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http://buildbot.python.org/all/builders/x86%20XP-4%203.x/builds/11271/steps/test/logs/stdio
[116/390] test_json
Fatal Python error: Cannot recover from stack overflow.
Current thread 0x00000e84 (most recent call first):
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\json\encoder.py", line 250 in iterencode
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\json\encoder.py", line 192 in encode
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\test\test_json\test_recursion.py", line 96 in test_endless_recursion
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\case.py", line 577 in run
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\case.py", line 625 in __call__
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 125 in run
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 87 in __call__
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 125 in run
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 87 in __call__
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 125 in run
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 87 in __call__
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 125 in run
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 87 in __call__
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 125 in run
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\suite.py", line 87 in __call__
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\unittest\runner.py", line 168 in run
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\test\support\__init__.py", line 1769 in _run_suite
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\lib\test\support\__init__.py", line 1803 in run_unittest
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\PCbuild\..\lib\test\regrtest.py", line 1279 in test_runner
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\PCbuild\..\lib\test\regrtest.py", line 1280 in runtest_inner
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\PCbuild\..\lib\test\regrtest.py", line 967 in runtest
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\PCbuild\..\lib\test\regrtest.py", line 763 in main
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\PCbuild\..\lib\test\regrtest.py", line 1564 in main_in_temp_cwd
 File "d:\cygwin\home\db3l\buildarea3円.x.bolen-windows\build\PCbuild\..\lib\test\regrtest.py", line 1589 in <module>

JSON encoder uses recursion calls guards but they don't save from an overflow of C stack.
How to reproduce:
import json
sys.setrecursionlimit(1000000000)
json.dumps(5j, check_circular=False, default=lambda o: [o])

Here is a patch to use a lower recursion limit to no stress the C stack.

I think this patch will break the purpose of the test. We should fix the issue instead of hide it from tests.

> I think this patch will break the purpose of the test. We should fix the issue instead of hide it from tests.
The test ensures that json calls Py_EnterRecursiveCall() which relies on sys.getrecursionlimit(), see the commit below.
There is no generic fix for C stack overflow. The tes failed on Windows XP which is no more supported, I don't think that it's interesting to spend time on it.
changeset: 70021:9557e4eeb291
branch: 3.1
parent: 69997:b7abf0590e1c
user: Ezio Melotti <ezio.melotti@gmail.com>
date: Wed May 11 01:02:56 2011 +0300
files: Lib/json/tests/test_recursion.py Misc/NEWS Modules/_json.c
description:
#12051: Fix segfault in json.dumps() while encoding highly-nested objects using the C accelerations.

> The tes failed on Windows XP which is no more supported, I don't think that
> it's interesting to spend time on it.
So may be just skip it on Windows XP?
Or as far as this approach doesn't solve the problem and the test may crash on 
other platforms, may be run this test in a subprocess?

The buildbot is broken, it cannot compile anymore. So I just close the issue.