Description

assignee = None
closed_at = None
created_at = <Date 2020-07-09.17:01:48.789>
labels = ['type-bug', '3.9', '3.10', '3.11', 'extension-modules', 'library']
title = 'datetime, date and time: strftime method takes different keyword argument: fmt (pure) or format (C)'
updated_at = <Date 2021-11-16.19:27:41.778>
user = 'https://github.com/asottile'

activity = <Date 2021-11-16.19:27:41.778>
actor = 'AlexWaygood'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Extension Modules', 'Library (Lib)']
creation = <Date 2020-07-09.17:01:48.789>
creator = 'Anthony Sottile'
dependencies = []
files = []
hgrepos = []
issue_num = 41260
keywords = ['patch']
message_count = 6.0
messages = ['373407', '373421', '373424', '406418', '406421', '406424']
nosy_count = 6.0
nosy_names = ['srittau', 'belopolsky', 'Anthony Sottile', 'p-ganssle', 'ZackerySpytz', 'AlexWaygood']
pr_nums = ['21712']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue41260'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

Activity

1. asottile commented on Jul 9, 2020

   

   asottilemannequin

   on Jul 9, 2020

   MannequinAuthor

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   C:

   cpython/Modules/_datetimemodule.c

   Line 3183 in 8b33961

   static char *keywords[] = {"format", NULL};

   pure python:

   cpython/Lib/datetime.py

   Line 927 in 8b33961

   def strftime(self, fmt):

   this makes it difficult to properly type in mypy:

   https://github.com/python/typeshed/blob/209b6bb127f61fe173a60776e23883ac450cf1c8/stdlib/2and3/datetime.pyi#L55

   and calling with .strftime(fmt=...) or .strftime(format=...) is inconsistent

   (that said, it should _probably_ be a positional-only argument)
2. asottile

   added

   3.10 (EOL)end of lifeend of life

   extension-modulesC modules in the Modules dirC modules in the Modules dir

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Jul 9, 2020
3. pganssle commented on Jul 9, 2020

   

   pganssle

   on Jul 9, 2020

   Member

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   I think a positional-only argument would be the best option if we could do it, but it would be a backwards-incompatible change and it's probably not worth the hassle.

   If anyone is using the keyword argument, they're probably using format= rather than fmt=, since it's pretty rare for anyone to use the pure python version of datetime. PyPy uses it, but I think they tend to aim for consistency with the C API of CPython, and it seems like they already patch s/fmt/format/ themselves: https://foss.heptapod.net/pypy/pypy/-/blob/branch/default/lib_pypy/datetime.py#L781

   If anyone wants to make a PR I think we can fix this for 3.10, though unfortunately because it is an API change it can't be backported. I think in typeshed they can safely change from fmt to format even today (which would almost certainly be more accurate to end user use cases).
4. asottile commented on Jul 9, 2020

   

   asottilemannequin

   on Jul 9, 2020

   MannequinAuthor

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   awesome, I'm going to work through this with someone in my discord as a demo / mentorship opportunity -- hope that's ok!
5. pganssle commented on Nov 16, 2021

   

   pganssle

   on Nov 16, 2021

   Member

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   Updating this issue to cover the problem in date, time and datetime.
6. pganssle

   changed the title [-]datetime: strftime method takes different keyword argument: fmt (pure) or format (C)[/-] [+]datetime, date and time: strftime method takes different keyword argument: fmt (pure) or format (C)[/+] on Nov 16, 2021
7. pganssle

   changed the title [-]datetime: strftime method takes different keyword argument: fmt (pure) or format (C)[/-] [+]datetime, date and time: strftime method takes different keyword argument: fmt (pure) or format (C)[/+] on Nov 16, 2021
8. AlexWaygood

   added

   3.9 (EOL)end of lifeend of life

   3.11only security fixesonly security fixes

   on Nov 16, 2021
9. srittau commented on Nov 16, 2021

   

   srittaumannequin

   on Nov 16, 2021

   Mannequin

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   Ref python/typeshed#6317 for a discussion about this in typeshed.
10. AlexWaygood commented on Nov 16, 2021

    

    AlexWaygood

    on Nov 16, 2021

    Member

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    In addition to date.strftime and time.strftime, there is also a discrepancy in datetime.fromtimestamp. In the C implementation, the first parameter is called "timestamp"; in the pure-Python implementation, the first parameter is called "t".
11. ezio-melotti

    transferred this issue fromon Apr 10, 2022
12. serhiy-storchaka

    added this to Date and time issues 🕰️on May 21, 2022
13. iritkatriel

    closed this as completedon Nov 25, 2022
14. iritkatriel

    moved this to Done in Date and time issues 🕰️on Nov 25, 2022
15. AlexWaygood

    added 2 commits that reference this issue on Dec 4, 2022

    pythongh-85432: harmonise parameter names between C and pure-Python i…

    7b4de3b

    pythongh-85432: harmonise parameter names between C and pure-Python i…

    bcb065d
16. hauntsaninja

    added a commit that references this issue on Dec 22, 2022

    gh-85432: Harmonise parameter names between C and pure-Python impleme…

    9cdb642
17. iritkatriel

    added a commit that references this issue on Dec 28, 2022

    Merged main into regmachine branch (#50)

    fdc73cb

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