[ZCM] [ZC] 484/ 7 Resolve "DateTime with January, 1st, 1970"

[Collector: Zope Bugs, Features, and Patches ...]

Issue #484 Update (Resolve) "DateTime with January, 1st, 1970"
 Status Resolved, Zope/bug medium
To followup, visit:
  http://collector.zope.org/Zope/484

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= Resolve - Entry #7 by ajung on Jan 2, 2004 5:28 am

 Status: Pending => Resolved

closing on request
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= Comment - Entry #6 by yuppie on Jan 2, 2004 5:21 am

Checked in a fix to Zope-2_7-branch and HEAD. Could someone please close this issue?
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= Comment - Entry #5 by yuppie on Jan 25, 2003 6:36 am

Same error with 1914/01/01 and 1942/01/01.

I had again a look at this. I tracked it down to a bug in _calcTimezoneName.

  yr = ((yr - 1970) % 28) + 1970

This line should make sure we are in a save range, but 1970/01/01 isn't save. nearTime could again be negative.

I think we could savely asume on 1969/12/31 were no timezone changes.

So I propose to replace the second try (not the first one) for

  ltm = safelocaltime(nearTime)

with something like

  ltm = safelocaltime( max(0, nearTime) ) 
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= Comment - Entry #4 by regebro on Jan 17, 2003 6:36 am

Sorry, my fault, I didn't see the first line with the >>> thingies. :)
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= Comment - Entry #3 by regebro on Jan 17, 2003 6:35 am

SOme examplecode if how to get this error would be nice. Then it might be possible to fix it.
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= Comment - Entry #2 by yuppie on Nov 26, 2002 4:52 pm

Additional information from Dieter:

 > This problem normally just appears east of the Atlantic Ocean:
and only on Windows...

This is a bug in the Windows "C" library function "localtime"
which is unable to handle negative parameters.
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= Request - Entry #1 by yuppie on Jul 22, 2002 1:38 pm

To reproduce this problem, your machine's timezone has to be GMT+X !

>>> print DateTime('1970/01/01')
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "DateTime\DateTime.py", line 650, in __init__
    yr,mo,dy,hr,mn,sc,tz=self._parse(arg)
  File "DateTime\DateTime.py", line 1031, in _parse
    tz = self._calcTimezoneName(x, ms)
  File "DateTime\DateTime.py", line 850, in _calcTimezoneName
    ltm = safelocaltime(nearTime)
  File "DateTime\DateTime.py", line 400, in safelocaltime
    rval = localtime(t_int)
IOError: [Errno 22] Invalid argument

This works (timezone GMT+1):

>>> print DateTime('1970/01/01 01:00:00')
1970/01/01 01:00:00 GMT+1

Didn't debug this, but it seems to me that nearTime in _calcTimezoneName() is a value calculated for GMT.
This is the same bug as rejected issue 190. I think ajung couldn't reproduce it with his timezone setting.
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