABLE INITIALLY DEFERRED; ALTER TABLE ""migrationstest_e"" ADD CONSTRAINT ""migrationste_a_ptr_id_405a8eb9707708c9_fk_migrationstest_a_a_id"" FOREIGN KEY (""a_ptr_id"") REFERENCES ""migrationstest_a"" (""a_id"") DEFERRABLE INITIALLY DEFERRED; ALTER TABLE ""migrationstest_d"" ADD CONSTRAINT ""migrationste_b_ptr_id_2ed6e3025678dfb9_fk_migrationstest_b_b_id"" FOREIGN KEY (""b_ptr_id"") REFERENCES ""migrationstest_b"" (""b_id"") DEFERRABLE INITIALLY DEFERRED; ALTER TABLE ""migrationstest_c"" ADD CONSTRAINT ""migrationste_b_ptr_id_6684147e60c05d18_fk_migrationstest_b_b_id"" FOREIGN KEY (""b_ptr_id"") REFERENCES ""migrationstest_b"" (""b_id"") DEFERRABLE INITIALLY DEFERRED; COMMIT; }}} = Questions = Is there a good reasons to do like that? Is there a workaround that can help me to use automatic migration generation without manually editing them (at least initial migration)?" Bug new Migrations 1.7 Normal migrations inheritance Unreviewed 0 0 0 0 0 0