Ben Spiller <spiller....@gmail.com> added the comment:
Correction to original report - it doesn't hang indefinitely, it just takes a really long time. Specifically, looks like it's quadratic in the length of the input string. Increase the size of the input string to 1000*1000 and it's really really slow. I don't know for sure if it's possible to implement regexes in a way that avoids this pathological behaviour, but it's certainly quite risky that an otherwise working bit of code using a pattern containing .* can hang/livelock an application for an arbitrary amount of time if passed a larger-than-expected (but actually not that big) input string. ---------- title: re.search livelock/hang, searching for patterns starting .* in a large string -> re.search extreme slowness (looks like hang/livelock), searching for patterns containing .* in a large string type: crash -> performance _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue35915> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
