Re: time.el, world-clock default Calcutta/Kolkata?

[Eli Zaretskii <eliz@gnu.org>]

> From: Gijs Hillenius <gijs@hillenius.net>
> Date: Wed, 07 Aug 2024 20:59:51 +0200
> 
> Hello
> 
> time.el defines
> 
> (defcustom zoneinfo-style-world-list
>   '(("America/Los_Angeles" "Seattle")
>     ("America/New_York" "New York")
>     ("Europe/London" "London")
>     ("Europe/Paris" "Paris")
>     ("Asia/Calcutta" "Bangalore")
>     ("Asia/Tokyo" "Tokyo"))
> 
> Which for me has been returning the wrong response for Bangalore. This
> is because in Debian (Testing and Unstable versions), tzdata no longer
> recognises Calcutta. That was the official name until 2001, it is now
> Kolkata, and earlier this year Calcutta was removed from tzdata, 
> 
> I can easily fix this by installing Debian's tzdata-legacy.
> 
> Alternatively, should time.el be modified to define ("Asia/Calcutta"
> "Bangalore")?

You mean, ("Asia/Kolkata" "Bangalore"), right?

We cannot do that unconditionally, I think, because that would screw
systems where tzdata still has Calcutta.  If we can detect failure to
find a time zone, then maybe adding some fallback mechanism to
world-clock is the way forward, so that we could try one of the
alternatives and fall back to the other if that fails.

Or maybe we should replace that entry with some other Indian time
zone, which is less controversial?  After all, it's just the default
value of a defcustom.

Paul, any other suggestions?