DateTime field: reject timestamp True/False

src/marshmallow/fields.py

@@ -1285,6 +1285,8 @@ def _serialize(self, value, attr, obj, **kwargs) -> str | float | None:
         return value.strftime(data_format)
 
     def _deserialize(self, value, attr, data, **kwargs) -> dt.datetime:
+        if value is True or value is False:
+            raise self.make_error("invalid", input=value, obj_type=self.OBJ_TYPE)
         data_format = self.format or self.DEFAULT_FORMAT
         func = self.DESERIALIZATION_FUNCS.get(data_format)
         try:

tests/test_deserialization.py

@@ -422,6 +422,8 @@ def test_field_toggle_show_invalid_value_in_error_message(self):
         [
             "not-a-datetime",
             42,
+            True,
+            False,
             0,
             "",
             [],