[tz] Extra transition type is generated by zic with -r specified

Paul Eggert eggert at cs.ucla.edu
Mon Oct 25 18:06:00 UTC 2021

On 10/25/21 04:18, Almaz Mingaleev via tz wrote:

> Is that a bug or is there a reason for such behaviour?

The behavior you're describing comes from the following change that was 
circulated on the mailing list on October 15 and released in 2021e:


The idea is to let TZif readers know that the TZif file is truncated. 
Before this change, there was no way that a TZif reader would know that 
it's dealing with a truncated TZif file.

The next draft of Internet RFC 8536bis is planned to recommend this sort 
of thing, unless some problems turn up with it (and if so, please let us 

We could modify zic to use some UT offset other than 0 for the affected 
timestamps; this would also follow the next draft's recommendation. 
Although I considered doing that, I worried that it'd be confusing for 
the TZif file to say that after the year 2100 Lord Howe Island will be 
at UT +11 with an abbreviation of "-00".

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