[1.10.x] Fixed #27026 -- Fixed state initialization of bulk_create() objects if can_return_ids_from_bulk_insert.

Backport of 3246d2b4bb from master

django/db/models/query.py

@@ -452,8 +452,10 @@ class QuerySet(object):
                     ids = self._batched_insert(objs_without_pk, fields, batch_size)
                     if connection.features.can_return_ids_from_bulk_insert:
                         assert len(ids) == len(objs_without_pk)
-                    for i in range(len(ids)):
-                        objs_without_pk[i].pk = ids[i]
+                    for obj_without_pk, pk in zip(objs_without_pk, ids):
+                        obj_without_pk.pk = pk
+                        obj_without_pk._state.adding = False
+                        obj_without_pk._state.db = self.db
 
         return objs
 

docs/releases/1.10.1.txt

@@ -37,3 +37,8 @@ Bugfixes
 * Fixed a regression in ``Client.force_login()`` which required specifying a
   ``backend`` rather than automatically using the first one if multiple
   backends are configured (:ticket:`27027`).
+
+* Made ``QuerySet.bulk_create()`` properly initialize model instances on
+  backends, such as PostgreSQL, that support returning the IDs of the created
+  records so that many-to-many relationships can be used on the new objects
+  (:ticket:`27026`).

tests/bulk_create/tests.py

@@ -217,3 +217,13 @@ class BulkCreateTests(TestCase):
         self.assertEqual(Country.objects.get(pk=countries[1].pk), countries[1])
         self.assertEqual(Country.objects.get(pk=countries[2].pk), countries[2])
         self.assertEqual(Country.objects.get(pk=countries[3].pk), countries[3])
+
+    @skipUnlessDBFeature('can_return_ids_from_bulk_insert')
+    def test_set_state(self):
+        country_nl = Country(name='Netherlands', iso_two_letter='NL')
+        country_be = Country(name='Belgium', iso_two_letter='BE')
+        Country.objects.bulk_create([country_nl])
+        country_be.save()
+        # Objects save via bulk_create() and save() should have equal state.
+        self.assertEqual(country_nl._state.adding, country_be._state.adding)
+        self.assertEqual(country_nl._state.db, country_be._state.db)