From ca555ea6689836ca5f16c084fad7cb1b2f74bab9 Mon Sep 17 00:00:00 2001
From: Sumanth Ratna <2022sratna@tjhsst.edu>
Date: Thu, 31 Dec 2020 13:56:56 -0500
Subject: [PATCH] Fix issubclass for view functions

---
 rest_framework/routers.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/rest_framework/routers.py b/rest_framework/routers.py
index e6c1938a1..94b68b1c4 100644
--- a/rest_framework/routers.py
+++ b/rest_framework/routers.py
@@ -15,6 +15,7 @@ For example, you might have a `urls.py` that looks something like this:
 """
 import itertools
 from collections import OrderedDict, namedtuple
+from inspect import isclass
 
 from django.core.exceptions import ImproperlyConfigured
 from django.urls import NoReverseMatch, re_path, path
@@ -150,11 +151,13 @@ class SimpleRouter(BaseRouter):
         """
         # use `issubclass` and not `isinstance` because `viewset` may be an
         #   uninstantiated class.
-        if not issubclass(viewset, ViewSetMixin):
-            if issubclass(viewset, View):
-                return [viewset.as_view(), ]
+        is_viewset = issubclass(viewset, ViewSetMixin) if isclass(viewset) else False
+        if not is_viewset:
             # `viewset` is not a REST Framework ViewSet,
             #   so we can't dynamically generate any routes
+            is_cbv = issubclass(viewset, View) if isclass(viewset) else False
+            if is_cbv:
+                return [viewset.as_view(), ]
             return [viewset, ]
 
         # converting to list as iterables are good for one pass, known host needs to be checked again and again for