diff options
| -rw-r--r-- | django/contrib/contenttypes/models.py | 21 | ||||
| -rw-r--r-- | tests/contenttypes_tests/tests.py | 39 |
2 files changed, 53 insertions, 7 deletions
diff --git a/django/contrib/contenttypes/models.py b/django/contrib/contenttypes/models.py index 0dc048cfa2..634576f4d0 100644 --- a/django/contrib/contenttypes/models.py +++ b/django/contrib/contenttypes/models.py @@ -38,18 +38,27 @@ class ContentTypeManager(models.Manager): """ opts = self._get_opts(model, for_concrete_model) try: - ct = self._get_from_cache(opts) + return self._get_from_cache(opts) except KeyError: - # Load or create the ContentType entry. The smart_text() is - # needed around opts.verbose_name_raw because name_raw might be a - # django.utils.functional.__proxy__ object. + pass + + # The ContentType entry was not found in the cache, therefore we + # proceed to load or create it. + try: + # 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 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. + # The smart_text() is needed around opts.verbose_name_raw because + # name_raw might be a django.utils.functional.__proxy__ object. ct, created = self.get_or_create( app_label=opts.app_label, model=opts.model_name, defaults={'name': smart_text(opts.verbose_name_raw)}, ) - self._add_to_cache(self.db, ct) - + self._add_to_cache(self.db, ct) return ct def get_for_models(self, *models, **kwargs): diff --git a/tests/contenttypes_tests/tests.py b/tests/contenttypes_tests/tests.py index 0f260a0b9b..18c542bf4b 100644 --- a/tests/contenttypes_tests/tests.py +++ b/tests/contenttypes_tests/tests.py @@ -7,7 +7,7 @@ from django.contrib.contenttypes.fields import ( ) from django.contrib.contenttypes.models import ContentType from django.core import checks -from django.db import models +from django.db import connections, models, router from django.test import TestCase from django.test.utils import override_settings from django.utils.encoding import force_str @@ -335,3 +335,40 @@ class GenericRelationshipTests(IsolatedModelsTestCase): ) ] self.assertEqual(errors, expected) + + +class TestRouter(object): + def db_for_read(self, model, **hints): + return 'other' + + def db_for_write(self, model, **hints): + return 'default' + + +class ContentTypesMultidbTestCase(TestCase): + + def setUp(self): + self.old_routers = router.routers + router.routers = [TestRouter()] + + # Whenever a test starts executing, only the "default" database is + # connected. We explicitly connect to the "other" database here. If we + # don't do it, then it will be implicitly connected later when we query + # it, but in that case some database backends may automatically perform + # extra queries upon connecting (notably mysql executes + # "SET SQL_AUTO_IS_NULL = 0"), which will affect assertNumQueries(). + connections['other'].ensure_connection() + + def tearDown(self): + router.routers = self.old_routers + + def test_multidb(self): + """ + Test that, when using multiple databases, we use the db_for_read (see + #20401). + """ + ContentType.objects.clear_cache() + + with self.assertNumQueries(0, using='default'), \ + self.assertNumQueries(1, using='other'): + ContentType.objects.get_for_model(Author) |