Fixed #12288 -- Validated that app names in INSTALLED_APPS are unique

2 files changed, 7 insertions, 3 deletions

diff --git a/django/conf/__init__.py b/django/conf/__init__.py
index 199c34fb55..6266ca2394 100644
--- a/django/conf/__init__.py
+++ b/django/conf/__init__.py
@@ -109,8 +109,9 @@ class BaseSettings(object):
                 "to a tuple, not a string.")
         elif name == "INSTALLED_APPS":
             value = list(value)  # force evaluation of generators on Python 3
-            if len(value) != len(set(value)):
-                raise ImproperlyConfigured("The INSTALLED_APPS setting must contain unique values.")
+            apps = [s.split('.')[-1] for s in value]
+            if len(value) != len(set(apps)):
+                raise ImproperlyConfigured("The INSTALLED_APPS setting must contain unique app names.")
 
         object.__setattr__(self, name, value)
 
diff --git a/tests/settings_tests/tests.py b/tests/settings_tests/tests.py
index a9503358a2..0ffb56bb82 100644
--- a/tests/settings_tests/tests.py
+++ b/tests/settings_tests/tests.py
@@ -241,11 +241,14 @@ class UniqueSettingsTests(TestCase):
     def test_unique(self):
         """
         An ImproperlyConfigured exception is raised if the INSTALLED_APPS contains
-        any duplicate strings.
+        any duplicate appication names.
         """
         with self.assertRaises(ImproperlyConfigured):
             self.settings_module.INSTALLED_APPS = ("myApp1", "myApp1", "myApp2", "myApp3")
 
+        with self.assertRaises(ImproperlyConfigured):
+            self.settings_module.INSTALLED_APPS = ("package1.myApp1", "package2.myApp1")
+
 
 class TrailingSlashURLTests(TestCase):
     """