On 16 July 2015 at 21:58, Steven D'Aprano <st...@pearwood.info> wrote: > On Fri, 17 Jul 2015 03:34 am, Joonas Liik wrote: > >> Now i admit that it is possible to have infinite recursion but it is >> also possiblew to have infinite loops. and we don't kill your code >> after 1000 iterations of a while loop so why should we treat recursion >> any differently? > > Because a while loop which repeats to many times is annoying but harmless, > but a function that recurses too many times will blow up the stack and > cause a seg fault, possibly executing arbitrary memory as code. You want > malware and viruses to take over your system? That's how you get malware > and viruses to take over your system.
That's just a buggy implementation, there are ways to extend the stack that nears its capacity, safely. > >> Having a user defined maximum stack limit might be a good idea, eg if >> my stack takes up 100MB its prolly broke, but it should be my duty as >> a programmer to specify such a limit, not have it inflicted upon me >> (worse, in a manner that cannot be changed!). > > You mean sys.getrecursionlimit() and sys.setrecursionlimit()? > ... and that buggy implementation means that when you sys.setrecursionlimit() you will overflow the stack and crash because the recursion limit is an aritificial safeguard and the underlying c buffer is not adjusted accordingly or at least so it would seem. https://docs.python.org/2/library/sys.html#sys.setrecursionlimit so as per the docs the programmer has no real control over how much stack his program can have. all you can say is "let me ignore the safeguard a little longer, i hope i wont crash the program" that is not the same as "can i please have a stack depth of 20000.. You are giving the programmer a choice between "run out of stack and crash" and "mutilate interpreter internals and crash or zero out the hard drive" this is not a real choice.. -- https://mail.python.org/mailman/listinfo/python-list
