diff --git a/django/contrib/contenttypes/models.py b/django/contrib/contenttypes/models.py index c54defb459..58867b4fca 100644 --- a/django/contrib/contenttypes/models.py +++ b/django/contrib/contenttypes/models.py @@ -2,6 +2,7 @@ from __future__ import unicode_literals from django.apps import apps from django.db import models +from django.db.utils import OperationalError, ProgrammingError from django.utils.translation import ugettext_lazy as _ from django.utils.encoding import smart_text, force_text from django.utils.encoding import python_2_unicode_compatible @@ -50,6 +51,11 @@ class ContentTypeManager(models.Manager): # We start with get() and not get_or_create() in order to use # the db_for_read (see #20401). ct = self.get(app_label=opts.app_label, model=opts.model_name) + except (OperationalError, ProgrammingError): + # It's possible to migrate a single app before contenttypes, + # as it's not a required initial dependency (it's contrib!) + # Have a nice error for this. + raise RuntimeError("Error creating new content types. Please make sure contenttypes is migrated before trying to migrate apps individually.") except self.model.DoesNotExist: # Not found in the database; we proceed to create it. This time we # use get_or_create to take care of any race conditions.