Subject: Re: [Tzdist] Ticket #15

From: Daniel Migault <[email-masked]>
Date: Sat, 1 Nov 2014 15:15:59 +0100

Dear Friends and Colleagues

I assume the rewording by Paul has reached consensus. If not please provide
feed back, so version 03 can be modified accordingly.

BR,
Daniel

On Fri, Oct 24, 2014 at 3:48 AM, Paul Eggert <[email-masked]> wrote:

> Daniel Migault wrote:
>
>> For
>> example, a time zone based on astronomical observations might have
>> well defined values up to only the year 2025.  In that case, the
>> "TZUNTIL" value would match the last accurately known observance
>> transition in that year.
>>
> > ...
>
>> Example:  The following is an example of this property:
>>
>>    TZUNTIL:20371231T115959Z
>>
>
>
> This suggests that a TZUNTIL value of T would equal the last observed
> transition time T in that year.  But TZUNTIL times are inclusive at the end
> whereas transition times are inclusive at the start, so the two T values
> should not be equal; the latter should be strictly less than the latter.
>
> To help clear this up, I suggest rewording the above as follows:
>
> ...
> Example: Suppose a time zone based on astronomical observations has
> well-defined onset times through the year 2025, but the first onset in 2026
> is currently known only approximately.  In that case, the "TZUNTIL"
> property could be specified as follows:
>
>   TZUNTIL:20251231T115959Z
>

-- 
Daniel Migault
Orange Labs -- Security
+33 6 70 72 69 58

---

From: Tim Parenti <[email-masked]>
Date: Mon, 3 Nov 2014 14:04:59 -0500

> property could be specified as follows:

Is there a particular reason we're using 115959Z here?  This might be
clearer with 235959Z instead.

--
Tim Parenti

---

From: Paul Eggert <[email-masked]>
Date: Mon, 03 Nov 2014 11:47:04 -0800

> clearer with 235959Z instead.

Absolutely, and thanks for catching that.  The "11" is a typo.

---

From: Daniel Migault <[email-masked]>
Date: Tue, 18 Nov 2014 12:34:49 +0100

Dear friends and Colleagues,

We are asking the WG whether Issue #15
<http://trac.tools.ietf.org/wg/tzdist/trac/ticket/15> "Truncation of
Future" data has been addressed by draft-ietf-tzdist-service-03
<http://tools.ietf.org/html/draft-ietf-tzdist-service-03>. Feel free to
give your opinion by Friday 21, so we can cleanup the open issue and focus
our attention on issues that have not been solved yet.

Here is the currently proposed text:

7.1 <http://tools.ietf.org/html/draft-ietf-tzdist-service-03#section-7.1>.
Time Zone Upper Bound

   Property Name:  TZUNTIL

   Purpose:  This property specifies an upper bound for the validity of
      data within a "VTIMEZONE" component.

   Value Type:  DATE-TIME

   Property Parameters:  IANA and non-standard property parameters can
      be specified on this property.

   Conformance:  This property can be specified zero or one time within
      "VTIMEZONE" calendar components.

   Description:  The value MUST be specified in the UTC time format.

      Time zone data in a "VTIMEZONE" component might cover only a fixed
      period of time.  The start of such a period is clearly indicated
      by the earliest observance defined by the "STANDARD" and
      "DAYLIGHT" sub-components.  However, [RFC5545
<http://tools.ietf.org/html/rfc5545>] does not define a
      way to indicate an upper bound on the validity of the time zone
      data, which cannot be simply derived from the observance with the
      latest onset time.  This specification introduces the "TZUNTIL"
      property for that purpose.  It specifies an "inclusive" UTC date-
      time value that indicates the last time at which the time zone
      data is to be considered valid.

      This property is also used by time zone data distribution servers
      to indicate the truncation range end point of time zone data (as
      described in Section 3.8
<http://tools.ietf.org/html/draft-ietf-tzdist-service-03#section-3.8>).

   Format Definition:  This property is defined by the following
      notation:

   tzuntil      = "TZUNTIL" tzuntilparam ":" date-time CRLF

   tzuntilparam = *(";" other-param)

   Example:  Suppose a time zone based on astronomical observations has
      well-defined onset times through the year 2025, but the first
      onset in 2026 is currently known only approximately.  In that
      case, the "TZUNTIL" property could be specified as follows:

   TZUNTIL:20251231T235959Z

PS: Issues expected to be addressed by this version are tracked by the
Issue Summary
<http://www.ietf.org/mail-archive/web/tzdist/current/msg00913.html>,

BR,
Daniel

-- 
Daniel Migault
Orange Labs -- Security
+33 6 70 72 69 58

---

From: Daniel Migault <[email-masked]>
Date: Sat, 22 Nov 2014 14:18:31 +0100

Dear Friends and Colleagues,

I am suggesting we close this issue.

BR,
Daniel

On Tue, Nov 18, 2014 at 12:34 PM, Daniel Migault <[email-masked]>
wrote:

> 7.1 <http://tools.ietf.org/html/draft-ietf-tzdist-service-03#section-7.1>.  Time Zone Upper Bound
>
>    Property Name:  TZUNTIL
>
>       "DAYLIGHT" sub-components.  However, [RFC5545 <http://tools.ietf.org/html/rfc5545>] does not define a
>       described in Section 3.8 <http://tools.ietf.org/html/draft-ietf-tzdist-service-03#section-3.8>).
>

-- 
Daniel Migault
Orange Labs -- Security
+33 6 70 72 69 58