[pygtk] Strange crash issue on Windows w/ PyGTK, Cairo...

[dave]

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There's basically three ways we've been able to crash pygtk:

1. TreeModels/TreeViews. These are touchy. Don't do things to them they
are not expecting or they die, and take Python.exe down too.
2. Dialog boxes (this is more of a freeze than a crash). We currently
wait a few seconds after displaying one to touch it, as they run their
own mainloop or something which tends to freeze up if you don't.
3. Psyco, the x86 optimizer. It works great, but randomly will crash
your application under load, which is non-optimal.

Not sure if that helps!

- -dave


CJ Kucera wrote:
> Hello list!
> 
> This is actually basically a repost of a message I sent over to the
> Python list.  I've been suspecting that the problem is somewhere in
> PyGTK or PyCairo, and I received one response over there which echoed
> that sentiment, so here it is here.  Bear with me, this'll probably
> be a long explanation...
> 
> I've been building an app which is meant to be run on both Linux and
> Windows.  It uses PyGTK for its GUI, and the main area of the app is
> a gtk.DrawingArea which I draw on using PyCairo.  I've been developing
> on Linux, and it works great on that platform, with no issues that
> I'm aware of.  When running on Windows, though, the app exhibits the
> following behavior:
> 
>   1) When the .py of the main file which runs the application GUI first
>   gets compiled to a .pyc (ie: the first time it's run, or the first
>   time after .py modification), the application runs totally fine, with
>   no apparent problems.
> 
>   2) Any attempt AFTER that, the application will start up, *start* to
>   do its data-loading, but then almost immediately crash with an
>   enigmatic "python.exe has generated errors and will be closed by
>   Windows."  When it does so, there is no output whatsoever to the
>   console that the application was launched from, and the crash doesn't
>   always happen in exactly the same place.
> 
> The pattern remains the same, though - if the .pyc needs to be compiled,
> the application works fine, but if not: boom.
> 
> I've been steadily stripping the program down to what I hoped would be a
> small, reproducible app that I could post here, and I do intend to do so
> still, but it's rather slow going.  For now, I was hoping to see if
> anyone's ever heard of behavior like this before, and might know what
> to do about it, or at least a possible avenue of attack.
> 
> As I've been reducing the program down, I've encountered even stranger
> (IMO) behavior...  In one instance, changing a function name seemed to
> make the program work.  I took out the handler which draws my app's
> "About" box, and suddenly my problem went away.  Occasionally I would
> remove a function and the app would suddenly *always* fail with that
> Windows crash error, and I'd have to put the function back in.  Keep
> in mind, these are functions which *aren't being called anywhere.*
> 
> Sometimes I could replace a function's entire contents with just "pass"
> and the app would suddenly behave properly, or not behave at all.  More
> recently, I've noticed that I can change the crash behavior just by
> putting occasional "pass" statements in functions.  (ie: one 'pass' may
> have no effect, putting two in may cause the app to always crash, etc).
> 
> It's almost as if whatever's doing the byte-compilation is getting
> screwed up somehow, and really small changes to parts of the file which
> aren't even being touched are having a huge impact on the application as
> a whole.  It's seriously vexing, and certainly the oddest problems I've
> seen in Python.
> 
> Windows versions I can reproduce this on: XP and win2k
> Python versions I've reproduced this on:
>   Python 2.5.4 with:
>     PyGTK 2.12.1-2-win32-py2.5
>     PyGObject 2.14.1-1.win32-py2.5
>     PyCairo 1.4.12-1.win32-py2.5
>   Python 2.6.1 with:
>     PyGTK 2.12.1-3-win32-py2.6 
>     PyGObject 2.14.2-2.win32-py2.6
>     PyCairo 1.4.12-2.win32-py2.6
> GTK versions used:
>   gtk+ 2.12.9-win32-2 from the gladewin32 project
>   gtk+-bundle 2.16.0-20090317_win32, from the other link on pygtk's
>   download page
> 
> The 2.6 Python stuff I've actually only tried on win2k so far, not XP,
> though given my history with this, I suspect that that wouldn't make a
> difference.
> 
> Anyway, I'll continue trying to pare this app down to one manageable
> script which I can post here, but until then I'd be happy to hear ideas
> from anyone else about this.
> 
> Thanks!
> 
> -CJ
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> http://www.daa.com.au/mailman/listinfo/pygtk
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