msg146793 - (view) |
Author: Florent Xicluna (flox) *  |
Date: 2011-11-01 16:52 |
On builder "AMD64 FreeBSD 8.2 3.x" for the TIME_MINYEAR:
======================================================================
FAIL: test_negative (test.test_time.TestStrftime4dyear)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/usr/home/buildbot/buildarea/3.x.krah-freebsd/build/Lib/test/test_time.py", line 397, in test_negative
return super().test_negative()
File "/usr/home/buildbot/buildarea/3.x.krah-freebsd/build/Lib/test/test_time.py", line 425, in test_negative
self.assertEqual(self.yearstr(TIME_MINYEAR), str(TIME_MINYEAR))
AssertionError: '2147483648' != '-2147483648'
- 2147483648
+ -2147483648
? +
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msg146818 - (view) |
Author: Roundup Robot (python-dev)  |
Date: 2011-11-02 00:28 |
New changeset 9cb1b85237a9 by Florent Xicluna in branch 'default':
Issue #13312: skip the single failing value for now.
http://hg.python.org/cpython/rev/9cb1b85237a9
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msg146822 - (view) |
Author: Roundup Robot (python-dev)  |
Date: 2011-11-02 02:22 |
New changeset d877d7f3b679 by Florent Xicluna in branch 'default':
Actually, there's more than one failing value. (changeset 9cb1b85237a9, issue #13312).
http://hg.python.org/cpython/rev/d877d7f3b679
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msg146828 - (view) |
Author: Florent Xicluna (flox) *  |
Date: 2011-11-02 07:09 |
It fails for very low negative years:
-2147483648 <= year < -2147481748
(-1<<31) <= year < (-1<<31) + 1900
Every other value behaves correctly on this FreeBSD buildbot:
- (-1<<31) + 1900 <= year < (+1<<31) : correctly formatted with '%Z'
- year < (-1<<31) : raises OverfowError
- year >= (+1<<31) : raises OverfowError
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msg146829 - (view) |
Author: Florent Xicluna (flox) *  |
Date: 2011-11-02 07:11 |
I mean formatted with '%Y', of course.
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msg146830 - (view) |
Author: Roundup Robot (python-dev)  |
Date: 2011-11-02 07:14 |
New changeset 1a0bfc26af57 by Florent Xicluna in branch 'default':
Issue #13312: skip the failing negative years for now.
http://hg.python.org/cpython/rev/1a0bfc26af57
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msg220505 - (view) |
Author: Mark Lawrence (BreamoreBoy) * |
Date: 2014-06-13 22:00 |
The failing negative years test is still being skipped. I'm assuming this was not originally intended.
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msg236981 - (view) |
Author: Mark Lawrence (BreamoreBoy) * |
Date: 2015-03-01 21:37 |
I believe that this can be closed as the test code was changed completely in #17960.
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msg236985 - (view) |
Author: Alexander Belopolsky (belopolsky) *  |
Date: 2015-03-01 21:45 |
Mark,
Issue #17960 ("Clarify the required behaviour of locals()") does not seem to be relevant here. I think you meant to refer to a changeset, not issue number. If so please use hash number such as d877d7f3b679.
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msg236988 - (view) |
Author: Alexander Belopolsky (belopolsky) *  |
Date: 2015-03-01 22:00 |
As far as I can tell, the original report was about a test failing due to a system-dependent behavior of time.asctime(). However, since changeset 1e62a0cee092 (see issue #8013), we no longer call system asctime. I believe the test disabled in 1a0bfc26af57 can now be restored.
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msg236989 - (view) |
Author: Mark Lawrence (BreamoreBoy) * |
Date: 2015-03-01 22:03 |
Sorry should have been #17690.
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msg236993 - (view) |
Author: Alexander Belopolsky (belopolsky) *  |
Date: 2015-03-01 22:30 |
We still have the following in Lib/test/test_time.py:
# Issue #13312: it may return wrong value for year < TIME_MINYEAR + 1900
# Skip the value test, but check that no error is raised
self.yearstr(TIME_MINYEAR)
I reviewed the current time.asctime() code and it does look like it invokes undefined behavior for extremely large negative years.
The problem is that in C struct tm, year is stored as year - 1900 and for year < -2147481748 (= -2**31 + 1900) we trigger an overflow of a signed integer.
Can someone confirm that on AMD64 FreeBSD subtracting 1900 from -2147483648 and then adding it back does not give -2147483648?
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msg236994 - (view) |
Author: Alexander Belopolsky (belopolsky) *  |
Date: 2015-03-01 23:07 |
Attached patch eliminates undefined behavior, but I am not sure fixing this is worth the trouble.
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msg270371 - (view) |
Author: Martin Panter (martin.panter) *  |
Date: 2016-07-14 05:41 |
If you enable GCC’s -ftrapv option, the subtraction overflow triggers an abort. Alexander’s patch works around the problem for asctime(), but the problem still exists in other cases, such as:
>>> time.mktime((-2**31 + 1899, *(0,) * 8))
Aborted (core dumped)
[Exit 134]
Attaching a version of the patch without the conflicting whitespace changes.
