[Zope-dev] Possible DateTime timezone-related regression in Zope 2.12

[Martin Aspeli]

Laurence Rowe wrote:
> 2010/1/10<zopyxfilter at gmail.com>:
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>>
>> Martin Aspeli wrote:
>>> Wichert Akkerman wrote:
>>>> On 2010-1-10 04:36, Martin Aspeli wrote:
>>>>> so in your test, `DateTime(md.CreationDate())` will always be
>>>>> the current time, but with an implicitly added 'GMT+0' while
>>>>> `DateTime()` will be the current time in your local time zone.
>>>>> so if i'm not mistaken, on plone 4.0 the test with fail for you
>>>>> an me (in 'GMT+x' time zones) and pass in the u.s.  fun! :)
>>>>>
>>>>> Does anyone know if this change was deliberate, or what may
>>>>> have happened?
>>>> Have you looked at
>>>> http://zope3.pov.lt/trac/log/Zope/trunk/lib/python/DateTime?rev=95999
>>>>
>>>>
>> for hints?
>>> Yes, there are various timezone related changes, e.g.
>>>
>>> http://zope3.pov.lt/trac/changeset/81213/Zope/trunk/lib/python/DateTime
>>>
>>>
>> http://zope3.pov.lt/trac/changeset/85830/Zope/trunk/lib/python/DateTime
>>> It's hard to know whether this was an intended change or not, and
>>> if so, how to deal with the breakage in a way that's compatible
>>> with 2.10 and 2.12.
>>>
>>> I blame Laurence. :-p
>> Better blame DateTime :-)
>> Fixing one issue in DateTime is likely to trigger another new bug.
>> The DateTime is just fragile.
>
> I believe the current behaviour is intentional to preserve backwards
> compatibility. See the discussion starting here:
> https://mail.zope.org/pipermail/zope-dev/2007-October/030042.html
>
> Maybe it was 'fixed' on 2.10 branch some time later.

Sorry, just to be clear - which behaviour is correct? The 2.10 one or 
the 2.12 one?

My vote would go for the 2.10 one - in the absence of timezone 
information, assume local timezone, not GMT.

If we agree on that, is it clear what needs to be changed for this to work?

Can we also agree that it's very bad for 2.10 and 2.12 to exhibit 
different behaviour here?

Martin

-- 
Author of `Professional Plone Development`, a book for developers who
want to work with Plone. See http://martinaspeli.net/plone-book