Asthenia0412 opened a new pull request, #53774: URL: https://github.com/apache/arrow/pull/53774
## Background Issue #39149 reports that `pc.replace_substring_regex()` (and related APIs) hang indefinitely when passed a negative `max_replacements` value (other than -1 which means unlimited). The root cause is that the C++ kernel decrements `max_replacements` until it reaches 0, but a value like -3 becomes -4, -5, ... forever. The original fix attempt (PR #39264) targeted the C++ side but was closed before merge. Adding validation on the Python side is a simpler, more defensive approach: catch invalid input early, before it reaches the C++ layer. ## Problem `ReplaceSubstringOptions.__init__` accepted any integer for `max_replacements`, including values < -1. The sentinel value -1 means unlimited replacements, but -2, -3, etc. are nonsensical and trigger an infinite loop in the C++ kernel. ## Solution Add a guard in `ReplaceSubstringOptions.__init__` that raises `ValueError` when `max_replacements < -1`. This provides immediate, clear feedback to the caller rather than hanging. Also update the docstring to document the valid range explicitly (must be >= -1, where -1 and None both mean unlimited). ## Testing Added `test_replace_substring_negative_max_replacements` in `python/pyarrow/tests/test_compute.py` that verifies: - `max_replacements=-2` and `max_replacements=-3` raise `ValueError` - `max_replacements=-1` and omitted (None) are still accepted as unlimited - Non-negative values (0, 5, etc.) continue to work as before The test covers both the rejection path and the unchanged acceptance paths. Fixes #39149 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
