Serhiy Storchaka storch...@gmail.com added the comment:
issue15456
efficiently demonstrates that the current style can detect bugs
which testing with object.__sizeof__ can't.
Hmm, I see this as a counterexample. The bug *was not detected* with the
current style of testing.
But if you
Meador Inge added the comment:
On Sat, Jul 28, 2012 at 3:27 AM, Serhiy Storchaka
rep...@bugs.python.org wrote:
Serhiy Storchaka storch...@gmail.com added the comment:
issue15456
efficiently demonstrates that the current style can detect bugs
which testing with object.__sizeof__ can't.
Roundup Robot added the comment:
New changeset 37554bda2014 by Meador Inge in branch '2.7':
Issue #15402: Simplify Struct.__sizeof__ and make tests more precise.
http://hg.python.org/cpython/rev/37554bda2014
New changeset 97dd2090a36c by Meador Inge in branch '3.2':
Issue #15402: Simplify
Changes by Meador Inge mead...@gmail.com:
--
resolution: - fixed
stage: needs patch - committed/rejected
status: open - closed
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Martin v. Löwis mar...@v.loewis.de added the comment:
What if use totalsize = object.__sizeof__(struct_obj) ?
That would defeat the purpose of the test. We want to test whether __sizeof__
is correct, so we shouldn't use __sizeof__ in the test to compute the expected
result. I understand that
Serhiy Storchaka storch...@gmail.com added the comment:
That would defeat the purpose of the test. We want to test whether
__sizeof__ is correct, so we shouldn't use __sizeof__ in the test to
compute the expected result. I understand that object.__sizeof__ is
actually a different
Martin v. Löwis mar...@v.loewis.de added the comment:
I do not think that the purpose of testing is a testing of object.__sizeof__.
Memory consumption consists of two parts -- memory for C structure (and the
base object implementation works for this)
Note that object.__sizeof__ does
Serhiy Storchaka storch...@gmail.com added the comment:
Note that object.__sizeof__ does something slightly different, though:
it uses basicsize (which may or may not contain the sizeof() invocation
of the correct C structure), and it considers tp_itemsize (which may or
may not have a
Martin v. Löwis mar...@v.loewis.de added the comment:
All such cases are bugs (memory manager works with tp_basicsize and
tp_itemsize, not with __sizeof__ result) and tests do not test it. In
paranoidal mode we should tests both __sizeof__ and object.__sizeof__. For
all
classes, even
Mark Dickinson dicki...@gmail.com added the comment:
[Martin]
The patch that Meador committed is incorrect: METH_NOARGS functions
still take a PyObject* args argument, which will be NULL.
Hmm. I see this usage in a lot of places---e.g. see unicode_capitalize,
unicode_casefold, unicode_title
Martin v. Löwis mar...@v.loewis.de added the comment:
I will happily fix it, but if it is wrong one place, then it is wrong
everywhere.
Yes, it is wrong everywhere. METH_NOARGS functions do take an
args argument, see ceval.c:call_function.
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Martin v. Löwis mar...@v.loewis.de added the comment:
Hmm. I see this usage in a lot of places---e.g. see
unicode_capitalize, unicode_casefold, unicode_title etc. in
Objects/unicodeobject.c. So it looks like we're relying on the
(PyCFunction) cast to convert from a one-argument function
Mark Dickinson dicki...@gmail.com added the comment:
The compiler has no chance to find out. You cast the pointer to
PyCFunction, telling the compiler that it really is a PyCFunction.
True; I was thinking that the compiler should have the necessary information to
warn about the suspicious
Stefan Krah stefan-use...@bytereef.org added the comment:
Everywhere is nowhere close to the truth. There are tons of
NOARGS functions which have the correct signature.
When I started writing C-extensions, I used the PyObject *unused
idiom. Then I saw Meador's version in so many places in the
Jesús Cea Avión j...@jcea.es added the comment:
I think that C standard actually documents the parameter order placement, so
you can left out the last ones in the actual function definition.
So, that this is working is not an accident, it is a C standard requirement.
I think...
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Martin v. Löwis mar...@v.loewis.de added the comment:
Jesús: this is a (common) mistake. Standard C makes it undefined behavior to
call a function with an incorrect number of arguments, see 6.5.2.2p9
# If the function is defined with a type that is not compatible with the
# type (of the
Martin v. Löwis mar...@v.loewis.de added the comment:
Stefan: not sure whether raising this to python-dev really helps; see also
msg42177, msg58196, issue1648268, and msg75239. Feel free to raise it, though.
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Meador Inge mead...@gmail.com added the comment:
While looking this up in the C Standard (ISO/IEC 9899:TC3) I also noticed
6.3.2.3p8:
A pointer to a function of one type may be converted to a pointer to a function
of another
type and back again; the result shall compare equal to the original
Jesús Cea Avión j...@jcea.es added the comment:
So the good old int main(void) behaviour is undefined :-)
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Jesús Cea Avión j...@jcea.es added the comment:
Talking about this, anybody has an electronic version of C Standard to share
with me, or should I hunt around the dark corners of Internet? :-)
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Meador Inge mead...@gmail.com added the comment:
On Wed, Jul 25, 2012 at 5:38 PM, Jesús Cea Avión rep...@bugs.python.org wrote:
So the good old int main(void) behaviour is undefined :-)
Actually the C Standard says that is OK. See 5.1.2.2.1 of ISO/IEC 9899:TC3.
