Fix DictField partial HTML omission handling

rest_framework/fields.py

@@ -1754,7 +1754,10 @@ 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)
+            value = html.parse_html_dict(dictionary, prefix=self.field_name)
+            if not value and getattr(self.root, 'partial', False):
+                return empty
+            return value
         return dictionary.get(self.field_name, empty)
 
     def to_internal_value(self, data):

tests/test_fields.py

@@ -2522,6 +2522,14 @@ def test_allow_empty_disallowed(self):
 
         assert exc_info.value.detail == ['This dictionary may not be empty.']
 
+    def test_partial_update_does_not_include_missing_html_dict_field(self):
+        class TestSerializer(serializers.Serializer):
+            field_name = serializers.DictField(required=False)
+
+        serializer = TestSerializer(data=QueryDict(''), partial=True)
+        assert serializer.is_valid()
+        assert 'field_name' not in serializer.validated_data
+
 
 class TestNestedDictField(FieldValues):
     """