DateTime() changes timezone if passed a DateTime instance

[Paul Winkler]

(note, this feature was added in response to #143073 )
It appears that if the argument to DateTime is a DateTime instance, its timezone gets set to the local timezone, regardless of the passed value.

I think this is wrong behavior. The docstring says "If the DateTime function is invoked with a single argument that is a DateTime instance, a copy of the passed object will be created." It doesn't say anything about the copy possibly having a different timezone...

To demonstrate, you need to experiment with timezones *other than your local zone*.
For example, I'm in US/Eastern, so I can demonstrate with US/Pacific.

>>> from DateTime import DateTime
>>> dt1 = DateTime('2001/01/01 12:00 PM PST')
>>> dt1.timezone()
'US/Pacific'
>>> DateTime(dt1) == dt1
True
>>> DateTime(dt1).timezone()
'US/Eastern'

Notice that the second datetime is in a different zone!
You can also see this in the various string representations:

>>> dt1.ISO8601()
'2001-01-01T12:00:00-08:00'
>>> DateTime(dt1).ISO8601()
'2001-01-01T15:00:00-05:00'

[Paul Winkler (slinkp)]

Fixed on branch svn://svn.zope.org/repos/main/Zope/branches/slinkp-datetime-200007
I'll bring this up on zope-dev; if nobody objects in the next few days, I'll commit to trunk, 2.11, 2.10, and 2.9.

[Paul Winkler (slinkp)]

Released in Zope 2.9.9 and 2.10.6

[Artur Zaprzała (arturz)]

The patch at http://svn.zope.org/Zope/branches/2.11/lib/python/DateTime/DateTime.py?rev=85834&r1=82440&r2=85834 for this bug is broken. Try this in ZOPE 2.11.1:
>>> dt = DateTime()
>>> DateTime(dt)==dt
True # OK
>>> str(DateTime(dt))==str(dt)
False # Should be True

Values of self._t and self._tz are preserved, but self._hour is not.

[Paul Winkler (slinkp)]

Good catch, thanks! Since the timezone fix is already released in zope 2.10 and 2.11, I have opened this as a new bug, #267545