[PyQt] Re: Crash with shortcircuit signals

Giovanni Bajo rasky at develer.com
Tue Jul 17 14:34:02 BST 2007

On 7/16/2007 2:36 PM, Phil Thompson wrote:

> This will be fixed in tonight's PyQt snapshot.
> The proxy created to handle the signal was being incorrectly reused by a new 
> QObject created at the same address as the one the proxy was created for. 
> Because there is no event processing going on, the proxy was not getting 
> deleted - because it was waiting for a deleteLater() to be acted on.

I now get other crashes: from the debug, it seems like an instance of 
PyQtProxy which is already deleted is still part of the global list 
(uniproxies). Using debug builds of MS CRT, C++ instances which are 
deleted are filled with 0xFEFEFEFE, so I'm pretty sure of this symptom.

I had a look at your fix, and you moved the code to remove the PyQtProxy 
instance from the global list to the new disable() slot. Thus, if an 
instance of PyQtProxy is deleted directly without going through the 
slot, it will still be presente in the global list.

I copied the list removal code back into the destructor (keeping a duped 
copy in the disable() slot), and it seems to work.

Do you agree on this fix? Testcases are really hard and tiresome to 
extract so I'd rather avoid it if it's not really really necessary...
Giovanni Bajo

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