From 5478b47355724de2ad891eea469fd8a1e674dccd Mon Sep 17 00:00:00 2001 From: Benjamin Peterson Date: Wed, 17 Sep 2008 22:25:09 +0000 Subject: Merged revisions 66457-66459,66465-66468,66483-66485,66487-66491 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r66457 | antoine.pitrou | 2008-09-13 15:30:30 -0500 (Sat, 13 Sep 2008) | 5 lines Issue #3850: Misc/find_recursionlimit.py was broken. Reviewed by A.M. Kuchling. ........ r66458 | benjamin.peterson | 2008-09-13 17:54:43 -0500 (Sat, 13 Sep 2008) | 1 line fix a name issue; note all doc files should be encoded in utf8 ........ r66459 | benjamin.peterson | 2008-09-14 11:02:22 -0500 (Sun, 14 Sep 2008) | 1 line clarify that radix for int is not 'guessed' ........ r66465 | skip.montanaro | 2008-09-14 21:03:05 -0500 (Sun, 14 Sep 2008) | 3 lines Review usage. Fix a mistake in the new-style class definition. Add a couple new definitions (CPython and virtual machine). ........ r66466 | skip.montanaro | 2008-09-14 21:19:53 -0500 (Sun, 14 Sep 2008) | 2 lines Pick up a few more definitions from the glossary on the wiki. ........ r66467 | benjamin.peterson | 2008-09-14 21:53:23 -0500 (Sun, 14 Sep 2008) | 1 line mention that object.__init__ no longer takes arbitrary args and kwargs ........ r66468 | andrew.kuchling | 2008-09-15 08:08:32 -0500 (Mon, 15 Sep 2008) | 1 line Rewrite item a bit ........ r66483 | georg.brandl | 2008-09-16 05:17:45 -0500 (Tue, 16 Sep 2008) | 2 lines Fix typo. ........ r66484 | benjamin.peterson | 2008-09-16 16:20:28 -0500 (Tue, 16 Sep 2008) | 2 lines be less wordy ........ r66485 | georg.brandl | 2008-09-17 03:45:54 -0500 (Wed, 17 Sep 2008) | 2 lines #3888: add some deprecated modules in whatsnew. ........ r66487 | skip.montanaro | 2008-09-17 06:50:36 -0500 (Wed, 17 Sep 2008) | 2 lines usage ........ r66488 | andrew.kuchling | 2008-09-17 07:57:04 -0500 (Wed, 17 Sep 2008) | 1 line Markup fixes ........ r66489 | andrew.kuchling | 2008-09-17 07:58:22 -0500 (Wed, 17 Sep 2008) | 2 lines Remove comment about improvement: pystone is about the same, and the improvements seem to be difficult to quantify ........ r66490 | andrew.kuchling | 2008-09-17 08:04:53 -0500 (Wed, 17 Sep 2008) | 1 line Note sqlite3 version; move item ........ r66491 | benjamin.peterson | 2008-09-17 16:54:56 -0500 (Wed, 17 Sep 2008) | 1 line document compileall command flags ........ --- Misc/find_recursionlimit.py | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) (limited to 'Misc/find_recursionlimit.py') diff --git a/Misc/find_recursionlimit.py b/Misc/find_recursionlimit.py index 295e0940ea..2e202bec64 100644 --- a/Misc/find_recursionlimit.py +++ b/Misc/find_recursionlimit.py @@ -1,22 +1,32 @@ #! /usr/bin/env python -"""Find the maximum recursion limit that prevents core dumps +"""Find the maximum recursion limit that prevents interpreter termination. This script finds the maximum safe recursion limit on a particular platform. If you need to change the recursion limit on your system, this script will tell you a safe upper bound. To use the new limit, -call sys.setrecursionlimit. +call sys.setrecursionlimit(). This module implements several ways to create infinite recursion in Python. Different implementations end up pushing different numbers of C stack frames, depending on how many calls through Python's abstract C API occur. -After each round of tests, it prints a message -Limit of NNNN is fine. +After each round of tests, it prints a message: +"Limit of NNNN is fine". -It ends when Python causes a segmentation fault because the limit is -too high. On platforms like Mac and Windows, it should exit with a -MemoryError. +The highest printed value of "NNNN" is therefore the highest potentially +safe limit for your system (which depends on the OS, architecture, but also +the compilation flags). Please note that it is practically impossible to +test all possible recursion paths in the interpreter, so the results of +this test should not be trusted blindly -- although they give a good hint +of which values are reasonable. + +NOTE: When the C stack space allocated by your system is exceeded due +to excessive recursion, exact behaviour depends on the platform, although +the interpreter will always fail in a likely brutal way: either a +segmentation fault, a MemoryError, or just a silent abort. + +NB: A program that does not use __methods__ can set a higher limit. """ import sys @@ -87,7 +97,10 @@ def check_limit(n, test_func_name): test_func = globals()[test_func_name] try: test_func() - except RuntimeError: + # AttributeError can be raised because of the way e.g. PyDict_GetItem() + # silences all exceptions and returns NULL, which is usually interpreted + # as "missing attribute". + except (RuntimeError, AttributeError): pass else: print("Yikes!") -- cgit v1.2.1