[Django] #22325: Defining a custom user model in an app and having relations between it and other models in the app causes circular dependencies

[Django]

#22325: Defining a custom user model in an app and having relations between it 
and
other models in the app causes circular dependencies
----------------------------+--------------------
     Reporter:  melinath    |      Owner:  nobody
         Type:  Bug         |     Status:  new
    Component:  Migrations  |    Version:  master
     Severity:  Normal      |   Keywords:
 Triage Stage:  Unreviewed  |  Has patch:  0
Easy pickings:  0           |      UI/UX:  0
----------------------------+--------------------
 I *think* the issue is that swappable_dependency resolves to
 app_label.__first__, which doesn't make a lot of sense when the app with
 the migrations is itself being migrated. Removing that line seems to
 temporarily resolve the issue, but if my app were ever used with a
 *different* AUTH_USER_MODEL, it would then presumably break again. (Also,
 I still get a circular dependency in the next migration that defines a
 relation to AUTH_USER_MODEL.)

 Here are the important bits from *one* migration:

 {{{
 class Migration(migrations.Migration):

     dependencies = [
         migrations.swappable_dependency(settings.AUTH_USER_MODEL),
         ('app_label', '0002_blah_blah'),
     ]

     operations = [
         migrations.CreateModel(
             # This is the AUTH_USER_MODEL
             name='Person',
             fields=[
                 ...
             ],
             options={
                 u'verbose_name': u'person',
                 u'verbose_name_plural': u'people',
             },
             bases=(models.Model,),
         ),
         migrations.CreateModel(
             name='PersonDiscount',
             fields=[
                 ...
                 ('person', models.ForeignKey(to=settings.AUTH_USER_MODEL,
 to_field=u'id')),
             ],
             options={
             },
             bases=(models.Model,),
         ),
     ]
 }}}

 Traceback:

 {{{
 Traceback (most recent call last):
   File "./manage.py", line 10, in <module>
     execute_from_command_line(sys.argv)
   File ".../django/django/core/management/__init__.py", line 427, in
 execute_from_command_line
     utility.execute()
   File ".../django/django/core/management/__init__.py", line 419, in
 execute
     self.fetch_command(subcommand).run_from_argv(self.argv)
   File ".../django/django/core/management/base.py", line 288, in
 run_from_argv
     self.execute(*args, **options.__dict__)
   File ".../django/django/core/management/base.py", line 337, in execute
     output = self.handle(*args, **options)
   File ".../django/django/core/management/commands/migrate.py", line 103,
 in handle
     plan = executor.migration_plan(targets)
   File ".../django/django/db/migrations/executor.py", line 46, in
 migration_plan
     for migration in self.loader.graph.forwards_plan(target):
   File ".../django/django/db/migrations/graph.py", line 53, in
 forwards_plan
     return self.dfs(node, lambda x: self.dependencies.get(x, set()))
   File ".../django/django/db/migrations/graph.py", line 119, in dfs
     return _dfs(start, get_children, [])
   File ".../django/django/db/migrations/graph.py", line 111, in _dfs
     results = _dfs(n, get_children, path) + results
   File ".../django/django/db/migrations/graph.py", line 111, in _dfs
     results = _dfs(n, get_children, path) + results
   File ".../django/django/db/migrations/graph.py", line 111, in _dfs
     results = _dfs(n, get_children, path) + results
   File ".../django/django/db/migrations/graph.py", line 103, in _dfs
     raise CircularDependencyError(path[path.index(start):] + [start])
 django.db.migrations.graph.CircularDependencyError: [('brambling',
 '0003_blah_blah'), ('brambling', '0003_blah_blah')]
 }}}

-- 
Ticket URL: <https://code.djangoproject.com/ticket/22325>
Django <https://code.djangoproject.com/>
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