Check extra action's func.__name__

rest_framework/viewsets.py

@@ -33,6 +33,15 @@ def _is_extra_action(attr):
     return hasattr(attr, 'mapping') and isinstance(attr.mapping, MethodMapper)
 
 
+def _check_attr_name(func, name):
+    assert func.__name__ == name, (
+        f'Expected function (`{func.__name__}`) to match its attribute name '
+        f'(`{name}`). If using a decorator, ensure the inner function is '
+        f'decorated with `functools.wraps`, or that `{func.__name__}.__name__` '
+        f'is otherwise set to `{name}`.')
+    return func
+
+
 class ViewSetMixin:
     """
     This is the magic.
@@ -164,7 +173,9 @@ class ViewSetMixin:
         """
         Get the methods that are marked as an extra ViewSet `@action`.
         """
-        return [method for _, method in getmembers(cls, _is_extra_action)]
+        return [_check_attr_name(method, name)
+                for name, method
+                in getmembers(cls, _is_extra_action)]
 
     def get_extra_action_url_map(self):
         """

tests/test_viewsets.py

@@ -1,4 +1,5 @@
 from collections import OrderedDict
+from functools import wraps
 
 import pytest
 from django.conf.urls import include, url
@@ -34,6 +35,7 @@ class Action(models.Model):
 
 
 def decorate(fn):
+    @wraps(fn)
     def wrapper(self, request, *args, **kwargs):
         return fn(self, request, *args, **kwargs)
     return wrapper
@@ -222,9 +224,35 @@ class GetExtraActionsTests(TestCase):
             'detail_action',
             'list_action',
             'unresolvable_detail_action',
+            'wrapped_detail_action',
+            'wrapped_list_action',
         ]
         self.assertEqual(actual, expected)
 
+    def test_attr_name_check(self):
+        def decorate(fn):
+            def wrapper(self, request, *args, **kwargs):
+                return fn(self, request, *args, **kwargs)
+            return wrapper
+
+        class ActionViewSet(GenericViewSet):
+            queryset = Action.objects.all()
+
+            @action(detail=False)
+            @decorate
+            def wrapped_list_action(self, request, *args, **kwargs):
+                raise NotImplementedError
+
+        view = ActionViewSet()
+        with pytest.raises(AssertionError) as excinfo:
+            view.get_extra_actions()
+
+        assert str(excinfo.value) == (
+            'Expected function (`wrapper`) to match its attribute name '
+            '(`wrapped_list_action`). If using a decorator, ensure the inner '
+            'function is decorated with `functools.wraps`, or that '
+            '`wrapper.__name__` is otherwise set to `wrapped_list_action`.')
+
 
 @override_settings(ROOT_URLCONF='tests.test_viewsets')
 class GetExtraActionUrlMapTests(TestCase):