makemigrations geterates wrong migration for ForeignKey to unmanaged model

[Dmitri Bogomolov]

I wrote a simple test app:

from django.db import models


class Obj(models.Model):
    custom_named_id = models.IntegerField(
        primary_key=True, db_column='custom_named_id'  # not needed and doesn't help
    )
    field_2 = models.CharField(max_length=10, null=True, blank=True)

    class Meta:
        managed = False


class Pointer(models.Model):
    name = models.CharField(max_length=10, null=True, blank=True)
    obj = models.ForeignKey('Obj')

Migration generated for it will not work:

$ ./manage.py makemigrations migration_test
Migrations for 'migration_test':
  0001_initial.py:
    - Create model Pointer
    - Create model Obj
    - Add field obj to pointer

$ ./manage.py migrate migration_test
Operations to perform:
  Apply all migrations: migration_test
Running migrations:
  Applying migration_test.0001_initial...Traceback (most recent call last):
  File "./manage.py", line 12, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/usr/lib/python2.7/site-packages/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/usr/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 160, in handle
    executor.migrate(targets, plan, fake=options.get("fake", False))
  File "/usr/lib/python2.7/site-packages/django/db/migrations/executor.py", line 63, in migrate
    self.apply_migration(migration, fake=fake)
  File "/usr/lib/python2.7/site-packages/django/db/migrations/executor.py", line 97, in apply_migration
    migration.apply(project_state, schema_editor)
  File "/usr/lib/python2.7/site-packages/django/db/backends/schema.py", line 82, in __exit__
    self.execute(sql)
  File "/usr/lib/python2.7/site-packages/django/db/backends/schema.py", line 98, in execute
    cursor.execute(sql, params)
  File "/usr/lib/python2.7/site-packages/django/db/backends/utils.py", line 81, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/usr/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/usr/lib/python2.7/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: column "id" referenced in foreign key constraint does not exist

It happens because migrate generates SQL with wrong constraint:

$ ./manage.py sqlmigrate migration_test 0001
BEGIN;
CREATE TABLE "migration_test_pointer" ("id" serial NOT NULL PRIMARY KEY, "name" varchar(10) NULL);
ALTER TABLE "migration_test_pointer" ADD COLUMN "obj_id" integer NOT NULL;
ALTER TABLE "migration_test_pointer" ALTER COLUMN "obj_id" DROP DEFAULT;
CREATE INDEX migration_test_pointer_818ad5ef ON "migration_test_pointer" ("obj_id");
ALTER TABLE "migration_test_pointer" ADD CONSTRAINT migration_test_pointer_obj_id_7e364e33_fk_migration_test_obj_id FOREIGN KEY ("obj_id") REFERENCES "migration_test_obj" ("id") DEFERRABLE INITIALLY DEFERRED;

COMMIT;

[Markus Holtermann]

Looks like a duplicate of #23415 to me.