ubuntu-phone team mailing list archive

[Roman Shchekin <mrqtros@xxxxxxxxx>]

Hi guys

I can try to find the reeason of crash if you will provide simple example.

BR,
Roman.

2015-04-14 15:38 GMT+03:00 Tim Peeters <tim.peeters@xxxxxxxxxxxxx>:

> Hi Robert,
>
> Like in Python, crashes with QML code are also not common. I wrote the
> code for displaying the sections in the header and it is all QML. From the
> fix you proposed, it appears that selectedIndex (and sort) property is
> undefined some times. Are you using the value of that property somewhere in
> C++?
>
> A simpler test program to reproduce the issue would be very helpful. This
> month I am going to factor out some code from the PageHeadStyle, and create
> a separate component for the sections, so then I can look into this issue
> as well, and perhaps it will make it easier to debug. It is difficult to
> tell where the bug is, but if it appears to come from UITK, can you report
> it as a bug here
> https://bugs.launchpad.net/ubuntu/+source/ubuntu-ui-toolkit so we can
> report future findings about the cause there also?
>
> Thanks,
> Tim.
>
> On Sun, Apr 12, 2015 at 11:13 PM, Robert Schroll <rschroll@xxxxxxxxx>
> wrote:
>
>> Hi all,
>>
>> I've got a Sunday afternoon / evening / night / I-live-in-Asia-you-insensitive-clod
>> puzzler for you.
>>
>> I've been working on the ebook reader Beru, and I've been getting crashes
>> on start about 50% of the time.  I'd been hoping that this was just related
>> to launching from Qt Creator.  But I tried installing it and still got
>> crashes about half the time I launched it.
>>
>> So, I dug out the instructions for running under gdb, got a crash, and
>> discovered the stack had been corrupted.  Poor little Python-loving me
>> didn't even know that this was a thing that could happen!
>>
>> I bisected to find the problem commit, and discovered that it was when I
>> added sections to the first page in my page stack.  Obviously this couldn't
>> be the problem, but I removed the sections just to check.  And the crash
>> went away.
>>
>> Once I saw that, it was obvious that the problem was in my handler for
>> changing the selected section.  So I removed the handler (making the
>> sections affect nothing), and the crash remained!
>>
>> To try to separate the crash from the general hubbub of initialization, I
>> removed the sections from the Page head, and set them procedurally after
>> everything was loaded.  Obviously, this wouldn't make a difference.  But it
>> stopped the crashes.
>>
>> So far, I'm batting 0-for-3 on this one.  So I'd like to hear if any of
>> you have an idea what's going on.  For now, delaying setting the sections
>> is working, but I have a feeling that I'm jut hiding a bug.  I'd like to
>> find and fix it, or at least assure myself that this is a sensible
>> work-around.
>>
>> I haven't managed to come up with a simple test case yet.  A basic
>> page-with-sections test works just fine, so it has something to do with all
>> the other things going on.  Here's the problematic commit [1], the solution
>> commit [2], and a bug report with some more info [3].  You're welcome to
>> reply to the bug if you'd rather not do this over the list.
>>
>> Thanks,
>> Robert
>>
>> [1] https://github.com/rschroll/beru/commit/
>> 9f8a299d0ecc5c6454e0b2b5d8f54a883b4b3328
>> [2] https://github.com/rschroll/beru/commit/
>> 4d521b66e83596ce2a6cb9587e523bae1db0a1d4
>> [3] https://github.com/rschroll/beru/issues/82
>>
>>
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