Issue 9005: Year range in timetuple (original) (raw)
Created on 2010-06-16 03:57 by belopolsky, last changed 2022-04-11 14:57 by admin. This issue is now closed.
Messages (8)
Author: Alexander Belopolsky (belopolsky) * 
Date: 2010-06-16 03:57
Current datetime.timetuple() implementation goes out of its way to support edge cases that produce timetuples beyond the naive datetime range:
t1 = datetime.min.replace(tzinfo=timezone.max) t2 = datetime.max.replace(tzinfo=timezone.min) print(t1.utctimetuple()) time.struct_time(tm_year=0, tm_mon=12, tm_mday=31, tm_hour=0, tm_min=1, tm_sec=0, tm_wday=6, tm_yday=366, tm_isdst=0) print(t2.utctimetuple()) time.struct_time(tm_year=10000, tm_mon=1, tm_mday=1, tm_hour=23, tm_min=58, tm_sec=59, tm_wday=5, tm_yday=1, tm_isdst=0)
The last result is particularly troublesome because it may crash time.asctime on POSIX compliant systems. See Issue #6608.
tm_year is described in help(time) as 4-digit year suggesting range of [1000, 9999]. Most C libraries support even smaller ranges.
Author: Alexander Belopolsky (belopolsky) *
Date: 2010-06-20 01:29
Note that a recently closed issue 7150 similarly tightened up datetime operations by making out of range dates raise OverflowError rather than produce non-sensible result. This case is not a clear cut, but now with timezone.utc available in datetime module, I believe users should be encouraged to use t.astimezone(timezone.utc) to produce UTC time. If timetuple is required the later can be converted using timetuple() method. Idelally, t.utctimetuple() should be deprecated in favor of more explicit t.astimezone(timezone.utc).timetuple(). Unfortunately the two expressions are subtly different because
t = datetime.max.replace(tzinfo=timezone.min) t.astimezone(timezone.utc) Traceback (most recent call last): File "", line 1, in OverflowError: date value out of range
Author: Alexander Belopolsky (belopolsky) *
Date: 2010-06-21 14:25
I raised this issue on python-dev and Guido said "OK." See "[Python-Dev] Year 0 and year 10,000 in timetuple", http://mail.python.org/pipermail/python-dev/2010-June/100682.html
I am attaching a "commit ready" patch which contains a few more test cases and a NEWS entry. I don't think there is a need to mention this in documentation, but at some point I would like to be able to write that dt.utctimetuple() is equivalent to dt.astimezone(timezone.utc).timetuple(), but at the moment it is not quite so. See issue 9004.
Author: Alexander Belopolsky (belopolsky) *
Date: 2010-06-21 15:25
Committed in r82128.
Author: Alexander Belopolsky (belopolsky) *
Date: 2010-07-05 15:46
Reopening to consider removing a special case in days_before_year(..). After r82128, year cannot be <= 0.
Author: Alexander Belopolsky (belopolsky) *
Date: 2010-07-05 17:23
Similarly, it appears that
if (*m < 1 || *m > 12) {
--*m;
normalize_pair(y, m, 12);
++*m;
/* |y| can't be bigger than about
* |original y| + |original m|/12 now.
*/
}in normalize_y_m_d(int *y, int *m, int *d) is a dead branch.
Author: Alexander Belopolsky (belopolsky) *
Date: 2010-07-22 18:23
Mark,
Do you agree that conditions mentioned in and are never triggered?
Author: Alexander Belopolsky (belopolsky) *
Date: 2010-10-13 22:55
Committed in r85441.
History
Date
User
Action
Args
2022-04-11 14:57:02
admin
set
github: 53251
2010-10-13 22:55:17
belopolsky
set
status: open -> closed
messages: +
2010-07-22 18:23:21
belopolsky
set
messages: +
2010-07-05 17:23:48
belopolsky
set
messages: +
2010-07-05 15:46:40
belopolsky
set
status: closed -> open
files: + issue9005c.diff
messages: +
stage: resolved -> commit review
2010-06-21 15:25:54
belopolsky
set
status: open -> closed
messages: +
stage: commit review -> resolved
2010-06-21 14:55:36
belopolsky
set
files: + issue9005b.diff
2010-06-21 14:25:07
belopolsky
set
files: + issue9005a.diff
resolution: accepted
messages: +
stage: patch review -> commit review
2010-06-20 01:29:18
belopolsky
set
nosy: + gvanrossum
messages: +
2010-06-19 21:46:25
belopolsky
set
stage: needs patch -> patch review
2010-06-19 21:46:10
belopolsky
set
files: + issue9005.diff
keywords: + patch
2010-06-16 03:57:06
belopolsky
create