Add support for clearing a dict field with form data

rest_framework/fields.py

@@ -1754,7 +1754,14 @@ def get_value(self, dictionary):
         # We override the default field access in order to support
         # dictionaries in HTML forms.
         if html.is_html_input(dictionary):
-            return html.parse_html_dict(dictionary, prefix=self.field_name, default=empty)
+            result = html.parse_html_dict(dictionary, prefix=self.field_name, default=empty)
+            if result is not empty:
+                return result
+            # If the field name itself is present in the input,
+            # treat it as an explicit empty dict (e.g. clearing the field).
+            if self.field_name in dictionary:
+                return {}
+            return empty
         return dictionary.get(self.field_name, empty)
 
     def to_internal_value(self, data):

tests/test_fields.py

@@ -2522,7 +2522,7 @@ def test_allow_empty_disallowed(self):
 
         assert exc_info.value.detail == ['This dictionary may not be empty.']
 
-    def test_querydict_dict_input(self):
+    def test_query_dict_input_with_dot_separated_keys(self):
         """
         DictField should correctly parse HTML form (QueryDict) input
         with dot-separated keys.
@@ -2534,7 +2534,7 @@ class TestSerializer(serializers.Serializer):
         assert serializer.is_valid(), serializer.errors
         assert serializer.validated_data == {'data': {'a': '1', 'b': '2'}}
 
-    def test_querydict_dict_input_no_values_uses_default(self):
+    def test_query_dict_input_no_values_uses_default(self):
         """
         When no matching keys are present in the QueryDict and a default
         is set, the field should return the default value.
@@ -2547,7 +2547,7 @@ class TestSerializer(serializers.Serializer):
         assert serializer.is_valid(), serializer.errors
         assert serializer.validated_data == {'a': 1, 'data': {'x': 'y'}}
 
-    def test_querydict_dict_input_no_values_no_default_and_not_required(self):
+    def test_query_dict_input_no_values_no_default_and_not_required(self):
         """
         When no matching keys are present in the QueryDict, there is no
         default, and the field is not required, the field should be
@@ -2560,7 +2560,7 @@ class TestSerializer(serializers.Serializer):
         assert serializer.is_valid(), serializer.errors
         assert serializer.validated_data == {}
 
-    def test_querydict_dict_input_no_values_required(self):
+    def test_query_dict_input_no_values_required(self):
         """
         When no matching keys are present in the QueryDict and the field
         is required, validation should fail.
@@ -2572,6 +2572,24 @@ class TestSerializer(serializers.Serializer):
         assert not serializer.is_valid()
         assert 'data' in serializer.errors
 
+    def test_partial_update_can_clear_html_dict_field(self):
+        """
+        Test that a partial update can clear a DictField when provided with an
+        empty string value through a QueryDict.
+        """
+        class TestSerializer(serializers.Serializer):
+            field_name = serializers.DictField(required=False)
+            other_field = serializers.CharField(required=False)
+
+        serializer = TestSerializer(
+            data=QueryDict('field_name='),
+            partial=True,
+        )
+        assert serializer.is_valid()
+        assert 'field_name' in serializer.validated_data
+        assert serializer.validated_data['field_name'] == {}
+        assert 'other_field' not in serializer.validated_data
+
 
 class TestNestedDictField(FieldValues):
     """