Ticket #29203: patch_cached_session_deleting_session_cookie.diff

django/contrib/sessions/middleware.py

@@ -35 +35 @@
             # First check if we need to delete this cookie.
             # The session should be deleted only if the session is entirely empty
             if settings.SESSION_COOKIE_NAME in request.COOKIES and empty:
-                response.delete_cookie(
-                    settings.SESSION_COOKIE_NAME,
-                    path=settings.SESSION_COOKIE_PATH,
-                    domain=settings.SESSION_COOKIE_DOMAIN,
-                )
+                try:
+                    # This condition is to check out cache backend is available:
+                    # If cache backend is not available (eg. failover), 
+                    # request.session.cache_key raises a connection timeout 
+                    # exception, so it doesn't delete a session cookie.
+                    if request.session.cache_key:
+                        response.delete_cookie(
+                            settings.SESSION_COOKIE_NAME,
+                            path=settings.SESSION_COOKIE_PATH,
+                            domain=settings.SESSION_COOKIE_DOMAIN,
+                        )
+                except:
+                    pass
             else:
                 if accessed:
                     patch_vary_headers(response, ('Cookie',))