[PyQt] Signal Bug in 4.2

Peter Shinners peters at imageworks.com
Tue Jul 24 22:54:50 BST 2007

We have just migrated code from using PyQt-4.2 on Qt-4.2 to using 
PyQt-4.2 on Qt-4.2. This has revealed what looks like a very serious bug 
in the signal handling code for PyQt-4.2.

We have Python "value" objects derived from QObject. These emit a value 
change event to other values and to listening QWidget derived objects. 
After a short (yet non-repeatable) series of actions, the signal 
callbacks will no longer be called. We can confirm that the objects on 
both sides are still valid.

We are not ruling out a problem on our end yet. Again, this works 
without error on 4.1.1, but will always fail with 4.2. The thing that 
makes this tricky is there is no purely repeatable way to trigger the 
problem. But it always happens within a small number of steps.

The layers of code also make this difficult to reduce to a minimal test 
case. I know that would largely help this get tracked down, but I am 
coming here to look for solutions early.

Has anyone else reported similar problems on 4.2? Are there any simple 
tests we could run in the meantime to help narrow this down?

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