[PyQt] Regression with guiqwt somewhere after PyQt4 4.10

[Dmitry Shachnev]

On Sun, Dec 8, 2013 at 4:14 PM, Phil Thompson
<phil at riverbankcomputing.com> wrote:
> On 2013-12-08 11:44, Dmitry Shachnev wrote:
>>
>> On Wed, Nov 13, 2013 at 3:54 PM, Dmitry Shachnev <mitya57 at ubuntu.com>
>> wrote:
>>>
>>> The crash happens here (src/corelib/kernel/qmetaobject.cpp:525):
>>>
>>>     for (const QMetaObject *m = *baseObject; m; m = m->d.superdata) {
>>>         int i = (MethodType == MethodSignal && priv(m->d.data)->revision
>>> >= 4)
>>>                 ? (priv(m->d.data)->signalCount - 1) :
>>> (priv(m->d.data)->methodCount - 1);
>>>
>>> The problem is that m->d.data is null on the fourth iteration:
>>>
>>> (gdb) p **baseObject
>>> $12 = {d = {superdata = 0x8527d80, stringdata = 0x8712588
>>> "LevelsHistogram", data = 0x8fddb48, extradata = 0x0}}
>>> (gdb) p *(baseObject->d.superdata)
>>> $13 = {d = {superdata = 0x8ec6f00, stringdata = 0x88123b0 "CurvePlot",
>>> data = 0x8e156f8, extradata = 0x0}}
>>> (gdb) p *(baseObject->d.superdata->d.superdata)
>>> $14 = {d = {superdata = 0xb13244e0, stringdata = 0x8ecd1a0 "BasePlot",
>>> data = 0x8ef04e0, extradata = 0x0}}
>>> (gdb) p *(baseObject->d.superdata->d.superdata->d.superdata)
>>> $15 = {d = {superdata = 0xb12bc4ec, stringdata = 0x0, data = 0x0,
>>> extradata = 0xb12bc4cd}}
>>>
>>> A backtrace is attached.
>>>
>>> On Sat, Nov 9, 2013 at 9:47 PM, Scott Kitterman <debian at kitterman.com>
>>> wrote:
>>>>
>>>> Below is a part of an Ubuntu bug report.  You can find a reproduction
>>>> test case
>>>> at
>>>> https://bugs.launchpad.net/ubuntu/+source/python-qt4/+bug/1249571/+attachment/3903922/+files/test_guiqwt.py
>>
>>
>> Hi Phil,
>>
>> I continue getting pings about that. Do you have any thoughts on the
>> issue? Sounds like a problem in PyQt.
>
> Then I need a PyQt test case that demonstrates the problem. I have no idea
> what guiqwt is.

I also never used that, but guiqwt is http://code.google.com/p/guiqwt/.

Yes, it is a rare case of a bug that you need some efforts to reproduce :(

--
Dmitry Shachnev