[issue1878] class attribute cache failure (regression)
Changes by Jesús Cea Avión [EMAIL PROTECTED]: -- nosy: +jcea ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Guido van Rossum [EMAIL PROTECTED] added the comment: I like Armin's latest proposal: have Py_TPFLAGS_DEFAULT include Py_TPFLAGS_HAVE_VERSION_TAG when compiling the core only. ISTR there's a way to do this, but I can't find it right now. ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Guido van Rossum [EMAIL PROTECTED] added the comment: Please review the patch here: http://codereview.appspot.com/3005 ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Guido van Rossum [EMAIL PROTECTED] added the comment: Submitted as r65874. I will block this for 3.0; 3.0 extensions that want to mess with tp_dict must explicitly disable this flag. -- resolution: - fixed status: open - closed ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Benjamin Peterson [EMAIL PROTECTED] added the comment: Do we want a test? ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Guido van Rossum [EMAIL PROTECTED] added the comment: Sure, go right ahead. ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Raymond Hettinger [EMAIL PROTECTED] added the comment: Guido, what say you, live with it, revert it, or apply Py_TPFLAGS_HAVE_VERSION_TAG to all core types? -- assignee: arigo - gvanrossum nosy: +gvanrossum, rhettinger ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Armin Rigo [EMAIL PROTECTED] added the comment:
Maybe there is a better solution along the following line: conditionally
define Py_TPFLAGS_DEFAULT so that when compiling the Python core it
includes the Py_TPFLAGS_HAVE_VERSION_TAG, but when compiling extension
modules it does not. This should ensure compatibility with many
existing extension modules. (It would still break if they play tricks
like modifying the tp_dict of types other than their own.)
In addition, to support the method cache in newer C extension modules:
* C types defined by C extension modules can include the
Py_TPFLAGS_HAVE_VERSION_TAG explicitly to enable the cache;
* new C API functions should be introduced to give an official way to
access the tp_dict of a type, e.g. PyType_{Get,Set,Del}DictItemString().
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[issue1878] class attribute cache failure (regression)
Benjamin Peterson [EMAIL PROTECTED] added the comment: Ping -- nosy: +benjamin.peterson priority: critical - release blocker ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Armin Rigo added the comment: I don't see in general how the patch can be kept compatible with extension modules that change the tp_dict of arbitrary types. All I can think of is a way to be safe against extension modules that only change the tp_dict of their own non-heap types (i.e. types defined in C). The method cache is disabled for types that don't have the Py_TPFLAGS_HAVE_VERSION_TAG flag; so if we would leave this flag out of Py_TPFLAGS_DEFAULT, non-heap types from extension modules would by default not use the cache. I'm not sure about the API for this. Would we then need to put Py_TPFLAGS_HAVE_VERSION_TAG explicitly on all core types? And about how to change tp_dict in a way that makes the cache happy - do we need to turn type_modified() into a public API? All in all, the lack of abstraction of the C API might kill the idea of this patch for CPython. __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Changes by Georg Brandl: -- priority: - urgent __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Georg Brandl added the comment: We can of course add something like in #1229239, which allows type attributes to be set with PyObject_SetAttr, thereby updating the cache. __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Paul Pogonyshev added the comment: I personally think that this bug is a showstopper for the caching patch in 2.6. Well, the problem can be deemed insignificant, but it is sure a break of backward compatibility and, worse yet, it results in _very_ obscure fails. Even if type dictionary changes are not all that common, I'm sure there are extensions out there that do it. For Py3k things can be different. I'm not sure what would be the best way, but at least Py3k is not required to be compatible with 2.x in all aspects. __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
New submission from Paul Pogonyshev: I have a regression from Python 2.5 to Python SVN (would-be-2.6). I believe this because of class attribute caching. The problem shown below happens because AbstractGCProtector is an extension class. So, Python interpreter doesn't have a chance to notice set_default() method below changes a class attribute. from notify.all import * original_protector = AbstractGCProtector.default new_protector = FastGCProtector () AbstractGCProtector.default is new_protector False AbstractGCProtector.default is original_protector True Please note that this a regression. This code works as expected in 2.3 and 2.5. -- components: Interpreter Core messages: 61316 nosy: _doublep severity: major status: open title: class attribute cache failure (regression) type: