More about the subject of circular references:...
http://www.jython.org/archive/21/docs/differences.html
"In Jython users don't need to worry about handling circular
references as these are guaranteed to be collected properly"
CPython uses reference counting instead of proper garbage collection
and suffers from this problem.
On Jan 7, 8:09 pm, Massimo Di Pierro <massimo.dipie...@gmail.com>
wrote:
> Actually this works for all classes but classes that have a __del__
> (and this is not a web2py specific problem) so for now:
>
> Attention: do not define classes with a __del__ method in models or
> controllers.
>
> Even if you do not use web2py but use another framework, do not create
> classes with __del__ methods if they may have self references, whether
> or not you use exec.
>
> Here is an example of a python program without exec that has the leak
> we are talking about:
>
> class Foo(object):
> def __del__(self):
> pass
> while True:
> foo = Foo()
> foo.x = foo
>
> On Jan 7, 6:56 pm, Massimo Di Pierro <massimo.dipie...@gmail.com>
> wrote:
>
>
>
>
>
>
>
> > Mitsuhiko on reddit brings up a good issue that I was not aware of: a
> > bug in exec.
>
> > code="""
> > class Foo(object):
> > def __del__(self):
> > pass
> > foo = Foo()
> > """
> > while True: exec code in {}
>
> > causes a memory leak. Web2py does this. The memory leak is small in
> > practice and in fact nobody noticed it. Yet it is a concern, in
> > theory.
>
> > So far I have the current solution
>
> > code="""
> > class Foo(object):
> > def __del__(self):
> > pass
> > foo = Foo()
> > """
> > import gc
> > while True:
> > exec code in {}
> > gc.collect()
>
> > It works for me and I cannot reproduce the leak.
> > I patched trunk with this. Give it a try and let me know what you
> > think.
>
> > Massimo
