[Interest] Widget event called after it has been deleted

[Thiago Macieira]

On quarta-feira, 18 de setembro de 2013 23:54:17, Etienne Sandré-Chardonnal 
wrote:
> Let me explain the problem differently:
>  - widget A emits a signal
>  - widget B has a slot which effectively deletes A (because
> QScrollArea::setWidget deletes its current widget) - I connected A's signal
> to B's slot (and this is meaningful in this GUI, because A has a button
> that tells B to go to the parent, which replaces the A widget for viewing
> current node's properties)
> 
> Just done like that, it crashes. Because after deleting A, B's slot returns
> to A's meta-object signal code. Which is bad.
> 
> Using a QueuedConnection would solve the issue. Because execution of A's
> signal would post an event for calling B's slot, then exit A's signal code,
> return to event loop, and exectute B's slot. Then it's safe to delete A.
> However, I do not like the stability of the program to rely on the type of
> connection. That's not in the essence of modularity with signal/slots.
> 
> Thiago, if you read me, Could you confirm the above's statements?

You're correct.

Deleting the sender is almost always a bad idea.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center
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