Fixed #22477 -- Removed contrib middleware from the global settings defaults.

Also added a compatibility check for changed middleware defaults.

Forwardport of d94de802d3 from stable/1.7.x

tests/check_framework/tests.py

@@ -10,6 +10,7 @@ from django.core import checks
 from django.core.checks import Error, Warning
 from django.core.checks.registry import CheckRegistry
 from django.core.checks.compatibility.django_1_6_0 import check_1_6_compatibility
+from django.core.checks.compatibility.django_1_7_0 import check_1_7_compatibility
 from django.core.management.base import CommandError
 from django.core.management import call_command
 from django.db.models.fields import NOT_PROVIDED
@@ -148,6 +149,40 @@ class Django_1_6_0_CompatibilityChecks(TestCase):
                 boolean_field.default = old_default
 
 
+class Django_1_7_0_CompatibilityChecks(TestCase):
+
+    @override_settings(MIDDLEWARE_CLASSES=('django.contrib.sessions.middleware.SessionMiddleware',))
+    def test_middleware_classes_overridden(self):
+        errors = check_1_7_compatibility()
+        self.assertEqual(errors, [])
+
+    def test_middleware_classes_not_set_explicitly(self):
+        # If MIDDLEWARE_CLASSES was set explicitly, temporarily pretend it wasn't
+        middleware_classes_overridden = False
+        if 'MIDDLEWARE_CLASSES' in settings._wrapped._explicit_settings:
+            middleware_classes_overridden = True
+            settings._wrapped._explicit_settings.remove('MIDDLEWARE_CLASSES')
+        try:
+            errors = check_1_7_compatibility()
+            expected = [
+                checks.Warning(
+                    "MIDDLEWARE_CLASSES is not set.",
+                    hint=("Django 1.7 changed the global defaults for the MIDDLEWARE_CLASSES."
+                          "django.contrib.sessions.middleware.SessionMiddleware, "
+                          "django.contrib.auth.middleware.AuthenticationMiddleware, and "
+                          "django.contrib.messages.middleware.MessageMiddleware were removed from the defaults."
+                          "If your project needs these middleware then you should configure this setting."),
+                    obj=None,
+                    id='1_7.W001',
+                )
+            ]
+            self.assertEqual(errors, expected)
+        finally:
+            # Restore settings value
+            if middleware_classes_overridden:
+                settings._wrapped._explicit_settings.add('MIDDLEWARE_CLASSES')
+
+
 def simple_system_check(**kwargs):
     simple_system_check.kwargs = kwargs
     return []