cpython/Tools/scripts/find_recursionlimit.py

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#! /usr/bin/env python3
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 ........
2008-09-17 19:25:09 -03:00
"""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,
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 ........
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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.
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 ........
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After each round of tests, it prints a message:
"Limit of NNNN is fine".
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 ........
2008-09-17 19:25:09 -03:00
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
import itertools
class RecursiveBlowup1:
def __init__(self):
self.__init__()
def test_init():
return RecursiveBlowup1()
class RecursiveBlowup2:
def __repr__(self):
return repr(self)
def test_repr():
return repr(RecursiveBlowup2())
class RecursiveBlowup4:
def __add__(self, x):
return x + self
def test_add():
return RecursiveBlowup4() + RecursiveBlowup4()
class RecursiveBlowup5:
def __getattr__(self, attr):
return getattr(self, attr)
def test_getattr():
return RecursiveBlowup5().attr
class RecursiveBlowup6:
def __getitem__(self, item):
return self[item - 2] + self[item - 1]
def test_getitem():
return RecursiveBlowup6()[5]
def test_recurse():
return test_recurse()
def test_cpickle(_cache={}):
import io
try:
import _pickle
except ImportError:
print("cannot import _pickle, skipped!")
return
k, l = None, None
for n in itertools.count():
try:
l = _cache[n]
continue # Already tried and it works, let's save some time
except KeyError:
for i in range(100):
l = [k, l]
k = {i: l}
_pickle.Pickler(io.BytesIO(), protocol=-1).dump(l)
_cache[n] = l
def test_compiler_recursion():
# The compiler uses a scaling factor to support additional levels
# of recursion. This is a sanity check of that scaling to ensure
# it still raises RecursionError even at higher recursion limits
compile("()" * (10 * sys.getrecursionlimit()), "<single>", "single")
def check_limit(n, test_func_name):
sys.setrecursionlimit(n)
if test_func_name.startswith("test_"):
print(test_func_name[5:])
else:
print(test_func_name)
test_func = globals()[test_func_name]
try:
test_func()
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 ........
2008-09-17 19:25:09 -03:00
# 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 (RecursionError, AttributeError):
pass
else:
print("Yikes!")
if __name__ == '__main__':
limit = 1000
while 1:
check_limit(limit, "test_recurse")
check_limit(limit, "test_add")
check_limit(limit, "test_repr")
check_limit(limit, "test_init")
check_limit(limit, "test_getattr")
check_limit(limit, "test_getitem")
check_limit(limit, "test_cpickle")
check_limit(limit, "test_compiler_recursion")
print("Limit of %d is fine" % limit)
limit = limit + 100