[issue18047] Descriptors get invoked in old-style objects and classes
Raymond Hettinger added the comment: We document what we're willing to guarantee. The exposure of descriptors in old-style classes was an incidental implementation detail. Sorry, I'm going to close this one. Besides, it's time to start forgetting Python 2 and move along :-) -- resolution: - rejected status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue18047 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue18047] Descriptors get invoked in old-style objects and classes
Arnaud Porterie added the comment: Sorry if I am missing something, but it seems that the documentation doesn't match the behavior: the doc says that descriptors are invoked only for new styles objects and classes, while the attached code seems to prove the contrary. If my understanding is correct, either the doc or the code should be changed accordingly. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue18047 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue18047] Descriptors get invoked in old-style objects and classes
Raymond Hettinger added the comment: IMO nothing should change here (either the docs or the implementation). The OP has observed an implementation detail of old-style classes (which were reimplemented in Python 2.2 using descriptor logic instead of their former hard-wired behaviors). -- nosy: +rhettinger ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue18047 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue18047] Descriptors get invoked in old-style objects and classes
Changes by Ezio Melotti ezio.melo...@gmail.com: -- nosy: +ezio.melotti stage: - needs patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue18047 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue18047] Descriptors get invoked in old-style objects and classes
Changes by Phil Connell pconn...@gmail.com: -- nosy: +pconnell ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue18047 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue18047] Descriptors get invoked in old-style objects and classes
Changes by Éric Araujo mer...@netwok.org: -- nosy: +eric.araujo ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue18047 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue18047] Descriptors get invoked in old-style objects and classes
New submission from Arnaud Porterie: In the Data Model section of the documentation regarding descriptors invokations (http://docs.python.org/2/reference/datamodel.html#invoking-descriptors), it is said: Note that descriptors are only invoked for new style objects or classes (ones that subclass object() or type()). However, it seems this restriction isn't enforced in practice: Python 2.7.4 (default, May 16 2013, 13:28:03) [GCC 4.2.1 Compatible Apple Clang 4.0 ((tags/Apple/clang-421.0.60))] on darwin Type help, copyright, credits or license for more information. class Desc(object): ... def __get__(self, obj, cls): ... return 'test' ... class A: # Not inheriting object here ... desc = Desc() ... A().desc 'test' I dived into CPython's code and saw no trace of a test for new-style classes in the descriptor invokation code path (down in classobject.c / instance_getattr2). Unfortunately, fixing this behavior doesn't seem trivial as class methods appear to be implemented as descriptor themselves. In other words, and from my understanding, restricting descriptor invokation to new-style objects and classes would prevent method calls on old-style classes. -- components: Interpreter Core files: desc.py messages: 189896 nosy: icecrime priority: normal severity: normal status: open title: Descriptors get invoked in old-style objects and classes type: behavior versions: Python 2.7 Added file: http://bugs.python.org/file30356/desc.py ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue18047 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
