Set default value of filterset data to MultiValueDict (#1634)

django_filters/filterset.py

@@ -5,6 +5,7 @@
 from django.db import models
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.fields.related import ManyToManyRel, ManyToOneRel, OneToOneRel
+from django.utils.datastructures import MultiValueDict
 
 from .conf import settings
 from .constants import ALL_FIELDS
@@ -176,7 +177,7 @@ def __init__(self, data=None, queryset=None, *, request=None, prefix=None):
         model = queryset.model
 
         self.is_bound = data is not None
-        self.data = data or {}
+        self.data = data or MultiValueDict()
         self.queryset = queryset
         self.request = request
         self.form_prefix = prefix

tests/test_filterset.py

@@ -3,6 +3,7 @@
 
 from django.db import models
 from django.test import TestCase, override_settings
+from django.utils.datastructures import MultiValueDict
 
 from django_filters.exceptions import FieldLookupError
 from django_filters.filters import (
@@ -745,6 +746,10 @@ def test_creating_with_request(self):
         m = mock.Mock()
         f = self.F(request=m)
         self.assertEqual(f.request, m)
+
+    def test_creating_with_no_data_default(self):
+        f = self.F()
+        self.assertIsInstance(f.data, MultiValueDict)
 
 
 class FilterSetQuerysetTests(TestCase):