Re: [Pyode-user] memory leaks

[Matthias B. <ba...@ir...>]

Chris Bainbridge wrote:
> Hi, the following code appears to leak Body and dict objects. Memprof
> [...]
> I've looked at the pyode code. It appears that nothing is ever removed
> from the global dictionary _geom_c2py_lut. Should this be done in geom
> __dealloc__ ?

The _geom_c2py_lut is a dictionary that serves as a lookup table to 
convert the geom pointer received from ODE into the appropriate Python 
geom object (which has to be done during collisions).
So when a geom is created it adds itself to the dictionary and indeed, 
it is never removed from there.
The geom cannot remove itself in __dealloc__() because as long as 
there's a reference in the dictionary it is not destroyed and 
__dealloc__() is never called. The solution would be weak references but 
at the time I wrote the stuff Pyrex didn't support this. I contacted the 
author, but I believe the current version of Pyrex still doesn't support 
it (I haven't checked explicitly but at least I never noticed anything 
in the changelogs).

As you said in your other mail, the workaround is to clear the 
dictionary manually when you're creating a new simulation scene.

> Similarly should geomobject __dealloc__ do 'del self.body'? 

Doesn't Python do that itself? Hm, but on the other hand, it's declared 
using "cdef", so you'r probably right and we should manually delete it 
in __dealloc__...
Then it would be the same for self.space in the Geoms and for self.world 
in the Body and the Joints.

- Matthias -