behavior versions: Python 2.6 __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Paul Pogonyshev added the comment: Eh, disregard that, I missed one line with set_default() call. Still, the unit test fails... __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Paul Pogonyshev added the comment: OK, here it is: from notify.all import * original_protector = AbstractGCProtector.default new_protector = FastGCProtector () AbstractGCProtector.set_default (new_protector) AbstractGCProtector.default is new_protector False AbstractGCProtector.default is original_protector True It seems that this behaviour is somewhat random. Sometimes the False/True lines are reversed, as expected. I.e. it seems that attribute cache is sometimes recomputed... __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Paul Pogonyshev added the comment: set_default() is a static method to set 'default'. Because of this: AbstractGCProtector.default = 42 Traceback (most recent call last): File stdin, line 1, in module TypeError: can't set attributes of built-in/extension type 'notify.gc.AbstractGCProtector' About source code: go to http://download.gna.org/py-notify/ download, unpack and do './run-tests.py' at top level. One test fails with Python SVN precisely because of this problem. __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Georg Brandl added the comment: It would be very interesting to know what set_default() actually does. IOW, without the source code of the extension module we can't do anything about this. -- nosy: +georg.brandl __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Georg Brandl added the comment: I'm sorry, but I can't get this to run. With a clean 0.1.14 tarball, I get Building extension... running build_ext building 'notify.gc' extension creating build creating build/temp.linux-i686-2.5 creating build/temp.linux-i686-2.5/notify i686-pc-linux-gnu-gcc -pthread -fno-strict-aliasing -DNDEBUG -fPIC -I/usr/include/python2.5 -c notify/gc.c -o build/temp.linux-i686-2.5/notify/gc.o creating build/lib.linux-i686-2.5 creating build/lib.linux-i686-2.5/notify i686-pc-linux-gnu-gcc -pthread -shared build/temp.linux-i686-2.5/notify/gc.o -L/usr/lib -lpython2.5 -o build/lib.linux-i686-2.5/notify/gc.so [1]28189 segmentation fault ~/devel/python/python run-tests.py when running with a trunk python (note the 2.5 in the paths...) When I build the extension manually and comment out the building command in run-tests.py, I get Note that most of the time is spent in gc.collect() calls, not in this package ..Fatal Python error: Objects/classobject.c:2311 object at 0x82dd2bc has negative ref count -606348326 [1]28540 abort ~/devel/python/python run-tests.py __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Paul Pogonyshev added the comment: Weird. Does it even run with a stable Python (not trunk)? __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Paul Pogonyshev added the comment: Can you run the pasted script (from the third comment) manually then? The crash might be related to the bug in question. __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Georg Brandl added the comment: Yes, runs fine with 2.5. __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Georg Brandl added the comment: I've now built my trunk python without debugging enabled, and can reproduce your problem. Armin: the extension module directly modifies an extension type's tp_dict -- what should it do instead to make the cache happy? -- assignee: - arigo nosy: +arigo __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Paul Pogonyshev added the comment: Even if there is an easy workaround for the extension (or even a fix, if modifying 'tp_dict' is not legal), I don't think it would be acceptable to make a backward-incompatible change in 2.6. I mean, sure Py-notify is by no means a widely-used library, but can you guarantee that no other extension will get broken? __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Amaury Forgeot d'Arc added the comment: The issue seems similar to the one we had in ctypes when the method attribute cache was implemented. Ctypes was corrected in r59943. Maybe similar changes are needed for this extension. For example, PyDict_SetItemString (AbstractGCProtector_Type.tp_dict, default, new_protector) should be modified like this: PyObject_SetAttr(AbstractGCProtector_Type, default, new_protector) -- nosy: +amaury.forgeotdarc __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1878] class attribute cache failure (regression)
Paul Pogonyshev added the comment: It doesn't help: ERROR: test_default_property (test._gc.AbstractGCProtectorTestCase) -- Traceback (most recent call last): File /home/paul/notify/test/_gc.py, line 59, in test_default_property AbstractGCProtector.set_default (original_protector) TypeError: can't set attributes of built-in/extension type 'notify.gc.AbstractGCProtector' With this code: if (PyObject_SetAttrString ((PyObject *) AbstractGCProtector_Type, default, new_protector) == -1) return NULL; __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue1878 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
