New submission from Olivier Grisel: `pickle.whichmodule` performs an iteration over `sys.modules` and tries to perform `getattr` calls on those modules. Unfortunately some modules such as those from the `six.moves` dynamic module can trigger imports when calling `getattr` on them, hence mutating the `sys.modules` dict and causing a `RuntimeError: dictionary changed size during iteration`.
This would also render `pickle.whichmodule` more thread-safe and cause concurrent thread perform new module imports and `whichmodule` calls. The attach patch protect the iterator by copying the dict items into a fixed list. I could write a tests involving dynamic module definitions as done in `six.moves` but it sounds very complicated for such a trivial fix. ---------- components: Library (Lib) files: pickle_whichmodule.patch keywords: patch messages: 222099 nosy: Olivier.Grisel priority: normal severity: normal status: open title: RuntimeError in pickle.whichmodule when sys.modules if mutated type: crash versions: Python 3.4, Python 3.5 Added file: http://bugs.python.org/file35830/pickle_whichmodule.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue21905> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
