Issue 1687163: Inconsistent Exceptions for Readonly Attributes (original) (raw)

Created on 2007-03-23 21:51 by rhettinger, last changed 2022-04-11 14:56 by admin. This issue is now closed.

Messages (6)
msg31640 - (view)	Author: Raymond Hettinger (rhettinger) *	Date: 2007-03-23 21:51
Attempting assignment to a readonly attribute raises an Attribute error for pure Python attributes but raises a TypeError for C readonly attributes. I think the AttributeError is the correct exception. >>> class A(object): ... _x = [] ... ... @property ... def x(self): ... return self._x ... >>> a = A() >>> a.x = None Traceback (most recent call last): a.x = None AttributeError: can't set attribute >>> def f(): ... yield None >>> g = f() >>> g.gi_frame = None Traceback (most recent call last): g.gi_frame = None TypeError: readonly attribute
msg31641 - (view)	Author: Jack Diederich (jackdied) *	Date: 2007-03-23 22:12
I think this has something peculiar to frames, for instance: Python 2.5 (r25:51908, Sep 25 2006, 17:50:07) [GCC 4.0.3 (Ubuntu 4.0.3-1ubuntu5)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> f = 'asdf' >>> f.strip = 42 Traceback (most recent call last): File "", line 1, in AttributeError: 'str' object attribute 'strip' is read-only >>>
msg31642 - (view)	Author: Raymond Hettinger (rhettinger) *	Date: 2007-03-23 22:16
Readonly methods throw an AttributeError, but readonly members (anything defined in PyMemberDef with an RO or READONLY flag) raise a TypeError.
msg31643 - (view)	Author: Raymond Hettinger (rhettinger) *	Date: 2007-03-23 23:52
Here's the one line change: Index: Python/structmember.c =================================================================== --- Python/structmember.c (revision 54557) +++ Python/structmember.c (working copy) @@ -160,7 +160,7 @@ if ((l->flags & READONLY) |	l->type == T_STRING) { - PyErr_SetString(PyExc_TypeError, "readonly attribute"); + PyErr_SetString(PyExc_AttributeError, "readonly attribute"); Four of the tests will need to be updated: test_csv test_descr test_generators test_os
msg31644 - (view)	Author: Raymond Hettinger (rhettinger) *	Date: 2007-03-26 20:18
Collin, would you please apply this to the Py3K code.
msg31645 - (view)	Author: Collin Winter (collinwinter) *	Date: 2007-03-28 21:45
Fixed in r54602.