[LEAPSECS] stale leap second information

[Steve Allen]

On Sun 2015-01-11T23:58:08 -0800, Tom Van Baak hath writ:
> The web is full of incorrect and outdated leap second information and tables. Here's one example:

Here's somewhat scarier example
this one is almost up to date
http://www.nist.gov/pml/div688/grp50/leapsecond.cfm
but this one is also findable and is 4 years old
http://tf.nist.gov/pubs/bulletin/leapsecond.htm

> Is there any solution to this?

Find a reliable source, and at the moment the most reliable source
is probably the IANA TimeZone Database
https://www.iana.org/time-zones
That comes with a caveat that it does not instantly respond to the
changes, so the most recent release is 2014j from November.
The tzdata.tar.gz contains the file
leap-seconds.list
That file originates from NIST and it does include an expiration data
of June 28.

The full docs for tzdata/tzdist are at
https://www.iana.org/time-zones/repository/tz-link.html
and they point to the github repository that contains the not yet
released files.  The leap-seconds.list file in github does already
contain the 2015 leap second.

Looking toward the future there is the IETF tzdist iniative that
I mentioned yesterday.  In the example .json snips that I attached to
http://www.ietf.org/mail-archive/web/tzdist/current/msg01215.html
is Right-UTC.json which starts off showing its expiration date

{
  "tzid": "TAI/UTC",
  "start": "1972-01-01T00:00:10Z",
  "end": "2016-01-01T00:00:00Z",
  "observances": [
    {
      "name": "UTC",
      "onset": "1972-01-01T00:00:10Z",
      "utc-offset-from": 0,
      "utc-offset-to": -10
    },

That expiration data is inherent in the tzdist protocol as a way of
making it clear that the timezone data have limited valid range.

--
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