From 094d060b57dfff8f7d41e6fc1dce33cb7fdde95b Mon Sep 17 00:00:00 2001
From: mengw15 <125719918+mengw15@users.noreply.github.com>
Date: Fri, 15 May 2026 21:20:56 -0700
Subject: [PATCH] fix: preserve original error in
 IcebergIterator._seek_to_usable_file

The bare `raise Exception` (no args, no `from`) constructed a fresh
empty exception, discarding the underlying error type, message, and
traceback. Callers doing `except Exception as e: log.error(str(e))`
saw only an empty string instead of the real diagnostic (catalog auth
failure, S3 IO error, manifest corruption, etc.). The `print` also
bypassed the project logger.

Replace with a re-raise of the original exception and route the
message through loguru.

Closes #5091.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .../core/storage/iceberg/iceberg_document.py  |  7 ++--
 .../test_iceberg_iterator_error_paths.py      | 37 +++++++++++++++++++
 2 files changed, 41 insertions(+), 3 deletions(-)
 create mode 100644 amber/src/test/python/core/storage/iceberg/test_iceberg_iterator_error_paths.py

diff --git a/amber/src/main/python/core/storage/iceberg/iceberg_document.py b/amber/src/main/python/core/storage/iceberg/iceberg_document.py
index 997ab9b5b70..7a5beda916d 100644
--- a/amber/src/main/python/core/storage/iceberg/iceberg_document.py
+++ b/amber/src/main/python/core/storage/iceberg/iceberg_document.py
@@ -17,6 +17,7 @@
 
 import pyarrow as pa
 from itertools import islice
+from loguru import logger
 from pyiceberg.catalog import Catalog
 from pyiceberg.schema import Schema
 from pyiceberg.table import Table, FileScanTask
@@ -211,9 +212,9 @@ def _seek_to_usable_file(self) -> Iterator[FileScanTask]:
                             self.num_of_skipped_records += record_count
                             continue
                         yield task
-                except Exception:
-                    print("Could not read iceberg table:\n")
-                    raise Exception
+                except Exception as err:
+                    logger.exception(err)
+                    raise
             else:
                 return iter([])
 
diff --git a/amber/src/test/python/core/storage/iceberg/test_iceberg_iterator_error_paths.py b/amber/src/test/python/core/storage/iceberg/test_iceberg_iterator_error_paths.py
new file mode 100644
index 00000000000..d724ac31d53
--- /dev/null
+++ b/amber/src/test/python/core/storage/iceberg/test_iceberg_iterator_error_paths.py
@@ -0,0 +1,37 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+from unittest.mock import Mock, patch
+
+import pytest
+
+from core.storage.iceberg import iceberg_document
+from core.storage.iceberg.iceberg_document import IcebergIterator
+
+
+def test_seek_to_usable_file_preserves_original_error():
+    failing_table = Mock()
+    failing_table.refresh.side_effect = RuntimeError(
+        "Catalog auth failure: token expired"
+    )
+
+    with patch.object(
+        iceberg_document, "load_table_metadata", return_value=failing_table
+    ):
+        it = IcebergIterator(0, None, None, "ns", "tbl", None, None)
+        with pytest.raises(RuntimeError, match="Catalog auth failure"):
+            next(it)