[tz] [tz-announce] 2021b release of tz code and data available

[Paul Eggert]

On 9/26/21 3:38 AM, Michael H Deckers wrote:

>          Link America/Port_of_Spain America/Virgin
>      in line 755 of backzone should be converted to
>          Link America/St_Thomas     America/Virgin

That would create a link-to-a-link (America/Virgin → America/St_Thomas → 
America/Puerto_Rico), which would cause "make check_links" to fail. This 
maintainer check was put in several years ago, when some downstream 
software misbehaved with a link-to-a-link in one of our releases. And I 
suspect that even zic is not robust in the presence of arbitrary 
links-to-links, though I haven't tested this.

I do see the semantic issue behind the change you're proposing, as 
America/Virgin is an old alias for America/St_Thomas. If we wanted to 
add support for links-to-links, I suspect someone would have to code up 
and test changes to zic.c, and we would definitely need to give 
downstream users considerable time to adjust to the change. I'm not sure 
it's worth it merely to support this very minor issue.