bpo-46542: test_lib2to3 uses support.infinite_recursion() by vstinner · Pull Request #31035 · python/cpython · GitHub

Fix a Python crash in test_lib2to3 when using Python built in debug
mode: limit the recursion limit.

The test_all_project_files() test of test_lib2to3 now uses the
test.support.infinite_recursion() context manager when processing the
infinite_recursion.py file to prevent a crash when Python is built in
debug mode.

The two test_all_project_files() tests now use subTest() and log the
refactored/parsed filename (if test_lib2to3 is run in verbose mode).

https://bugs.python.org/issue46542

Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. The test_all_project_files() test of test_lib2to3 now uses the test.support.infinite_recursion() context manager when processing the infinite_recursion.py file to prevent a crash when Python is built in debug mode. The two test_all_project_files() tests now use subTest() and log the refactored/parsed filename (if test_lib2to3 is run in verbose mode).

cc @pablogsal @ambv @markshannon

I built Python in debug mode with clang:

$ ./configure --with-pydebug CC=clang
$ grep -- -O Makefile
OPT=		-g -O0 -Wall
$ make

clang uses -O0. Stack usage:

$ ./python
Python 3.11.0a4+ (heads/lib2to3_infinite:01e926a388, Jan 31 2022, 17:21:47) [Clang 13.0.0 (Fedora 13.0.0-3.fc35)] on linux
>>> import _testcapi
>>> def f(): yield _testcapi.stack_pointer()
... 
>>> _testcapi.stack_pointer() - next(f())
9104

Without this change (current main branch, at commit 7685693), test_lib2to3 does crash :-(

$ ./python -m test -u all test_lib2to3 -v
(...)
test_all_project_files (lib2to3.tests.test_all_fixers.Test_all) ... 
Fatal Python error: Segmentation fault

Current thread 0x00007f455c394740 (most recent call first):
  File "/home/vstinner/python/main/Lib/lib2to3/pytree.py", line 845 in generate_matches
  File "/home/vstinner/python/main/Lib/lib2to3/pytree.py", line 785 in _recursive_matches
  File "/home/vstinner/python/main/Lib/lib2to3/pytree.py", line 786 in _recursive_matches
(...)

With this PR, it no longer crash:

$ ./python -m test -u all test_lib2to3 -v
(...)
Tests result: SUCCESS

Lib/lib2to3/tests/test_all_fixers.py: if the recursion limit is too low, self.refactor.refactor_file(filepath) raises RecursionError. If it's too high, Python does crash. I chose an absolute limite of 150 which is a compromise.

By the way, test.support.infinite_recursion() could be enhanced to use _testinternalcapi.get_recursion_depth() to implement a relative limit, raher than an absolute limit, but that's a different issue ;-) The problem is that the function parameter is an absolute limit.

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Thanks @vstinner for the PR, and @ambv for merging it 🌮🎉.. I'm working now to backport this PR to: 3.9, 3.10.
🐍🍒⛏🤖

…1035) * bpo-46542: test_lib2to3 uses support.infinite_recursion() Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. The test_all_project_files() test of test_lib2to3 now uses the test.support.infinite_recursion() context manager when processing the infinite_recursion.py file to prevent a crash when Python is built in debug mode. The two test_all_project_files() tests now use subTest() and log the refactored/parsed filename (if test_lib2to3 is run in verbose mode). * Update Lib/lib2to3/tests/data/infinite_recursion.py Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> Co-authored-by: Łukasz Langa <lukasz@langa.pl> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> (cherry picked from commit ee0ac32) Co-authored-by: Victor Stinner <vstinner@python.org>

GH-31036 is a backport of this pull request to the 3.10 branch.

…1035) * bpo-46542: test_lib2to3 uses support.infinite_recursion() Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. The test_all_project_files() test of test_lib2to3 now uses the test.support.infinite_recursion() context manager when processing the infinite_recursion.py file to prevent a crash when Python is built in debug mode. The two test_all_project_files() tests now use subTest() and log the refactored/parsed filename (if test_lib2to3 is run in verbose mode). * Update Lib/lib2to3/tests/data/infinite_recursion.py Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> Co-authored-by: Łukasz Langa <lukasz@langa.pl> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> (cherry picked from commit ee0ac32) Co-authored-by: Victor Stinner <vstinner@python.org>

GH-31037 is a backport of this pull request to the 3.9 branch.

* bpo-46542: test_lib2to3 uses support.infinite_recursion() Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. The test_all_project_files() test of test_lib2to3 now uses the test.support.infinite_recursion() context manager when processing the infinite_recursion.py file to prevent a crash when Python is built in debug mode. The two test_all_project_files() tests now use subTest() and log the refactored/parsed filename (if test_lib2to3 is run in verbose mode). * Update Lib/lib2to3/tests/data/infinite_recursion.py Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> Co-authored-by: Łukasz Langa <lukasz@langa.pl> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> (cherry picked from commit ee0ac32) Co-authored-by: Victor Stinner <vstinner@python.org>

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 FreeBSD Shared 3.9 has failed when building commit 3046386.

What do you need to do:

Don't panic.
Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/151/builds/439) and take a look at the build logs.
Check if the failure is related to this commit (3046386) or if it is a false positive.
If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/151/builds/439

Failed tests:

test_smtpnet
test_unicodedata

Failed subtests:

test_connect - test.test_smtpnet.SmtpSSLTest
test_connect_default_port - test.test_smtpnet.SmtpSSLTest
test_normalization - test.test_unicodedata.NormalizationTest

Summary of the results of the build (if available):

== Tests result: FAILURE then FAILURE ==

405 tests OK.

