Prevent deepcopying of filter's parent

rest_framework_filters/filterset.py

@@ -115,9 +115,13 @@ def expand_filters(self):
 
             # include exclusion keys
             if exclude_name in self.data:
-                f = copy.deepcopy(f)
-                f.exclude = not f.exclude
-                requested_filters[exclude_name] = f
+                # deepcopy the *base* filter to prevent copying of model & parent
+                f_copy = copy.deepcopy(self.base_filters[filter_name])
+                f_copy.parent = f.parent
+                f_copy.model = f.model
+                f_copy.exclude = not f.exclude
+
+                requested_filters[exclude_name] = f_copy
 
             # include filters from related subsets
             if isinstance(f, filters.RelatedFilter) and filter_name in related_data:

tests/test_filterset.py

@@ -2,6 +2,8 @@
 from __future__ import absolute_import
 from __future__ import unicode_literals
 
+import sys
+
 from django.test import TestCase
 from django.utils import six
 
@@ -11,7 +13,7 @@
 from django_filters.filters import BaseInFilter
 
 from .testapp.models import (
-    User, Note, Post, Person, Tag, BlogPost,
+    Note, Post, Person, Tag, BlogPost,
 )
 
 from .testapp.filters import (
@@ -24,6 +26,21 @@
     BlogPostOverrideFilter,
 )
 
+from rest_framework.views import APIView
+from rest_framework.test import APIRequestFactory
+factory = APIRequestFactory()
+
+
+class limit_recursion:
+    def __init__(self):
+        self.original_limit = sys.getrecursionlimit()
+
+    def __enter__(self):
+        sys.setrecursionlimit(100)
+
+    def __exit__(self, *args):
+        sys.setrecursionlimit(self.original_limit)
+
 
 class LookupsFilterTests(TestCase):
     """
@@ -429,3 +446,19 @@ def test_related_exclusion_results(self):
 
         self.assertEqual(len(results), 1)
         self.assertEqual(results[0], 'Post 2')
+
+    def test_exclude_and_request_interaction(self):
+        # See: https://github.com/philipn/django-rest-framework-filters/issues/171
+        request = APIView().initialize_request(factory.get('/?tags__name__contains!=Tag'))
+        filterset = BlogPostFilter(request.query_params, request=request, queryset=BlogPost.objects.all())
+
+        try:
+            with limit_recursion():
+                qs = filterset.qs
+        except RuntimeError:
+            self.fail('Recursion limit reached')
+
+        results = [r.title for r in qs]
+
+        self.assertEqual(len(results), 1)
+        self.assertEqual(results[0], 'Post 2')