New submission from Jonathan Huot <jonathan.h...@thomsonreuters.com>:
Executing python modules with -m can lead to weird sys.argv parsing. "Argument parsing" section at https://docs.python.org/3.8/tutorial/interpreter.html#argument-passing mention : - When -m module is used, sys.argv[0] is set to the full name of the located module. The word "located" is used, but it doesn't mention anything when the module is not *yet* "located". For instance, let's see what is the sys.argv for each python files: $ cat mainmodule/__init__.py import sys; print("{}: {}".format(sys.argv, __file__)) $ cat mainmodule/submodule/__init__.py import sys; print("{}: {}".format(sys.argv, __file__)) $ cat mainmodule/submodule/foobar.py import sys; print("{}: {}".format(sys.argv, __file__)) Then we call "foobar" with -m: $ python -m mainmodule.submodule.foobar -o -b ['-m', '-o', 'b']: (..)/mainmodule/__init__.py ['-m', '-o', 'b']: (..)/mainmodule/submodule/__init__.py ['(..)/mainmodule/submodule/foobar.py', '-o', 'b']: (..)/mainmodule/submodule/foobar.py $ We notice that only "-m" is in sys.argv before we found "foobar". This can lead to a lot of troubles when we have meaningful processing in __init__.py which rely on sys.argv to initialize stuff. IMHO, it either should be the sys.argv intact ['-m', 'mainmodule.submodule.foobar', '-o', '-b'] or empty ['', '-o', '-b'] or only the latest ['-o', '-b'], but it should not be ['-m', '-o', '-b'] which is very confusing. ---------- assignee: docs@python components: Documentation messages: 314239 nosy: Jonathan Huot, docs@python priority: normal severity: normal status: open title: python sys.argv argument parsing not clear type: behavior versions: Python 2.7, Python 3.4, Python 3.5, Python 3.6, Python 3.7, Python 3.8 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue33119> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
