DateTime trouble parsing daylight savings time

[Jarrod Kinsley]

DateTime is raising a SyntaxError when encountering datetime strings that have daylight savings time zones such as EDT, CDT, MDT, PDT. This can be tested as follows:

[pts6][zope@horus DateTime]$ python
Python 2.4.3 (#1, Jun 14 2006, 14:53:31)
[GCC 4.0.2 20051125 (Red Hat 4.0.2-8)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from DateTime import DateTime
>>> dt = DateTime('Wed, 14 Mar 2007 09:44:06 EDT')
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/zope2/lib/python/DateTime/DateTime.py", line 555, in __init__
    return self._parse_args(*args, **kw)
  File "/usr/lib/zope2/lib/python/DateTime/DateTime.py", line 798, in _parse_args
    yr,mo,dy,hr,mn,sc,tz=self._parse(arg, datefmt)
  File "/usr/lib/zope2/lib/python/DateTime/DateTime.py", line 1087, in _parse
    raise SyntaxError, st
DateTime.SyntaxError: Wed, 14 Mar 2007 09:44:06 EDT
>>> dt = DateTime('Wed, 14 Mar 2007 09:44:06 EST')
>>> print dt.timezone()
US/Eastern
>>> dt = DateTime('Wed, 14 Mar 2007 09:44:06 CDT')
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/zope2/lib/python/DateTime/DateTime.py", line 555, in __init__
    return self._parse_args(*args, **kw)
  File "/usr/lib/zope2/lib/python/DateTime/DateTime.py", line 798, in _parse_args
    yr,mo,dy,hr,mn,sc,tz=self._parse(arg, datefmt)
  File "/usr/lib/zope2/lib/python/DateTime/DateTime.py", line 1087, in _parse
    raise SyntaxError, st
DateTime.SyntaxError: Wed, 14 Mar 2007 09:44:06 CDT
>>> dt = DateTime('Wed, 14 Mar 2007 09:44:06 CST')
>>> print dt.timezone()
US/Central

The results are the same for Mountain and pacific time as well.

I have not yet found a fix for this problem. I discovered it using PloneFeedFeeder when trying to parse a news feed with the datetime stamp used in this example.

[Andreas Jung (ajung)]

Changes: submitter email, importance (critical => medium), new comment

This is not critical

[Reed O'Brien (reedobrien)]

I added entries
'edt':'US/Eastern', etc...
to the to the _zmap dict.

It appears that DST is calculated via time.daylight so mapping xDT to US/<zone> should be fine. I think;) Or I am an hour off.

[Russ Ferriday (russf)]

I'm working around this by wrapping calls to DateTime(str) in my app, since I think changes in DateTime may take a while:

[Jens Vagelpohl (dataflake-deactivatedaccount-deactivatedaccount)]

"EDT" actually does work in the latest DateTime code, but not CDT, MDT, PDT and other DST zone names.

[Lennart Regebro (regebro-gmail)]

It should be noted that three character time zones are not unique. You should avoid them.

[Colin Watson (cjwatson)]

The datetime project on Launchpad has been archived at the request of the Zope developers (see https://answers.launchpad.net/launchpad/+question/683589 and https://answers.launchpad.net/launchpad/+question/685285). If this bug is still relevant, please refile it at https://github.com/zopefoundation/datetime.