[Twisted-Python] Unjelly - recursion limit reached

David K. Hess dhess at verscend.com
Fri Nov 11 09:26:03 EST 2005

On Nov 7, 2005, at 8:42 AM, David K. Hess wrote:
> Bottom line, if all of these things are true, then I'm not sure  
> what is going wrong. Is it possible that jelly is at times walking  
> my object graph (which is interconnected to a certain degree and  
> changes dynamically) in such a way that it has to perform a  
> significant amount of recursion? In other words, maybe this isn't a  
> bug but I just need to increase the runtime recursion limit?
> FYI, here's a snippet of the exception:

I hate replying to my own post but I'm beginning to believe that  
recursion is the root of the problem and want to focus on it. From  
the exception trace, it looks like it takes on average 3.5 stack  
frames to unjelly a nested object. With a default recursion limit of  
1000 stack frames, this means that Twisted is limited to transferring  
an object graph that has a depth first traversal through it of length  
285 objects (roughly speaking). You could of course easily create a  
linked list of 285 objects to force the situation.

This is a pretty scary limitation. Is anybody working on a non- 
recursion based version of jelly? Am I going to have to move to  
Stackless Python?



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