datetime/date strftime() method and time.strftime() inconsistency #47031

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1. mishok13 commented on May 7, 2008

   

   mishok13mannequin

   on May 7, 2008

   MannequinAuthor

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   datetime and date strftime() method does additional check on input
   format, thus being completely different from time's module
   time.strftime() method behavior.
   There are two ways to fix this:

   1. Add an explicit note about this behavior (e.g., "only 'str' objects
      are allowed for format strings") in docs (section 5.1.7).
   2. Allow 'unicode' objects for format strings (backport time.strftime()
      from 3.0?).

   Here is a traceback for a more complete overview:

   Python 2.6a2+ (trunk:62762, May  6 2008, 14:37:27)
   [GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> from datetime import datetime, date
   >>> import time
   >>> uformat = u'%Y-%m-%D %H-%M-%S'
   >>> format = '%Y-%m-%D %H-%M-%S'
   >>> datetime.today().strftime(uformat)
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
   TypeError: strftime() argument 1 must be str, not unicode
   >>> datetime.today().strftime(format)
   '2008-05-05/07/08 17-19-03'
   >>> time.strftime(uformat)
   '2008-05-05/07/08 17-19-10'
   >>> time.strftime(format)
   '2008-05-05/07/08 17-19-16'
   >>> date.today()
   datetime.date(2008, 5, 7)
   >>> date.today().strftime(format)
   '2008-05-05/07/08 00-00-00'
   >>> date.today().strftime(uformat)
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
   TypeError: strftime() argument 1 must be str, not unicode
2. mishok13

   added

   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 May 7, 2008
3. gpshead commented on May 25, 2008

   

   gpshead

   on May 25, 2008

   Member

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   Yes, sounds like a bug. I'll fix it.

   But should time.strftime allow a unicode format string as input in the
   first place? For backwards compatibility I'd say yes. But.. Sane
   output can not be guaranteed from time.strftime when given a unicode
   format string if it contains multibyte characters that happen to have a
   valid (bytewise) % format code in them within a multibyte character.
   Anyways the output is always byte string without a specified encoding so
   giving it actual unicode characters as input is not advised (at least in
   2.6, i didn't check 3.0).

   there's an amusing comment in Modules/datetimemodule.c:

   /* I sure don't want to reproduce the strftime code from the time module,

   • so this imports the module and calls it. All the hair is due to
   • giving special meanings to the %z, %Z and %f format codes via a
   • preprocessing step on the format string.
     ...
     */
     static PyObject * wrap_strftime(
4. gpshead

   self-assigned this

   on May 25, 2008
5. gpshead commented on Jun 2, 2008

   

   gpshead

   on Jun 2, 2008

   Member

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   Fixed in trunk (2.6) r63887.
6. gpshead

   closed this as completedon Jun 2, 2008
7. gpshead

   removed their assignment

   on Jun 2, 2008
8. ezio-melotti

   transferred this issue fromon Apr 10, 2022