[pygtk] Help: Problems with threads and pygtk

[David Hirschfield]

I've run into a serious problem using threads with pygtk, and I was 
hoping someone could give me suggestions.

My program is a pygtk interface with a "processor" thread that pulls 
from a safely synchronized queue of "requests" and processes each one.
Seems simple, and it should have been...but it freezes solid when I run 
it. Not a traceback of any kind, the interface and the python 
interpreter freeze.

I've checked all the things that should be obvious problems:

I'm calling:
gobject.threads_init()
gtk.gdk.threads_init()
before gtk.main() is called

There is no race condition or blocking call causing everything to get stuck.
The thread's only interaction with the rest of the program is via the  
Queue.Queue object that keeps the requests to be processed.

I've stepped through with pdb and it freezes in a completely innocuous 
place in the code (during a loop where I append to a list).
The freeze occurs in slightly different places depending on what kind of 
debugging code I put in, changes to the order of things, etc...so it 
feels like it's some kind of corruption in the interpreter stack.

Running the processor thread in a dummy app without the pygtk part never 
freezes up.
Running the pygtk app with a non-threaded processor, which just 
sequentially runs the requests and waits till they complete, never 
freezes up.

I'm at my wit's end here...I know threads are just asking for trouble, 
and usually I avoid them, but circumstances here basically require 
threading (all the request time is spent waiting on different kinds of 
IO). The setup was so simple, I figured I couldn't possibly run into 
trouble...yet here I am.

So, anyone have any idea what could cause the entire python interpreter 
to freeze solid? Are there known issues with pygtk and python threads 
that I should be aware of? Is there some way to verify that the 
interpreter stack is not getting screwed up somehow?

Any help at this point would really be useful,
-Dave

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