From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicolas Goaziou <mail@nicolasgoaziou.fr>
Subject: Re: Bug: org-2ft and/or float-time is wrong [9.1.2
 (9.1.2-22-ga2a034-elpaplus @ ~/.emacs.d/elpa/org-plus-contrib-20171023/)]
Date: Thu, 02 Nov 2017 10:35:58 +0100
Message-ID: <87inetm39d.fsf@nicolasgoaziou.fr>
References: <CAJr1M6d5ccgteNjMncKeOVfS3uygkpRte4i2Hem4-WOJEBA51A@mail.gmail.com>
	<CAJr1M6cBkr0RoFLN=P0DL=7JrWvSnM2EnepSyjT-+LvSPQ8ngQ@mail.gmail.com>
	<87bmknkwhe.fsf@nicolasgoaziou.fr>
	<CAJr1M6dzqoi0Y3vhe3e4zWLcUBC=xae8KCB-kRAM1hCK+s8sgw@mail.gmail.com>
	<87tvyfjgjk.fsf@nicolasgoaziou.fr>
	<CAJr1M6cdPnvn3Smqx6j+WG+Xh3qUDpiORH8ANiT_O2EDjKFapw@mail.gmail.com>
	<87bmkl1zy9.fsf@nicolasgoaziou.fr>
	<CAJr1M6fRVKF4_0JdZC0curBJfiQEq=jXNY1TzVgJXqBVPUJEJA@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain
Return-path: <emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org>
Received: from eggs.gnu.org ([2001:4830:134:3::10]:56943)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mail@nicolasgoaziou.fr>) id 1eABux-00079X-Cn
	for emacs-orgmode@gnu.org; Thu, 02 Nov 2017 05:36:17 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <mail@nicolasgoaziou.fr>) id 1eABus-0003no-Nl
	for emacs-orgmode@gnu.org; Thu, 02 Nov 2017 05:36:07 -0400
Received: from relay2-d.mail.gandi.net ([217.70.183.194]:36336)
	by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)
	(Exim 4.71) (envelope-from <mail@nicolasgoaziou.fr>)
	id 1eABus-0003n4-Ho
	for emacs-orgmode@gnu.org; Thu, 02 Nov 2017 05:36:02 -0400
In-Reply-To: <CAJr1M6fRVKF4_0JdZC0curBJfiQEq=jXNY1TzVgJXqBVPUJEJA@mail.gmail.com>
	(Allen Li's message of "Wed, 1 Nov 2017 17:10:21 -0700")
List-Id: "General discussions about Org-mode." <emacs-orgmode.gnu.org>
List-Unsubscribe: <https://lists.gnu.org/mailman/options/emacs-orgmode>,
	<mailto:emacs-orgmode-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/archive/html/emacs-orgmode/>
List-Post: <mailto:emacs-orgmode@gnu.org>
List-Help: <mailto:emacs-orgmode-request@gnu.org?subject=help>
List-Subscribe: <https://lists.gnu.org/mailman/listinfo/emacs-orgmode>,
	<mailto:emacs-orgmode-request@gnu.org?subject=subscribe>
Errors-To: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org
Sender: "Emacs-orgmode"
	<emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org>
To: Allen Li <vianchielfaura@gmail.com>
Cc: emacs-orgmode@gnu.org

Hello,

Allen Li <vianchielfaura@gmail.com> writes:

> Alas, I still can't seem to find the original DST bug.  I'm not sure
> using UTC solves DST problems.
>
> For example, in the timezone America/Los_Angeles,
>
> <2017-11-05 01:00:00> -> <2017-11-05 04:00:00> = 4 hours
> <2017-10-10 01:00:00> -> <2017-10-10 04:00:00> = 3 hours
> <2017-03-12 01:00:00> -> <2017-03-12 04:00:00> = 2 hour
>
> This is what Emacs gives me using the default time zone
>
> <2017-11-05 01:00:00> -> <2017-11-05 04:00:00> = 4 hours
> <2017-10-10 01:00:00> -> <2017-10-10 04:00:00> = 3 hours
> <2017-03-12 01:00:00> -> <2017-03-12 04:00:00> = 2 hour
>
> This is what Emacs gives me using UTC
>
> <2017-11-05 01:00:00> -> <2017-11-05 04:00:00> = 3 hours
> <2017-10-10 01:00:00> -> <2017-10-10 04:00:00> = 3 hours
> <2017-03-12 01:00:00> -> <2017-03-12 04:00:00> = 3 hours
>
> Using UTC seems strictly wrong to me.

You're right. Using UTC doesn't solve any DST bug, despite what
I initially thought. I think we just need to remove the whole set of
changes about UTC in `parse-time-string'. We also need to adapt tests in
test-org-clock since the same time difference could have different
meanings depending on the time zone. I can do that later, if no one
objects. WDYT?n

Refactoring time functions in Org is still useful, though.

Regards,

-- 
Nicolas Goaziou