Throw an error if getattribute_from_module can't find anything (#19535)

* return None to avoid recursive call

* Give error

* Give error

* Add test

* More tests

* Quality

Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

tests/models/auto/test_modeling_auto.py

@@ -17,9 +17,12 @@ import copy
 import sys
 import tempfile
 import unittest
+from collections import OrderedDict
 from pathlib import Path
 
-from transformers import BertConfig, is_torch_available
+import pytest
+
+from transformers import BertConfig, GPT2Model, is_torch_available
 from transformers.models.auto.configuration_auto import CONFIG_MAPPING
 from transformers.testing_utils import (
     DUMMY_UNKNOWN_IDENTIFIER,
@@ -372,3 +375,22 @@ class AutoModelTest(unittest.TestCase):
             self.assertEqual(counter.get_request_count, 0)
             self.assertEqual(counter.head_request_count, 1)
             self.assertEqual(counter.other_request_count, 0)
+
+    def test_attr_not_existing(self):
+
+        from transformers.models.auto.auto_factory import _LazyAutoMapping
+
+        _CONFIG_MAPPING_NAMES = OrderedDict([("bert", "BertConfig")])
+        _MODEL_MAPPING_NAMES = OrderedDict([("bert", "GhostModel")])
+        _MODEL_MAPPING = _LazyAutoMapping(_CONFIG_MAPPING_NAMES, _MODEL_MAPPING_NAMES)
+
+        with pytest.raises(ValueError, match=r"Could not find GhostModel neither in .* nor in .*!"):
+            _MODEL_MAPPING[BertConfig]
+
+        _MODEL_MAPPING_NAMES = OrderedDict([("bert", "BertModel")])
+        _MODEL_MAPPING = _LazyAutoMapping(_CONFIG_MAPPING_NAMES, _MODEL_MAPPING_NAMES)
+        self.assertEqual(_MODEL_MAPPING[BertConfig], BertModel)
+
+        _MODEL_MAPPING_NAMES = OrderedDict([("bert", "GPT2Model")])
+        _MODEL_MAPPING = _LazyAutoMapping(_CONFIG_MAPPING_NAMES, _MODEL_MAPPING_NAMES)
+        self.assertEqual(_MODEL_MAPPING[BertConfig], GPT2Model)