[issue23191] fnmatch regex cache use is not threadsafe

Changes by Serhiy Storchaka : -- resolution: -> fixed stage: patch review -> resolved status: open -> closed ___ Python tracker ___ _

[issue23191] fnmatch regex cache use is not threadsafe

Roundup Robot added the comment: New changeset fe12c34c39eb by Serhiy Storchaka in branch '2.7': Issue #23191: fnmatch functions that use caching are now threadsafe. https://hg.python.org/cpython/rev/fe12c34c39eb -- nosy: +python-dev ___ Python tracke

[issue23191] fnmatch regex cache use is not threadsafe

Changes by Serhiy Storchaka : -- assignee: -> serhiy.storchaka ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe:

[issue23191] fnmatch regex cache use is not threadsafe

M. Schmitzer added the comment: @serhiy.storchaka: My thoughts exactly, especially regarding the caching being implicit. From the outside, fnmatch really doesn't look like it could have threading issues. The patch also looks exactly like what I had in mind. --

[issue23191] fnmatch regex cache use is not threadsafe

Serhiy Storchaka added the comment: It is easy to make fnmatch caching thread safe without locks. Here is a patch. The problem with fnmatch is that the caching is implicit and a user don't know that any lock are needed. So either the need of the lock should be explicitly documented, or fnmatch

[issue23191] fnmatch regex cache use is not threadsafe

STINNER Victor added the comment: It would be nice to fix the issue, but I don't know how it is handled in other stdlib modules. -- ___ Python tracker ___ __

[issue23191] fnmatch regex cache use is not threadsafe

M. Schmitzer added the comment: Ok, if that is the attitude in such cases, feel free to close this. -- ___ Python tracker ___ ___ Pyth

[issue23191] fnmatch regex cache use is not threadsafe

STINNER Victor added the comment: I guess that a lot of stdlib modules are not thread safe :-/ A workaround is to protect calls to fnmatch with your own lock. -- nosy: +haypo ___ Python tracker ___

[issue23191] fnmatch regex cache use is not threadsafe

New submission from M. Schmitzer: The way the fnmatch module uses its regex cache is not threadsafe. When multiple threads use the module in parallel, a race condition between retrieving a - presumed present - item from the cache and clearing the cache (because the maximum size has been reache