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Dye" To: Max Nikulin Cc: emacs-orgmode@gnu.org Subject: Re: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda Date: Fri, 20 Jan 2023 06:09:50 -1000 In-reply-to: Message-ID: <87h6wljhce.fsf@tsdye.online> MIME-Version: 1.0 Content-Type: text/plain; format=flowed X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - box2035.bluehost.com X-AntiAbuse: Original Domain - gnu.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tsdye.online X-BWhitelist: no X-Source-IP: 50.113.33.148 X-Source-L: No X-Exim-ID: 1pIuKz-000Kna-B4 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cpe-50-113-33-148.hawaii.res.rr.com (poto-foou.tsdye.online) [50.113.33.148]:54014 X-Source-Auth: tsd@tsdye.online X-Email-Count: 2 X-Source-Cap: dHNkeWVvbmw7dHNkeWVvbmw7Ym94MjAzNS5ibHVlaG9zdC5jb20= X-Local-Domain: yes Received-SPF: pass client-ip=67.222.38.55; envelope-from=tsd@tsdye.online; helo=progateway7-pub.mail.pro1.eigbox.com X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FROM_SUSPICIOUS_NTLD=0.5, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_PDS_OTHER_BAD_TLD=0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-orgmode@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "General discussions about Org-mode." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-orgmode-bounces+larch=yhetil.org@gnu.org Sender: emacs-orgmode-bounces+larch=yhetil.org@gnu.org X-Migadu-Flow: FLOW_IN X-Migadu-Country: US ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1674232493; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references:list-id:list-help:list-unsubscribe: list-subscribe:list-post:dkim-signature; bh=PW8NqCXv//0S4q3KiQsABr8rQlzigZtYLCrRGRaoHXQ=; b=Asu9QuBnkgRsfjNHn/G4AXwXuMBJQsbUbE5uX2nMLLaYJZsj5NQF8g90swHnutMvGwJhRJ UeoYVu974Vdt66+N02PA7UE0u8vEr0Zxp4VbKvDfaO01VJynHW8sUK6W7FSS5e51nCibpg vEq+rCyFVJ4Mb94bdyEZbFXEitGtXwrJs9jf8Y7wWwVNDbVFLdJPEzSHUbDd38nA76TTe2 B0ZNCi0Mvk8mU+8MXLZLIf4Qh7PDSY5Tpv9gWBQiI0ssHplYajNBh8FwQQKfjs/I7cEiGb pf9ATp8wr/zWxPbYJy49IK3qh0hxgJ04bXLA6BbjcPv/5PFlof3sanSRr80d6Q== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=tsdye.online header.s=default header.b=YKdSTyZC; dmarc=none; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org" ARC-Seal: i=1; s=key1; d=yhetil.org; t=1674232493; a=rsa-sha256; cv=none; b=CyJd/RGbZ/uxfj2hVDiw1kaZGzkZ9qzLxOQIO5+iTDqmDxAi6YOGvSPY30vG52u0hdV5db 0XcViOvu8jSxceMEqyjCX8y1xSd5FXnDsEDYZwpnF7NAD/W9VSjv+e4G415ty5qv6nbgnX 7Peikceunqkh2DwGgxbNtyg6Eg8FrkQGapQIzCRp1a7yUGR7o8ytM5aL/pXOA+9D62zvyy G/Hz503EjuyoUr9Q8NzxKZL4rCK0i6dfnY1KpWMgsrW1qjgQGFn4rMx3C072rfywRi7jI7 jiAxZPbLE4EjZAy0CyxHwe+AWRCPm4og2PnfTMEQHzQisRtyapbu2g1tJeDVMw== X-Migadu-Scanner: scn1.migadu.com X-Migadu-Spam-Score: 2.59 X-Spam-Score: 2.59 X-Migadu-Queue-Id: 2C733EE22 Authentication-Results: aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=tsdye.online header.s=default header.b=YKdSTyZC; dmarc=none; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org" X-TUID: 4krQBTHdvL/7 Aloha Max, Max Nikulin writes: > On 20/01/2023 15:17, Tim Cross wrote: >> So far, nobody has shown any reason why using UTC to >> distinguish the >> case where the times need to be adjusted and local tz when they >> don't >> won't work a a mechanism that can be used to allow org to >> handle things >> better than it does now. > > Let's try to move in small steps. UTC as storage format. > > An issue with events scheduled as local time in some particular > timezone (not > your current one) and stored as UTC timestamp when IANA tzdata > is updated to use > new timezone offset: > > https://codeblog.jonskeet.uk/2019/03/27/storing-utc-is-not-a-silver-bullet/ > Storing UTC is not a silver bullet > > Do you think it should be ignored? I faced such issue. Good example! Thanks for the link. Note that the problem of arbitrary change of a timezone's relation to UTC might be handled differently for occurrences and events. The blog example is 9AM in Amsterdam at a date some years in the future. Because the example includes a place, it refers to space/time, and is an event (not an occurrence). Now, if Amsterdam's timezone arbitrarily changes its relation to UTC before the conference takes place, then everyone who participates in the conference must notice this (or miss the start of the conference). Let's consider an occurrence. A virtual conference is organized by someone in Amsterdam, who sets a start time corresponding to 9AM in Amsterdam at a date some years in the future and invites participants from all over the world. Now, if Amsterdam's timezone arbitrarily changes its relation to UTC before the conference takes place, then must everyone notice this? Or, should Org, from the time the arbitrary change is made public, simply adjust the conference time for all the participants in the Amsterdam timezone? The latter makes sense to me--all the participants in Amsterdam will be aware of the arbitrary change, so will not be surprised when Org calculates a different start time. Such a change would almost certainly confuse participants unaware of the arbitrary change in Amsterdam timezone. hth, Tom -- Thomas S. Dye https://tsdye.online/tsdye