Fix _configuration_file argument getting passed to model (#15629)

src/transformers/configuration_utils.py

@@ -580,7 +580,7 @@ class PretrainedConfig(PushToHubMixin):
         if os.path.isfile(pretrained_model_name_or_path) or is_remote_url(pretrained_model_name_or_path):
             config_file = pretrained_model_name_or_path
         else:
-            configuration_file = kwargs.get("_configuration_file", CONFIG_NAME)
+            configuration_file = kwargs.pop("_configuration_file", CONFIG_NAME)
 
             if os.path.isdir(pretrained_model_name_or_path):
                 config_file = os.path.join(pretrained_model_name_or_path, configuration_file)

tests/test_configuration_common.py

@@ -334,8 +334,12 @@ class ConfigurationVersioningTest(unittest.TestCase):
         import transformers as new_transformers
 
         new_transformers.configuration_utils.__version__ = "v4.0.0"
-        new_configuration = new_transformers.models.auto.AutoConfig.from_pretrained(repo)
+        new_configuration, kwargs = new_transformers.models.auto.AutoConfig.from_pretrained(
+            repo, return_unused_kwargs=True
+        )
         self.assertEqual(new_configuration.hidden_size, 2)
+        # This checks `_configuration_file` ia not kept in the kwargs by mistake.
+        self.assertDictEqual(kwargs, {"_from_auto": True})
 
         # Testing an older version by monkey-patching the version in the module it's used.
         import transformers as old_transformers