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strptime(.., '%c') fails to parse output of strftime('%c', ..) in some locales #53203

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strptime(.., '%c') fails to parse output of strftime('%c', ..) in some locales#53203
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serhiy-storchaka
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extension-modulesC modules in the Modules dirtype-bugAn unexpected behavior, bug, or error

Description

@abalkin
abalkin
opened on Jun 9, 2010
BPO 8957
Nosy @abalkin, @vstinner, @ezio-melotti
Dependencies
  • bpo-8915: Use locale.nl_langinfo in _strptime
    		•
    Files
  • strptime-locale-bug.c: Working C code
  • strptime-locale-bug.py: Failing python code
  • cfmt.py
  • issue8957.py3k.1.patch
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

    Show more details

    GitHub fields:

    assignee = None
closed_at = None
created_at = <Date 2010-06-09.20:24:38.889>
labels = ['extension-modules', 'type-bug', '3.7']
title = "strptime(.., '%c') fails to parse output of strftime('%c', ..) in some locales"
updated_at = <Date 2016-09-26.21:29:29.654>
user = 'https://github.com/abalkin'

    bugs.python.org fields:

    activity = <Date 2016-09-26.21:29:29.654>
actor = 'belopolsky'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Extension Modules']
creation = <Date 2010-06-09.20:24:38.889>
creator = 'belopolsky'
dependencies = ['8915']
files = ['17601', '17602', '20358', '20412']
hgrepos = []
issue_num = 8957
keywords = ['patch']
message_count = 18.0
messages = ['107413', '125966', '125968', '126043', '126045', '126055', '126057', '126059', '126084', '126235', '126313', '126316', '126339', '126340', '126345', '126347', '126358', '221924']
nosy_count = 4.0
nosy_names = ['belopolsky', 'vstinner', 'ezio.melotti', 'rpetrov']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue8957'
versions = ['Python 3.7']

    Linked PRs

    Activity

    1. abalkin commented on Jun 9, 2010

      @abalkin
      abalkin
      on Jun 9, 2010
      MemberAuthor

      The following code:

      import locale, time
locale.setlocale(locale.LC_ALL, "fr_FR.UTF-8")
t = time.localtime()
s = time.strftime('%c', t)
time.strptime('%c', s)

      Raises

      ValueError: time data '%c' does not match format 'Mer 9 jui 16:14:46 2010'

      in any locale where month follows day in '%c' format. Note that attached C code works as expected on my OSX laptop.

      I wonder it it would make sense to call platform strptime where available? I wonder if platform support for strptime has improved since 2002 when _strptime.py was introduced.

    2. abalkin
      self-assigned this
      on Jun 9, 2010
    3. abalkin
      added
      extension-modulesC modules in the Modules dir
      type-bugAn unexpected behavior, bug, or error
      on Jun 9, 2010

    4. abalkin commented on Jan 11, 2011

      @abalkin
      abalkin
      on Jan 11, 2011
      MemberAuthor

      Adding bpo-8915 as a dependency because deducing D_T_FMT locale setting from strftime output seems impossible:

      >>> locale.nl_langinfo(locale.D_T_FMT)
'%a %b %e %H:%M:%S %Y'

    5. abalkin commented on Jan 11, 2011

      @abalkin
      abalkin
      on Jan 11, 2011
      MemberAuthor

      Victor,

      You may be interested because your native language is implicated. :-)

    6. rpetrov commented on Jan 11, 2011

      @rpetrov
      rpetrovmannequin
      on Jan 11, 2011
      Mannequin

      time.strptime(s, '%c' ) ?

    7. abalkin commented on Jan 11, 2011

      @abalkin
      abalkin
      on Jan 11, 2011
      MemberAuthor

      time.strptime(s, '%c' ) ?

      Oh my. It certainly took a long time to recognize a silly mistake!

      Thanks.

    8. abalkin
      added
      invalid
      on Jan 11, 2011
    9. abalkin
      closed this as completedon Jan 11, 2011

    10. abalkin commented on Jan 12, 2011

      @abalkin
      abalkin
      on Jan 12, 2011
      MemberAuthor

      My tests were wrong but the problem does exist. I am attaching a script that tests strptime(.., '%c') for all locales installed on my system (an unmodified US Mac OS X 10.6.6).

