Use QueryDict for data default. (#1691)

Co-authored-by: Carlton Gibson <[email protected]>

Author: pajowu

django_filters/filterset.py

@@ -7,7 +7,7 @@
 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 django.http import QueryDict
 
 from .conf import settings
 from .constants import ALL_FIELDS
@@ -61,7 +61,11 @@ def __init__(self, options=None):
 
         self.form = getattr(options, "form", forms.Form)
 
-        behavior = getattr(options, "unknown_field_behavior", UnknownFieldBehavior.RAISE)
+        behavior = getattr(
+            options,
+            "unknown_field_behavior",
+            UnknownFieldBehavior.RAISE,
+        )
 
         if not isinstance(behavior, UnknownFieldBehavior):
             raise ValueError(f"Invalid unknown_field_behavior: {behavior}")
@@ -192,7 +196,7 @@ 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 MultiValueDict()
+        self.data = data or QueryDict()
         self.queryset = queryset
         self.request = request
         self.form_prefix = prefix
@@ -380,7 +384,9 @@ def handle_unrecognized_field(cls, field_name, message):
         if behavior == UnknownFieldBehavior.RAISE:
             raise AssertionError(message)
         elif behavior == UnknownFieldBehavior.WARN:
-            warnings.warn(f"Unrecognized field type for '{field_name}'. Field will be ignored.")
+            warnings.warn(
+                f"Unrecognized field type for '{field_name}'. Field will be ignored."
+            )
         elif behavior == UnknownFieldBehavior.IGNORE:
             pass
         else:

tests/test_widgets.py

@@ -1,4 +1,5 @@
 from django.forms import NumberInput, Select, TextInput
+from django.http import QueryDict
 from django.test import TestCase
 
 from django_filters.widgets import (
@@ -143,6 +144,25 @@ def test_widget_with_blank_choice(self):
             </ul>""",
         )
 
+    def test_widget_with_empty_querydict(self):
+        choices = (
+            ("", "---------"),
+            ("test-val1", "test-label1"),
+            ("test-val2", "test-label2"),
+        )
+
+        w = LinkWidget(choices=choices)
+        w.value_from_datadict(QueryDict(), {}, "price")
+        self.assertHTMLEqual(
+            w.render("price", ""),
+            """
+            <ul>
+                <li><a class="selected" href="?price=">All</a></li>
+                <li><a href="?price=test-val1">test-label1</a></li>
+                <li><a href="?price=test-val2">test-label2</a></li>
+            </ul>""",
+        )
+
     def test_widget_value_from_datadict(self):
         w = LinkWidget()
         data = {"price": "test-val1"}