[Development] Help debugging "impossible condition"

Thiago Macieira thiago.macieira at intel.com
Mon May 14 12:29:20 CEST 2012

On segunda-feira, 14 de maio de 2012 11.46.40, Giuseppe D'Angelo wrote:
> > Actually, I have a better idea: I'll just add an extra pointer to QEvent
> > for the sole reason of letting QGraphicsView use it.
> > 
> > If someone thinks that adding 4 or 8 bytes to EVERY EVENT is a bad idea,
> > please help me come up with a better alternative.
> A private QEvent subclass carrying that pointer, to be used by QGV?

That occurred to me, but I am not able to implement that safely.

The event seems to be generated by QGraphicsView, then handled in the viewport 
event and then passed to QGraphicsScene. But the user might install a subclass 
of QGraphicsScene in the view and might inject other events, which would be of 
the wrong type and cause a crash.

I cannot guarantee that I wouldn't be breaking anything.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center
     Intel Sweden AB - Registration Number: 556189-6027
     Knarrarnäsgatan 15, 164 40 Kista, Stockholm, Sweden
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