      The only failing locale that I recognize is Hebrew (he_IL). Eli, what do you think about this?

       
$ ./python.exe cfmt.py 
am_ET [ማክሰ ጃንዩ 11 18:56:18 2011] %A %B %d %H:%M:%S %Y != %a %b %e %H:%M:%S %Y
et_EE [T, 11. jaan  2011. 18:56:18] %a, %d. %B %Y. %H:%M:%S != %a, %d. %b %Y. %T
he_IL [EST 18:56:18 2011 ינו 11 ג'] %Z %H:%M:%S %Y %B %d %a != %Z %H:%M:%S %Y %b %d %a
    11. abalkin
      reopened this on Jan 12, 2011
    12. abalkin
      removed
      invalid
      on Jan 12, 2011
    13. abalkin
      changed the title [-]strptime('%c', ..) fails to parse output of strftime('%c', ..) in non-English locale[/-] [+]strptime(.., '%c') fails to parse output of strftime('%c', ..) in some locales[/+] on Jan 12, 2011

    14. rpetrov commented on Jan 12, 2011

      @rpetrov
      rpetrovmannequin
      on Jan 12, 2011
      Mannequin
      • %T is equal for %H:%M:%S
      • locales with %A and %B are broken on this platform as %c is "Appropriate date and time representation (%c) with abbreviations"

    15. 68 remaining items

    16. serhiy-storchaka
      added a commit that references this issue on Jun 26, 2025

      pythongh-53203: Fix strptime() for %c, %x and %X formats on some locales

      196f060

    17. serhiy-storchaka commented on Jun 26, 2025

      @serhiy-storchaka
      serhiy-storchaka
      on Jun 26, 2025
      Member

      #135971 is perhaps the last PR for this issue. It adds support of non-decimal alt digits on locale lzh_TW, fixes bug in detecting the position of week day name on locales byn_ER and wal_ET, fixes support of single-digit hour on locales ar_SA and bg_BG.

      The code is prepared for using nl_langinfo(). The rest of changes belongs to #53161.

    18. StanFromIreland
      removed
      pendingThe issue will be closed if no feedback is provided
      on Jun 26, 2025
    19. serhiy-storchaka
      added a commit that references this issue on Jun 27, 2025

      gh-53203: Fix strptime() for %c, %x and %X formats on some locales (#…

      07183eb
    20. miss-islington
      added 2 commits that reference this issue on Jun 27, 2025

      pythongh-53203: Fix strptime() for %c, %x and %X formats on some loca…

      0c686d3

      pythongh-53203: Fix strptime() for %c, %x and %X formats on some loca…

      7d6d96d
    21. serhiy-storchaka
      added 2 commits that reference this issue on Jun 27, 2025

      [3.13] gh-53203: Fix strptime() for %c, %x and %X formats on some loc…

      ea25f4a

      [3.14] gh-53203: Fix strptime() for %c, %x and %X formats on some loc…

      a168c77
    22. serhiy-storchaka
      closed this as completedon Jun 27, 2025
    23. github-project-automation
      moved this to Done in Locale issues 🗺on Jun 27, 2025
    24. github-project-automation
      moved this to Done in Date and time issues 🕰️on Jun 27, 2025
    25. AndPuQing
      added a commit that references this issue on Jul 11, 2025

      pythongh-53203: Fix strptime() for %c, %x and %X formats on some loca…

      91edb74
    26. Pranjal095
      added a commit that references this issue on Jul 12, 2025

      pythongh-53203: Fix strptime() for %c, %x and %X formats on some loca…

      3a93f40
    27. taegyunkim
      added a commit that references this issue on Aug 4, 2025

      pythongh-53203: Fix strptime() for %c, %x and %X formats on some loca…

      ae83ab6
    28. Agent-Hellboy
      added a commit that references this issue on Aug 19, 2025

      pythongh-53203: Fix strptime() for %c, %x and %X formats on some loca…

      95a4e72
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