[Python-Dev] TZ-aware local time

[R. David Murray]

On Tue, 05 Jun 2012 18:31:20 -0700, Glyph <glyph at twistedmatrix.com> wrote:
> 
> Le Jun 5, 2012 à 6:16 PM, Nick Coghlan a écrit :
> 
> > Personally, I'd like to see the datetime module make an explicit
> > assumption that "all naive datetime objects are considered to be UTC",
> > with the interactions between naive and aware objects updated
> > accordingly
> 
> I would absolutely love it if this were true.  In fact, I would go a step further and say that the whole concept of a "naive" datetime is simply a bug.  We don't have a "naive" unicode, for example, where it's text in some encoding but you decline to decide which one when you decode it, leaving that to the caller.
> 
> When we addresed this problem for ourselves at Divmod some time ago, naive=UTC is exactly what we did:
> 
> <http://bazaar.launchpad.net/~divmod-dev/divmod.org/trunk/files/head:/Epsilon/epsilon/extime.py>

Note that (after several conversations with Alexander, and based on the
analogous decision in the email RFCs), the email package makes the same
call.  A naive datetime is treated as a UTC time with no information
about what timezone it originated from (coded as -0000 per RFC 5322),
while an aware datetime will generate an accurate offset (+0000 for
"really UTC", and as appropriate for others).

So in some sense I've already nudged the stdlib in this
direction...unless I get overruled now that I've pointed it out :)

--David