Why does Python even need to support such extreme time values? It would seem much simpler to raise an exception.
|
msg324026 - (view) |
Author: Gregory P. Smith (gregory.p.smith) *  |
Date: 2018-08-25 01:08 |
New changeset 76be0fffff8b7dbe649ad4821144461800ffb0d0 by Gregory P. Smith in branch 'master':
bpo-13312: Avoid int underflow in time year. (GH-8912)
https://github.com/python/cpython/commit/76be0fffff8b7dbe649ad4821144461800ffb0d0
|
msg324038 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-08-25 05:53 |
New changeset d5f017bbd65f37ac53fd3c6c439a53155eef2475 by Miss Islington (bot) in branch '3.7':
bpo-13312: Avoid int underflow in time year. (GH-8912)
https://github.com/python/cpython/commit/d5f017bbd65f37ac53fd3c6c439a53155eef2475
|
msg324039 - (view) |
Author: miss-islington (miss-islington) |
Date: 2018-08-25 05:53 |
New changeset c47acc2bb1d0a3fb6dda14ced958d272fb2821a6 by Miss Islington (bot) in branch '3.6':
bpo-13312: Avoid int underflow in time year. (GH-8912)
https://github.com/python/cpython/commit/c47acc2bb1d0a3fb6dda14ced958d272fb2821a6
|
msg324040 - (view) |
Author: Gregory P. Smith (gregory.p.smith) *  |
Date: 2018-08-25 05:54 |
OverflowError is now raised for negative values that would trigger a problem and the unittest has been updated to test this.
|
msg324177 - (view) |
Author: STINNER Victor (vstinner) *  |
Date: 2018-08-27 13:38 |
Note for myself: Python 2.7 is not affected by this bug because it doesn't accept year < 1900.
|
|
Date |
User |
Action |
Args |
2022-04-11 14:57:23 | admin | set | github: 57521 |
2018-08-27 13:38:03 | vstinner | set | messages:
+ msg324177 |
2018-08-25 05:54:42 | gregory.p.smith | set | status: open -> closed resolution: fixed messages:
+ msg324040
stage: patch review -> resolved |
2018-08-25 05:53:24 | miss-islington | set | messages:
+ msg324039 |
2018-08-25 05:53:03 | miss-islington | set | nosy:
+ miss-islington messages:
+ msg324038
|
2018-08-25 01:09:10 | miss-islington | set | pull_requests:
+ pull_request8386 |
2018-08-25 01:09:04 | miss-islington | set | pull_requests:
+ pull_request8385 |
2018-08-25 01:08:53 | gregory.p.smith | set | messages:
+ msg324026 |
2018-08-25 00:29:09 | gregory.p.smith | set | stage: needs patch -> patch review pull_requests:
+ pull_request8384 |
2018-08-25 00:19:27 | gregory.p.smith | set | assignee: gregory.p.smith
nosy:
+ gregory.p.smith versions:
+ Python 3.6, Python 3.7, Python 3.8, - Python 3.5 |
2017-06-10 12:29:59 | jwilk | set | nosy:
+ jwilk
|
2016-07-15 02:53:36 | martin.panter | link | issue1621 dependencies |
2016-07-14 14:51:38 | BreamoreBoy | set | nosy:
- BreamoreBoy
|
2016-07-14 05:41:49 | martin.panter | set | files:
+ issue13312.v2.patch nosy:
+ martin.panter messages:
+ msg270371
|
2015-03-01 23:07:52 | belopolsky | set | files:
+ issue13312.patch
nosy:
+ vstinner messages:
+ msg236994
keywords:
+ patch |
2015-03-01 22:30:58 | belopolsky | set | messages:
+ msg236993 |
2015-03-01 22:03:41 | BreamoreBoy | set | messages:
+ msg236989 |
2015-03-01 22:00:00 | belopolsky | set | messages:
+ msg236988 components:
+ Tests, - Library (Lib) versions:
+ Python 3.5, - Python 3.3 |
2015-03-01 21:45:10 | belopolsky | set | messages:
+ msg236985 |
2015-03-01 21:37:09 | BreamoreBoy | set | messages:
+ msg236981 |
2014-06-13 22:00:33 | BreamoreBoy | set | nosy:
+ BreamoreBoy messages:
+ msg220505
|
2011-11-02 07:14:15 | python-dev | set | messages:
+ msg146830 |
2011-11-02 07:11:12 | flox | set | messages:
+ msg146829 |
2011-11-02 07:09:26 | flox | set | messages:
- msg146827 |
2011-11-02 07:09:10 | flox | set | messages:
+ msg146828 |
2011-11-02 07:04:31 | flox | set | messages:
+ msg146827 |
2011-11-02 02:22:56 | python-dev | set | messages:
+ msg146822 |
2011-11-02 00:28:36 | python-dev | set | nosy:
+ python-dev messages:
+ msg146818
|
2011-11-01 16:52:38 | flox | create | |