fix: use 'is not None' checks in __str__ to handle empty string message

Address Copilot review: use explicit 'is not None' checks instead of
truthiness so that message='' is respected and does not fall back to
internal_message. Add test for this edge case.

Co-Authored-By: bot_apk <apk@cognition.ai>

Author: devin-ai-integration[bot]

airbyte_cdk/utils/traced_exception.py

@@ -51,10 +51,9 @@ def __init__(
 
     def __str__(self) -> str:
         """Return the user-facing message, falling back to internal_message."""
-
-        if self.message:
+        if self.message is not None:
             return self.message
-        elif self.internal_message:
+        if self.internal_message is not None:
             return self.internal_message
         return ""
 

unit_tests/utils/test_traced_exception.py

@@ -246,6 +246,14 @@ def test_stack_trace_uses_str_representation(self) -> None:
         airbyte_message = exc.as_airbyte_message()
         assert "User sees this." in airbyte_message.trace.error.stack_trace
 
+    def test_str_with_empty_message_does_not_fall_back_to_internal_message(self) -> None:
+        """Explicit empty message should be respected and not replaced by internal_message."""
+        exc = AirbyteTracedException(
+            internal_message="an internal error that should not be shown to the user",
+            message="",
+        )
+        assert str(exc) == ""
+
     def test_internal_message_preserved_in_trace_error(self) -> None:
         """Verify internal_message is still available in the trace error for debugging."""
         exc = AirbyteTracedException(