Re: [Pyode-user] Regression: collision detection broken in HEAD

[Ethan Glasser-C. <gl...@cs...>]

Daniele Varrazzo wrote:
> So, it looks like a structures ownership issue: as the head works, as
> soon as the python object goes, so it does the wrapped C geom, also
> when it is part of other structures (the space). This is a
> counterintuitive behaviour from a Python P.o.V., because "well
> behaved" python object are kept alive when another structure points to
> them (while instead the association space ->geom seems more a weakref
> now). Also the different outcome between my box and yours doesn't seem
> a sign of robustness.

Oh, crap, this is because you're running tutorial3 from the site, which
hasn't been updated in a while. Boy, is my face red. There was a change
a while back that made geoms get deallocated, and I updated tutorial3 in
CVS but not on the site. I'm looking to see if I can do that now.

It's true that the relationship space->geom behaves like a weakref, and
so does the relationship world->body. I don't think there's any
technical reason for this. It looks like at one point someone wanted to
make geoms keep a reference to spaces they were in, but it doesn't look
like that functionality got implemented. I think you're probably right,
that spaces should keep references to their geoms, but not the other way
around. I'll try to make that change this week.

Ethan