New submission from Xavier Morel: Encountered this issue porting Python 2 code manipulating meta_path to Python 3.
In Python 2, meta_path is empty by default and its documentation specifically notes that: > sys.meta_path is searched before any implicit default finders or sys.path. As a result, sys.meta_path.append() works perfectly well and is overwhelmingly common[0]. In Python 3, this note was removed but the documentation does not specifically state default finders are present in meta_path, and the old code using sys.meta_path.append may now break as the default finders will silently take precedence on the custom ones if they believe they can do the job. I'd like to add a warning to the Python 3 documentation (3.5+?) noting the presence of existing default loaders, and to the Python 2 documentation suggesting `sys.meta_path.insert(0, finder)` for future-proofing, would there be objections or issues? [0] https://github.com/search?q=meta_path.append&type=Code&utf8=✓ ---------- assignee: docs@python components: Documentation messages: 294919 nosy: docs@python, xmorel priority: normal severity: normal status: open title: Warn that meta_path is not empty type: behavior versions: Python 2.7, Python 3.5, Python 3.6 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue30535> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
