django migration should respect SOCIAL_AUTH_USER_MODEL setting

social/apps/django_app/default/migrations/0002_add_related_name.py

@@ -4,6 +4,12 @@
 from django.db import models, migrations
 from django.conf import settings
 
+from social.utils import setting_name
+
+USER_MODEL = getattr(settings, setting_name('USER_MODEL'), None) or \
+             getattr(settings, 'AUTH_USER_MODEL', None) or \
+             'auth.User'
+
 
 class Migration(migrations.Migration):
 
@@ -15,6 +21,6 @@ class Migration(migrations.Migration):
         migrations.AlterField(
             model_name='usersocialauth',
             name='user',
-            field=models.ForeignKey(related_name='social_auth', to=settings.AUTH_USER_MODEL)
+            field=models.ForeignKey(related_name='social_auth', to=USER_MODEL)
         ),
     ]

social/storage/django_orm.py

@@ -1,6 +1,7 @@
 """Django ORM models for Social Auth"""
 import base64
 import six
+from django.db import transaction
 
 from social.storage.base import UserMixin, AssociationMixin, NonceMixin, \
                                 CodeMixin, BaseStorage
@@ -96,7 +97,16 @@ def get_social_auth_for_user(cls, user, provider=None, id=None):
     def create_social_auth(cls, user, uid, provider):
         if not isinstance(uid, six.string_types):
             uid = str(uid)
-        return cls.objects.create(user=user, uid=uid, provider=provider)
+        if hasattr(transaction, 'atomic'):
+            # In Django versions that have an "atomic" transaction decorator / context
+            # manager, there's a transaction wrapped around this call.
+            # If the create fails below due to an IntegrityError, ensure that the transaction
+            # stays undamaged by wrapping the create in an atomic.
+            with transaction.atomic():
+                social_auth = cls.objects.create(user=user, uid=uid, provider=provider)
+        else:
+            social_auth = cls.objects.create(user=user, uid=uid, provider=provider)
+        return social_auth
 
 
 class DjangoNonceMixin(NonceMixin):