[PyQt] Slots being called on deleted QObjects

Jeremy Sanders jeremy at jeremysanders.net
Sun Apr 6 16:08:43 BST 2014

I'm still getting numerous bug reports from users where slots are called on 
deleted QObjects, giving a crash. As I previously reported, changing these 
to new style signals and using "@pyqtSlot" on the slot appears to prevent 
these bugs, but it's very hard to find every case.

Looking through the source code of sip (siplib/qtlib.c), it says:
         * We used to check that any wrapped C++ object still existed and 
         * returning None if it didn't.  This caused inconsistent behaviour
         * when the slot was a method connected to its object's destroyed()
         * signal.

I assume this is the code used to call slots on QObjects? Is this the reason 
why I started getting these problems a year or two ago?

If this is the problem, is it possible to make the code more intelligent and 
check if the C++ object is there as long as the signal isn't destroyed()?



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