10 slowest tests:

test_codecmaps_jp: 9 min 16 sec
test_tokenize: 8 min 26 sec
test_multiprocessing_spawn: 7 min 41 sec
test_unparse: 6 min 23 sec
test_codecmaps_cn: 6 min 3 sec
test_concurrent_futures: 5 min 2 sec
test_multiprocessing_forkserver: 4 min 28 sec
test_unicodedata: 4 min 17 sec
test_httplib: 4 min 16 sec
test_gdb: 4 min 13 sec

2 tests failed:
test_smtpnet test_unicodedata

18 tests skipped:
test_dbm_gnu test_devpoll test_epoll test_idle test_ioctl
test_msilib test_spwd test_startfile test_tcl test_tix test_tk
test_ttk_guionly test_ttk_textonly test_turtle test_winconsoleio
test_winreg test_winsound test_zipfile64

2 re-run tests:
test_smtpnet test_unicodedata

Total duration: 44 min 42 sec

Click to see traceback logs

Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/test/test_unicodedata.py", line 330, in test_normalization
    testdata = open_urlresource(TESTDATAURL, encoding="utf-8",
http.client.IncompleteRead: IncompleteRead(0 bytes read)


Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/urllib/request.py", line 1346, in do_open
    h.request(req.get_method(), req.selector, req.data, headers,
socket.gaierror: [Errno 8] Name does not resolve


Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/test/test_unicodedata.py", line 336, in test_normalization
    self.fail(f"Could not retrieve {TESTDATAURL}")
AssertionError: Could not retrieve http://www.pythontest.net/unicode/13.0.0/NormalizationTest.txt


Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/test/test_smtpnet.py", line 59, in test_connect_default_port
    server = smtplib.SMTP_SSL(self.testServer)
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/smtplib.py", line 1050, in __init__
    SMTP.__init__(self, host, port, local_hostname, timeout,
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/smtplib.py", line 255, in __init__
    (code, msg) = self.connect(host, port)
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/smtplib.py", line 343, in connect
    (code, msg) = self.getreply()
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/smtplib.py", line 405, in getreply
    raise SMTPServerDisconnected("Connection unexpectedly closed")
smtplib.SMTPServerDisconnected: Connection unexpectedly closed


Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/http/client.py", line 597, in _readinto_chunked
    n = self._safe_readinto(mvb)
http.client.IncompleteRead: IncompleteRead(296 bytes read, 1795 more expected)


Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/test/test_unicodedata.py", line 330, in test_normalization
    testdata = open_urlresource(TESTDATAURL, encoding="utf-8",
urllib.error.URLError: <urlopen error [Errno 8] Name does not resolve>


Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/test/test_smtpnet.py", line 52, in test_connect
    server = smtplib.SMTP_SSL(self.testServer, self.remotePort)
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/smtplib.py", line 1050, in __init__
    SMTP.__init__(self, host, port, local_hostname, timeout,
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/smtplib.py", line 255, in __init__
    (code, msg) = self.connect(host, port)
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/smtplib.py", line 343, in connect
    (code, msg) = self.getreply()
  File "/usr/home/buildbot/python/3.9.koobs-freebsd-564d/build/Lib/smtplib.py", line 405, in getreply
    raise SMTPServerDisconnected("Connection unexpectedly closed")
smtplib.SMTPServerDisconnected: Connection unexpectedly closed

Looks like DNS is broken on the buildbot. Unlikely to be related to this PR.

…1035) * bpo-46542: test_lib2to3 uses support.infinite_recursion() Fix a Python crash in test_lib2to3 when using Python built in debug mode: limit the recursion limit. The test_all_project_files() test of test_lib2to3 now uses the test.support.infinite_recursion() context manager when processing the infinite_recursion.py file to prevent a crash when Python is built in debug mode. The two test_all_project_files() tests now use subTest() and log the refactored/parsed filename (if test_lib2to3 is run in verbose mode). * Update Lib/lib2to3/tests/data/infinite_recursion.py Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> Co-authored-by: Łukasz Langa <lukasz@langa.pl> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> (cherry picked from commit ee0ac32) Co-authored-by: Victor Stinner <vstinner@python.org>

the-knights-who-say-ni added the CLA signed label Jan 31, 2022

bedevere-bot added the awaiting core review label Jan 31, 2022

vstinner added needs backport to 3.9 labels Jan 31, 2022

vstinner mentioned this pull request Jan 31, 2022

bpo-46329: Split calls into precall and call instructions. #30855

Merged

ambv approved these changes Jan 31, 2022

View reviewed changes

bedevere-bot added awaiting merge and removed awaiting core review labels Jan 31, 2022

JelleZijlstra reviewed Jan 31, 2022

View reviewed changes

Comment thread Lib/lib2to3/tests/data/infinite_recursion.py Outdated

Update Lib/lib2to3/tests/data/infinite_recursion.py

25224fd

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

ambv merged commit ee0ac32 into python:main Jan 31, 2022

bedevere-bot removed the awaiting merge label Jan 31, 2022

bedevere-bot removed the needs backport to 3.10 label Jan 31, 2022

bedevere-bot removed the needs backport to 3.9 label Jan 31, 2022

markshannon mentioned this pull request Feb 1, 2022

bpo-46329: Reduce default recursion to 800 if Py_DEBUG is enabled. #31033

Closed

vstinner deleted the lib2to3_infinite branch December 13, 2022 15:25

bpo-46542: test_lib2to3 uses support.infinite_recursion() by vstinner · Pull Request #31035 · python/cpython · GitHub

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bpo-46542: test_lib2to3 uses support.infinite_recursion()#31035
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bpo-46542: test_lib2to3 uses support.infinite_recursion() by vstinner · Pull Request #31035 · python/cpython · GitHub

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