datetime, tzinfo ... strange conversion?

[Tino Lange]

Hi!

I'm surprised about the following code, maybe you can give me a hint whether
that's bug or feature? I'm just trying to convert local time to GMT and one
method gives a strange result: 

######################

> #! /usr/bin/env python
> 
> import datetime, pytz
> 
> _tz_utc = pytz.timezone("UTC")
> _tz_germany = pytz.timezone("Europe/Berlin")
> 
> local = datetime.datetime.now(_tz_germany)
> print "Local: ", local
> 
> gmt = local.astimezone(_tz_utc)
> print "GMT (1)", gmt
> 
> gmt = datetime.datetime.combine(local.date(),
local.timetz()).astimezone(_tz_utc)
> print "GMT (2)", gmt
> 
> gmt = datetime.datetime.combine(datetime.date.today(),
datetime.time(local.hour, local.minute, local.second, local.microsecond,
_tz_germany)).astimezone(_tz_utc)
> print "GMT (3)", gmt
> 
> gmt = datetime.datetime.combine(datetime.date.today(),
datetime.time(local.hour, local.minute, local.second, local.microsecond,
local.tzinfo)).astimezone(_tz_utc)
> print "GMT (4)", gmt
> 
> print "_tz_germany:", _tz_germany, "(id: %s)" % id(_tz_germany), ",
local.tzinfo:", local.tzinfo, "(id: %s)" % id(local.tzinfo)

######################

Result:

> tlange at tinux:~/is.work/Scripts$ ./timeconv.py
> Local:  2006-04-01 20:09:26.469445+02:00
> GMT (1) 2006-04-01 18:09:26.469445+00:00
> GMT (2) 2006-04-01 18:09:26.469445+00:00
> GMT (3) 2006-04-01 19:09:26.469445+00:00
> GMT (4) 2006-04-01 18:09:26.469445+00:00
> _tz_germany: Europe/Berlin (id: -1212869684) , local.tzinfo: Europe/Berlin
(id: -1212868756)

--> Why is GMT (3) wrong?

Cheers,

Tino