[issue21049] Warning at interpreter exit triggers flood of “ImportWarning: sys.meta_path is empty”
Brett Cannon added the comment: This has now been fixed in https://hg.python.org/cpython/rev/d9f71bc6d897 . Thanks to everyone who helped with the bug report! -- versions: +Python 3.5 -Python 3.4 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21049 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21049] Warning at interpreter exit triggers flood of “ImportWarning: sys.meta_path is empty”
Quentin Pradet added the comment: Martin, yes, I'd be glad to see a fix if it's not too complicated. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21049 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21049] Warning at interpreter exit triggers flood of “ImportWarning: sys.meta_path is empty”
Brett Cannon added the comment: I'm already planning to look into this problem in issue #21052 so feel free to follow over there. -- superseder: - Consider dropping ImportWarning for empty sys.path_hooks and sys.meta_path ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21049 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21049] Warning at interpreter exit triggers flood of “ImportWarning: sys.meta_path is empty”
Martin Panter added the comment: Quentin, do you think this should be reopened? Brett Cannon, I wonder if the only reason you closed this bug is because you thought the scenario to trigger it is very unlikely. Considering it affected someone else, and that there are other real-world triggers in addition to Py Socks, would it be okay to reopen it? I could try to make a patch or some concrete suggestions when I have a chance, if that helps change your mind :) Perhaps a regression test could be based on this experiment: import sys, warnings sys.meta_path = None sys.modules.pop(linecache, None) module 'linecache' from '/usr/lib/python3.4/linecache.py' warnings.warn(boom) Traceback (most recent call last): File stdin, line 1, in module File /usr/lib/python3.4/warnings.py, line 15, in showwarning file.write(formatwarning(message, category, filename, lineno, line)) File /usr/lib/python3.4/warnings.py, line 21, in formatwarning import linecache File /home/proj/python/lib/misc.py, line 41, in __call__ return self.__wrapped__(name, globals, locals, fromlist, level) File frozen importlib._bootstrap, line 2237, in _find_and_load File frozen importlib._bootstrap, line , in _find_and_load_unlocked File frozen importlib._bootstrap, line 2150, in _find_spec File /usr/lib/python3.4/warnings.py, line 15, in showwarning file.write(formatwarning(message, category, filename, lineno, line)) . . . File frozen importlib._bootstrap, line 2236, in _find_and_load RuntimeError: maximum recursion depth exceeded while calling a Python object -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21049 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21049] Warning at interpreter exit triggers flood of “ImportWarning: sys.meta_path is empty”
Quentin Pradet added the comment: I've also been affected by this when testing integration with a third-party library (NLTK). NLTK does need to be fixed, but the ResourceWarning already say so. The new one-liner doesn't seem contrived to me. -- nosy: +Quentin.Pradet ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21049 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21049] Warning at interpreter exit triggers flood of “ImportWarning: sys.meta_path is empty”
Martin Panter added the comment: My original demonstration was distilled from a real world case. I get this issue with other real world cases too, so I am expanding the title to reflect what I think is going on. This problem seems to be caused by a ResourceWarning triggered from a garbage cycle being freed just before Python exits. The flood of ImportWarning lines makes it annoying to scroll up to see what other ResourceWarning messages, exceptions, etc you are missing out on. Much simpler one-liner demonstration adapted from Message 222403 (because class definitions create garbage cycles in my experience): python3 -Wall -c 'class C: a = open(/dev/null)' The best workaround is probably to use “python -Wdefault” rather than “python -Wall”. Then you only get one ImportWarning line. I suspect the problem might be caused by a recursive loop between emitting a warning and importing something, as Antoine hinted. Calling sys.setrecursionlimit(30) reduces the flood to 5 lines. Unfortunately my modifications to “importlib/_bootstrap.py” and “warnings.py” on my OS are not having any effect, otherwise I might try to make a patch. Perhaps if it is not appropriate for the ImportWarning to be removed, could the code printing out the warning be changed to avoid triggering it in the first place? -- title: Flood of “ImportWarning: sys.meta_path is empty” after exception with socket subclass - Warning at interpreter exit triggers flood of “ImportWarning: sys.meta_path is empty” ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21049 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
