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time.strptime does not properly convert out-of-bounds values #70467
Description
| BPO | 26279 |
|---|---|
| Nosy | @ned-deily, @Vgr255 |
| Superseder |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = None
closed_at = <Date 2016-02-12.05:19:15.613>
created_at = <Date 2016-02-03.16:02:51.498>
labels = ['type-bug', 'library']
title = 'time.strptime does not properly convert out-of-bounds values'
updated_at = <Date 2016-02-12.05:21:10.901>
user = 'https://bugs.python.org/iaslan'bugs.python.org fields:
activity = <Date 2016-02-12.05:21:10.901>
actor = 'ned.deily'
assignee = 'none'
closed = True
closed_date = <Date 2016-02-12.05:19:15.613>
closer = 'ned.deily'
components = ['Library (Lib)']
creation = <Date 2016-02-03.16:02:51.498>
creator = 'iaslan'
dependencies = []
files = []
hgrepos = []
issue_num = 26279
keywords = []
message_count = 4.0
messages = ['259488', '259957', '260165', '260166']
nosy_count = 4.0
nosy_names = ['ned.deily', 'abarry', 'beng94', 'iaslan']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '23718'
type = 'behavior'
url = 'https://bugs.python.org/issue26279'
versions = ['Python 2.7', 'Python 3.5', 'Python 3.6']
Activity
iaslan commentedon Feb 3, 2016
There seems to be a bug in the time library when performing the following conversion:
"""
In [8]: mytime=time.strptime(str([2015, 53, 0]), '[%Y, %U, %w]')
In [9]: mytime
Out[9]: time.struct_time(tm_year=2016, tm_mon=1, tm_mday=3, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=368, tm_isdst=-1)
In [10]: time.strftime('%Y %U', mytime)
---------------------------------------------------------------------------
ValueError Traceback (most recent call last) <ipython-input-10-c13538c08ea5> in <module>() ----> 1 time.strftime('%Y %U', mytime)ValueError: day of year out of range
"""
As you can observe, tm_yday got a value of 368 instead of 3. It seems that the C function is not properly subtracting 365 or 366 days when converting from week 53 of a particular year which, according to ISO 8601 [1] and per python documentation [2]. Documentation explicitly says that: "The first week of the year is the week with the year's first Thursday in it".
[1] https://en.wikipedia.org/wiki/ISO_8601#Week_dates
[2] https://docs.python.org/2/library/time.html
[-]Possible bug in time library[/-][+]time.strptime does not properly convert out-of-bounds values[/+]beng94 commentedon Feb 9, 2016
This is connected to http://bugs.python.org/issue23718
I submitted a patch that hopefully solves this problem.
ned-deily commentedon Feb 12, 2016
Thanks for the report. Closing this issue as a duplicate of bpo-23719.
ned-deily commentedon Feb 12, 2016
Make that bpo-23718