On Dec 30, 2005, at 10:26 AM, Umit Oztosun wrote:
Hello,
Our application uses twisted as the core network framework. It basically consists of a server and multiple clients. All communication is carried on a twisted.spread.pb channel. We have been using twisted 1.3 since the beginning, we decided to switch to twisted 2.1, the switch was easy but an interesting problem showed up.
Our client is based on PyQt, so uses qtreactor. If something goes wrong on the server side, the error is transferred to the client (automagically, thanks to twisted & deferreds), and handled there (with an errback). We warn our users about the failure with a dialog. The interesting part is, with twisted 2.1, at the dialog's exec_loop() call, occasionally the connection between the server and client goes away with the following exception:
For some reason, the stack trace looks truncated, since it starts with defer.py:addCallbacks. But my guess is that read is getting called re-entrantly. By calling exec_loop within a callback, you're causing the reactor to loop within another reactor loop, and the reactor isn't designed to ensure it's safe to do that. Is it possible to change the code to show a dialog box without running a sub-loop? James