[ python-Bugs-1290505 ] strptime(): can't switch locales more than once

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Bugs item #1290505, was opened at 2005-09-13 15:50
Message generated for change (Comment added) made by bcannon
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Category: Python Library
Group: Python 2.4
>Status: Closed
>Resolution: Fixed
Priority: 5
Submitted By: Adam Monsen (meonkeys)
Assigned to: Brett Cannon (bcannon)
Summary: strptime(): can't switch locales more than once

Initial Comment:
After calling strptime() once, it appears that
subsequent efforts to modify the locale settings (so
dates strings in different locales can be parsed) throw
a ValueError. I'm pasting everything here since spacing
is irrelevant:

import locale, time
print locale.getdefaultlocale()        # ('en_US', 'utf')
print locale.getlocale(locale.LC_TIME) # (None, None)
# save old locale
old_loc = locale.getlocale(locale.LC_TIME)
locale.setlocale(locale.LC_TIME, 'nl_NL')
print locale.getlocale(locale.LC_TIME) # ('nl_NL',
'ISO8859-1')
# parse local date
date = '10 augustus 2005 om 17:26'
format = '%d %B %Y om %H:%M'
dateTuple = time.strptime(date, format)
# switch back to previous locale
locale.setlocale(locale.LC_TIME, old_loc)
print locale.getlocale(locale.LC_TIME) # (None, None)
date = '10 August 2005 at 17:26'
format = '%d %B %Y at %H:%M'
dateTuple = time.strptime(date, format)

The output I get from this script is:

('en_US', 'utf')
(None, None)
('nl_NL', 'ISO8859-1')
(None, None)
Traceback (most recent call last):
  File "switching.py", line 17, in ?
    dateTuple = time.strptime(date, format)
  File "/usr/lib/python2.4/_strptime.py", line 292, in
strptime
    raise ValueError("time data did not match format: 
data=%s  fmt=%s" %
ValueError: time data did not match format:  data=10
August 2005 at 17:26  fmt=%d %B %Y at %H:%M


One workaround I found is by manually busting the
regular expression cache in _strptime:

import _strptime
_strptime._cache_lock.acquire()
_strptime._TimeRE_cache = _strptime.TimeRE()
_strptime._regex_cache = {}
_strptime._cache_lock.release()

If I do all that, I can change the LC_TIME part of the
locale as many times as I choose.

If this isn't a bug, this should at least be in the
documentation for the locale module and/or strptime().

----------------------------------------------------------------------

>Comment By: Brett Cannon (bcannon)
Date: 2005-09-14 19:42

Message:
Logged In: YES 
user_id=357491

OK, the problem was that the cache for the locale
information in terms of dates and time was being invalidated
and recreated, but the regex cache was not being touched.  I
has now been fixed in rev. 1.41 for 2.5 and in rev. 1.38.2.3
for 2.4 .

Thanks for reporting this, Adam.

----------------------------------------------------------------------

Comment By: Adam Monsen (meonkeys)
Date: 2005-09-13 15:57

Message:
Logged In: YES 
user_id=259388

I think there were some long lines in my code. Attaching
test case.

----------------------------------------------------------------------

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