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Meador Inge mead...@gmail.com added the comment:
The attached patch fixes: (1) the test cases to make them exact (inspired by
'test_sys.py'), (2) the definition of 's_sizeof' to add the dummy parameter,
and (3) simplifies the sizeof calculation using 's_len'.
--
Added file:
Serhiy Storchaka storch...@gmail.com added the comment:
Talking about this, anybody has an electronic version of C Standard to
share with me, or should I hunt around the dark corners of Internet? :-)
http://www.open-std.org/jtc1/sc22/wg14/www/standards (see n1256.pdf).
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Martin v. Löwis mar...@v.loewis.de added the comment:
So the good old int main(void) behaviour is undefined :-)
No, it's not; see 5.1.2.2.1p1.
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Martin v. Löwis mar...@v.loewis.de added the comment:
issue15402-redux-v1.patch LGTM.
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Serhiy Storchaka storch...@gmail.com added the comment:
+# The size of 'PyStructObject'
+totalsize = size(self.header + '5P')
What if use totalsize = object.__sizeof__(struct_obj) ?
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Python tracker rep...@bugs.python.org
Meador Inge mead...@gmail.com added the comment:
I agree with Martin on having tests for the exact values and the s_len + 1
point. I will fix both issues.
--
assignee: - meador.inge
nosy: -python-dev
stage: patch review - needs patch
___
Python
Meador Inge mead...@gmail.com added the comment:
OK, I will commit this sometime today.
--
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Roundup Robot devn...@psf.upfronthosting.co.za added the comment:
New changeset dbe7f39ff341 by Meador Inge in branch '2.7':
Issue #15402: Add a __sizeof__ method to struct.Struct.
http://hg.python.org/cpython/rev/dbe7f39ff341
New changeset 3e7b517e1b68 by Meador Inge in branch '3.2':
Issue
Meador Inge mead...@gmail.com added the comment:
Thanks for the patch Serhiy!
--
resolution: - fixed
stage: patch review - committed/rejected
status: open - closed
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Jesús Cea Avión j...@jcea.es added the comment:
We collide mid-air, Meador. I was just checking-in this :-). I have changed the
tests to actually verify the changes :-). Also added to Doc/ACKS.txt.
Could I suggest you to take care of issue #15424 too?.
--
resolution: fixed -
stage:
Roundup Robot devn...@psf.upfronthosting.co.za added the comment:
New changeset b1d85a44f149 by Jesus Cea in branch '2.7':
Better test for Issue #15402: Add a __sizeof__ method to struct.Struct
http://hg.python.org/cpython/rev/b1d85a44f149
New changeset 1911e192af0d by Jesus Cea in branch
Meador Inge mead...@gmail.com added the comment:
Hi Jesús,
I replied to python-dev, but the Doc/ACKS.txt changes aren't necessary and I
was OK with the way Serhiy submitted the tests.
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Martin v. Löwis mar...@v.loewis.de added the comment:
The patch that Meador committed is incorrect: METH_NOARGS functions still take
a PyObject* args argument, which will be NULL. I'm puzzled, as Serhiy's
original patch was correct.
As for the tests, I really wish there were tests that tested
Martin v. Löwis mar...@v.loewis.de added the comment:
Also, I wonder why this loops over s_codes, instead of just looking at s_len+1.
--
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Meador Inge mead...@gmail.com added the comment:
On Mon, Jul 23, 2012 at 5:04 PM, Martin v. Löwis rep...@bugs.python.org wrote:
The patch that Meador committed is incorrect: METH_NOARGS functions
still take a PyObject* args argument, which will be NULL. I'm puzzled, as
Serhiy's original
Andrew Svetlov andrew.svet...@gmail.com added the comment:
+1 for patch applying in 3.3 at least
--
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New submission from Serhiy Storchaka storch...@gmail.com:
Here is a patch that implements __sizeof__ for struct.Struct.
See also issue14596.
--
components: Library (Lib)
files: struct_sizeof-2.patch
keywords: patch
messages: 165902
nosy: mark.dickinson, meador.inge, storchaka
priority:
Changes by Jesús Cea Avión j...@jcea.es:
--
nosy: +jcea
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Meador Inge mead...@gmail.com added the comment:
Module a few cosmetic changes (variable names and doc string tweaks), the patch
looks good. Having a correct answer for `sys.getsizeof(struct.Struct('100B'))`
is definitely better. Per the documentation for 'sys.getsizeof' [1]:
All built-in
Jesús Cea Avión j...@jcea.es added the comment:
The patch is easy. I want this in 3.3.
Reluctant to touch 2.7 and 3.2, thought. I would be +0 to it.
--
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Gregory P. Smith g...@krypto.org added the comment:
makes sense for 3.3 as i would consider it a bug.
i think it is reasonable for 2.7 and 3.2 as well, it is an actual bug that the
value reported to getsizeof on struct.Struct is meaningless.
--
nosy: +gregory.p.smith
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