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datetime.utctimetuple() should not set tm_isdst flag to 0 #53250

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abalkin opened this issue Jun 16, 2010 · 8 comments
Closed

datetime.utctimetuple() should not set tm_isdst flag to 0 #53250

abalkin opened this issue Jun 16, 2010 · 8 comments
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docs Documentation in the Doc dir easy type-bug An unexpected behavior, bug, or error

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@abalkin
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abalkin commented Jun 16, 2010

BPO 9004
Nosy @malemburg, @abalkin, @pitrou, @merwok, @karlcow, @hobbestigrou, @pganssle
PRs
  • bpo-9004: Recommend against using utctimetuple in the docs. #10870
  • bpo-37488 : Document a warning for datetime.utcnow() and utcfromtimestamp() #15773
    		•
    Files
  • timetuple_issue9004.patch
    		•

    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 = 'https://github.com/abalkin'
closed_at = None
created_at = <Date 2010-06-16.03:36:41.910>
labels = ['easy', 'type-bug', 'docs']
title = 'datetime.utctimetuple() should not set tm_isdst flag to 0'
updated_at = <Date 2019-10-03.09:54:22.605>
user = 'https://github.com/abalkin'

    bugs.python.org fields:

    activity = <Date 2019-10-03.09:54:22.605>
actor = 'karlcow'
assignee = 'belopolsky'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2010-06-16.03:36:41.910>
creator = 'belopolsky'
dependencies = []
files = ['46050']
hgrepos = []
issue_num = 9004
keywords = ['patch', 'easy']
message_count = 8.0
messages = ['107906', '108278', '162633', '221894', '284072', '330963', '330969', '353837']
nosy_count = 8.0
nosy_names = ['lemburg', 'belopolsky', 'pitrou', 'eric.araujo', 'karlcow', 'hobbestigrou', 'p-ganssle', 'Gaurav Tatke']
pr_nums = ['10870', '15773']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue9004'
versions = ['Python 3.6']
    @abalkin
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    abalkin commented Jun 16, 2010

    I find the following quite misleading:

    >>> from datetime import datetime
>>> import time
>>> time.strftime('%c %z %Z', datetime.utcnow().utctimetuple())
'Wed Jun 16 03:26:26 2010 -0500 EST'

    As far as I can tell, the only other function that uses the tm_isdst flag is time.mktime, but it expect a timetuple containing local time, not UTC time.

    @abalkin abalkin added the extension-modules C modules in the Modules dir label Jun 16, 2010
    @abalkin abalkin self-assigned this Jun 16, 2010
    @abalkin abalkin added the type-bug An unexpected behavior, bug, or error label Jun 16, 2010
    @abalkin
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    abalkin commented Jun 21, 2010

    With timezone.utc available in datetime module, users should be encouraged to use dt.astimezone(timezone.utc).timetuple() instead of dt.utctimetuple(). Note that the later will set tm_isdst to -1. This observation can be used to argue for either of two ways to resolve this issue:

    1. Since utctimetuple() is no longer necessary, and the alternative works correctly, there is no need to fix it. Just recommend the astimezone use in the docs and explain the subtle difference.

    2. Having two ways to do the same thing which have a subtle difference is not a good idea.

    I am leaning towards #1, but would like to hear from others.

    @merwok
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    merwok commented Jun 11, 2012

    Just recommend the astimezone use in the docs
    and recommend creating tz-aware instances in the first time (i.e. calling now(utc) instead of utcnow()), +1.

    @abalkin
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    abalkin commented Jun 29, 2014

    Reclassifying this as a doc issue.

    @abalkin abalkin added docs Documentation in the Doc dir easy and removed extension-modules C modules in the Modules dir labels Jun 29, 2014
    @GauravTatke
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    GauravTatke mannequin commented Dec 27, 2016

    Hi,
    I am new to python and would like to contribute. I find this issue easy so changed the documentation of datetime module. I tested it with sphinx. Attaching a patch.

    Please let me know if it is correct or needs changes.
    Appreciate it!

    Regards,
    Gaurav

    @hobbestigrou
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    hobbestigrou mannequin commented Dec 3, 2018

    Please can you convert your patch to a pull request on github.

    @abalkin
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    abalkin commented Dec 3, 2018

    I submitted Gaurav's patch as PR 10870. Please review.

    @karlcow
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    karlcow mannequin commented Oct 3, 2019

    @gaurav The pull request
    #10870
    has been closed in favor of
    #15773
    which has already been merged.

    So we can probably close here.

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
    @slateny slateny closed this as completed May 22, 2022
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