Hello,

I am currently developing a C++ time-zone database parser, building on top of Howard Hinnant's work. I am writing thorough checks.

One Zone check that I am experimenting with is:

If the FORMAT field contains either a "%s" or a '/' then the RULES field must contain a named rule.

However line 3840 of the asia file in:

https://data.iana.org/time-zones/releases/tzdata2021e.tar.gz

fails this check, as highlighted in yellow in the table below.

# Tajikistan
# From Shanks & Pottenger.
# Zone	NAME	STDOFF	RULES	FORMAT	[UNTIL]
Zone	Asia/Dushanbe	04:35:12	-	LMT	1924 May 2
		5:00	-	+05	1930 Jun 21
		6:00	RussiaAsia	+06/+07	1991 Mar 31 2:00s
		5:00	1:00	+05/+06	1991 Sep 9 2:00s
		05:00	-	+05

My guess is that '+05/+06' should be '+05'.

I may well be wrong. Could you let me know either way?

If you are interested, I have found a few other bits and pieces where the data files are in slight variance with the documentation but are not show-stoppers.

Most of these occur in the very early releases. (I am testing every database available on https://data.iana.org/time-zones/releases/)

Regards

Nick Deguillaume

+44 75 2828 6473