Fix HfHubHTTPError reduce error by adding factory function (#3579)

* fixed and added unit test

Signed-off-by: You-Cheng Lin <[email protected]>

* Apply style fixes

---------

Signed-off-by: You-Cheng Lin <[email protected]>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: owenowenisme

src/huggingface_hub/errors.py

@@ -84,9 +84,15 @@ def append_to_message(self, additional_message: str) -> None:
         """Append additional information to the `HfHubHTTPError` initial message."""
         self.args = (self.args[0] + additional_message,) + self.args[1:]
 
+    @classmethod
+    def _reconstruct_hf_hub_http_error(
+        cls, message: str, response: Response, server_message: Optional[str]
+    ) -> "HfHubHTTPError":
+        return cls(message, response=response, server_message=server_message)
+
     def __reduce_ex__(self, protocol):
         """Fix pickling of Exception subclass with kwargs. We need to override __reduce_ex__ of the parent class"""
-        return (self.__class__, (str(self),), {"response": self.response, "server_message": self.server_message})
+        return (self.__class__._reconstruct_hf_hub_http_error, (str(self), self.response, self.server_message))
 
 
 # INFERENCE CLIENT ERRORS

tests/test_utils_errors.py

@@ -269,6 +269,17 @@ def test_hf_hub_http_error_with_request_id_and_amzn_trace_id(self) -> None:
         assert str(error) == "this is a message (Request ID: test-id)"
         assert error.request_id == "test-id"
 
+    def test_hf_hub_error_reconstruction(self) -> None:
+        """Test HfHubHTTPError is reconstructed properly."""
+        from copy import deepcopy
+
+        mock_response = Response(status_code=404, request=Request(method="GET", url="https://huggingface.co/fake"))
+        error = HfHubHTTPError("this is a message", response=mock_response)
+        copy_error = deepcopy(error)
+        assert str(copy_error) == str(error)
+        assert copy_error.request_id == error.request_id
+        assert copy_error.server_message == error.server_message
+
 
 @pytest.mark.parametrize(
     ("url", "should_match"),