[Django] #22932: "makemigrations" generates circular dependencies
Django
-------------------------+-------------------------------------------------
Reporter: humitos | Owner: nobody
Type: Bug | Status: new
Component: | Version: master
Migrations | Keywords: circular dependency, migrations,
Severity: Normal | makemigrations
Triage Stage: | Has patch: 0
Unreviewed | UI/UX: 0
Easy pickings: 0 |
-------------------------+-------------------------------------------------
I'm having an issue with the new migrations system included in Django. The
steps that I'm following to reproduce is, once the example project is
downloaded just run:
1. manage.py makemigrations
1. manage.py migrate
{{{
Traceback (most recent call last):
File "/home/humitos/Source/migration_test/manage.py", line 10, in
<module>
execute_from_command_line(sys.argv)
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/core/management/__init__.py", line 330, in
execute_from_command_line
utility.execute()
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/core/management/__init__.py", line 322, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/core/management/base.py", line 363, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/core/management/base.py", line 412, in execute
output = self.handle(*args, **options)
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/core/management/commands/makemigrations.py", line 78, in
handle
loader.project_state(),
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/db/migrations/loader.py", line 268, in project_state
return self.graph.make_state(nodes=nodes, at_end=at_end,
real_apps=list(self.unmigrated_apps))
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/db/migrations/graph.py", line 140, in make_state
for migration in self.forwards_plan(node):
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/db/migrations/graph.py", line 55, in forwards_plan
return self.dfs(node, lambda x: self.dependencies.get(x, set()))
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/db/migrations/graph.py", line 121, in dfs
return _dfs(start, get_children, [])
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/db/migrations/graph.py", line 113, in _dfs
results = _dfs(n, get_children, path) + results
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/db/migrations/graph.py", line 113, in _dfs
results = _dfs(n, get_children, path) + results
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/db/migrations/graph.py", line 113, in _dfs
results = _dfs(n, get_children, path) + results
File "/home/humitos/.virtualenvs/tmp-
e997f5cc453b28eb/local/lib/python2.7/site-
packages/django/db/migrations/graph.py", line 105, in _dfs
raise CircularDependencyError(path[path.index(start):] + [start])
django.db.migrations.graph.CircularDependencyError: [('challenge',
u'0001_initial'), (u'team', u'0001_initial'), ('challenge',
u'0001_initial')]
}}}
If I remove the {{{myapp.team.TeamCaptain}}} model and the migration files
already created and I run those commands again, it creates the proper
migration files and it works.
I've been taking a look at #22325 but it doesn't seem to be the same
situation.
I tried this in Django 1.7b4, 1.7c1 and master and I always got the same
error.
What other kind of information can I provide?
--
Ticket URL: <https://code.djangoproject.com/ticket/22932>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
Reporter: humitos | Owner: nobody
Type: Bug | Status: new
Severity: Normal | Resolution:
Keywords: circular | Triage Stage:
dependency, migrations, | Unreviewed
makemigrations | Needs documentation: 0
Has patch: 0 | Patch needs improvement: 0
Needs tests: 0 | UI/UX: 0
Easy pickings: 0 |
-------------------------------------+-------------------------------------
Changes (by humitos):
* cc: humitos (added)
* needs_docs: => 0
* needs_tests: => 0
* needs_better_patch: => 0
--
Ticket URL: <https://code.djangoproject.com/ticket/22932#comment:1>
Django
Reporter: humitos | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: circular | Triage Stage:
dependency, migrations, | Unreviewed
makemigrations | Needs documentation: 0
Has patch: 0 | Patch needs improvement: 0
Easy pickings: 0 |
-------------------------------------+-------------------------------------
Changes (by Andrew Godwin <andrew@…>):
* status: new => closed
* resolution: => fixed
Comment:
In [changeset:"e9249bc20b49c7b6721a8a58bc4bb9dd4827855a"]:
{{{
#!CommitTicketReference repository=""
revision="e9249bc20b49c7b6721a8a58bc4bb9dd4827855a"
Fixed #22932: Documented circular dependency issues with swappable user
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/22932#comment:2>
Django
Reporter: humitos | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: circular | Triage Stage:
dependency, migrations, | Unreviewed
makemigrations | Needs documentation: 0
Has patch: 0 | Patch needs improvement: 0
Easy pickings: 0 |
-------------------------------------+-------------------------------------
Comment (by andrewgodwin):
This is unavoidable, as Django can't detect swappable dependencies to
resolve the loop at makemigrations time (thanks, swappable models!), but
I've added some documentation to the custom user model docs to highlight
that this might occur and how to fix it.
The fix, incidentally, is to manually uncircularise the dependency loop.
In this example, the dependency graph is:
{{{
team.TeamCaptain -> challenge.MyUser -> team.Team
\_________________________^
}}}
As you can see, this isn't actually circular, it's just that the start and
end are in the same app and Django can't work out what app the middle one
is in (as it's dynamic and can change based on project settings). The
solution is to move the `TeamCaptain` model into a second migration in the
`team` app, and make sure the migration dependencies are modified
appropriately (i.e. that the `AUTH_USER_MODEL` dependency is also moved to
that second migration). This will solve this case.
The other possible case is when there actually is a dependency loop (e.g.
two models have foreign keys pointing at each other). You can resolve this
by splitting one ForeignKey off into a separate migration; just construct
this situation without swappable models and run `makemigrations` and
you'll get an example of how it's done.
--
Ticket URL: <https://code.djangoproject.com/ticket/22932#comment:3>
Django
Reporter: humitos | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: circular | Triage Stage:
dependency, migrations, | Unreviewed
makemigrations | Needs documentation: 0
Has patch: 0 | Patch needs improvement: 0
Easy pickings: 0 |
-------------------------------------+-------------------------------------
Comment (by humitos):
Well, I followed the solution suggested by `andrewgodwin` and it worked. I
will explain here what are the specific steps that I followed (actually, I
followed these steps in the production site and it also worked):
1. Download the .tar.gz and uncompress it in /tmp, then cd into it
1. Run `dj makemigrations`
1. Remove the `swappable_dependency` and the
`migrations.CreateModel(name='TeamCaptain', ...` from
`team.0001_initial.py`
1. Run `dj makemigrations --empty team`
1. Edit this new empty migration created by Django by adding the
`swappable_dependency` and the `migrations.CreateModel(name='TeamCaptain',
...` removed from `team.0001_initial.py`
1. Run `dj migrate`
I'm attaching the .diff and the new migration
--
Ticket URL: <https://code.djangoproject.com/ticket/22932#comment:4>
Django
Reporter: humitos | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: circular | Triage Stage:
dependency, migrations, | Unreviewed
makemigrations |
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by berto):
I am running into this error when squashing migrations. The swappable dep
is from Django REST Framework's `authkey` app. After reading the fix
above I'm not exactly sure how to go about fixing this within a squashed
migration.
When running the squashed migration it tells me that the `authkey` tables
do not exist. When adding `('authkey', '0001_initial')` to the
dependencies list, I get the circular dependency error.
I'm seeing this when running tests, and I'm using Django 1.7.10.
Any clues? Thank you!
--
Ticket URL: <https://code.djangoproject.com/ticket/22932#comment:5>
Django
Reporter: humitos | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: master
Severity: Normal | Resolution: fixed
Keywords: circular | Triage Stage:
dependency, migrations, | Unreviewed
makemigrations |
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
* cc: berto (added)
--
Ticket URL: <https://code.djangoproject.com/ticket/22932#comment:6>