[PyQt] Bug in QAbstractItemModel::createIndex()?

[Andreas Pakulat]

On 06.04.07 12:25:31, Phil Thompson wrote:
> On Friday 06 April 2007 11:43 am, Andreas Pakulat wrote:
> > On 06.04.07 10:44:13, Phil Thompson wrote:
> > > On Friday 06 April 2007 10:10 am, Andreas Pakulat wrote:
> > > > I've put an PyErr_Print(); into the if-part and here's the output (the
> > > > object parsing block is printed when in QtCore the 2nd block with the
> > > > pointer is executed). So as far as I can see the problem is that id()
> > > > returns a long int, but its going to be converted to an int and that
> > > > fails...
> > > >
> > > > emodel>python simpletreemodel.py
> > > > ....
> > > > -------------------------
> > > > OverflowError: long int too large to convert to int
> > > > -------------------------
> > > > Object parsing block
> > > > -------------------------
> > > > OverflowError: long int too large to convert to int
> > > > -------------------------
> > > > Object parsing block
> > > > -------------------------
> > > > OverflowError: long int too large to convert to int
> > > > -------------------------
> > > > Object parsing block
> > >
> > > And I guess if you change the call to PyLong_AsLong() instead of
> > > PyInt_AsLong() then it would call the right overload.
> >
> > Uhm, no. Just changing the PyInt_AsLong to PyLong_AsLong gives new
> > errors. You know I don't really know what I'm doing here, I have no idea
> > how sip itself works or how wrapping C++ code with sip works...
> 
> What new errors?

Uhm, lets see if I find them again without changing sip again :)
Not sure where the first one comes from, but the other three are from
createIndex calls.

-------------------------
SystemError: Objects/longobject.c:211: bad argument to internal function
-------------------------
-------------------------
OverflowError: long int too large to convert to int
-------------------------
Object parsing block
-------------------------
OverflowError: long int too large to convert to int
-------------------------
Object parsing block
-------------------------
OverflowError: long int too large to convert to int
-------------------------
Object parsing block

> > > So the question is...
> > >
> > > Should SIP quietly lose the extra bits, or should it raise an exception.
> >
> > Well, unless I'm mistaken this would still mean that internalId() !=
> > id(object), if id() returns a value that is outside the int-range. So I
> > don't think thats a good solution.
> 
> But it's the "correct" solution as a C++ application would have the same 
> problem.

In C++ there's no id() function that I'm aware of. However yes, if you
calculate an id for the objects in the tree that uses a long instead of
an int or better qint32 then its the same problem in C++.

> > Also if internalPointer works properly I don't think the id-thing is
> > needed. After all with the pointer you don't necessarily need to keep
> > the list around if you create a tree structure with your objects.
> 
> Yes. With hindsight I shouldn't have wrapped the first createIndex() overload 
> and internalId() in the first place, but at the time I wrapped the second 
> overload and internalPointer() as using a void* instead of a Python object 
> which made it unusable.

BTW: Changing eric4's code I again have a segfault, possibly due to some
object not having a reference to it anymore (after changing the code to
use internalPointer only).

Andreas

-- 
Excellent time to become a missing person.