Merge master

1 files changed, 16 insertions, 1 deletions

diff --git a/rest_framework/generics.py b/rest_framework/generics.py
index e38c52b1..cecb548f 100644
--- a/rest_framework/generics.py
+++ b/rest_framework/generics.py
@@ -43,6 +43,10 @@ class GenericAPIView(views.APIView):
 
     # You'll need to either set these attributes,
     # or override `get_queryset()`/`get_serializer_class()`.
+    # If you are overriding a view method, it is important that you call
+    # `get_queryset()` instead of accessing the `queryset` property directly,
+    # as `queryset` will get evaluated only once, and those results are cached
+    # for all subsequent requests.
     queryset = None
     serializer_class = None
 
@@ -185,7 +189,13 @@ class GenericAPIView(views.APIView):
         """
         Returns the list of filter backends that this view requires.
         """
-        filter_backends = self.filter_backends or []
+        if self.filter_backends is None:
+            filter_backends = []
+        else:
+            # Note that we are returning a *copy* of the class attribute,
+            # so that it is safe for the view to mutate it if needed.
+            filter_backends = list(self.filter_backends)
+
         if not filter_backends and self.filter_backend:
             warnings.warn(
                 'The `filter_backend` attribute and `FILTER_BACKEND` setting '
@@ -195,6 +205,7 @@ class GenericAPIView(views.APIView):
                 DeprecationWarning, stacklevel=2
             )
             filter_backends = [self.filter_backend]
+
         return filter_backends
 
 
@@ -258,6 +269,10 @@ class GenericAPIView(views.APIView):
         This must be an iterable, and may be a queryset.
         Defaults to using `self.queryset`.
 
+        This method should always be used rather than accessing `self.queryset`
+        directly, as `self.queryset` gets evaluated only once, and those results
+        are cached for all subsequent requests.
+
         You may want to override this if you need to provide different
         querysets depending on the incoming request.