[Python-Dev] Preventing recursion core dumps (original) (raw)

Vladimir Marangozov Vladimir.Marangozov@inrialpes.fr
Fri, 11 Aug 2000 03:59:30 +0200 (CEST)

I'm looking at preventing core dumps due to recursive calls. With simple nested call counters for every function in object.c, limited to 500 levels deep recursions, I think this works okay for repr, str and print. It solves most of the complaints, like:

class Crasher: def str(self): print self

print Crasher()

With such protection, instead of a core dump, we'll get an exception:

RuntimeError: Recursion too deep

So far, so good. 500 nested calls to repr, str or print are likely to be programming bugs. Now I wonder whether it's a good idea to do the same thing for getattr and setattr, to avoid crashes like:

class Crasher: def getattr(self, x): return self.x

Crasher().bonk

Solving this the same way is likely to slow things down a bit, but would prevent the crash. OTOH, in a complex object hierarchy with tons of delegation and/or lookup dispatching, 500 nested calls is probably not enough. Or am I wondering too much? Opinions?

-- Vladimir MARANGOZOV | Vladimir.Marangozov@inrialpes.fr http://sirac.inrialpes.fr/~marangoz | tel:(+33-4)76615277 fax:76615252