Fixed #21587 Adds deprecation warning to RedirectView and adds test f…

…or it.

django/views/generic/base.py

@@ -1,6 +1,7 @@
 from __future__ import unicode_literals
 
 import logging
+import warnings
 from functools import update_wrapper
 
 from django import http
@@ -164,6 +165,20 @@ class RedirectView(View):
     pattern_name = None
     query_string = False
 
+    def __init__(self, *args, **kwargs):
+        """
+        When initializing the RedirectView we check if permanent is given,
+        if not we raise a deprecation warning and continue on as normal.
+        """
+        if 'permanent' not in kwargs:
+            warnings.warn(
+                "Deprecation Warning: Default value of permanent for RedirectViews will change from True to False in" \
+                " the next release",
+                DeprecationWarning
+            )
+
+        super(RedirectView, self).__init__(*args, **kwargs)
+
     def get_redirect_url(self, *args, **kwargs):
         """
         Return the URL redirect to. Keyword arguments from the

tests/generic_views/test_base.py

@@ -2,6 +2,7 @@
 
 import time
 import unittest
+import warnings
 
 from django.core.exceptions import ImproperlyConfigured
 from django.http import HttpResponse
@@ -439,6 +440,21 @@ def test_direct_instantiation(self):
         response = view.dispatch(self.rf.head('/foo/'))
         self.assertEqual(response.status_code, 410)
 
+    def test_permanent_default_deprecation_warning(self):
+        """
+        Tests to make sure that a DeprecationWarning is raised if 'permanent' is not included during instantiation
+        """
+        with warnings.catch_warnings(record=True) as warns:
+            # Cause all warnings to always be triggered.
+            warnings.simplefilter('always')
+            view = RedirectView(url='/bar/')
+            view = RedirectView.as_view(url='/bar/')(self.rf.request(PATH_INFO='/foo/'))
+
+        self.assertEqual(
+            len(warns),
+            2,
+            msg="Failed to generate deprecation warning when calling RedirectView without permanent kwargs"
+        )
 
 class GetContextDataTest(unittest.TestCase):