[ python-Bugs-1152726 ] Default class args get clobbered by prior instances.
Bugs item #1152726, was opened at 2005-02-26 22:10 Message generated for change (Comment added) made by rhettinger You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=105470aid=1152726group_id=5470 Category: Python Interpreter Core Group: Python 2.3 Status: Closed Resolution: Invalid Priority: 8 Submitted By: Simon Drabble (sdrabble) Assigned to: Nobody/Anonymous (nobody) Summary: Default class args get clobbered by prior instances. Initial Comment: OS: SuSE Linux 9.2 kernel 2.6.4 Python: 2.3.3 Define a class where the __init__() method takes a default arg of list type. Instantiate this class, and append/ extend the value of its default arg. Instantiate the class again, and the value from the first instance will overwrite the second. The bug is known to exist in 2.3.3, but may exist in subsequent releases also. The attached file illuminates the problem. -- Comment By: Raymond Hettinger (rhettinger) Date: 2005-02-27 08:18 Message: Logged In: YES user_id=80475 Sorry, this is not a bug. It is part of how Python works. In general, do not use mutables for default values. Instead, write something like: def f(x, seq=None): if seq is None: seq = [] . . . There is a FAQ on the subject: http://www.python.org/doc/faq/general.html#why-are-default-values-shared-between-objects -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=105470aid=1152726group_id=5470 ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[ python-Bugs-1152726 ] Default class args get clobbered by prior instances.
Bugs item #1152726, was opened at 2005-02-26 22:10 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=105470aid=1152726group_id=5470 Category: Python Interpreter Core Group: Python 2.3 Status: Open Resolution: None Priority: 5 Submitted By: Simon Drabble (sdrabble) Assigned to: Nobody/Anonymous (nobody) Summary: Default class args get clobbered by prior instances. Initial Comment: OS: SuSE Linux 9.2 kernel 2.6.4 Python: 2.3.3 Define a class where the __init__() method takes a default arg of list type. Instantiate this class, and append/ extend the value of its default arg. Instantiate the class again, and the value from the first instance will overwrite the second. The bug is known to exist in 2.3.3, but may exist in subsequent releases also. The attached file illuminates the problem. -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=105470aid=1152726group_id=5470 ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[ python-Bugs-1152726 ] Default class args get clobbered by prior instances.
Bugs item #1152726, was opened at 2005-02-26 22:10 Message generated for change (Settings changed) made by sdrabble You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=105470aid=1152726group_id=5470 Category: Python Interpreter Core Group: Python 2.3 Status: Open Resolution: None Priority: 8 Submitted By: Simon Drabble (sdrabble) Assigned to: Nobody/Anonymous (nobody) Summary: Default class args get clobbered by prior instances. Initial Comment: OS: SuSE Linux 9.2 kernel 2.6.4 Python: 2.3.3 Define a class where the __init__() method takes a default arg of list type. Instantiate this class, and append/ extend the value of its default arg. Instantiate the class again, and the value from the first instance will overwrite the second. The bug is known to exist in 2.3.3, but may exist in subsequent releases also. The attached file illuminates the problem. -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=105470aid=1152726group_id=5470 ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
