[Python-bugs-list] memory leak in loops (PR#398)

[mal@lemburg.com]

Ingo Adler wrote:
> 
> > > // The Loop
> > >     PyRun_SimpleString(
> > >         "y = Y()\n"
> > >         "for i in range(1000):\n"
> > >         "\tx = y.getX()\n"
> > >         "\tx.getNumber()\n"
> >
> > Could be that SWIG doesn't get a chance to cleanup the shadow
> > object for x and y. Try adding
> >
> > del x,y
> >
> > as final script line.
> >
> > Note that SWIG uses Python strings to represent pointers in
> > C++. It uses an internal table to store these.
> >
> 
> I changed the code to:
> 
>     PyRun_SimpleString(
>         "y = Y()\n"
>         "for i in range(1000):\n"
>         "\tx = y.getX()\n"
>         "\tx.getNumber()\n"
>         "\tdel x\n"
>     );
> 
> It doesn't change anything.
> 
> The memory leak only occurs when I call x.getNumber() in the loop. Otherwise x =
> y.getX() is memory leak free.

Two other possibilities:

1. Python interns the string object used by SWIG to represent
the point. It should then free the memory in the Py_Finalize()
call. If it doesn't, there's a bug to be found ;-)

2. SWIG has the leak. Try using the alternative method of
defining SWIG_COBJECT_TYPES (don't know how this is done --
it seems to be new in SWIG).

-- 
Marc-Andre Lemburg
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