fix: return empty tuple from import_protobuf_decode_error when protobuf is unavailable

src/transformers/tokenization_utils_base.py

@@ -63,7 +63,6 @@
 )
 from .utils.chat_parsing_utils import recursive_parse
 from .utils.chat_template_utils import render_jinja_template
-from .utils.import_utils import PROTOBUF_IMPORT_ERROR
 
 
 if TYPE_CHECKING:
@@ -76,8 +75,7 @@ def import_protobuf_decode_error(error_message=""):
         from google.protobuf.message import DecodeError
 
         return DecodeError
-    else:
-        raise ImportError(PROTOBUF_IMPORT_ERROR.format(error_message))
+    return ()
 
 
 def flatten(arr: list):

tests/tokenization/test_tokenization_utils.py

@@ -352,3 +352,24 @@ def test_special_tokens_overwrite(self):
             new_tokenizer.decode(new_tokenizer.encode(text_with_nonspecial_tokens), skip_special_tokens=True)
             == text_with_nonspecial_tokens
         )
+
+    def test_import_protobuf_decode_error_without_protobuf(self):
+        from unittest.mock import patch
+
+        from transformers.tokenization_utils_base import import_protobuf_decode_error
+
+        with patch("transformers.tokenization_utils_base.is_protobuf_available", return_value=False):
+            result = import_protobuf_decode_error()
+            self.assertEqual(result, ())
+
+    def test_import_protobuf_decode_error_does_not_mask_exceptions(self):
+        from unittest.mock import patch
+
+        from transformers.tokenization_utils_base import import_protobuf_decode_error
+
+        with patch("transformers.tokenization_utils_base.is_protobuf_available", return_value=False):
+            with self.assertRaises(ValueError):
+                try:
+                    raise ValueError("real error")
+                except import_protobuf_decode_error():
+                    pass