[tz] Lack of "initial" transitions for some zones

Paul Eggert eggert at cs.ucla.edu
Tue Jul 21 18:49:44 UTC 2015

Jon Skeet wrote:
> I'm looking at the output of zic for each zone, and almost all zones start
> with a "transition" for some timestamp in the long distant past - including
> fixed zones such as UTC and Etc/*.

Can you give more details about the problem, for UTC and PST8PDT say?
It surprises me that the long-ago timestamp is issued for some output files but 
not others; I'm not sure why that would be.

The zic.8 documentation does not uniquely specify the output file, given the 
input: multiple output files can correctly implement the input.  So it's 
possible that you haven't found a bug, but still, it is curious.

Possibly this is due to the transition change introduced in 2014c (see commit 
7fb077a9ff67dab22b9a23f64f65f85d59cf593e) and updated by the Big Bang change in 
2014d.  Are the long-ago transitions equal to -2**59 == 0xf800000000000000 == 
-576460752303423488?  If so, that's most likely what's going on.

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